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ORNL-TM-2999.txt
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OAK RIDGE NATIONAL LABORATORY
V operated by
UNION CARBIDE CORPORATION
N NUCLEAR DIVISION
-~ for the
U.S. ATOMIC ENERGY COMMISSION
ORNL- TM- 2999
COPY NO. -
DATE - April, 1970
QUALITY-ASSURANCE PRACTICES IN CONSTRUCTION AND MAINTENANCE
OF THE MOLTEN-SALT REACTOR EXFERIMENT
B. H. Webster
Abstract
At
T The MSRE was built at Oak Ridge National ILaboratory to demonstrate
the practicality of the molten-salt reactor concept. Site construction
and installation of auxiliary systems were by outside contractors, while
the primary reactor systems were installed by ORNL forces. Design, pro-
curement, construction, and maintenance followed ASME codes, ORNL
practices, and special procedures developed for the MSRE by the ORNL
Reactor Division group primarily responsible for quality assurance, This
report describes the program, the problems that were encountered, and the
lessons that were learned. Four years of reliable operation of the MSRE -~
proved the success of the quality-assurance program.
Keywords: reactors, fused salts, MSRE, inspection, construction,
maintenance, quality assurance, construction contractors, inspection
procedures, material control, cleanliness control, welder qualifications,
inspection of welds, leak testing.
&\f;
o NOTICE This document contains information of a preliminary nature
and was prepared primarily for internal use ot the Ook Ridge National
Laboratory. It is subject to revision or correction and therefore does
not represent a finel report.
DISTRIBUTION GFLIHIS DOCUMENT IS UNLIMITED
-~
e
- —— LEGAL NOTICE
This report was preparad as an account of Government sponsored work. Nejther the United States,
nor the Commission, nor any person acting on behalf of the Commission:
A. Makes any warranty or representation, expressad or implied, with respect to the accuracy,
completeness, or usefulness of the information contained in this report, or that the use of
any information, apparatus, method, or process disclosed in this report moy not infringe
privately owned rights; or
B. Assumes any licbilities with respect to the use of, or for damages resulting from the use of
any information, apparatus, method, or process disclosed in this report.
As used in the obove, ‘‘person acting on behalf of the Commission®’ includes any employee or
controctor of the Commission, or employee of such contractor, to the extent that such employee
or contractor of the Commission, or employee of such contractor prepares, disseminates, or
provides access to, any information pursuant to his employment or contract with the Commission,
of his employment with such contractor.
.
iid
CONTENTS
Page
Abstract
INTRODUCTION . . v v v v v v v v e e v e e e e e e e e 1
SITE CONSTRUCTION. ., ., . . v . v v v v v e e e e e . 1
Choosing the Location . . . . . . . . 1
Site Preparation. . . . . . e e . . 2
Major Building Modlflcatlons 2
Outside Modifications , . ., . . . C e e e L
Summary of Site Modification and Constructlon e e e 5
INSTALLATION OF EQUIRMENT AND SYSTEMS. . . . + v o & . . ., 2
Material Control, . . . . . . . v « « . . 5
Welder Qualification . . . . . . . . T
Duties of X-10 Inspection Engineering at the Constructlon
Site Covering Cost-Flus-Fixed-Fee (CFFF) Contract Work . . . T
Reactor Division Quality Control Activities . . T
Summary of Quality Control Procedures Used in Connectlon
With CPFF Work . . . . . . 8
ASSEMBLY AND INSTALLATION OF MSRE FUEL AND COOLANT SYSTEM. . . . . 8
Materials Control . . o v v v v v v o v v 4 4 0 e e e e 9
Welding . . . . . et e e e e e e e e e e e e e 9
Inspection for Cleanllness. e e e e e e e e e e e e e e e e e 10
Leaktesting of Components, Subassemblies, and Systems . . . . . 11
Assembly and Installation of Components and Piping. . . . . . . 12
Installation and Checkout of Electrical Wiring, Heaters,
and Bquipment. « ¢ « ¢ o v o v 0 0 e v 6 v e e 0w e e e e 13
Remote Maintenance Practice During the Construction Period. « . 14
Preoperational Testing of Auxiliary Equipment and Systems.. . . 1k
MATINTENANCE. + « v v o v v v v v v v v e s e v e e e e e v e e e s 15
Routine and Programmed (Preventive) Maintenance . . . . . . . . 15
Shutdown Maintenance. + + « v o « « « « « v o v s s e v v . .. 16
SU.WARY OF QUALITY COMOL BACTICES . . . . . . . . - . . - . s % 18
OVERALL CONCLUSIONS AND RECOMMENDATIONS. . « « v v v & « v o« « o+ & 18
APEENDICES
Appendix A -- Weld Inspection Report. . . . ¢« « « o o o o + & 21
Appendix B -- Welding Procedure Specification . . . .« . + . . . 25
Appendix C -- Non-Ferrous Materal Specifications. . . . . . . . 37
Appendix D -- Cleaning and Storing of Pipe and Fittings
to be Used in MSRE Constructicon. . « + « « + « . L1
LEGAL NOTICE
This report was prepared as an account of work
sponsored by the United States Government. 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 e ‘fl,”’},?'R'ED
legal liability or responsibility for the accuracy, com- ey e TR TG :
pleteness or usefulness of any information, apparatus, ke : O LI;
product or process disclosed, or represents that its use
would not infringe privately owned rights,
iv
CONTENTS
(continued)
APIENDICES (continued)
Appendix E -- Control of Material After Delivery to
Building 7503 . . . .
Appendix F -- ORNL Operator’'s Quallflcatlon Test
Specification QTS-33 for Inert-Gas-Shielded
Tungsten-Arc Welding of INOR-8 Alloy Fipe,
Flate and Fittings to Inconel Material, , . . .
Appendix G -- Welding, Brazing, and Weld Inspection of
INOR-8 Components ., ., . . .
Appendix H -- Materials Which Have Been Analyzed for Use on
INOR-8 and Stainless Steel for the Molten-Salt
Reactor Experiment, . . . . . . . .
-
*
Appendix I -- Helium ILeak Test Procedure, . . . . +v v o o o o .
Appendix J -- Fixtures and Components During Assembly , . e .
Appendix K -- Check List — Reactor Cell Salt System |, . . .
Appendix L -- Fuel Drain Tank No., 2 in Jig , . .
Appendix
Check Off List for Main Blower Startup
QUALITY-ASSURANCE PRACTICES IN CONSTRUCTION AND MAINTENANCE
OF THE MOLTEN-SALT REACTOR EXTERIMENT
B. H. Webster
INTRODUCTION
The Molten=-Salt Reactor Experiment has been proved by four years of
operation to be a well-built, reliable reactor. This report describes the
quality-assurance program followed in the construction and maintenance of
the system. The intent is to describe the details involved in putting
together a sound, workable, relatively trouble-free system.
The report is divided into sections covering site preparation, in-
stallation of auxiliary systems and equipment, construction of the salt
systems, and maintenance along with conclusions and recommendations.
STTE CONSTRUCTION
Choosing the Location
The site chosen for the MSKE was an existing facility in which one
reactor had operated and in which preparations had been made for instal-
lation of another reactor. The facility was built for the Aircraft Reac-
tor Experiment (ARE), which was operated in 195Lk. It was later modified
for the Aircraft Reactor Test (ART), and at the time the Aircraft Nuclear
Propulsion Program was terminated, a considerable amount of electrical
equipment had been installed, the reactor cell had been built, and most of
the auxiliary equipment had been purchased.
The basis for the decision to use this facility for the MSRE was
economic, Unfortunately several years had passed since the ARE and ART
programs had been terminated, and conseguently the records, drawings,
specifications, inspection reports, etc., on the building, equipment, and
services were scattered and some were lost. In order to make use of these
facilities for the MSRE, it was necessary for the project designers and
draftsmen to determine the condition of the equipment and the services, as
well as the various cells and buildings, in order to either design the
new system to fit in with the old or modify the o0ld in order to make it
fit in with the new system.
Needless to say, the assurance of guality in the adaptation of old
facilities to new systems is often a difficult task. Such was the case
for the MSRE.
Site Preparation
In May 1961, a small (~ $20,000) site preparation contract was awarded
to the H. K. Ferguson Company, who was at that time ORNL's prime CPFF con-
tractor. This contract included excavation for the fuel drain tank cell,
modification of the structure around the radiator cell, installation of a
new entrance into the east side of the reactor building, and removal of
unneeded piping conduit and equipment. The drawings and specifications
for this job were prepared by the ORNL Plant and Equipment Division (BE)
design group and approved by ORNL Reactor Division management. The P&E
Division supplied a construction inspector to ascertain that all specifi-
cations were met., The inspector kept a daily log, which is on record in
ORNL Laboratory Records Department. Since no high-quality welding,
pressure-vessel inspection, or other code work was involved, no other
records were keprt on this phase of construction.
Major Building Modifications
The prime contract for the major building modifications was awarded
to Kaminer Construction Company of Chamblee, Georgia. This phase of the
modification was started in September 1961. The design and specifications
were Pprepared by the P&E design group in cooperation with the Reactor Di-
vision (RD) design section and with special assistance on welding specifi-
cation and procedures from Metals and Ceramics Division (M&C) personnel.
Interpretation of Specifications
A short time after work had begun on the major building modifications,
a question arose concerning the intent of the specifications covering the
structural integrity of the reactor and fuel drain tank cells (classified
as secondary containment). The specifications had been written to cover
cases under the ASME Unfired Pressure Vessel Code, Section 8. At this
time certain changes were being made in this section to cover Nuclear
Vessel Code cases. After considerable discussion and negotiation between
representatives from RD, M&C, and Kaminer Construction Company, the fol-
lowing amendments were made in the specifications: Interpretation of ASME
Boiler and Pressure Vessel Code, Section 8, Special Cases 1177, 1270N,
1272N, and 12TLN.
Assuring the Use of Specified Materials
Stating the type materisl to be used in any given situation is ob-
viously only a beginning. In order to assure that materials meet the
specifications, testing and inspection must begin at the vendor's or in
some cases at the steel mills and fabrication plants. Once an acceptable
melt was established, heat numbers were assigned to all materials made
from this particular melt. This identification, showing the heat number
and inspection request number, was stamped on the material so that it was
identifiable even after installation. Records were kept on all materials
to cover identification, location in system, cleanliness, and weld-
inspection report that included welder's name, filler metal used, etc. (see
UCN Form 1149 in App. A). All records on materials, etc., noted above are
stored in the ORNL Laboratory Records Department.
Establishing Welding Procedures and Training and Qualification of Welders
Having established the procedure by which welding should be done, the
next task was toc "qualify" the procedure. This was done by the FE and
M&C weld-qualification groups (if a procedure to cover the specification
was not available). Welders were then trained and qualified to use the
procedure (see WPS-1402 and UCN-3312 for typical Weld Qualification Pro-
cedure, App. B)
Inspection of Welds, Material, and Equipment
Qualifying Inspectors. All inspection required to cover the work
performed by outside contractors (Kaminer Construction Company, Chicago
Bridge and Iron, etc.), as well as by manufacturers and vendors, was
performed by personnel from the ORNL Inspection Engineering (IE) group.
These people were usually chosen for a particular phase of work because
of their background in that field. 11 inspectors were required to go
through a training period in order to qualify for the tasks they were to
pverform. In general the curriculum for this training was taken fiom the
SNT (Society for Non-Destructive Testing) manual and was designed to cover
Section 8 of the ASME Code and the special cases noted previously. This
has since been revised to cover Section 3, Nuclear Vessel Code., With in-
creasing emphasis being placed on quality control, it is suggested that
CRNL should study the methods used for training inspectors, who should
be gualified and certified.
Inspection and Records of Work Performed by Kaminer Construction and
Subcontractors. Drawings and specifications were issued to the IE in-
spectors. FEach inspector worked closely with the FE construetion in-
spector and with supervisors and craftsmen of the contractor so that he
was constantly aware of all work planned or in progress on which his ser-
vices were required. The inspector had the responsibility to see that all
work within his jurisdiction was performed according to the specifications,
and he had authority through the constructicn inspector to reject any work
that did not meet these specifications. He also was responsible for main-
taining records on welds, stress relieving, heat treatment, leak-testing,
etc A1l such records are now in ORNL Laboratory Records Department,
Cutside Modificaticns
The contract for outside modifications and construction was awarded
to Hixon Construction Company of Knoxville, Tennessee. The outside work
consisted of construction of an offgas filter house and offgas stack,
installation of stack fans, and installation of the cooling tower, pumps,
and piping. The criteria for this phase of construction were established
by design groups from the Reactor and General Engineering Divisions. The
design was done by P&E. Inspection was performed by the GE construction
inspector, by representatives from Inspection Engineering, and by Reactor
Division ccordinators. A daily progress report and a log were kept by the
construction inspector, All records are now in the ORNL Laboratory Records
Department,
&
summary of Site Modification and Construction
In general the site preparation work went smoothly One major problem
was a misinterpretation of the specifications. It appears that in the
future more thought should be given to specification writing, and a meeting
of the minds as to the interpretations of the specifications should be
reached insofar as possible before the work is started. In particular, the
inspection procedures for components purchased from outside vendors should
be clarified; since many of these components are only spot-checked, the
risk of inferior materials and workmanship is much greater. Also the over-
all quality control standards should be more detailed and -should be under-
stood and accepted by all groups involved.
As stated in the preceding descriptions, all inspection and quality
control work was done in accordance with the specifications and procedures
prepared by Reactor Division and P&E Division design groups. These draw-
ings, specifications, procedures, and records are located in the ORNL
Laboratory Records Department.
INSTALLATION OF EQUIEMENT AND SYSTEMS
The H. K. Ferguson Company was awarded a CPFF contract to install the
service and auxiliary systems and equipment., These included instrument
air compressors and piping; control room piping and equipment; leak de-
tectors; water, steam, and offgas piping and equipment; and all electrical
systems and equipment, including heater wiring up to the junction boxes
at the cell walls. The above work was started shortly after building
modifications were completed.
Material Control
A1l materials and equipment for the CPFF contract work were procured
by ORNL purchasing departments. All materials and equipment were more or
less standard items and were relatively easy to obtain, except for the
high-quality stainless steel piping used in some of the systems.
Procurement, Inspection, and ITdentification of Critical Materials
The critical material, whether fabricated into tanks, heat exchangers,
etc., by outside vendors or delivered to the laboratory as raw material,
was required to meet Metals and Ceramics Division Specifications (index
in App. C). The specifications were written through a joint effort of the
General Engineering, Metals and Ceramics, and Reactor Divisions. Inspec-
tion procedures were established by M&C, Reactor, and IE personnel, All
critical materials (Met Spec Material) were spot-checked at the vendor's
plant., Heat numbers of materials were etched or stamped at 12-in., inter-
vals on all materials, along with the inspection request number (IR No.).
The identification was maintained up to and through the installation period
and was noted on all weld inspecticn reports. Inspection, certifications,
and identification of all critical weld rod were accomplished by the same
procedure as that noted for pipe, fittings, etc.
Inspection of Critical Materials After Delivery to ORNL
Critical materials were delivered 1in care of the Inspection Engineering
Department. Upon receipt of this material, each item was inspected by one
or more of the following methods: dye-penetrant testing, ultrasonic exami-
nation, and radioagraph examination.
Material Cleaning Procedures
After certificaticn, all pipe, tubing, and fittings were delivered to
the 7000-area cleaning station, and cleaning was accomplished by the pro-
cedure of Appvendix D (Cleaning and Storing of Pipe and Fittings to be Used
in MSRE Construction). Records of cleaning results were maintained on
the form included in this appendix, The records are now on file in the
MSEE Maintenance Engineer's office.
Control of Material at 7503 Stores
With all the inspection, certification, and identifying of materials
that had gone before, there remained one very critical control point: how
to handle the receiving and issuing records at the construction site stores.
These problems were handled by the procedure in Appendix E (Control of Ma-
terials After Delivery to Building 7503).
Welder Qualification
All weld procedures to be used by H. K. Ferguson were already quali-
fied and are a matter of record. It remained only to qualify the welders
for the several procedures. This qualification was performed at the Y-12
test shop under the surveillance and instruction cof Y-12 Inspection Engi-
neering personnel.
Duties of X~10 Inspection Engineering at the Construction Site
Covering Cost-Plus-Fixed-Fee (CPFF) Contract Work
One or more inspectors from Inspection Engineering was assigned to
the construction site to handle inspection that came under their Jjuris-
diction. These duties included;:
1, inspection of all code welding (dye-penetrant, radio-graph, ete.),
2 witnessing all pressure and leak-testing of all code pipe and vessels,,
3. inspection of all materials before and during installation, and
L
record keeping on all the above activities.
Reactor Division Quality Control Activities
In addition to coordinating the efforts of the CPFF contractor with
design, Pprocurement, inspection, etc., the Reactor Division quality con-
trol group assumed the responsibility for and carried out the following:
1. Wrote cleaning and test procedures for systems not covered by
the Code, such as compressed air systems, water systems, etc. Formulated
check-off lists for equipment and systems to cover preoperational testing.
2. Worked with CPFF crafts and supervisors in carrying out the
cleaning, testing, and checkout of piping, wiring, and equipment.
3. Formulated, with help of P&E engineers, leak-test procedures
for testing vapor-suppression system. Worked with CPFF contractor per-
forming and documenting test.
L, Routinely checked piping and components during and after instal-
lation for cleanliness; notified craft supervision when additional cleaning
was required. Made daily checks on installed piping to assure ends were
closed; notified supervision of violations.
The problem of keeping the installed piping and components clean
and preventing foreign material getting into open-end piping and equipment
proved to be a major one. This area of quality control should be stressed
in future (and present) quality control procedures:!
Summary of Quality Control Procedures Used in
Connection with CPEFF Work
All critical piping, heat exchangers, tanks, etc., were fabricated
from materials certified to meet ASME codes and specifications formulated
from these codes. Critical piping and components were inspected and
tested according to ASME Codes provisions or approved procedures derived
from them. All work (critical and other) was inspected by Inspection
Engineering personnel and Reactor Division quality control personnel.
Check=-off lists were used to assure that wiring, piping, and equipment
were installed in accordance with drawings and procedures. All systems
were tested by acceptable procedures, and the test results were documented.
Records of weld inspection, material certification, leak and pressure tests,
preoperational tests, cleanliness, etc., are on file either in the ORNL
Laboratory Records Department or in the MSRE Maintenance Engineer's office.
ASSEMBLY AND INSTALLATION OF MSRE FUEL AND COOLANT SYSTEMS
All designs and specifications for the primary systems were either
formulated by the Reactor Division design group or were prepared under
their direct surveillance, Many of the designs, specifications, and pro-
cedures were derived from information furnished by the Reactor Division
development group.
Most of the major components were fabricated and tested in Y-12 shoPs.
All work on the primary and auxiliary systems inside the reactor cell,
coolant cell, and fuel drain cells was performed by ORNL craftsmen from
the P&E and I&C Divisions.
Materials Control
Procedures the same as those described in the foregoing section were
used to control the receipt, identification, storage, and issue of materials
used in the primary and auxiliary systems inside the coolant, reactor, and
fuel drain cells, This system apparently worked well, since there was no
known instance in which the wrong material was used in either the primary
or auxiliary systems.
Welding
The material used in the primary systems was INOR-8 (now known as
Hastelloy-N or Incoloy 806). Because there had not been much experience
with this material, it was necessary that welding procedures be specified
and tested. Welding Procedure Specification WES-1402 (App. B) was tested
and approved for welding INOR-8 materials. (See also form UCN-3312 in
App. B, which was used for recording the development information.) In
addition, several other '"mew'" procedures were necessary, such as those for
welding INOR-8 to Inconel, INOR-8 to stainless steel, etc. These pro-
cedures were developed by the EE weld inspection group and by M&C person-
nel and were carried out under their striect surveillance.
Welder Qualification
Welders were qualified to meet the above specifications per ORNL
Operators Qualification Test Specification QTS-33 for inert-gas-shielded
tungsten-arc welding of INOR-8 alloy pipe, plate, and fittings to Inconel
material. (See QIS-33, App. F, which is typical of all procedures.)
Weld Inspection
P&E inspectors were used exclusively on welding performed by ORNL
craftsmen. All inspectors were required to be qualified; that is, they
were required to actually perform the type of welding they were to in-
spect. This had distinct advantages, because when an inspector who is not
a qualified welder looks at a completed weld, he can usually only say
"The weld is good" or "The weld is bad," Rarely will he be qualified to
instruet the welder in what he should do to make corrections if the weld
10
does not meet the specifications. On the other hand, an inspector who is
a qualified welder can usually spot the improper technique while the welding
is in progress. Corrections can then be made with a minimum of delay. It
seems clear that much time and effort could be (and was) saved by these
highly competent inspectors.
Inspection techniques were formulated with the several ASME and ASTM
codes as guide lines. ORNL Inspection Emgineerihg and Metals and Ceramics
personnel then categorized these several procedures into six classes (A
through F) with respect to the quality requirements of the welds. For
example, Schedule B inspections required inspection of fit-up, inspection
of the root pass before final closure, dye-pPenetrant inspection on each
pass, and a radiograph of the completed weld; whereas Schedule F required
only visual inspection. The designer specified on each drawing the in-
spection schedule, and a copy of each drawing was issued to the welding
inspectors (see table of inspection schedules in App. G).
Stress Relijeving of Welds
All TNOR-8 welds and adjacent piping were stress relieved by a pro-
cedure based on ASME Boiler and Pressure Vessel Code, Section III N-532.
The welding inspector was responsible for inspecting the preparation for
the stress-relieving operation and recording the information. The records
of all stress-relieving cperations are on file in the MSRE Maintenance
Engineer's office.
Inspection for Cleanliness
In addition to the cleanliness control described in Appendix D,
INOR-8 required cther more stringent controls. INOR-8 (Hastelloy-N)
is a high-nickel alloy which will alloy at the MSRE operating temperature
of approximately 1200°F with any metal or alloy having a low melting point;
fcr example, sluminum, zine, lead, etc, In addition, sulphur-bearing
compounds are incompatible with INCR-8 at elevated temperatures., Many of
the lubricants normally used in machining metals were known to have high
sulphur content. Therefore because of the contamination potential associ-
ated with machining, fabricating, and assembling the piping and components,
11
rigid safegfiards were established, Several different types and brands of
lubricants, marking materials, permanent and temporary insulation, etc.,
were analyzed for the metals and compounds listed above. (See App. H for
results of these analyses.) The reactor site storekeeper was instructed
to refrain from storing materials that were noct compatible with INOR-8 or
stainless steel. Lists of materials compatible with INOR-8 and with stain-
less steel were prepared from the analyses and issued to the craft super-
visors. A constant vigil was maintained by the weld inspectors and by
Reactor Division quality control personnel. All INOR-8 vessels and piping
were carefully surveyed for evidence of contamination. All surfaces were
carefully cleaned immediately prior to installation of heaters and insu-
lation, regardless of lack of evidence of contamination, This strict and
seemingly expensive operation apparently was worthwhile, since there is
no evidence of damage to the materials in the system after years at ele-
vated temperatures.
Leaktesting of Components, Subassemblies, and Svstems
Components such as the reactor vessel, heat exchangers, pumps, and
fuel drain tanks were leaktested at the Y-12 fabrication site. Much of
the piping for the primary and auxiliary systems was prefabricated and in
many cases leaktested before installation. Leaktest specifications (i.e.,
type of test to be performed) were noted on the drawings. Detailed pro-
cedures and record forms were written by the Reactor Division quality con-
traol group located at the MSRE construction site. Flow diagrams were
"color-coded" to indicate the leaktest status and type of test performed.
These flowsheets are a part of the permanent record, along with the test
results noted on the leaktest forms. All leaktests were witnessed by
Reactor Division quality control personnel.
All primary-system piping was leaktested by using the mass-spectrometer
method (helium leaktest). Wherever possible the piping was evacuated, en-
cased in plastic, and flooded with helium. The leaktest was then performed
and recorded per procedure MSRE-SK-216 and form UCN-5113 (see App. I) with
a consolidated leak-detector machine. In some cases it was necessary to
pressurize the piping and move the leak-detector probe over the welds and
12
surface of the pipe, after which the assembly was enclosed in plastic and
the probe inserted into the bag at the highest point. If no leak was
indicated, after walting for some predetermined length of time, an amount
of helium equal to the allowable leak was injected into the bag at the
lowest point to check the sensitivity of the leak-detector machine., The
results of these tests are recorded and are a part of the permanent record.
Hydrostatic and other pressure and leak tests were performed as in-
dicated on the design drawings. The form (App. I) was used to record the
results of all such tests.
Valid leak tests were performed on all piping systems. Leak testing
was performed by craftsmen and witnessed by Reactor Division quality con-
trol personnel. Helium leaktesting was guite time-consuming because of
the shortage of trained craftsmen. It would appear to be desirable to
consider instituting a training program in this field as soon as practical.
Agsembly and Installation of Components and Piping
One of the major objectives of the MSRE was to prove that it could
be maintained. To make this possible it was necessary to assemble the
equipment so that exact duplicates could be fabricated if the need arose,
Reactor Cell Component Assembly
A fixture was designed to support the components in the same position
relative to each other as they would be after they were installed in the
reactor cell., The elevations and center lines of the components and the
slopes and angles of the piping and flanges were established by a group
of civil engineers with precision optical tooling. Some of the people
involved in formulating the assembly procedures attended a school con-
ducted by the Brunson Cptical Instrument Co. for training in the use of
Precision optical instruments.
When installed in the cell, the components fitted together with re-
markable accuracy. A photograph of ccmponents while on the fixture and
after installation in the cell is shown in Appendix J.
All dimensions were recorded on as-built drawings and are on file in
the MSRE Maintenance Engineer's office. One major side benefit from this
method of assembly was the easy access for welding and other associated work.
13
In addition, with the major components being assembled outside the
cell, the in-cell installation of auxiliary piping, electrical, and thermo-
couple leads, etec., was simplified. A check list indicating the care that
was taken to assure that all was in order before the assembly was installed
ig reproduced in Appendix K., This type of final check is an important
part of any quality-assurance progranm,
Fuel Drain Cell Components Assembly and Installation
The general procedures noted above were also used to assemble the
two fuel drain tanks, steam domes, and the fuel flush tank. The center
lines, elevations, etc., were established on the tanks, steam domes, etc.,
and the fixture was then made to fit the critical points noted on the in-
stallation drawings. The photograph in Appendix L shows the drain tank
assembly located on the fixture.
All dimensions were recorded on as-built drawings. The assembly was
lowered into the cell and a cutting platform was fitted to the salt inlet
and outlet lines (no flanges in these lines). The location of the cutting
platform relative to the tank was noted on the as-built drawings. In case
it should become necessary, the steam dome or the drain tank, or the two
items together, may be removed and an exact duplicate fabricated and in-
stalled by remote and semiremote methods.
Installation and Checkout of Flectrical Wiring,
Heaters, and Equipment
As in the case of the auxiliary piping, the installation of the elec-
trical systems was a Jjoint effort between the CPFF contractor and the IE
crafts. Installation of motors, switchgear, wiring, and thermocouple leads
outside the fuel cells and up to the final junction at the cell walls was
performed by the contractor. The heaters, electrical leads, and thermo-
couple leads inside the cells were installed by P&E craftsmen. The equip-
ment outside the cell was checked out, and the motors were '"bumped™ for
proper rotation by the contractor. Heater leads and thermocouple leads
were "run out," tested for grounding, and identified at the cell walls by
the contractor. The heaters, heater leads, and thermocouple leads inside
14
the cells were installed and checked out by P&E craftsmen, after which
tie-ins were made at the cell walls and the total system was checked out
from the control panels.
Records were kept on the above tests and are now located in the equip-
ment files in the MSRE Maintenance Engineer's office., This part of the
work was well coordinated and very little trouble or confusion was en-
countered.
Remote Maintenance Practice During the Construction Period
The remote maintenance development group was in constant communication
with the system design and construction groups. During the design and con-
struction period, procedures were written, and tools and equipment were
designed, fabricated, and tested. In order to check out some of the tools
and procedures, maintenance equipment was set up, and several pieces of
equipment were removed and reinstalled. These practice runs were helpful
in establishing the procedures and technigues to be used later in per-
forming the remote maintenance. The fuel pump rotary element and motor,
the primary heat exchanger, one of the cell space coolers, and several
heater assemblies were removed and replaced remotely.
Preoperational Testing of Auxiliary
Egquipment and Systems
Cleaning and test procedures were written for each system or sub-
system before and during the construction period by the Reactor Division
quality control group.
Water System
As sections of the cooling-water systems were completed, the piping,
valves, pumps, flowmeters, etc., were flushed out, leaktested, and given
a preliminary check for pump ocutput, etc. by CPFF craftsmen and witnessed
by Reactor Division quality control personnel. When the entire water sys-
tem was completed, the total system was given a preliminary checkout.
After preliminary testing, the system was turned over to the MSRE opera-
tions group.
15
Instrument Air System
After completion of the instrument system, each line was taken loose
from the instrument and the entire piping system was blown down. The
filters were changed and the piping was reconnected. A leak test was then
performed on the total system. Flowmeters, pressure switches, etc., were
tested for performance and accuracy. The preoperational testing was per-
formed by CIPFF craftsmen and witnessed by the Reactor Division quality
control people who wrote the test procedures. Test results were docu-
mented and records are on file in the MSRE Maintenance Engineert's office.
Preoperational testing of other auxiliary systems was performed in
essentially the same manner,
MATNTENANCE
Maintenance 1is a vital part of any facility and was especially so in
the Molten-5alt Reactor Experiment. As mentioned earlier in this report,
one of the major objectives of the MSRE was to demonstrate its maintain-
ability so that reactor downtime could be kept to g minimum. Because of
this, planning, scheduling, procurement, and necessary design changes
Played a vital role in the overall operation.
Routine and Programmed (Preventive) Maintenance
Just prior to the completion of the MSRE, ORNL had set up a mainte-
nance system called "Programmed Maintenance.' This required that mainte-
nance to be performed on a piece of equipment be specified and fed into
the K-25 TEM computer. At a predetermined frequency, IBM cards were de-
livered to the foreman who was to perform the work. After considering the
alternate maintenance programs, it seemed advisable to make use of this
program.
Accordingly a master list of all equipment in the MSRE system was
compiled, and in cooperation with the operations group, an estimate was
made on the percentage of time the equipment would be in use. Then, with
the manufacturer's maintenance manual as a guide, a maintenance program
16
for each piece of equipment was listed and fed into the IEM computer.
This listing included a description of the eqguipment, frequency of service,
maintenance to be performed, type of lubricant, etec.
The maintenance cards were delivered (approximately one week in ad-
vance of the scheduled maintenance date) to the MSRE Maintenance Engineer,
who initiated a work request. The work request, with the TEM card at-
tached, was directed to the E&E Craft Supervisor. A copy of the work re-
quest and the maintenance card were issued to the operations Shift Super-
visor. The Shift Supervisor shut down and tagged out the equipment at
the request of the FE supervisor. The maintenance was performed by the
craftsmen, and in most cases, depending on the nature of the job, was
witnessed by a representative of the Reactor Division quality control
group or by the craft foreman. (Examples of this were the witnessing of
the preventive maintenance performed on the component cooling blowers;
the lubrication and tensioning of the drive belt; and the leaktesting of
the dome flange. All this work was performed according to predetermined
procedures.) Adjustments were made from time to time of frequency, type
of lubricant, etc.
According to the feedback received from those who used the mainte-
nance cards, the program appears to be relatively economical. Many pro-
blems were noted in time to prevent major breakdown and repairs; however,
it appears more refinement of the program is needed, especially with re-
spect to freguency.
Shutdown Maintenance
For the most part, MSRE shutdowns were preplanned and scheduled. The
following describes the planning and scheduling methods used. 1In general,
the same methods were followed for nonscheduled shutdowns.
Planning
Trmediately after a reactor startup, planning was started for the
next shutdown. In most cases, a target date was set for completion of a
run based on the need for inspection of the core specimens. As operating
experience dictated, proposed changes and modifications were added to the
list. Equipment repairs were added as the occasion warranted.
L7
Procurement and design were started as soon as practical after the
need arose. Procedures or Jjob descriptions were written well in advance
of the shutdown to allow time for everyone involved to become familiar
with the tasks to be performed.
Information and planning mettings were held with the craftsmen and
supervisors., For some remote maintenance tasks, mockups were built, and
training and practice sessions were held with craftsmen, supervisors, and
Reactor Division quality control representatives.
Scheduling
The list of work to be performed was detailed and firmed up as far
in advance of the shutdown as possible. The critical path method was used
for showing the sequence and estimated duration of each task, such as
design, procurement, writing of procedures, practice sessions, installa-
tion, and testing., The sequences of work were established as a joint
effort of the operations and maintenance group. Estimates of job duration
were made by the EFE supervisors.
As work progressed, more tasks were usually added to the list, and
because of this the schedule was updated periodically. This method of
scheduling proved to be very satisfactory, and the estimates became more
accurate as time progressed. On the last few shutdowns, estimates were
correct to within approximately 5%.
Witnessing the Critical Shutdown Work
Critical tasks, such as remote maintenance, repairs or modifications
to component cooling pumps, main blowers, radiator door lifting mechanism,
etc., were observed and coordinated by Reactor Division guality control
personnel, Procedures and job descriptions were modified as required so
that they reflected the actual work performed and therefore were more
nearly accurate for similar future tasks. A checkoff list was used to
assure that all was in order before equipment or systems were reacti-
vated after each maintenance period (see example in App. M).
18
SUMMARY OF QUALITY CONTROL PRACTICES
Quality control procedures were formulated for all critical work not
covered by existing codes and procedures, and record forms were designed,
if they did not exist, for documenting critical inspection and testing.
Inspectors were traired (to some degree) for following and documenting
the work. Coordination of quality control and craft effort was difficult
in the early stages but improved as the job progressed.
(VERALL CONCLUSIONS AND RECOMMENDATIONS
Basic quality control procedures should be standardized for the whole
laboratory as soon as practical, Specific procedures for a project should
be formulated and agreed upon as soon as possible after criteria and speci-
fications are written. The project quality control director should be
intimately involved in formulating specific procedures not covered by the
various codes. Assembly of the quality control procedures incorporating
existing codes and specific detailed procedures should be accomplished
through the joint efforts of the several quality control groups and the
designer and specification writers, All quality control procedures and
specifications should be ircorporated into one manual. Adequate forms
for documenting quality contrel should be designed prior to the beginning
of work.
The quality control rersonnel (inspectors) should be responsible to
the project gquality control director, and they should have authority to
direct craft superviscrs to stop work not being performed according to
the specifications. If the standards specified in quality control pro-
cedures are to be met, those who perform the work and those who witness
that performance must be adequately trained. To accomplish this, quality
control inspectors should be formally trained, tested, and certified, and
craftsmen and craft superviscrs should receive basic training in quality
control procedures and practices.
If this phase of the effort is viewed with the respect it is due,
there is every reason tc believe that the construction and tesfing of a
reactor system can be performed smoothly and efficiently and that the
startup of the reactor should be relatively trouble-free,
#\
19
APEENDICES
st
21
Appendix A
Weld Inspection Report
WELD
DISTRIBUTION:
INSPECTION REPORT
23
Report No.
DRAWING NUMBER
WORK ORDER NUMBER
DATE
COMPONENT TITLE
WELD NUMBER
WELDING SPECIFICATION
"WELDING PROCESS
TYPE JOINT
INSPECTION SPECIFICATION
INSPECTION SCHEDULE
BASE
MATERIALS
FILLER METAL
TYPE
|
IR