ORNL-TM-3939.txt

ORNL-TM-3939

  

MSR COMPONENT REPLACEMENTS USING
REMOTE CUTTING AND

WELDING TECHNIQUES

Peter P. Holz

 

 

 

OPERATED BY UNION CARBIDE CORPORATION ¢ FOR THE U.S. ATOMIC ENERGY COMMISSION

 
 

 

This report was prepared as an account of work sponsored by the United
States Gavernment., Neither the United States nor the United States Atomic
Energy Commission, nor any of their employees, nor any of their contractors,
subcontractors, or their employees, makes any warranty, express or implied, or
assumes any legal liability or responsibility for the accuracy, completeness or
usefulness of any information, apparatus, product or process disclosed, or
represents that its use would not infringe privately owned rights.

 

 
ORNL-TM-3939

Contract No. W-7405-eng-26

Reactor Division

MSR COMPONENT REPLACEMENTS USING
REMOTE CUTTING AND WELDING TECHNIQUES

Peter P. Holz

December 1972

OAK RIDGE NATIONAL LABORATORY
Oak® Ridge’y Tenhessee 37830
operated by
UNION CARBIDE CORPORATION
for the
U.S. ATOMIC ENERGY COMMISSION

p—————————————NOTICE e
This report was prepared as an account of work B SO0
sponsored by the United States Government. Neither o
the United States nor the United States Atomic Energy wh

Commission, nor any of their employees, nor any of by
their confractors, subcontractors, or their emplovyees, |

makes any warranty, express or implied, or assumes any

legal liability or responsibility for the accuracy, com-

pleteness or usefulness of any information, apparatus,

product or process disclosed, or represents that its use

would not infringe privately owned rights,

 

 

Ve
T ol

Cg e BT TR e T

’ ‘:&'!,k';“',r'i_,h_ W

.i LEn T

i i ;‘
ABSTRACT

1ii

CONTENTS

1. INTRODUCTION

2. CONCLUSIONS AND SUMMARY .

3. STATUS OF THE TECHNOLOGY

3.1 Cell I1llumination

3.2

3.3

3.1.1 Lighting Provisions for Maintenance .
In-Cell Viewing Apparatus

3.2.1 Direct Viewing Through Lead Glass or Zinc-
Bromide Windows . e e e e . .

3.2.2 Optical Equipment: Mirrors, Periscopes,
and Fiber Optics

3.2.3 Closed Circuit Television .

3.2.4 Special Inspections .

In=Cell Handling Tools .

3.3.1 Lifting Devices .

3.3.2 Miscellaneous Long-Handled Tools

3.3.3 Portable Ketaining Brackets .

3.3.4 Thermocourle and Electrical Connector Tools .
Tool and Equipment Conveyance Means

Pipe Cutting Equipment .

3.5.1 Pipe Cutters

3.5.2 Seal Weld Cutters .

Equipment for Pipe Spreading .

Carriers and Conveyance Means for Use Within the Cell
Carriers for Use Outside the Cell .

In-Cell Preparations for Equipment Reinstallation

10
10
10
10
11
11
11
12
12
20
25
25
25

26
3.10 In-Cell Cleanliness Control .

3.11 Conveyance of Components to Reinstallation ILocation .

3.12 Pipe Alignment Technology .

3.13 Weld Preparation and Tack Welding of Pipe Joints

3.14 Closure Welding . . . . . .
3.14.1 Pipe Welding . « « « v v« v o o o « o«
3.14.2 Seal Welding

3.15 Inspection and Acceptance Tests .

APPENDIX A

iv

Calculations for Anticipated Maximum Delections and
Restoration Forces for Cutting INOR-8 Piping Material .

APPENDIX B

1) Proposal for Development of a Split-Bearing-Sleeve
Carriage for Remote Maintenance Applications in
Nuclear Reactor Systems . . ¢« v v ¢ ¢ ¢ ¢ ¢ o « &

2) Manufacturers Information on Split-Roller Bearings

REFERENCES

26
27
27
31
34
34
37
40

43

49

55

57
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

Fig.

L L L L T

10.

11.

12.

13.

v

ILLUSTRATIONS

Typical Replacement Joint Location

ORNL Cutter or Machining Head Mbduie

ORNL Orbital Cutting Equipment

Seal Plate Welds . & « v v o v o« o o « o o« &
Sandwich Seal Weld . . .« . « « « « ¢« « &
Canopy Weld Schemes .

Seal Lip Closures .

Component Pipe Stub Weld Joint Positioner Arrangement .

Pipe Alignment Jig for Line Cutting and Welding . . .
ORNL Orbital Welding System . . . . . . . .
Equipment Hook-Up, ORNL Weld System .

Conceptual Diaphragm or Sandwich Seal Weld with ORNL

Weld Head Supported from a Motorized Carousel Linkage .

Flanged Vessel Seal Weld Closure Scheme for
Orbital System Inserts . s e e e e

Conceptual Design .

Expected Life of Cutter Blades . . .

Page

13
14
21
. 22
23
24
29
29
. 35

36

38

39

41

16
vii

MSR COMPONENT REPLACEMENTS USING REMOTE CUTTING
AND WELDING TECHNIQUES

P. P. Holz

ABSTRACT

In molten salt reactor systems the maintenance of components in high-
radiation zones will be accomplished by using remotely operated tools.
System components, such az pumps, heat exchangers, and wvalves will be ex-
changed by cutting the inlet and outlet pipe connections, replacing the
component, and welding the pipe by remote means.

Remote maintenance requires special equipment for viewing and close
inspection of equipment and systems inside the cell to determine what is
wrongs; it also requires special apparatus to convey tools to the place where
work is to be performed. The main steps in remote maintenance procedures
will be severing the pipe and other connections, spreading the pipe ends to
provide clearance for removing the component, conveying the component from
its location inside the cell into a shielded carrier, and transporting the
carrier outside. Reinstalling a new component to replace the one removed
will involve the steps of maintaining cleanliness control, conveying the
replacement equipment to its cell location, realigning the component and
the pipe ends for reassembly, tack welding to hold components in place dur=-
ing final closure welding, and then performing the inspection and acceptance
checks to assure that the repairs have met quality and reliability standards.
Seal weld cutting and rewelding may be required for some vessel enclosures.

Overall system maintenance planning to precede future large scale molten
salt breeder reactor construction by industry is envisioned as a four-stage
evolution:

1) Technology study — consideration of remote maintenance requirements
in conceptual design

2) Simulation test mockups — component tests under simulated reactor
conditions -

3) General engineering reactor project mockups — tests in reactor
system mockups

4) Small demonstration reactor — tests under actual reactor conditions.

Accordingly, this report is intended to serve as a useful program out-
line guide. The report describes in detail how we intend to perform remote
maintenance within the severe in-cell radiation and temperature environments.
It also describes the current status of the technology required to perform
each remote maintenance task, giving special emphasis to the functions we
need to perfect on a first order priority: remote cutting, welding, and
positioning device development. Additional development programs are recom-
mended to provide all of the needed remote-control devices to demonstrate
complete maintenance procedures for removing and replacing all types of
components in the high-radiation, high~temperature zones within the reactor
viii

shielding. The "state of the art" for many of the functional tasks such as

viewing, lighting, component and equipment movement and transfer is already

adequate for remote control operations, and hence will not require special
efforts at this time.
1.0 INTRODUCTION

After reactor operations at high-power levels have built up the radia-
tion levels in the shielded cells containing the nuclear system components,
the problems of maintenance and repair become more difficult and more im-
portant. No reactor is immune to these problems. The need for remote toolw
ing and apparatus to cut, bevel, and weld piping in high-radiation level
zones 1is of utmost importance for the replacement of reactor components that
have failed in service.

Exact specifications to cover anticipated temperatures and radiation
and contamination levels in the molten-salt reactor cell at the time of a
maintenance shutdowrn are not as yet available, but tentative estimates are
given in R. W. McClung's report on "Remote Inspection of Welded Jointg."?

"Anticipated temperstures in the reactor cell range from 1000
to 1200°F. However, localized cooling for both welding and in-
spection can probably bring temperatures down to the range 200
to 600°F and possibly even to 200 to 400°F.

The anticipated level of radiation3® in the reactor cell ten
days after the system is shut down and drained is expected to
be approximately 10° R/hr. The dominant radiation will be

gamma rays from relatively noble fission products deposited on
the metal surfaces of the heat exchanger tubes and on the
graphite in the core vessel. The area of highest dose rate
(caleculated to be 1.4 X 10° R/hr) is at the midplane immediately
adjacent to a heat exchanger. Values in other portions of the
cell may be 25 to 30% of the maximum. Most of the radiation
will have photon energies of 0.8 MeV and below."

The elevated cell temperatures and radiation levels eliminate any
possibility of personnel accesg into the cell for any direct work whatever
on molten salt breeder reactor maintenance. It will be essential that all
work be done remotely.

It is planned to replace a component by severing its pipe connections,
rebeveling the ends of the in-cell piping, aligning the beveled ends with
those of the replacement, and rewelding the component into the system, all
by the use of remote-control equipment. Adequate viewing, inspection, pipe
spreading, and pipe alignment equipment must also be available and demon-
strated to be operable by remote control to support the basic operations of
remote cutting and rewelding.

Best estimates now indicate that Hastelloy, Inconels, or special 300
series stainless steel alloys, will be used for all the salt-containing
pipe and component materials for molten salt breeder reactors. Pipe sizes
are expected to range from 1 to 20 inches and pipe wall thicknesses from
1/4 to 1 inch. Cylindrical diameters for the heat exchangers and core
vessel will be in the order of 5 feet and 30 feet respectively. The pri-
mary system metal selections add a number of restrictions to common repair
tool and lubricant materisl selections. No aluminum or other low-melting
alloys, and no sulfur-bearing oils can be used where they might possibly
contact Hastelloy N, because these materials may react to cause a loss
of desired Hastelloy N properties. Similarly, for stainless steels,
chlorine-free materials must be used.

Semi-remote maintenance igs the preferred and safest approach because
it reduces personnel radiation exposures and simplifies the problems of
decontamination prior to undertaking nuclear repair operations. However,
the ability to perform maintenance by remote control requires that the
reactor system be designed to provide access to all components, to allow
for conveyance of tools and equipment within the cell areas, and to pro-
vide also for the storage of contaminated repair tools and related equip-
ment when they are not in use. The reactor designers, stress analysts,
and reactor maintenance engineers must confer during all design stages
to be sure that clearances are adequate for maintenance access and equip-
ment replacement and that the layout of pipe-runs and components, with
provisions for support and expansion, represents the optimum compromise
between maintenance needs and nuclear materials inventory in the system.

It is recognized that providing for remote-control removal and
replacement of all components of a reactor system would be prohibitively
expensive. In practice, therefore, the degree of ease provided for re-
mote maintenance must depend upon the anticipated frequency of maintenance
for each component. Pumps, (particularly the rotary pump elements, the
Jjet pumps used for filling the salt system, and the jet pumps used in con-
junction with the gas separators), valves, heat exchanger bundles, samplers,
and other items may fail or need maintenance more frequently than, say,
the reactor vessel, which is designed for a 30-year maintenance~free life.

A higher anticipated frequency of maintenance could Justify rather elaborate
remote~control devices to speed up and make more reliable the operations of
repair or replacement.

There is, however, a degree of uncertainty in predicting the locations
at which one should be prepared to make repairs by remote control. To re-
duce the risk of having the reactor system shut down a long time for repair
and maintenance, general purpose devices should be readied at the outset to
handle unexpected repair operations in virtually all locations with minimum
delay. The codes for in-service inspection of nuclear reactor systems re-
cognhize the problem of examining radiocactive areas where human access is
impossible and suggest that it will be necessary to devise and develop
methods for the inspection of vessels, pipe, and equipment to detect flaws
by remote means. There is a general need for remote handling, position-
ing, cutting, and welding equipment with which to repair the flaws dis-
closed. One could conceivably adapt the inspection equipment for applica-
tion with repair work.

It can be seen from the above that replacement and certain in-place
repairs of radioactive components involve the capability to perform a
nunber of sequential steps or functions many of which are essentially the
same for most components. The equipment to perform these functions can be
developed generally, independent of the specific details of a particular
reactor design, if the reactor design is developed with adeguate attention
to the requirements of remote maintenance and of the remotely controlled
equipment. If, in some cases, the provisions for the performance of a
particular function restricts the degigher too much, a modified plece of
equipment may have to be developed concurrent with the reactor design phase.
It is recommended, therefore, that maintenance development for each of the
four stages of evolution proceed along the following general pattern:

I. Technology study

1. Prepare a general survey of maintenance needs of a reactor
system based on a general design concept.

2. During the conceptual design stage, plan how the maintenance of
each of the radiosctive components of a reactor system will be
performed.

3. From the remote maintenance plans, determine the functions needed
and select for study those functions for which there is little or
no previous experience.

4. Conduct studies to identify restrictions which each function may
place on the reactor design. Work with the reactor designer to
provide for maintenence operations in the design of the reactor
system equipment arrangement.

IT. Simulation test mockups

1. Proceed with the development of equipment to perform the various
funetions and with the demonstration in a mockup designed to simu-
late features of the reactor system. Alter the details of the
equipment design snd the reactor design as required to minimize
inconvenience, increase safety and reliability, reduce cost, or
provide for other considerations which may be significant.

ITT. General engineering reactor project mockups

1. Prepare for, and carry out the demonstration of the remote main-
tenance plan, including all of the functions, in a reactor mockup.
Perfect the detailed procedures and check lists.

2. Acquire and test all of the equipment needed for maintenance of
the actual reactor systemn.

IV. ©Small demonstration reactor

Use as much of the maintenance equipment as is necessary during the
reactor system construction phase to assure that there have been no
changes in the design which would compromise the maintenance plan.

We have already proven the remote cutting and welding operations on
pipe to be feasible with adequate piping supports for cutting, and with
near precision pipe end realignment for welding. Limited studies made on
how to support and realign in-cell reactor piping revealed many new prob-
lem areas and uncertainties, and pointed out urgent needs for developmental
experimentation before one can proceed to develop apparatus, equipment,
and techniques for this work. We, therefore, recommend that the next
step be a more thorough technology study along with mockup tests to
establish pipe springback allowances and pipe realignment tolerance re=-
quirements. Cutting and welding machinery can thereafter be adapted to
meet the best pipe support and positioning criteria we are gble to
egstablish. We suggest a new review of automated commercial pipe cutting
and welding equipment for that time. The industrial development of such
machinery is presently proceeding at a fast pace; therefore, automated
cutting and welding equipment should beccme readily available from
commercial sources for adaptions for our work with reactor maintenance
tasks.

In this report we have used the reference design for the single
fluid molten-salt breeder reactor to determine the need for the component
replacement capability and have developed a remote maintenance plan for
the replacement of typical components. The plan is generally based on
the ORNL maintenance technology employing an orbital carriage which
clamps onto a pipe to propel the cutting and/or welding heads around the
circumference of a pipe, while a programmer~controller automatically
controls the operations involved in pipe cutting, beveling, and welding.
For the cutting and welding of flange seals or seals of other types,; we
plan to utilize the same or similar equipment, except for the carriage
and carriage drive. Many seal closure designs are available; the report
illustrates and discusses the maintainability of several typical con-
figurations. The "Status of the Technology” section describes the sequen-
tial steps or functions which are needed to carry out a maintenance plan
and discusses briefly the status of equipment and operating experience
for each of the functions. The future development requirements for re-
mote maintenance equipment are described including some cost estimates
and suggested priorities. This report includes recommendations from our
pipe alignment studies in Appendix A, and suggests piping arrangements
for simplified maintenance. Figure 1 illustrates the recommended mount-
ing of components for ease of replacement. The location for the replace-
ment joint can be predesignated and supports provided so that the pipe
spreading and realignment requirements can be handled in greatly simpli-
fied fashion using standard threaded, hydraulic or pneumatic jacking
equipment. Section 3.12.1.1 of the "Experience Status — Pipe Alignment
Schemes” and Appendix B, "Proposal for the Development of a Split-Bearing-
Sleeve Carriage for Remote Maintenance Applications in Nuclear Reactor
Systems," both discuss the highly important subject of equipment and pipe
alignment in more detail and suggest development experimentation with
sleeves to simplify remote maintenance operations, at least for the
smaller pipe sizes.

This report does not include detailed recommendations for the
development of special materials for construction for the maintenance
equipment to meet the contemplated high temperature and high radiation
service requirements. A study should be performed to determine the maxi-
mum temperature and radiation intensity to be expected within the reactor
cells and to estimate the additional research and develcpment needed to
select and test materials that will stand up under these conditiomns.
ORNT. WG T3-2396

 

 

 

  

 

  

 

 

 

 

 

 

 

 

 

&
Y -~ 2,
£ & &
& 9 <
e o~ X
< ’ ¢ 5
& Lt s
$fi§;¥§§ — l B ! :
EF T T e
C NN\ 6\945’\\ NN NN
< o
\ W
. &
AN

ALIGNMENT EQUIPME-NT NOT SHOWN

Fig. 1. Typical Replacement Joint Location
2.0 CONCLUSIONS AND SUMMARY

For the sake of completeness, we have included in the report a descrip-
tion of the equipment and technology for performing all of the functions
needed for the replacement of a component. Many of these, such as lighting,
viewing, and component and maintenance equipment movement reflect the
benefit of extensive experience gained during the operation of the HRT, MSRE,
and other reactor projects. We believe that they are adequately understood
and require essentially no development study before a reactor grade item
could be designed.

There are other functions such as carriage orbit propulsicn, pipe
cutting and welding, which have received only limited evaluation for
possible application to molten salt reactors in connection with our work
on the orbital pipe welding system with programmed automated cutting,
beveling, and welding accessories.?3%2° These studies led to the develop-
ment of an automated pipe welding system which is now being used by the
Tennessee Valley Authority in their Browns Ferry Nuclear Plant construction,
and which has served as a prototype and pattern for the units to be used
in the Fast Flux Test Facility at Hanford. The development of an industrial
capability for the production of the automated welder increases our confi-
dence that the equipment, after modification for the enviromment and for
the remote operation, will perform the functions needed for reactor compo-
nent replacement. However, there are some aspects of the modifications
needed to permit remote operation for which further study would help in
optimizing the equipment design. We would reevaluate the automated weld-
ing equipment which has become available commerclally since the start of
our earlier welding program, choose the one which best suits our needs,
modify as necessary, and test it under conditions simulating some of those
expected in a reactor system. We would expect that the basic eguipment
for development and testing would be built from standard line materials
and that substitute materials would not be needed at this time.

The urgent function for which phas: I studies and phase IT simulation
would be helpful to the early phases of a reactor project is that of pipe
and component alignment in preparation for welding. We are proposing that
where possible the pipe be made flexible enough to permit the necessary
displacement needed for proper aligmnment. Some preliminary estimates
described in Appendix "A" indicate that for most pipe sizes this would be
a practical approach. For the very large pipes, or for cases where the
pipe length does not permit much flexibility, we are proposing that a
short section of pipe be tailored to fit between the misaligned pipe ends
and that it be welded in place with the remote welder. Our studies have
indicated that the approach is feasible, but we would like toc gain some
experience in applying the welder to such situations. A proposal for
developing a gear-driven split-bearing-sleeve carriage for pcssible main-
tenance applications is included in Appendix B. This more rigid carriage
would gain additional torque capability for pipe cutting and beveling work,
would be more readily adaptable for internal pipe cleaning applications,
and hopefully, would also simplify solutions to alignment problems for
small pipe sizes by serving to minimize the displacement of pipe ends
after being cut. The clamping of the carriage might be enough to hold the
displacement t¢ limits within tolerance ranges acceptable for rewelding.
MeClung* has described the development necessary to provide equip-
ment for performance of the inspection function and much of this will
be accomplished during the program for the in-service inspections of
reactor vessels. We believe that the necessary transport function needed
for moving the inspection equipment along the pipe welds can be obtained
with the weld carriages. However, the influence of this inspection
function on the basic carriage design should be evaluated before final
carriage desigh selections are made.

In the future, during phase IIT, the general engineering reactor
project mockups, when it 1s time to test the moclten salt reactor system
designs using semblance of the more complicated systems and components,
it would be a great advantage to be able to perform remote maintenance
tests on the mockups. This will help to assure that the reactor system
components in the final design are capable of belng maintained. The
satisfactory performance of remote-handling devices, cleanliness control,
and operating techniques can also be proved in mockup tests, giving
increased confidence in their reliability and providing training in
maintenance techniques that will someday reduce downtime.

3.0 STATUS OF THE TECHNOLOGY
3.1 Cell Illumination
3.1.1 Lighting Provisions for Maintenance

3.1.1.1 Experience. In the HRE, the HRT, and the MSRE, in-cell
lighting proved adequate for repair purposes.=?®=?42°:6
Integral lights on the underside of a portable shield
provided suoplemental illumination when required. The
lights included dimmer controls, placed external to the
cell, to provide contrast and shadow effects. Portable,
suspended lights were used as required to help distin-
guish special objects.

3.1.1.2 Future Development Requirements. Update the lighting
equipment to be sure that selections represent the best
currently available commercial eguipment. Permanent in-
cell wiring and lighting, if used, should consist of
materials to withstand cell radiation exposure levels of
up to the order of 10*!R and ambient cell temperatures of
about 1200°F, and up to 1500°F for short periods.

3.2 In-Cell Viewing Apparatus

 

3.2.1 Direct Viewing Through Lead Glass or Zinc-Bromide Windows

3.2.1.1 Current Concepts. Direct viewing is usually adeguate for
unobstructed straight line-of-gsight and general area ob-
servations. For reactor maintenance operations it will be
necessary to provide gamma~ray shielding. Commercially

 
marketed lead-glass shield plugs and zinc-bromide windows
are commonly used and are generally satisfactory for vision,
illumination and shielding. Shield effectiveness is gen-
erally proportional to density. Density values for major
reactor shielding materials are as follows:

Concrete density about 2.2
Tron " "oon7.8
Aluminum " 2.7
Lead " " 11.3
Lead Glass " " 6.2
Zinc-Bromide Solution " 2.5

Hence lead glass shield plugs have approximately 80% of
the gamma shielding value of iron, and zinc-bromide
windows provide approximately 10% better shielding than
concrete.

3.2.1.2 FExperience. ORNL and others, including all hot cell
operators, have had considerable experience with lead
glass and zinc=bromide for shielded viewing applications.
Theoretical design information is readily available” and
actual selection details are listed in the design and

operations reports for various nuclear installations. ®?8

3.2.1.3 PFuture Development Requirements. None

 

3.2.2 Optical Equipment: Mirrors, Periscopes, and Fiber Optics

 

3.2.2.1 Definition. The use of mirrors to assist direct viewing
has proven helpful for many remote observations. Simple
tilt-linkages can be operated in conjuuction with long
handled tools to provide sufficient manipulations for
adequately aligning the mirror for viewing. Commercially
available periscopes, omniscopes, telescopes, and fiber-
optics equipment can be obtained to meet all sorts of
needs in nominal radiation and high-temperature environ-
ments, and have been used effectively in reactor repair
and in hot cell work applications.
3.2.2.2

3.2.2.3

3.2.2.4

3.2.3 Closed

Experience. ORNL has varied experience with optical equip-

ment in numerous applications. The "blanket mirror viewing
device" and viewing scopes used in conjunction with HRT core
hole plugging operationsz’g, optical tooling devices and
periscopes used in the MSRE®? 87 r’ and the periscope used in
examinations of the Boiling NUf}ear Superheater Power Station
(BONUS) at Rincon, Puerto Rico = are examples of apparatus
used in some of ORNL's remote viewing experiences. A report
on nuclear vessel repairs at Savannah River®? lists some of
DuPont's optical tooling experiences.

Future Development Requirements. Fiber optics is a rela-
tively new science with potential for observations in ars:as
where access limitations and/or obstructions prevent the
use of more conventional viewing equipment. We recommend

a literature search into nuclear applications of the techno-
logy. All optical equipment must meet the in-cell environ-
mental conditions expected to prevail at the ftime of repair,
and must be tested under actual, or simulated conditions.
Insulation, shielding, or cooling development may be neces-
sary for scme of the equipment.

Cost Estimate. A quarter-manyear effort should be scheduled

for the first phase of a maintenance development program to

investigate optical viewing means and to provide recommenda=-
tions and estimates for subsequent feasibility testing and
mockup studies.

Circuit Television

 

3.2.3.1

3.2.3.2

Experience. Many advances have been made in televigion
technology for nuclear applications during the past few
vears. General Electric Company, Westinghouse, and others
routinely use TV for in-service and specilal inspections of
reactors.??13’14 (losed circuit TV performance evaluations
are also available from in-cell surveillance and from hot
cell users.”?1® ORNL has also used television for observ-
ing reactor repair and surveillance of the HRT and MSRE
reactors.17/18

 

Future Development Requirements. The TV camera and wiring
must be able to withstand the in-cell temperature and radia-
tion field. Insulation, shielding, or cooling system develop-
ment may be necessary.
3.2.3.3

10

Cost Estimate. It is recommended that a guarter manyear
effort and El0,000 equipment money be provided for Phase T
of a maintenance development program to procure radiation
and temperature resistant TV equipment, and to update de-
sign criteria, performance specifications and cost estimates
for subsequent development work.

3.2.4 Bpecial Inspections

3.2.4.1

Experience and Future Development Requirements. Refer to
the report by R. W. MeClung, Remote Inspection of Welded
Joints, ORNL-TM-3561, September 1971.

3.3 In-Cell Handling Tools

3.3.1 Lifting Devices

3.3.1.1

3.3.1.2

3.3.1.3

Concept and Experience. Qak Ridge National Laboratory's
standard practive has been to build cradle-type lifting
devices for all reactor system components at the time of

the components' initial installation in the cell; and this
has greatly simplified the subsequent remote handling.®’*°

It is necessary, however, to build the fixtures with features
that facilitate the use of remote "slip-on" guides or hook-
insert rings for handling. Experience has shown also that
where possible, programs for crane movements should be for-
mulated and documented while the plant is being built.

Future Development Requirements. All in-cell handling tools
and 1lifting fixtures are usually of all-metal construction of
materials compatible with the Hastelloy N primary system
material, and of simple designs employing mechanical linkages.
The tools and fixtures, therefore, have little or no depen-
dence upon in-cell environmental conditions during maintenance
pericds, with the exception of metal expansion when exposed
to the elevated temperature in the cell., Little time and
effort will be required to adapt tools of earlier designs

for future applications. Specific fixtures and tools, how-
ever, must be proof tested, and operating procedures must be
established and documented either during the construction of
the reactor, or in full-scale mockup tests.

Cost Estimates. An engineering effort of about 1 1/2 man-
years for design and development of handling tools will be
required, plus $20,000 for materials and prototype equip-
ment.

3.3.2 Miscellaneous ILong-Handled Tools

3.3.2.1 Concept and Experience. Tools in this category include

simple, long-handled utility hooks and rods for in-cell
uses to install, or remove, insulation, heaters, etc. The
3.3.2.2

11

tools are a’so used to assist pickup and transfer operations;
typical tool designs and operations are documented for HRT
repair work. 8220721

Future Development Required. None specifically; tools will
be developed along with the components they will serve.

3.3.3 Portable Retaining Brackets

3.3.3.1

3.3.3.2

Concept and Experience. Reactor cell roof blocks and cell

 

sides should contain hooks and shelves upon which to hang
or set portable brackets for the temporary parking of mis-
cellaneous small in-cell items, such as insulation jackets,
heaters, etc., and repair tools. Portable brackets resembl-
ing c%ses fcr milk bottles were used for HRT and MSRE cell
work.

Future Development Required. None specifically; brackets

 

will be developed along with the components they will support.

3.3.4 Thermocouple and Electrical Connector Tools

3.3.4.1

3.3.4.2

3.4.1.1

Concept and Experience. Simple, long-handled, scissor-action

 

tools were designed for HRE and MSRE in-cell thermocouple
maintenance. The base of the thermocouple tool accommodates
the male and female halves of a couple. The tool's actuator
is used to open or close the scissor linkage to either make

or break the coupling. Similar tools are also available for
push-pull type electrical connector assembly and disassembly.
Wrenches with long handles are available for use with multiple-
pin connectors for instruments and controls. The wrench is
used to engage and turn the connector's screw coupling. A
scissor motion actuator, built into the wrench tool, is em-
ployed <o align and make or break the coupling halves. Thermo-
couple tools, electrical connector tools and other ORNL handl-
ing equipment items are described in the ORNL Remote Main-
tenance Catalogue.??

Future Development Required. None, except for material sub-

 

stitutions.
3.4 Tool and Equipment Conveyance Means

Concept and Experience. It is assumed that the portable

 

shield maintenance technology developed for the HRE and the
MSRE will be applied with molten salt breeder reactors.>?
Cell conditions will determine the need for air locks, etc.,
however, the basic scheme, proven in prior operation of the
experimental reactors, will be to utilize portable shields
of lead or steel and to arrange this metallic shielding to
protect the operator from radiation after access holes have
been opened on top of the cell blocks. The portable shield
12

will also provide the operator with a shielded platform for
loading tools into the cell. Loading holes will be located
within a circular turntable insert within the portable shield
platform to permit the tools and/or fixtures to be located
and centered over the work area as required. The underside
of the shield will also include hooks and bars to provide
temporary hanger supports for maintenance tools and mobile
equipment or components items. The platform of the portable
shield will again also be comprised of two separate sections
to allow total access for the transfer of large equipment
items into the cell through the portable shield's platform
frame opening. The reactor building would be temporarily
evacuated for this type of maintenance operation. The trans-
fers of large equipment items entail closed circuit TV opera-
tions and a zinc-bromide viewing window from a distant spe-
cially shielded control room.

3.4,1.2 TFuture Development Required. The portable maintenance shield
approach must be incorporated into the original cell and cell
roof block layout design. Mockup trials will be required to
establish operating instructions and guides for maintenance.
Costs for this effort are undetermined at present.

3.5 Pipe Cutting Equipment

3.5.1 Pipe Cutters

3.5.1.1 Experience. In 1968 and 1969 ORNL developed and tested pro-
totype units of the automated, orbital pipe cutting and weld-
ing machinery as part of a feasibility study for the MSR
maintenance program,?> The machining head (see Fig. 2) was
able to cut pipe, trim the ends square, and prepare end bevels
on schedule 40 stainless steel pipes in sizes up to 6 inches
in diameter with relatively little difficulty. However,
problems arose in cutting Inconel because of its work-hardening
tendencies, and more difficulties are expected for work on pipe
sizes larger than 6 in. as the cutting operations were slow,
cutter feed rates were minimal, and cutters dulled rapidly and
required frequent replacement.

A1l ORNL machining tests were performed on horizontal
piping. Figure 3 illustrates a cutting operation on 6 in.
pipe. Slitting saws and double bevel cutters tracked true
within approximately 0.003 in. Single bevel cutters tend to
walk out of, and away from the cut, especially on the harder
Inconel pipe. The cutter drive motor power and speed control
capabilities appeared adequate. Observations indicated, however,
that the carriage drive is the limiting factor on cutting cap-
ability. We observed roller slippage on the pipe and frequently
tripped the carriage drive roller circuit breaker protection.
Cutter feed and carriage travel speed adjustment changes, how-
ever, restored operations. The carriage and machining head
withstood loading and vibrations caused by the milling cutters,
 

 

 

o

| . ' | PHOTO 7655k

 

 

 

 

N

 

 

   

. Fig. 2. ORNL Cutter or ‘Mach'_in,ilng"‘;.fHe‘é_'df‘_.,wafiié"l;__

        

 

   

  

 

 

0

 
 

 

 
 

PHOTO 76550

14

ORNL Orbital Cutting Equipment

Fig. 3.

 

 

 
15

but only with proper travel speed and tool feed selection.
Improvements, however, are required to provide a stronger and
more positive cutter depth control and to provide more stable
longitudinal adjustments. A split-bearing sleeve carriage
concept development is proposed (see 2.5.1.2) which could pro-
vide means for a more rigid cutting assembly which could still
be remotely installed and operated for. in-cell pipe cutting
needs. Otherwise, improved locking clamps are desired in con-
juncticn with the present carriage for prevention of long-
itudinal anc radial cutter shifts. Pipe collar clamps are
required for pipe cutting operations where the pipe slopes

in excess of 5 degrees from horizontal.

We have cut with high-speed and Circocloy alloy slitting
saws and milling cutters. The alloyed tool steel appeared to
stay sharper longer, — possibly by as much as a factor of cne
and a half. Tests with carbide cutter blades showed an even
longer blade life. Carbide tools, however, are brittle, and
we did break some blades, probably as a result of blade chatter.
Efficient cutting requires the thickest possible chip per
cutting tooth, but this may have to be compromised consider-
ably to obtain reasonable cutter life and proper surface
finish. This is particularly true in the case of high-
nickel steels where the base material tends to work-harden
with the result that chip removal is inadequate or incom-
plete. Results from Inconel machining experiments indicate
that the cutting edges of all cutter teeth must be generously
relieved to provide ample clearance for chip fallout. Allow-
ing chips to fall out freely will minimize the Inconel work
hardening caused by trapped chips. It is also quite important
that all teeth of a cutter engage the work during cutting.
Off=the-shelf commercial cutters used appeared to cut with
usually only about a fourth of their teeth, and imprcved
cutting was noted where cutters were reground lccally to
precision specification. Almost 75% tooth engagement can
be attained.

The importance of proper tool travel and cutter speed
adjustments, especially for cutting Inconel materials, can-
not be minimized. Available machine shop machining data do
not apply to the orbital cutting assembly because our equip-
ment does not have the driving power of shop machines. Also,
dry machining is specified for nuclear rzactor system ri’r-
tenance because coolants are either hazardous or might con-
taminate the nuclear system. Therefore the tool travel,
cutting speeds, and tool feed rates must be several magni-
tudes lower than usual shop practice.

Table I shows the number of inches of cut a blade can
be expected to make before it must be resharpened. The table
also shows how deep the blade would cut in traveling the in-
dicated number of inches around a 6-in.-diam pipe, taking a
30 mil or a 12 mil cut, as indicated,
Table 1.

Expected Life of Cutter BRlades

 

Description

Blade Lifetime

 

In Stainless Steel

In Inconel

 

 

 

Saw Tooth Speed 70 to 80 ft/min 50 £t/min
Carriage Speed 3 1/4 in./min 1 in./min
Feed Per Tooth . 0005 in.
Inches of Total Depth Inches of Total Depth
cut, average of cut, 6-inch cut, average of cut,
depth 30 mils. pipe wall. depth 12 mils. 6-inch
inches inches inches pipe wall.
inches.
1/16-in.-thick slitting saw,
3 in. dia., 32 teeth
high speed steel 530 3/4
1/16-in. -thick slitting saw,
3 in. dia., 32 teeth
Circoloy alloy* 800 1 1/8 730 7/16
3/32-in.-thick slitting saw,
3 in. dia., 32 teeth
high speed steel 430 5/8
3/32-in.~-thick slitting saw,
3 in. dia., 32 teeth
Circoloy alloy* 650 7/8 600 11/32
70° included double angle mill
2 3/4 in. dia., 20 teeth, 1/2 in. wide
high-speed steel 470 11/16 420 1/4

 

*¥Trade name for Circular Tool Company (Providence, R.I.) special high-speed steel alloyed blades of
high carbon, medium chrome, high vanadium, high tungsten and medium cobalt composition.

9T
17

We selected cutting speeds between 70 and 80 surface
fpm for cutting stainless steel materials, and chose 50 fpm
for Inconel in order to achieve reasonable cutter life.

These cutting speeds correspond to approximately 100 and 62.5
revolutions/min for the 3-in.-diam alloy steel slitting saws.
Feed per tocth selectilions compatible with tool strength and
tool rigidity were 0.001 in. for stainless steel work and
0.005 in. for Inconel with 3 1/4 and 1 in./min (traversing
surface) blade travel rates. Our feed per tooth rates are
low when compared to rates in standard machine shop work,
but are still creditable considering our small-sized and
low~powered equipment. Our cutter motor consists essen-
tially of a 1/3 hp electric drill. The depths of cut depend
on available hp and cutter shapes, and on the sharpness of
the cutters, as they in turn affect the power required at
the cutter motor spindle. We repeatedly cut 0.030 in. deep
into stainless steel, and 0.015 in. into Inconel.

All of our machining operations with the ORNL orbital
equipment must be accomplished in the standard "milling up"
mode of operation where the cutter tooth in contact with the
pipe is moving in the same direction as the carriage. We
lack rigidity for reverse, or "climb mill" cutting. Our
carriage's torsion bar clamping action on the carriage roller
does not give enough friction contact for climb cutting.

Oak Ridge National Laboratory alsc has experience with
the Trav-L-Cutter pipe saw and Guillotine pipe saws manufac-
tured by the E. H. Wachs Company of Wheeling, Illinois, and
with pipe cutting and beveling machines of the H & M Pipe
Beveling Machine Company of Tulsa, Cklahoma.

The Wachs eguipment is available with air or electric
drives in horsepower ratings equivalent to machine shop saws.
H & M equipment is electrically driven; their cutters are
furnished with either pneumatic or electrical drives.

One of the prime objectives of the Fast Flux Test Faci-
lity (FFTF) at Hanford is to perform nuclear fuels testing
for the Liquid Metal Fast Breeder Reactor (IMFBR) program.
The test facility must have the capability to install and
remove fuel assemblies by remotely controlled equipment. A
sizeable program is underway at the Hanford Engineering De-
velopment ILaboratory (HEDL) to develop and test equipment with
which to cut and weld the open- and closed-loop reactor top
closures for removal and reinstallation of experimental test
assemblies.®* ORNL is monitoring their development of cutting,
welding, and related equipment for application to relatively
small (6.72-in. mean diameter) pipe. They are testing their
equipment in a mock-up at 500°F. Their material and equip-
ment selections are intended to withstand 10° R/hr gamma
radiation exposures.
18

3.5.1.2 Future Development Required. Cell layout and available
orbit clearance around pipes for the sawing and beveling
equipment will be important factors in determining the
selection of machinery for remote maintenance and repair
operations. The ORNL equipment described is compact and
lightweight. Our carriage-cutter head working unit is
designed to be remotely clamped around a pipe and is about
4 in. thick in radial dimension, and 10 1/2 in. long. The
technology for its application to cut and/or bevel pipes
remotely by automated programmed controls is established.
Our compact equipment, however, is limited in power for both
the tool travel propulsion and the tool feed.

 

Subsequent sections of this report and Appendix "B"
discuss an alternate carriage design using a split-bearing
sleeve. The split-sleeve carriage is supported by a set
of split-bearings on each end. A separate motor gear drive,
mounted to the pipe, couples to a split-gear which is per-
manently attached to one of the sleeve's end bearings and
drives the sleeve around the pipe. This alternate design
offers considerably more rigid and uniform carriage pro-
pulsion than is available from the flexible, horseshoe-
shaped ORNL carriages. Rigid carriages are desirable for
pipe cutting service; cutter tool vibrations, or tool
chatter are minimized, and cutter shift tendencies are
eliminated. A strong possibility exists, however, that
pipe ends will tend to spring apart radially (and axially)
when cut. The magnitude of this shift tendency will be
determined by actual process system layout and piping sup-
ports. It will be most pronounced with short pipe runs, and
in the larger pipe sizes. We, therefore, anticipate that the
split-bearing sleeve carriage design may be limited to cut-
ting applications on the smaller pipe sizes, say, up to
through 6= or 8-inch pipes. Beyond these sizes strong pos-
sibilities prevail that sleeve end bearings cannot withstand
the forces resulting from the spring-action when the pipe is
cut, and the bearings msy be deformed or crushed. These
carriages would also reguire a minimum of 10 inches pipe
clearance, as contrasted to the 4-inch radial clearance re-
quirement for basic ORNL carriages.

Split-sleeve carriage rigidity offers advantages for
remotely operated pipe cutting and pipe end beveling opera-
tions, plus the possibility of mounting and supporting cut-
ters or brushes to such carriages for internal pipe cleaning
needs. (See 2.9.1.2). Also, these carriages could probably
be used for maintaining pipe alignment during pipe cutting
operations. (See Appendix "B"). These potential benefits
seem to outweight the aforementioned disadvantages and sug-
gest that a development program would be Jjustified to estab-
lish feasibility and limitations.
3.5.1.3

19

The Wach's equipment has ample power, but the equipment
is considersbly larger and heavier (by a factor of 10 plus);
it requires substantial orbit clearance. The outside dimen-
sions for a Wach's Trav-IL~Cutter are 24 3/4 X 11 1/2 x 20 in.,
as compared to 9 X 4 X 10 1/2 in. for the ORNL orbital equip-
ment. Guillotin saws do not reguire orbit clearance. They
usually fit a space in the order of 6 in. beyond each pipe
side, with their operating mechanism in a fixed plane extend-
ing up to 3 1/2 pipe diameters on one side for a width of
about 6 inches along the pipe. Guillotine saws can be util-
ized only tc sever or straight cut pipes; they cannot make
bevel cuts.

Cost Estimates. No work has been done to adapt commercial

sawing machinery for remote installation. An equipment
design, development, fabrication and checkout program is
estimated to require about 1 3/4 manyears of effort plus
about $24,000 for materials, fabrication, test samples, and
mockups. The cost excludes prototype machinery acquisition
costs of about $3800 for a Trav-IL-Cutter and about $1200 for
a Guillotine saw with up to 8-in. pipe sawing capacity.

There esre a number of manufacturers who market pipe
cutting and beveling machines and lathes for pipe-end pre-
parations. The machines are normally used by pipe fabri-
cators and bty large construction companies to prebevel pipe
ends for corstruction welding. Typical machinery consists
of circular gear tracks, or horseshoe-shaped gear tracks,
to be installed over pipes, with the track utilized to orbit
either a torch or an end mill for cutting and/or beveling.
ORNL has experience in using an H & M "Pipe-End-Prep Lathe"
track to handle 14 to 20 in. pipes. H & M equipment has
potential for conversion to remote operation. It is defini-
tely adequate for flame-cut and bevel preparations, but lacks
a properly functioning precision "out<of-round" slide attach-
ment to accurately monitor and gauge the out of roundness
prevailing in commercial pipes so that compensating tool
position changes can be made. The writer believes that H & M
type equipment offers certain merits for consideration.
Equipment dimensions, weight, and orbit clearances are in
between the dimensions listed for ORNL and Wachs' equip-
ment. If the H & M equipment is to be used for reactor work,
individual tracks should be selected for each pipe size. The
frame-tracks for multiple pipe size application lack some
rigidity, and may offer too large an envelope when used on
the small end of thelr pipe capacity range. It is estimated
that, if performed in conjunction with the previously pro-
posed work for developing remotely operated saws, the develop-
ment of a workable H & M track to handle a representative
12 in. pipe cut and bevel preparation would require 3/4 man-
vear and $8500. Additional costs for H & M equipment items
would be in “he order of $2500.
20

A note of caution is repeated: labor, material, and
machinery costs quoted previocusly are based on standard
cutting practice with environmental temperature service
limited to possibly as high as 300°F, and radiation levels
up to about 104 R/hr. It may be necessary to develop sub-
stitute materials to meet the contemplated high-temperature
and high-radiation service requirements. All costs for such
development and for substitute materials of construction will
be additive. A study should be performed first to determine
the limiting cell conditions so as to determine the addition-
al research and development needs.

3.5.2 Seal Weld Cutters

 

3.5.2.1 Experience. There are a nurber of schemes for seal welding,

3.5.2.2

including Diaphragm and Seal Plate Weld schemes, Fig. 4g
Sandwich Seal Weld schemes, Fig. 5; Canopy Weld schemes,
Fig. 63 and Seal Lip Closures, Fig. 7. The welded seals
shown in the illustrations are types for which standard cut-
ting equipment can be adapted to work by remote control.
More detailed discussions are given in Section 2.14.4,

"Seal Weld Closure Welding."

Various milling and/or grinding means are normally used
with conventional hand tooling to sever the seals. To the
best of the writer's knowledge, with the exception of mount-
ing portable grinders to extension handles to locate the
tool operator away from any direct radiation beams, and/or
to permit the installation of portable lead shielding bet-
ween the work and the operator, Oak Ridge National Labora-
tory, to date, has had no experience in totally remote
cutting of seal welds.

Future Development Required. Specific tool, tool support,

 

and tool manipulation devices will vary for each of the
types of seal weld listed. Osak Ridge National Laboratory
has agssembled a file of gseal weld cutter tooling selections
based on published maintenance information and on cobserva-
tions of naval shipboard practices. The file includes in-
formation on grinders and grinding wheels, pipe cutters and
cutter bits, saws and blades, pipe-end prep machines and
tools, pipe centering and pipe expansion devices.

No time or cost estimate can be prepared prior to
selecting the seal Jjoint or Joint designs. The develop-
ment effort for the joint cutter should be performed in
conjunction with reweld machinery trials. It is recom-
mended that the designers select tentative seal weld con-
figurations now and thereby permit the developer to pro-
ceed with a feasibility study that could include tooling
design, purchase, adaption, and tests. Test results should
influence and provide direction to the final MSBR seal design.
21

ORNL DWG T73-2389

.1 L~ /\LTar:u.x\'n:-
= // menen Hegs
s <A |V abeu batied

 

 

 

1 i:-:-:::.—i
\
\
\
\
N\
\

\

"

 

 

 

 

 

 

 

 

 

 

  

 

NN\

PrOFr SC EME A. .

 

 

{

Fig. 4. Seal Plate Welds
V&D

GRIND FINIS
WELD

 

LIGHT TAaCK sTop
BoLT TWO'PLACES

EMERGEVCY

ORNL DWG T73-2390C

 

 

 

 

= ™ SAW GROOVE

N\NV// A

 

 

 

 

 

 

 

 

Fig. 5. Sandwich Seal Weld

 

cc
23

}\ ORNL DWG 73-2391

S

*
.
o ”
7

S T T
o,

 

 

 

 

 

 

 

 

 

\
O\
7

0 /'/’//,/,\/}
(0 7 s // S
St 7
N 7 Qfi
./ \
¥ X 7

 

 

N\
\\\\\L‘/’
X B \\\\\ \ > 501 7P.
{\0 /// /// \\\\\ //// . "%}o\_

) |i‘/\ / :

Al /
A
SHIM 4.

7

7 .

 

  

 

 

Fig. 6. Canopy Weld Schemes
24

 

ORNL DWG T3-2392

I ' 0

F LA D +
NN

SN

 

 

 

 

 

 

 

 

   

 

.

  
  

I CoNVENTIONAL

 

 

 

 

 

 

 

 

 

 

 

 

/

J=N
g

T SPECIAL

 

 

/
~

 

 

 

4

A

 

 

 

 

 

 

 

 

 

 

   

    

(i L 2L Ll i Lk bhedeid]
LA N T

 

. -
V‘

 

 

 

 

 

 

 

 

 

 

 

Fig. 7. Seal Lip Closures
3.5.2.3

3.6.1.1

3.6.1.2

25

Cost Estimates. It 1s estimated that a budget of three man-
years and $40,000 could establish worthwhile guidclises for
preliminary seal-cut and seal-reweld feasibility evaluation.
(Note: Ttem 2.14.2, "Closure Welding — Seal Welds" develop-
ment costs are included with this estimate. )

The cost estimate caution listing stated previously also
applies here.

3.6 Equipment for Pipe Spreading

 

Concept and Limited Experience. After cutting the pipes

on each side of a component one must spread them apart to
permit the ready removal of the component. Depending on

loop layout. it may also be necessary to jack up one or the
other of the pipe ends adjacent to the cut to eliminate bind-
ing for the remainder of a cut. For remote operational needs
it is planned to utilize the special pipe alignment machinery
discussed in Section 2.12, "Pipe Aligning Technology" to also
serve the plpe spreading needs, at least for the smaller pipe
sizes. ~

 

We have limited experience in resolving pipe restrain-
ing problems associated with pipe slitting operation. Split-
saw cutter bench tests showed the importance of selecting the
proper pipe support location relative to the orbiting plat-
form. Care must be taken to permit free movement of the cut
piece, and to prevent the binding of this piece against the
saw. Slit-saw cutter materials are brittle; our test trials
showed that it i1s possible to crack and break a restrained
saw blezde.

 

Future Development Required. Refer to item 2.12, "Pipe
Aligning Technology' . '

3.7 Carriers and Conveyance Means for Use Within the Cell

3.7.1.1 Experience. Carrier technology from ORNL and other in-

3.7.1.2

stallations is available so that specialists in carrier de-
sign can meet whatever requirements are established by the
final design of system components.

Future Development Required. None anticipated.

3.8 Carriers for Use Qutside the Cell

 

3.8.1.1 Experience. Carrier technology from ORNL and other install-

3.8.1.2

ations is available so that specialists in carrier design can
meet whatever requirements are encountered.

Future Development Reguired. None anticipated.
3.9 In-Cell Preparations for Equipment Reinstallation

3.9.1.1 Definitions and Experience. Final preweld pipe-end joint

3.9.1.2

3.9.1.3

3.10.1.1

 

preparations include kerf and/or chip removal from the open
pipe joint, removal of salt including salt traces clinging

to the pipe wall and the installation of a suitable purge
block plug into the pipe near the open joint. One must also
establish acceptable environmental, off-gas airlock and
ventilation conditions for the cell. All cutting chips

from mechanical sawing, kerf from plasma flame cutting, and
salt residue on interior pipe walls adjacent to the cut
joint, must be totally removed from the pipe prior to in-
stalling purge blocks or making a facsimilie in preparation
for final pipe rewelding. Provisions must be made and in-
corporated with air locks and ventilation systems, to permit
the cell off-gas system to safely handle purge and welding
gases from subsequent pipe rewelding operations. ORNL has
had considerable experience for some of the categories from
operational maintenance experiences with homogeneous reactors
and the MSRE.”’©’23 Additional information is also available
from the remocte top closure evaluation work of the FFTIF at
Hanford, Washington.Z2%

Future Development Required. A study should be started early
in a reactor project and should combine the efforts of the
reactor designers and maintenance personnel to assure that
the piping system layout provides adequate clearances for
maintenance equipment and for the introduction of replace-
ment components. The group should discuss all phases of the
repair and reinstallation requirements. Special tools and
other requirements that become apparent from the discussions
(such as a pipe wall scraper for removing traces of salt from
pipe interior) should be listed and categorized. Where pos-
sible, new tooling requirements should be combined with exist-
ing tooling, or at least with the masts and manipulators of
existing long-handled tools.

 

Cost Estimates. It is esgstimated that 1 1/4 manyears and
$18,000 will be required to perform the supplemental work,
including the cleanliness control work discussed in Section
2.10 below.

3.10 In-Cell Cleanliness Control

 

Definitions and Experience. TIn-cell cleanlinegs control in-
cludes all the precautionary measures to assure that all
prewelding cleanliness requirements of the ASME Code and
RDT Standards are met and maintained throughout the welding
cperation. Wiping joints with acetone solvent and lint-
free rags before welding, proper filing of defects observ-
ed between passes, and brushing of all weld beads, etc. are
terms of cleanliness control that have been found to be
necessary. =°726227
3.10.1.2

3.11

27

Future Development Required. Cleanliness control development
requirements and associated costs are included with the 1list-
ing of item 2.9 above.

Conveyance of Components to Reinstallation Iocation

3.11.1.1 Experience. Carrier and conveyance technology can be ob-

3.11.1.2

3,12.1.1

tained from ORNL and other installations for direct applica-
tion tc remcte maintenance problems.

 

Future Development Reguired. None anticipated.
3.12 Pipe Alignment Technology

Concept and Experience. There is only limited practical
experience with the use of remote control equipment to spread
the ends of pipe after cutting, to position new components in
proper alignment, and to hold them in position during welding.
Most of the available reactor maintenance experience docu-
mentation refers to underwater maintenance, with either the
cell or the component partially flooded. Molten Salt Breeder
Reactor (MSER) maintenance must be performed under dry conti-
tions. The limited dry experience that is available is pri-
marily from work in the MSRE mockup and in the MSRE cell
where specially mounted screw-jacks were installed in con-
junction with freeze flanges in the primary pipe system to
spread or close the flanges. Instructions for pipe align-
ment were developed as a part of the extensive Westinghouse
Pennsylvania Power and Light Company study for the Pennsyl-
vania Advanced Reactor Program (PAR)2% of the late 1950!s.
The PAR was planned to use a circulating aqueous slurry fuel
pressurized to 1000 psi. The designers recognized that a
circulating fuel would increase the radiation levels in the
reactor system areas and that completely remote maintenance
would be mandatory. The remote control devices and pro-
cedures planned for use on the PAR system are described in
the following paragraphs.

The primary coolant systems of the PAR consisted of
closed loops, each with but one point fixed. Hence, posi-
tioners to realign the pipe for welding were not required
to apply bending moments to the piping and only simple radi=-
al and axial motions were needed to grip the pipe and to
align the pipe ends. PAR loop piping was expected to encount-
er thermal cycles which would introduce stresses that would
cause the pipe ends to spring from their original position
when the pipe was cut. The PAR design criteria regulated
primary pipe stresses to limit pipe expansions so that no
point of the piping would move in excess of 1/2 inch during
the flexure from hot to cold position. Their reactor vessel,
because of its weight and hanger design, had the completely
fixed position. All other components and the piping were
28

free to move about the reactor in a horizontal plane. Be-
cause of this flexibility, only relatively simple positioner
devices were required to properly held piping for severance
operations and to realign the replacement piping prior to
welding. Narrow clamping band units on each side of the

cut points included jaws to firmly grip the pipe. The cut-
ting and welding equipment could move radially and axially
for realignment and mounting. Cut points were preselected

on horizontal pipe runs to further reduce bending moment
requirements for the replacement piping. The PAR primary
system (16-in. pipe) positioner design assumed that the maxi-
mum loads to be imposed on the pipe, in either the radial or
the axial direction, would be 15 tons and that a l-in. axial
movement of the pipe to provide clearance would be adequate
for removal of the components. Replacement components con-
tained nozzle configurations identical with the removed com-
ponent. Crane access was chosen to position new components
within 1 in. of the final in-cell location. All axial and
radial loads were transmitted to permanently installed struc-
tures. These supports were designed not to deflect under the
calculated loads required for pipe manipulations. During the
removal of a component, identical positioners would be lowered
over the piping onto the rigid steel structures on each side
of the cut point. After the positioners were locked to the
supports, their self-contained hydraulic systems were to
provide all the forces required to restrain or align the
piping. Final alignment was to be accomplished to within
1/32 in.

The termination of the PAR project precluded complete
testing of the maintenance schemes to show that they would
accomplish all the restraining and pipe aligning manipula-
tions required for proper cutting and rewelding work set-
ups. The project, however, did conduct equipment tests to
establish remote maintenance feasibility and to provide
valuable guidelines for further studies.

Among the problems that remained when the PAR work
had discontinued was the fact that the maintenance equip-
ment and the positioning equipment components were bulky
and complex. Many positioners were required to handle the
numerous pipe sizes, and each demanded a great deal of cell
room. Although ORNL's approach to positioning will generally
follow PAR guidelines, we plan to use greatly simplified
apparatus. For example, piping will generally be cut at
component stub nozzles. The positioner support therefore
can be incorporated to the component’s structure or framing
at considerable space savings. Pipe deflection movements
can be minimized. TFigure 8 exemplifies a possible arrange-
ment.
29

ORNL DWG T3-2393

 

 
  
 

 

 

 

 

 

 

TF

 

 

 

 

 

i COMPONENT ‘A ) i’ .
I ) ™ i '
| ( ™

I [} e ] 1 i
F vy A
\ . 3
~{1 .

 

 

 

 

COMMON PRAMING T ]
LS S

N
N

Fig. 8. Component Pipe Stub Weld Joint Positicner Arrangement

ORKL DWG T3-239k

CRANL
~ ~CYLE2

 
   
 
 
 

TvP, TCP SYot

__TYR
APLCS

 

Fig. 9. Pipe Aligmment Jig for Line Cutting and Welding
30

Component (A) and typical connecting pipes (B) and (C)
are commonly supported by framing (D). Preselected cut-point
area (E) has accurately machined (to better than normal mill
dimensional tolerances) piping, precision indexed to compo-
nent reference lines. A permanent pipe clamping fixture (F)
is both adjustable and removable. The fixture includes a
centered ring groove to accomodate a ring welded to the pipe.
The integral pipe ring permits the fixture to shift axially
during loop heatup expansion and cooldown contraction to
minimize the introduction of bending moments and stresses to
the pipe. The mating surfaces of the pipe clamp fixture will
contain antigall spray coatings. A typical component replace-
ment operation is presently envisioned as follows:

1. Mount the "orbital vehicle" carriage over area (E).
Insert an inspection module. Verify that clamp (F) is se-
cured over pipe (B). Apply module's inspection gear to pro-
perly index the carriage at the preselected cut-plane; lock
carriage drive to pipe.

2. Install a catch pan and a vacuum cleaner system
for "hot chip" control. Install a cutter module in exchange
for the inspection module. Test indexing — proceed to cut.

3. Transfer equipment to pipe line (C); repeat opera-
tions 1 and 2.

4. Detach component (A) from its support, attach a
1lifting fixture. Use crane for removal,

5. Enter replacement component (A'). Tts pipe stub
has been previously machined to template indexing data.
Component (A') is bagged, except for stub pipe weld ends,
and lowered in place. Bolt component (A') to supports.
Attempt to match stubs and piping. If stub ends are too
long, matchmark pipe, remove component, remachine. If stubs
are too short, obtain wax impressions for machining a spool
piece insert. Fit as required to attain joint alighment.
Adjust the permanent pipe clamp fixture (F) if required, but
only for small displacements to avoid excessive strains.

We plan to use special custom-built spool inserts to
connect pipes for rewelding in places where it is otherwise
impossible to attain satisfactory pipe-end alignment for
rewelding. Many components contain multiple pipe connections.
Depending on the respective azimuth locations of the pipe
stubs on the replacement component, equipment maintenance
procedures to be developed in the mockup will more than
likely require spool plece connectors for the makeup of
some of these lines. The spool piece scheme avoids the
prestressing of pipes for fitup on the final line attach-
ments of multiple lines.
31

6. Reinstall "orbital vehicle" carriage with the in-
spection module insert over pipe (B). Check the final align-
ment of the pipes and align the carriage. Clamp and lock
carriage drive to pipe. ©Swap to cutter module, mill the
adjoining pipe ends to get the precision needed. Remove the
cutter module, clean the prepared Jjoint; then install the
weld module. Tack or stagger weld matched pipe ends to
avoid distortion. Perform similar work on pipe line (C).
Finally, finish weld both joints.

7. Remove repair equipment. Adjust the supports and
tighten bolts. Whenever a pipe section or component is re-
moved after having been in service, residual stresses can
exist in the piping and will appear as forces and moments
upon cutting the pipe. The forces and moments will be pre-
sent even though the piping may have been installed initially
in a stress-free condition. Stresses can be caused by dif-
ferences between the ambient temperature at which the piping
was ingstalled and that which exists during maintenance opera-
tion, by thermal cycling in system operation, by changes due
to yielding at high-temperature operation (creep), or by
changes of configureation caused by welding, or by shifting
of pipe support hangers, supports, or structures. The sug-
gested scheme for cutting only in the vicinity of the com-
ponent nozzle stubs and for using common-component pipe
restraint clamp supports locates pipe cut points adjacent to
rigid components and tends to reduce radial pipe movements
and pipe bending moments. The scheme thereby minimizes pro-
blems with replacement components. The scheme alsc compen-
sates for axial pipe shifts by letting the pipe clamp fixture
shift freely with the pipe's axis. Appendix A lists cal-
culated maximum pipe shifts to be anticipated in cutting of
pipe in a maintenance operation on a typical right angle bend
pipe-line installation. The illustrations selected represent
"ideal" balanced symmetrical layouts; in practice piping
systems will more than likely be far more complex. The de-
flection and restoration force figures, however, illustrate
the magnitude of the problem, and the problems dependence
upon pipe size and lengths of pipe runs. The longer the
pipe'ts length, the greater its deflection, or shrinkage upon
cutting, — but the restoration force requirements decrease
with increased pipe lengths to reduce the overall problem
of jockeying pipes about to align an old in-cell pipe end
with the pipe stub of a newly installed component. Smaller
diameter pipes are less rigid, hence considerably less force
is required to move the smaller lines within the cell.
Accordingly, the ideal cell pipe layout, from a maintenance
standpoint, consists of long runs of small diameter balanced
geometry pipe lines. We also note negligible angular pipe
deflections for the proposed pipe supports affixed to a com-
mon base with the respective components; the magnitude of the
angular deflection, or rotation, upon cutting the pipes 1is
not sufficient to cause problems of matchup for butted ends
for re-welding if the pipe ends are squared to usual tolerances.
3.12.1.2

32

Reactor designers cannot predict all possible trouble
areas, or it may not be practical to provide pipe stub posi-
tioners at every location where they might be needed. There-
fore, a portable pipe aligmnment jig for line cutting and weld-
ing, such as shown in Fig. 9, will be needed to provide for
pipe maintenance anywhere within the system. The cable-
supported positioner assembly could swing into place over the
pipe to be cut. Then, two hydraulic cylinders, housed with-
in the jig's top cover, would be energized to extend a set
of contoured shoes to firmly grip the pipe and press it into
the alignment jig and reestablish radial alignment. Matching
corner-cable slings are in tension to balance the applied
hold-down forces. Narrow clamps designed to grip the pipe
firmly should be installed butted up to each side of the
jig's shoes to minimize pipe bending moment stresses when
the pipe is cut.

Future Development Requirements. We should establish which

 

vessels are to be replaced, which ones to be repaired in
place, and which components of vessels are to be removed for
repair or replacement. Expected pipe flexibility needs should
be estimated for comparison, and for the vessels that are to
be replaced it must be determined how pipe sizes, wall thick-
ness, length and method of attachment to the vessel will
influence the flexibility. A tightly coupled arrangement
such as that proposed for the MSBR's2? does not permit much
flexibility and it may therefore become necessary to resort
to the use of tailored spool pieces for short large dia-
meter pipe runs. Where the large coolant salt piping could
have long runs, there may be enough flexibility available to
permit some maintenance pipe alignment, however, even:lere
pipe in the 20 inch pipe range is not easily bent. The
smaller service lines (6 and 8 inches diameter) could be made
flexible enough to permit relatively easy alignment after the
vessel is installed and the larger lines welded together.

The references to the PAR imply that the largest vessel, or
the reactor vessel, would be fixed and that the other compo-
nents would then be adjusted to it for alignment. The actual
supports, rotations, and tilts of these "other components”
remain the major problems to be resolved, along with the
problems of properly holding the pipes for final alignment
before welding. The designer-maintenance study group (see
itme 2.9, "In-Cell Preparations for Equipment Reinstallation")
should analyze all in-cell pipe systems for anticipated pipe
deflection shifts and movements when the pipes are severed
during component replacement maintenance operations. Their
analyses should determine the equipment and pipe support types
needed, the locations of the cut planes, and the space needed
for pressure cylinder ingertion to move the pipe ends as required.

Alternatively, a study should be sponsored to investigate
possible merits of utilizing commercilally available split-
bearing sleeves to retain pipe alignment for cutting and to
3.12.1.3

3.13

3.13.1.1

33

reestablish alignment for preweld and weld-tacking assembly,
as detailed in Appendix B. There may be a pipe size restric-
tion for an effective range where split-bearing sleeves per-
mit a highly simplified approach to pipe alignment maintenanece
needs. An investigatory program should start early in the
reactor project. Split bearing sleeve maintenance, even if
practicable only for the smaller pipe sizes, would permit
substantial overall cost savings.

Cost Estimates. A feasibility study on a selected small pipe
size of 3-in. sched 40 stainless steel pipe, or of 3-in. 40
Inconel pipe, for split-bearing sleeve maintenance would en-
tail about 3/4 manyears and approximately $15,000. A Phase
IT extension to determine range limitations for the scheme
should be a program of approximately like magnitude. Costs
of Phase IIT final checkouts including more complex alignment
apparatus for the larger pipe sizes are indeterminate at this
time. Work for this phase should be combined with full-scale
mockup schemes of actual component installations, which would
entail considerable manpower, material, equipment, and related
costs.

Weld Preparation and Tack Welding of Pipe Joints

Concept and Experiénce. At present it is proposed to use

 

"buttered” weld metal rings that are integrally attached to
the pipe stubs of the replacement component, or to the re-
placement pipe.?? A "buttered" ring is prepared by deposit-
ing weld metal around the pipe stub interior and then machin-
ing the deposit to a washer shape. The integral weld metal
ring 1s shaped and spaced to simulate a Kellogg<type rectan-
bular ring consumable insert. The final machining of the
washer is to be made to match the mating in-cell pipe end by
using templates made from wax impressions. The washer shap-
ed pipe end offers the additional advantage of having a fairly
rigid end configuration capable of withstanding moderate abuse
during pipe handling operations. The final pipe alignment
positioning, however, is critical. The prepared end shape of
the in-cell pipe section consists of a nominal 1/16-inch root
face and a bevel angle. This rootface is comparatively flimsy;
hence vulnerable to nicking or deformation with bumping or
other improper pipe handling. It is desirable to attempt to
contact the joint face only in a butted plane. It may become
necessary to temporarily protect the in-cell pipe-joint ends
with bumper shields until a replacement component (with its
integral pipe stub ends) is lowered to final elevation.

The integral ring and stub will be tack welded to the
in-cell pipe using the automated orbital pipe welding equip-
ment as soon as proper aligmment is obtained. All aligning
machinery must remain energized for the tacking operations to
clamp and restrain the pipe sections and thereby firmly seat
3.13.1.2

34

the pipe ends. Sufficient tacks must be placed to avoid

the breaking of tacks after restraint removal, or during root-
pass welding. Preliminary feasibility trials seem to indi-
cate that the above procedure can be made to work properly.23’25
Future Development Requirements. To be discussed under Sec-
tion 2.14.1, "Closure Welding — Pipe Welding'.

 

3.14 Closure Welding

 

3.14.1 Pipe Welding

3.14,1.1

3.14.1.2

Experience. The ORNL automated welding feasibility study
report,<3 a follow-up report on further weld development

with the ORNL system,25 and a report on automated orbital
welding with recently available commercial equipment systems,26
as well as an ORNL film on Automated T/\Teléling,z'7 all describe
automated orbital welding operations in considerable detail.
Some consideration was given to adapting the original ORNL
equipment for remote application, however, essentially no
proper scale demonstrations were attempted, and this still
remains to be done. It is now also important to monitor

the progress of the newly available commercial automated
orbital welding systems.25’26 Five companies started market-
ing such equipment in 1972. The AEC is planning to use such
machinery extensively for the pipe system construction of
IMFBR facilities. Tt may become appropriate to conduct
future maintenance welding experimentation with these com-
mercial systems to utilize trained, knowledgable operators
and qualified welding and inspecting procedures.

The ORNL automated equipment consists of an "orbital"
carriage that clamps onto a pipe and propels the welding
apparatus around the circumference of the pipe. The carriage
accommodates interchangeable heads for cutting pipe or for
making tungsten inert-gas-arc welds. There is an automatic
welding programmer-controller that constantly maintains all
conditions necessary to produce high quality welds. There is
also a hand operated pendant unit to provide alternative start
and stop controls. To begin automated welding, an appropriate
procedure is dialed into the programmer-controller, a button
is pushed, and the machine takes over to produce the weld and
then shuts itself off. A recorder coupled to the system is
used to record the major welding parameters including current,
arc voltage, carriage speed, wire feed rate, and start and
stop. Figures 10 and 11 show the welding system.

Future Development Requirements. Automated welding is now
operational for direct pipe welding in construction applica-
tions.?® Commercial equipment systems are now marketed below
$40,000 to automatically butt-weld pipes from 3 to 36 in.
diameter and for wall thicknesges of 3/16 to 1 1/2 in. The

 
 

 

 

35

 

PHOTO Y-106815

 

[

 

 

i
i
i
i
1

 

"

= . Fig. 10. ORNL Orbital Welding System

 
r— - A e —
A

* s

-
s

~—- 460 Vo (60 amp) AC Supply

 

120_Y,(5_smm) AG Supnly

I

 

 

 

. WSepbied "‘-o"
o by

grn m m -
L ek, TR e
‘:'h"l."fl"_'-' ’

  

 

 

Fig. 11.

-~ o ;
S e r et tmrrf e s C— - - =" AE s ed 5 mmme m e

   

CRNL DWG T3~2395

/

 

S "

!
t
! £
!
! ‘.mmmm,

.‘.

 

 

S e —-— - —-c.-——,--? -t e

 

      
   
  

A N T | ey

(Rear A;mon)

 

 

 

 

 

 

 

 

Equipment Hook-Up, ORNL Weld System '

9¢

 
37

machines orbit the pipe for welding. Welds produced meet
ASME and RDT Code Standards for nuclear-gquality gas-tungsten-
arc welding of pipe. The commerical machines for the present
must be manually mounted on pipes, and operator understanding
and judgment are required for the setups. The ORNL orbitazl
carrizge and automated welding equipment can be installed re-
motely and operated from a remote station.

3.14.1.3 Cost Estimates. There is a choice of custom building individ-
ual OFENL type systems one at a time at roughly 1 1/2 to 2
times the costs of the commercial mass produced systems, or
of attempting to devise means and procedures to adapt and con-
vert the commercial machinery to remote control applications.
Since most nuclear piping systems will probably be built with
automated welding equipment by the late 1970's, it is recom-
mended that the commercially available equipment be adapted
for remote control operation. It is estimated that two man-
years of effort plus $40,000 for supporting services and
materials will be required in addition to purchase of a com-
mercially available automated welding system, estimated to
cost $38,000.

The note of caution, however, must be repeated. As with
the pipe cutting and beveling equipment, all present materials
of construction for either the ORNL or the commercial welder
will not withstand environmental temperatures in excess of
300°F and mag not hold up for an acceptable life in radiation
fields of 10 R/hr. A program must therefore be sponsored to
develop substitute materials, to conduct furnace tests, and
thereafter, toc build prototype weld heads for total weld sys-
tem checkout in suitable high-temperature test cells. Esti=-
mating costs for this work would be premature and will be
developed when environmental conditions are set more firmly,
and after the establishment of the remote handling capability
for commercial welders.

3.14.2 Seal Welding

3.14.2.1 Description. Seal weld closures were illustrated and dis-
cussed in Section 2.5.2. We expect that the welding head
used in ORNL experiments, or a commercial head of eguivalent
design, could be adapted to follow the circular path of the
seal perimeter by attaching the head to the end of a jib-
boom, which is centered on the vessel flange, as shown in
Fig. 12. Adaptive controls will be used to properly locate
the torch and to adjust the torch-tungsten positioning for
minor geometrical contour irregularities and/or minor fitup
inconsistencies of mating seal members. For seal welds on
the side of the vessel, it is possible to support the same
type weld head from a carriage to ride a rail track about
the perimeter of a vessel, as illustrated in Fig. 13. We
have completed a concept study for a crawler-carriage to
38

ORNL DWG T73-2397

 

P .\/\ Alternate Dshed Heal
7~ A
7 S
//
O Flat Top Flabe Closure
7/
/I

 

 

S

Provisions for future seals away
from the heat effected zone

 

e ?‘ R
B

 

 

 

Foxr CUITING:
Use air or electric cutting tools, grinders, plasma torch, and/or gouging torch

Fig. 12. Conceptual Diaphragm or Sandwich Seal Weld with ORNL
Weld Head Supported from a Motorized Carousel Linkage
39

ORNL DWG 73-2398

 

Concepbual Flanged Heat Exchanger Veasel

 

 

[
|
iju;

cutting head, & & plisma torohywith

subsequarts grind cleatiing,

For Cutting use eithermbsef

 

 

 

 

— T T T T T T T I T T T T L I L T T I T T TS i e amas . . —~
S
ST e
L T—
e T T e e e et - .- - . . - e <
- e e LTS e e —_———— - — —_—
—— i —_ o ——— e —— — —_

 

Flanged Vessel Seal Weld Closure Scheme

for Orbital System Inserts

Fig. 13.
3.14.2.2

3.14.2.3

3.15.1.1

v~

4{

C

ride a set of seal lips as shown in Fig. 14. The final
design for seal weld closures will govern the selection
of the type of carriage to be used with a weld head which
is common to other systems.

Future Development Required. New types of carriages and

 

weld~head propulsion schemes are needed for seal weld ap-
plicationg. Presently available weld heads from the com-
mercial systems can perform the heliarc seal welds required
and the heads need only to be adapted for remote control and
automated seal welding operation. It is reasonable to as-
sume that the weld heads developed for pipe welding could be
used interchangeable in the seal welder.

Cost Estimates. Approximately three manyears and $40,000

should be budgeted if this work can be performed in conjunc-

tion with recommended item 2.5.2, "Seal Weld Cutters'" devel-
opment. The special high-temperature and high-radiation
equipment stipulations listed under item 2.14.1, "Closure
Welding — Pipe Welding" again also apply for seal welding
equipment.

3.15 1Inspection and Acceptance Tests

 

Concept and Experience. The technology of remote inspection

 

and acceptance testing by means of the more conventional
penetrant checks, radiography and sonic inspection is de-
scribed in the report "Remote Inspection of Welded Joints",
ORNL-TM-3561, September 1971, by R. W. McClung. In addition,
it now appears that it may be possible to evaluate the data
recorded as the weld is being made and from the data to
determine the likelihood of a flaw in each weld pass. It is
known, from experience, that excessive arc voltage and low
current will cause lack of weld penetration; low arc voltage
and high current, or low wire feed and high weld current will
cause melt-through; high wire feed and low weld current will
ball the bead; inconsistent carriage travel and hence, uneven
weld speeds will result in uneven bead depth and contour;
ete. The Recorder shown with the welding system in Figures
10 and 11 charts welding current, arc voltage, carriage speed
and wire feed rate. The charted record can be compared to
previously prepared acceptable standards. If all plots fall
within predetermined allowable band-widths, this is evidence
of a good weld. Simultaneously incurred irregularities to
any two of the charted functions should cause concern.
(single plot deviations usually indicate instrument cali-
bration, or signal noise fluctuations.) Usually, a careful
visual inspection, with the chart’s time scale used to cal-
culate the specific location of the suspected flaw, will
confirm a weld defect. It is hoped that the Code writers

and the inspection agencies will amend their present in-
gspection policies to permit the substitution of information
ORNL DWG T3-2399

CUT ©R WELD ¥oRULE
- WELD INSERT SHown

  
  

_ CLAMPING
ADJUSTMENT

LIP contacT RIDER(®)

"

 

N
>~ - b‘\' -
SIS

Fig. 14. Conceptual Design — Remote Seal Device

7
3.15.1.2

42

from recorder charts for those Code requirements that can-
not be established with reliability by remote means.

Future Development Required. Recommendations for future
development work on remote inspection and acceptance tests
are contained in McClung's report on "Remote Inspection of
Welded Joints'".?
43
APPENDIX A

CALCULATIONS FOR ANTICTPATED MAXTMUM DEFLECTIONS
AND RESTORATION FORCES FOR CUTTING INOR-8 PIPING MATERIAL

In considering the problems of remote maintenance on molten salt
reactor systems, we have been concerned about how pipe ends might move
or spring apart after a cut is made to remove some component which is
to be replaced. The weight of components and of the pipe itself will
impose stresses as will thermal expansion or thermal cycling after the
system was installed. One can anticipate that the pipe ends will surely
shift or deflect after a cut has been made. To be able to realign the
pipe and hold it in position for rewelding will require some sort of
clamping mechanism which will have to be designed to overcome the forces
exerted on the pipes. Force will also be required to restore the cut
pipe to its original position prior to realighing and rewelding the re-
placement component into the system.

Two pipe layouts have been analyzed to obtain an approximation of the
magnitude of the problem. The cases are somewhat simplified and idealized
to permit ready analysis, but the calculated deflection values should
nevertheless be reasonable approximations. In any event, with standard
supports and braces for the components of the system, the calculated
stresses on runs of pipe are such as to cause the cut ends to deflect
about an inch or less, not as much as a foot or so. This information
is important in determining what sort of equipment will be needed for
aligning and holding pipes to be rewelded. The cases that were analyzed
were selected to illustrate the effects of pipe length and pipe diameter
on the magnitude of the deflection when a cut is made. The calculations
of the amount of deflection and the forces required to restore the de-
flected pipe to its original position indicate values that we can live
with, provided that we use proper foresight in establishing the system
design to meet reasonable requirements for future maintenance.

Calculations

For a molten salt reactor system operating near 1300°F over a three-
year period, we have calculated the maximum deflection of pipe ends after
cutting and calculated the forces required to restore the pipe ends to
their original position. These calculations are based on the assumption
that the system piping was originally installed so that stresses were
within those established by the criteria of Code Case 1315. The following
paragraphs and illustrations describe the calculations that were performed
and show the results that were obtained.

Given:

1. Maximum permissible creep rate:
Code allowable maximum = 1% in 100,000 hrs

= ,26% in 3 years
4ty

2. Assume:

a)

b)

the uniform creep rate conservatively will not exceed 50%
max. Select a uniform creep rate of .13% (this represents
~ 1/7 of the maximum thermal expansion).

there is no stress in the pipe at assembly.

3. Calculate:

a)

b)

Pipe Shifts vs. Pipe Lengths for

1) A typical piping arrangement; both ends of the pipe run are
fixed; no permanent pipe end support guides at cut point.

2) A typical piping arrangement; both ends of the pipe run are
fixed; the fixed pipe end supports include a common fixed
base with guides on each side of the pipe cut to restrain
the pipe being cut.

The magnitude of the restoration force to be applied to the cut
pipe (first case) to return the pipe to its precut location.

1) Force vs. Pipe Length

2) Force vs. Pipe Size
CASE WITHOUT GUIDES

 

 

45

PIPE SHIFTS VS. PIPE LENGTHS

 

 

 

N\

: >
::;fefore cooldown <
A:f;fter cut T

N
AN

 

 

 

 

 

 

 

 

' -m—AX‘
L+ 24 ;6"
- o ——— -
N
<
o
—
3 5!
Q
+
2
¢ = angular shift at cut
Ax = linear shift at cut—horizontal plane
-i_ Ay = linear shift at cut—vertical plane
T | Az = total linear shift
© £ = partial pipe length¥
777 —
® = 0 for piping arrangement shown
Ax = 0.0013 (£ + 30)
Ay = 0.0013 (£ + 30)
= ay
Az = J B2 + AT-?
PIPE LENGTH¥* LINEAR PIPE SHIFTS AT CUT
5 4+ 2'6" = 76" Ax, Ay = 0.117" Az = 0.17"
10t + 2'6" = 12'6" Ax, Ay = 0.195" Az = 0,28"
15" + 2t6" = 17'6" Ax, Ay = 0.273" Az = 0.38"
20" + 2'e" = 22t6" Ax, Ay = 0.351" Az = 0.50"

*Pipe lengths were selected to correspond to lengths used for the Case
With Support Guides where the +2'6" is the distance between fixed end
supports, with the pipe cut made 6" from the rear support fixture.
46

CASE WITH SUPPORT GUIDES

 

 

 

 

 

 

 

 

 

 

 

/,
— J
PTIPE SHIFTS VS. PIPE LENGTHS I ; 2
before cooldown LV
‘ N ¥ | /1
9
/ nR Al
> S
5 e ot [ .7
T ot A : h-*-iBO
}
= |
= g
-
B o
o
A

 

= angular shift at cut

= linear shift at cut, wvertical plane

fll‘ll

linear shift at cut, horizontal plane

= resultant shift, after cut, Y-plane

 

h%gafi
i

= partial pipe length¥*
<— GUIDE

—

  

 

77 :cp = sin™1 Er%zl Ay = O for pipe arrangement shown

ax = ax" 4+ [+ 24) - (4 + 24) cos o]

Where Ax’' is Ax for case without guides.

 

 

 

 

sy = 0.0013 (30 + &)

1 ]o.0013 (30 +.z)]

®E ST T2y

Ax = 0.0013 (30 + 2) + [4 + 24 - £ + 24 cos o]

[ ] term=0 .. Ax = .0013 (30 + 2)
PIPE LENGTH* ANGULAR AND LINEAR PIPE SHIFTS

Q_ A Ay 5y

5¢ 4+ 26" = 7'6" 0°-4! 0.117" 0 0.117"
10" + 2'6" = 12'6" 0°-4' 0.195" 0 0.195"
15" + 2'6" = 17'6" 0° -4 0.273" 0 0.273"
207 + 216" = 22'6" 0° -4* 0. 351" 0 0.351"
47

RESTORATION FORCE VS. PIPE SIZE AND LENGTH

 

o= 8

nomnu

 

W(pounds ) —=

6" Sched. 80 Pipe (.432 wall)
20" Sched. 80 Pipe (1.031 wall)

Force W to restore:

linear line shift £
force to restore I
modulus of elasticity

partial pipe length¥*
moment of inertia

i u

_=1/3w3
by = —%7

~-3EI Ay
2>

8. 405
61. 440

—
1l

40. 49 A
2599.07 A

H
l

(W is the force required to return the
pipe its precut position.)

 

 

 

6" Sched. 80 Pipe 20" Sched. 80 Pipe
PIPE LENGTH W (pounds) W (pounds)
51 4 216" = 71E" 760 49,000
10 + 2'6" = 12'6" 250 16,200
15 + 2'6" = 17'6" 125 8,000

20" + 216" = 22t6"

75 4,750
49
APPENDIX B

PROPOSAL FOR DEVELOPMENT OF A SPLIT-BEARING-SLEEVE CARRTAGE
FOR REMOTE MAINTENANCE APPLICATIONS IN NUCLEAR REACTOR SYSTEMS

We recommend the building and testing of a more rigid gear-driven
carriage to supplement our present flexible horseshoe-shaped friction-
roller-drive carriage. The gear-driven carriage could be used to ad-
vantags for increased torque capacity remote cutting and beveling work,
for highest tracking accuracy needs, and for internal pipe cleaning ap-
plications. The substitute carriage consists of a split sleeve which is
supported by split roller bearings on each end. A motorized split-gear
track is attached to one of the end bearings to orbit the sleeve about
the pipe.

The split-sleeve carriage might also provide a simplified solution
to pipe alignment problems. It is recommended that a determination be
made to establish how much initial pipe displacement can be withstood by
a sleeve supported on split bearings. This will show whether the split-
bearing-sleeve can be used for remote maintenance pipe cutting needs for
some of the reactor service pipe lines. A test program is suggested to
ascertain feasibility, to seek the pipe size limits for which split-bearings
are capable of transmitting moments, and to compare the non-conventional
approach to more commonly accepted alignment technology based on restraints
attached to loose pipe ends.

Maintenance operations with split-bearing-sleeve eguipment are exampli-
fied below:

1. Sk. 1

 

 

LEEVE |GUIDE

|

SPLIT EEARIEG

 

-
i

i

 

(
Q

 

 

|
|
COMPONENT
FOR
REPLACEMENT

 

 

Determine where to cut pipe relative to the replacement component’s
prefabricated end stub (distance xf); locate and attach split bearing B¥
to pipe accordingly (distance x); bearing B includes a preassembled split
front bushing guide. (The split bearings might include a soft material
or knurled bushing sleeve to fit inside the inner race for better attach-
ment to the pipe and to make allowance for probably out-of-roundness of
the pipe. Otherwise, one must consider two separate functional devices,
one to firmly clamp the pipe and one to center the bearing on the pipe.
The latter could be in form of on attachment to the pipe clamp.)

*Stocked Split-Roller-Bearings are commercially available from the Cooper
Split Roller Bearing Corporation, Pittsburgh, Pa., and from other bearing
manufacturers on special order.
50

2. Sk. 2

Insert the lower half of bearing A with a split gear sector attached
to the bearing front face into a locating cradle. Position the cradle
about bearing B. Next, place the top half of bearing A, with its top
gear section preattached, to mate to its lower half. Now permanently
install bearing~-gear assembly A to the pipe. Remove the locating cradle.

 

 

 

[©)] @)

2 E} 2
':T_'l

%4: %E Efi %m

EQ A = 5}_::%

"8 & oF o8

o 801 %: %Ig

 

 

 

 

 

  

. , COMPONENT FOR
= - gd | X REPLACEMENT
% & T

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ALY

 

3. Sk. 3

Install a cradled motor assembly ahead of gear-bearing assembly A.
Check the adjustment of the cradle during tightening to ensure free rota-
tion of the bearing. Install the split sleeve. Test drive the sleeved
assembly. The split sleeve contains a large cavity to fit a cutter head
module with its sawblade, or the weld head module with its torch. It
could also include hosed pressurization, or vacuum exhaust, for chip dis-
posal or accumulation. Install the cutter head and connect the orbital
system's power and control cables to the drive gear motor and the module
insert. (It is possible to easily adapt the balance of ORNL's automated
orbital weld-cut system for this application.)
51

 

 

 

 

 

 

 

o

 

 

 

 

 

 

 

 

 

 

 

 

—
l_.i
g 3 0
= PLAN VIEW S
g + ] o
o8 | —
& Of 31 a
‘Typical g
Sleeve OQutline o
- , O
) : t
" Lo
Component r-f-—
777777777777 bl

 
  
   

Heater

 

Let us assume we have cut through the pipe to remove the replace-
ment component and that the bearing supported maintenance sleeve asgsembly
is still attached. It is guite likely that a shift will occur in the pip-
ing upon severing each line. This shift would be most pronounced for the
free end of the permanent pipe as the component is usually anchored and its
short stubpipe locates to the anchor support. With the pipe shift, the
sleeve may now be placed in straini in fact, it is doubtful that the sleeve
would then be rotatable. Strain gauges attached axially to the sleeve's
exterior would be used to indicate the magnitude and the direction of pipe
shift. Heat could be applied to the permanent piping in selected locations
to permit stress-relieving. The building crane could be utilized for direct
up pull, or in combination with slings, pulleys, etc. for required pipe
movements in other planes. Eventually, sleeve rotation could then be re-
established and final precision pipe shift adjustments could then be made
likewise after inserting and observing dial gauges attached to sleeve
bosses on each side of the pipe cut-line for guidance. We could transfer
pipe stress concentrations away from the pipe cut location and thereby
realign the pipe ends formed by the cut to assure near concentric pipe
alignment for the stub end of the replacement component. The ensleeved
stress-relief approach which aligns pipe ends prior to component removal
should establish useable pipe aligmment for subsequent reassembly. Dangers
from banging into (and upsetting) fragile weld joint contours on the pipe
ends are minimized where the pipe fitup is established prior to removing
one of the pipe joint members and subsequent re-entry is with an identical
pipe. The maintenance sleeve is dissambled from the joint prior to component
removal. We would resort to more conventional pipe realigning means if a
sleeve and/or its bearings are permanently damaged as a result of excegsive
pipe moment force action upon severing the pipe.
52

5. End Preparations and Internal Pipe Cleaning

Sk. 5

Motor

 

 

 

 

 

 

In-Cell Pip

Permanent (fi
\" H

 

 

 

 

 

 

 

  

 

 

| |
< O O
PO

- &l @ ap
S~ oo o w d
© < O .+
D & QP T ¢,
™ o 4 o o
O — — = o
M <fl£—c ;M

The regular maintenance sleeve and the component, including its
pipe stub with end bearing 'B', have been removed.

Attach an alternate split sleeve to the remaining bearing 'A'-
gear-motordrive while it is still installed near the end of the per-
manent in-cell pipe. The alternate sleeve includes internal wide-
bearing inserts in location 'C'. This sleeve can be built to accom-
modate the ORNL machining head module for preparing a beveled pipe
end. As this sleeve is self-propelled, it may also include provisions
for attaching the equipment needed for all internal pipe cleaning.
53

6. Reassembly

Sk. 6 (Upper)

Reassembly problems differ for various components and depend upon
available axial room for entry of the component with its pipe stub(s).
A guided entry utilizing the 'B'-~bearing tapered sleeve-guide is pre-
ferred if space is available. The split 'B'-bearing-guide-sleeve com-
bination is preassembled on the replacement component's stub-pipe end
while the component is out of the cell. The split maintenance sleeve
would be reinstalled over the 'A'-bearing prior to installing the re-
placement component. The component would be first lowered to a final
elevation support platform and then scooted into place while guiding
the pipe stub into the funnel end of the sleeve. The sleeve would
guide the pipe stub into its proper location relative to the in-cell
pipe.

  
 
   

   

Replacement
Component

   

maximum stallation clearance

   
  
 

 

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

T
i3
—-— - —F - -— i
o0
S E
T 53

x

minimum installagion clearance |
——qfl-

Sk. 6 (Lower)

For the case of only vertical access for a replacement component,
pipe ends would have to be butted. The cradle assembly scheme described
with Sk. 2 would apply.

After assembly of the component by either scheme, the rewelding of

the pipe ends would be accomplished with the weld head module installed
into the sleeve cavity.
55

REFERENCE INFORMATION

| ot b 4 s S T T ¥ W e FETAR s o e

   
  
   

3
|

et e N R |

! <
‘-\_ROLLER 35:33313335)

¢ C e

PEDESTAL CAP

TOP HALF HOUSING

- —— HALF SEAL
———— HALF OUTER RACE

HALF CAGE WITH ROLLERS

 

CAGE JOINT “*U'"" CLIPS

 

o TWOHALF CLAMPING RINGS

o HALF INNER RACE

Ty / oo HALF INNER RACE
Wvu-nl. “VL—___“———V

‘--a...._"”-u.,_

[

———— TWO HALF CLAMPING RINGS

. T - _
na e T

NS J
A

rg e e ————- - == HALF CAGE WiTH ROLLERS

;f\\ CAGE JOINT ““U” CLIPS

 

HALF OUTER RACE
HALF SEAL

 

 

— BOTTOM HALF HOUSING

PEDESTAL BASE
56

REFERENCE INFORMATION

 

 
     

ASSEMBLY PROCEDURE oz

] Loosen holding holts and remove top holf of pedestal ond top half of
cartridge housing. Lift out rolier assembiy end inner race. Withdrow
spring steel ‘U’ clips on opposite sides of roller assembly. Seporate
halves of roller assembly and put to one side — lay on clean piece of
popar. Remove the four bolts holding the clamping collors around the
inner raca — moke sure to kesp the moating halves of clamping collars
togather. Saporate the holves of the innar race and wash thoroughly with
good claaning solvent and dry with lint-free wiping material or let stand
untit completely dry. In the same manner, cleon ond dry the clomping
collars, both halves of the roller assembly and the outer roce. It is not
nzcessary to remova the outer racs from the cartridge housing to clean it.
(If ever necessary to ramove the outer race, first make sure that ol side
nipping -scraws and holding back -screws where fitted cre removed.)

2 For normal staedy load service, the shaft must be of nominal size
within the limits of plus 0.000" 1o minus 0.002", and cylindricaliy true.
Clean and lightly oil the arso of tha shaft to receive the inner roce and
ploce the two haolves of the inner race in the proper uxial location. Tap
the halves of the inner race until secure and snug on the shabt, NEVER
HIT THE RACE WITH A HAMMER OR OTHER HARD METALLIC
TOOL.. USE WOOD OR PLASTIC MALLET. There should be o slight
gap ot both ands of the halves of the inner race. Put clamping collars in
place, making sure they fit snugly against the race shoulder. Clamping
collar jeint should overlap the roce joint by about %’ te ¥ on Ex.
ponsion Type Bearings. The amount of overlap is extremely important for
the fitted clamping collor of fixed type inner races. It will be noted there
is an grrow on this collar which must coincide with the morked race joint.
This ensures the alignmen? of the shoulders of ths inner race. Use lock-
ing washers under the heads of the clomping collor bolts, and start te
tighten tnem, but before final tightening of bolts, check axial location of
inner race to make sure it is in the corrsct position on the shaft so that
it will be central with tha rest of the unit when ossembled. fn coses
whers axiol expansion has to be handled, the inner race is offset so thot
after full expansion of the shaft has taken place, the races and relling
elemants will all be central with one another. Also check to make sure
that the two halves of the inner race ore NOT TOUCHING each other,
and that the slight gap is opproximately equal on both sides, The gap is
pu.posely built into the bearing, and should there be NO gap, the shafr
is undetzlze which will result In unsatisfactary performance. I the shaft
is within the required limits, the proper amount of gap is autematically
present when the clomping collars are finally tightened. Now finish
tightening of clamping collar bolts, using o pisce of pipe on the socket
wranch to moks sure they ore cbsolutely tight. 5se Torque Table on
page 12. All four bolts should be pulled up evenly whan tightening the
innar race on the shaft, In the expansion typs unit, check both clamping
tings %0 sse that they ars hord ageinst the race shoulder atl around. ln
the cose of the fixed unit, check the end clamping coliar to make sure
it is hard ogoinst the sheulder all around.

~

oJ Plaes bottem half of pedestal in position and lightly oil tha spher-
ical scot for the cortridga. Tha position of the bottom half of cartridge
will determine on which side of pillow block the grease fitting will ba far
lubrication. Toke care to locate bottom half of cartridge so that graase
fitting is easily occessible. If the bearing is to be lubricated by grease,
apply the required quantity inside of the lower half of the cartridge with
the half outer race in positian ond then place in the bottom half of the
pedestal. Jack up the shaft slightly if this has not olrsady been done.

T om ke U5 Par OF :

  
 

¥
?
. <
” 5

Split

BEARINGS

 

  

L ROLLER

 

Toke holf ¢ roller assembiy, grease well oll over if bearing is to be
lubricated by greass, and then plece on inner race ond slide around uneil
it is siting on the bottem half outer race, with the ends of the cage
flush with the housing jaint face,

4 Remove locking pins {2) from ecch aluminum triple labyrinth secl
ond place saal around shaft in correct position with ralation to cartridge
grooves and reinsert locking pins. The seals, when correctly assembled,
will grip the shaft firmly ond revelve with it but will permit axtal move -
ment of the shoft when necessary.

5 Remave jocking arrangement, allowing shaft to rest evenly in the
bearing.

6 Grease the ramaining half roller assembly oll over (with faiely heovy
coot) ond ploce over exposed port of inner race. Replace spring "'U™
clips by lightly topping into recesses in roller pockets, thus locking the
halves of the roller assembly togathar.

7 Greose with the required amount, the inside of top half of cartridge
with haolf outer race in position. Make sure the joints of ths cartridge
housing, both top and bottom halves, ore absolutely clean before apply -
ing grease. Place top holf of cortridge into position over assembled
bearing ond seals moking sure that joints match the bottom half. Use
locking washers on holts and tighten up evenly all four balrs in cortridgs.
Make sure end foces of cortridge are flush when complately tightened.

8 Apply a coating of oil on the spherical seat of the tap half of the
pedestal and place in position, but do not tighten up bolts.

9 ' possible, turn shaft slowly two or three times %o parmit the
cortridge to find its own alignment so that the loading of the rollers is
evenly distributad. If this is not possible, make sure thot cartridge facss
are absolutely square with the shaft,

]DTighten up top half of unit. Give bearing three or four shots with
grease gun to fill ths greose pussages so thot next time the basaring is
grsased you will be sure that grease is getting to the rolling parts, Use
discretion when greosing, according to speed and duty. Do not overfili
with grease, otherwise o ‘' Hot Becring'' moy resuit.

]] 0il Lubrication. Follow above instructions except substitute lubri-
cating oil for grease. Oil level in bottem half of cartridge should bs as
outlinaed undar OHL LUBRICATION on page 13.

 

Skould further details be required regarding fitting and lubrication of the beering, pleose contoct

COOPER SPLIT ROLLER BEARING CORPORATION
1725 Washington Road, Pittsburgh, Pesnsylvanio 15241

Woild-Wide Salas and Servics

A~ARGENTING = AUSTRALIA - BOLIVIA ~BRAZIL - 3BRITISH WEST INDIES - CANADA ~CENTRAL EUROPE --CEYLON - CHILE =EGYPT

GREAT SRITAIN = IMDIA — |HDOMESIA — MALAYA « MAURITIUS ~ MEXICO - NEW ZEALAND ~ PERU ~SCANDANAVIA ~UNITED STATES —VENEZUELA
!/

10.

11.

12.

13.

14.

15,

57
-~

REFERENCES

R. W. McClung, Remote InsPectlon of Welded Joints, ORNL-TM-3561
(September 1971).

J. 5. Culver, Viewing Equipment for Use in the HRT Core and Blanket

Vessels, ORNL-2886 (March 1960).

Internal Memo, P. P. Holz to I. Spiewak, '"Dry Maintenance Facility
for the HRT", October 11, 1960.

Internal Memo, J. P. Jarvis to 8. E. Beall, "Use of the Dry Mainte-
nance Facility for HRT Maintenance", May 17, 1962.

P. P. Holz, "Remote Maintenance Through Portable Shields", ANS Winter
Meeting, Pittsburgh, Pa., November 1966, (complete paper available
from author).

R. Blumberg and E. C. Hise, MSRE Design and Operations Report — Part
X — Maintenance Equipment and Procedures, ORNL-TM-910 (June 1968).

Theodore Rockwell III, Reactor Shielding Design Manual, Naval Reactors
Branch, Division of Reactor Development, USAEC, Chapter 6, TID-7004
(March 1956).

R. C. Robertson, MSRE Design and Operations Report, Part I, Descrip-
tion of Reactor Design, ORNL-TM-728 (January 1965).

Internal Memo, B. D. Draper and E. C. Hise to Distribution, "Remote
Maintenance Procedures Report', November 26, 1959.

Internal Memo, A. A. Abbatiello to Distribution, "Optical Tooling for
the MSRE", June 4, 1962,

Correspondence, P. P. Holz to Distribution, "Trip Report to BONUS,
(Boiling Nuclear Superheater Power Station), Rincon, Puerto Rico,
September 25, 1967 to October 13, 1967'.

J. P. Maloney, et al, Repair of a Nuclear Reactor Vessel, DP-1199,
Dupont Savannah & Rlver Laboratory (June 1969).

D. S. Ritchie, et al, "Remote Controlled Viewing for the Dragon
Reactor Main Pressure Vessel', Atomic Energy Establishment, Winfrith,
England, Dragon Froject Report 228, October 1963.

R. N. Duncan and D. L. Richardson, Final Report on BONUS Reactor
Boiler Fuel Element Inspection, October 5 to 12, 1967, Report APED-
5392 (Class I), Nuclear Energy Division, General Electric Company,
San Jose, California, November 1967.

Conceptual Degign of a Surveillance and In-Service Inspection System
for the Reactor Vessel Fast Flux Test Facility, Phase B Report,
Chapter 3, Southwest Research Institute, San Antonia, Texas, Dec. 31,
1969, (report prepared for the Pacific Northwest Laboratory by the
Battelle Memorial TInstitute).
16.

17.

18.

19.

20.

21.

22.

23,

2.

25.

26.

27.

28.

29.

30.

Conceptual Design of a Surveillance and In-Service Inspection System
for the Primary Piping and Components, Fast Flux Test Facility,
Chapter 3, Phase C Report, Southwest Research Institute, San Antonia,
Texas, Januarv 16, 1970, (report prepared for the Pacific Northwest
Laboratory, Battelle Memorial Institute).

Internal Memo, P. P. Holz to Distribution, "Miniature TV Camera
Manipulator"”, (for HRT viewing), November 26, 1959,

R. L. Moore, Closed Circuit Televigion Viewing in Maintenance of
Radioactive Systems at ORNL, ORNI~TM-2032 (November 1, 1967), (paper
also presented to the ANS Winter Meeting, Pittsburgh, Pa., Nov. 1966).

 

M. W. Rosenthal, et al, The Development Status of Molten-Salt Breeder
Reactors, ORNL—4812 " Chapter 12 (August 1972).

Internal Memo, P. P. Holz to Distribution, "Some Miscellaneous Mainte-
nance Tools Used to Manipulate ILoose Objects in the HRT Core", Nov. 17,
1959.

Internal Memo, P. P. Holz to Distribution, "Additional Miscellaneous
Maintenance Tools Used in the HRT Core", September 26, 1960.

"ORNL Remote Maintenance Tool Catalogue No. 58", June 1960. (Compila-
tion of tools and procedures by the Mechanical Department, Engineer-
ing and Mechanical Division. )

P. P. Holz, Feasibility Study of Remote Cutting and Welding for
Nuclear Plant Maintenance, ORNL-TM-2712 (November 1969 ).

 

R. F. Gilmore, Open— and Closed=Loop Closure Remote Cutting and Weld-

ing Evaluation, Battelle Northwest Laboratory Report BNWL-1303 (UC-38),

May 1970.

P. P Holz, The ORNL Automated Orbital Pipe Welding Systems, ORNL 4830

, o q . e G

G. M. Goodwin and P. P. Holz, Automated Orbital Welding of Type 304
Stainless Steel Pipe with the Astro-Arc System, ORNL-TM Report

 

(draft issue distributed for comments July 1972.)

"Automated Welding", Film available from the ORNL Film Library, 1971.
Pennsylvania Advanced Reactor Project — Layout and Maintenance, WCAP
1104 and 1105, Vol. IV, Parts 1 and 2, Westinghouse Electric Corp.
and Pennsylvania Power and Light Company, March 1959, Chapters 3, 4,

and 5 (chapter 4.2 for Alignment Discussions).

Molten-Salt Reactor Program Semiannual Progress Report for Period
Ending Feb. 28, 1969, ORNL-4396, Chapter 5—MSBR Design (Aug. 1969).

J. R. Tallackson, private communication to R. W. MeClung, Jan. 29, 1971.