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R. E. LEUZE

  
 
 
 
 
 
 
  

CENTRAL BESLANRCH Lilfany
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OAK h?ifi?-é:' NATIONAL l.noutmv
Lo nnmwfip BY-

CARBIDE AND: CARBON CHEMICALS DIVISIONR
UN'UN flflfl.lbt AND UAR-UN BQRPDRATIDN I
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L Report Fumber: ORNL-980
This decument comsists of 36

pages. .
Copy __z of 112 , Series A .

Contract Ho. W-ThO5, eug 26
CHEMICAL TECHNOLOZY DIVISION
LABORATORY SECTION

DRY FLUORIDE PROCESS STATUS REPORT

R. E. Isuze

Experimental work by:

H. B. Graham Ces P. Johnston
A. B. Green R. E. Leuze
CLASSIFICATION ancm To: D"_E“g!:_,,mm_-_ S
BY AUTHOLRFTY OF aovawnie _fi./j S D ——
fi-&&mm _..7 As 2
DATE ISSUED

Mak 27 1859

 

OAK RIDGE NATITONAL ILABORATORY
Operated by
CARBIDE AND CARBON CHEMICAILS COMPANY
A Divislon of Union Carbide and Carbon Corporaticn
Pogt Offlee Box P
Osk Ridge, Tennesses

    

 

        
 

 

MARTIN MARIETTA ENEAGY 5YSTEMS LB

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— -

1.0
2.0
3.0
5.0

590

6.0

T0

8,0

9.0

Contents

Abstract

Introduction

Summary

Preparation of UFg from Uranium Metal

k,1 Fluorination E;luipment and Procedure
k.2 Fluorination Results

Adsorption of Fission Products and Plutonium
5.1 Adsorption on Copper

5.2 Adsorption on Alundum

Filtration of Uranium Hexafluoride

6.1 Filtration Equipment and Procsdure
6.2 Filltration Results and Discussion
Regublimation of Uranium Hexafluoride

T-1 Sublimation Equipment and Procedure
7.2 Resublimation Results and Discussion
Overall Results

Recormendationg

9.1 Preparation of Uranium Hexafluoride
9.2 Adsorption Techniques

9.3 Digtillation Studies

9.4 Phase Diagram

ORNL-~ 980

nge No.

O O 1 o W

10

13
1k
1k
15
16
16
17
17
19
19
19
19
20

 
- 4 ceIL- 980

Conterrfi_é .(@ontinuea) Page No.
9.5 Filtration : 20
9,6 Equipment Development 20
10.0 Bibliography 2l
Tables
1. Remowval of Plutopnium and Fission Products from Uranium 22

by Fluorination

2, Removal of Plutonium and Fission Products from Gaseous 2l
TF¢ by Adsorption on Copper

3. Removal of Plutonium and Fission Products from Gaseous 25
UFg by Adsorption on Alundum

4. Removal of Plutonium and Fission Products from Gaseous 26
Ufi'é by Filtration

5o Removal of Plutonium and Fission Products from UFg by 27
Batch Sublimation

6. Overall Results for Dry Procesgsing , 28

7. Purity of UFg after Dry Processing 30

Filgures

1. Schematie Diegram Por Dry Fluoride Experiments 32

2, Fluorinator .\ssembly 33

3, Copper Adsorpticm Trap 34

k, Alundum Adsorpticmn Bed 35

5, Filtration Assembly | 36
iy =5- | ORML- 960

il MR T Ml

Urenium hexafluoride was prepared by the direet combination of
irradisted wranium metal wilth elemental fluorine and subsequently de-
contaminated by adsorption, filtration, and sublimation on a laboratory

geale,
g -6~ ORNL- 980

2.0 Introduction

Early in project history, a dry fluorinmation method(l’é) vas considered
for separating wranium from fission products, plutonium, and other trans-
uranic elements. This method consisted of converting uranium to the hexa-
fluoride and effecting the separation by distillation; however, it was
necegsary to place the major effort on other processes which would require
less development time. It now seems desireble to make a thorough evaluation
of fluorination methods since they offer the following advantages over the
present wet processes: (1) smaller equipment with few or no moving parts
is required; (2) the waste volume is minimized since fluorine is the only
major chemical used; (3) fission products are obtained in a concentrated
form making them easily recoverable; (4) the uranium is recovered as UFg
which requires a small storage volume and which is the feed material for the
isotopic separation plants; (5) it may be possibdle to process short cooled
material, thus reducing the uranium Inventory requirements. There are two
outstanding limitations to this type process: (1) the high cost of fluori-
nating agents and (2) the danger involved in handling volatile radiocactive
materials.

Before a dry fluorination process for decontaminating wranium and plu-
tonium may be seriously considered; the actual separations obtainable mmst
be demonstrated. Fluorination, copper adsorption, Alumdum adsorption, f1l-
tration, and resublimation were Investligated as methods of seperating uranium
from plutonium and fission productz. These serve as preliminary studies

upon which a future progrem can be based. .
_ -1- ORNL- 980

3.0 Summary

The plutonium content of UFg prepared from uranium metal irradiated
335 days in the CORNL pile and cooled 30 months was reduced to<l Pu «
ct/m/mg U by passing the UFg through a bed of Alundum, and then either
filtering or resubliming the product. Fission product beta activity in
the same material was reduced to 1 - 50 cts/m/mg U by filtering and re-
subliming the UFg. |

Alundum adsorption was the most effective means of removing plutonium
from UF;, giving separation factors of 13-96 and rendering that plutonium
passing through the bed non-volatile so it could be removed by filtration
or regublimation. Plutonium separation factors for the other steps were:
fluorination; 1.1 - 2.4; copper adsorption, 1.1 - Th; filtratién not pre-
ceded by Alundum adsorption, 1.4 - 4; and resublimation not preceded by
Alundum adsorption, 1.3 - 290

Filtration of UFg through barrier backing at 70°C was the most effective
method of removing the fission products and gave a beta decontamination
factor of 103. Because of the larger amount of ruthenium passing through
the filter at 230°¢, fihe fission product beta decontamination factor was
only 300. Filtration, however, has two limitatioms: (1) it does not remove
volatile fission product fluorides, and (2) the barrier backing camnot be
satisfactorily dried after washing it free of plutonium and fission products.

Other beta decontamination factors were: resublimation, 12-330; fluorination,
L ~8- ORNL~ 980
mmary {continued)

 

2-133 Alundum adecrptiom, l.k; =and copper adsorption, 1.1.

Uranimm losses were 1 - 3% for Alundum adscrption, 1 - 24% for resubli-;
wation, end 0.3% for fluorination, copper adsorption, and £iltration. The
lossss rin Alundum and resublimation may be reduced by improved operating
techniques,

The progrem proposed for the immediste future Includes (1) a survey of
other methods of preparing UFg from uranium metal, (2) a study of adsorption
technigues for ramoving plubonium from UFg, avd (3) an investigation of
fracblonal distillation for remeoving the volatile fissiom product fluorides

from UFg.

k.0 Preparstion of UFg from Ursnium Metal

Uranium wetal may be converted Yo uranium hexstflucride by several dif-
ferent methods. The umetsl may be reacted with hydrogen to glve uranium
hydride which cam thea be reacted with szhydrous HF to glve UFLB )o This
UF), is then reacted with flucrine to produce UFg.

Uranium metel reacts with the interhelogens, C1F3 arnd BrF3, to give
vranium hexafluorlde. Uranium may alse be combined directly with elemental
fluorine to produce Ung(e) o Thege various methods have certaln advantages
and dlsadvantages which will not be discussed here. The direct combination
of fluorine with uranium was used to produce UFg in these laboratory experi-
ments because of its convenience and not because it was felt to be superior

to the other procedures.
SRy -9- ORNL- 980

4.1 Fluorination Equipment and Procedure
Fluorine was transferred from cylinders through a bed of sodium

fluoride to|remove HF and then through s monel, Hoke needle valve and a
glass rotameter into the fluorinstor (Figure 1). The fluorinator was a
cup made from a 2 inch piece of 1-1/2 inch nickel +tubing (Figure 2). The
cup was placed in a stand fabricated from a stainless steel flange and
stainless steel pipe. The fluorinator top was a disc of nickel sheet with
a fluorine inlet and a UFg outlet. This assembly was sealed between stain-
less steel flanges using an aluminum wire gasket. A conical electric heater
wag used to bring the reactor and uranium metal up to temperature.

The alwminum jacket was removed mechanically from a 40 - 250 gram
piece of slug irradiated in the ORNL pile. The oxide film was removed in
nitric acid and then the wranium was thoroughly dried and placed in the
fluorinator. After evacuating the equipment, the temperature was raised
to 300-350°C and 20 ml/min of fluorine was fed to the reactor. A sharp
rise in temperature gave evidence that the reaction had staxrted. The ex-
ternal heat was then removed, and the fluorine flowrate was increased to
about 250 ml/min. The temperature rose to about 400°C and gradually dropped
to 300°C. When fluorination wes nearly complete; a rise in temperature of
150-200°C in a few seconds indicated that only a small amount of unreacted
" metal remained. After the reaction subsided, external heat was applied to
raise the temperature to 500°C for 30 minutes before stopping the fluorine

flow. This procedure removed the last traces of metal and Tower fluorides.

e,
wnNNg -10- ORNL- 980

 

Fluorination Equipment and Procedure (continued)

 

The UFg produced was passed through adsorbers and/or filters to effect
decontamination and finally condensed in traps cooled in dry ice and tri-
chlorethylene (Figure 1). Gases passing through the cold trap were sent
to a soda lime trap and vented to the hood exhaust.

After filuorination was complete, the equipment was evacuated and swept
free of fluorine by means of nitrogen. The fluorinator was dissolved in

nitric acid, and an aliquot of this solttion was weed for analyses.

4.2 Fluorination Results

 

The results obtained for the fluorination of ursnium metal irradi-
ated 335 days and cooled 30 months are presented in Table 1. From & to 20%
of the plutonium remained in the reactor, while only 0.0006 - 0.08% of the
uranium remained behind. Gross B, Gross ¥, Ru B, TRER, CsB, and Srp decon-
tamination factors were all within the range of 2 - 13.

The higher uranium losses in experiments 1 and 14 were a result of in-
complete fluorination due to too short a heating period in a fluorine atmos-
phere after the reaction had subsided. The high values for the fission pro-
duct decontaminétion factors and plutonium.hold up in Experiments 1, 2, and
3 resulted from increased reactor size and the uneven temperatures in the
reactors. Since the only fission products present form non-volatile or only
slightly volatile fluorides, the main reason for the low and inconsistant

decontamination factors was solid entrainment in the gaseous UF5.

TRORE—
Gl -11- ORNL- 980

Fluorination Results (continued)

 

In experiments 7, 14, 16, and 17, the reaction was started by first
filling the equipment with nitrogen instead of evacuating it. As a result,
the plutonium remaining in the reactor was 30-40% instead of 4 - 20%. The
reason for this difference 1s not understood; however, a test (Exp. 18) was
made to determine plutonium hold up when the equipment was first evacuated
and the uranium then fluorimated with a mixture of 55% nitrogen and 45%
fluorine. The plutonium remaining in the reactor in this case was only 10%.
Ag yet no method is known for keeping all the plutonium in the reactor nor
for removing it all by volatilization when fluorine gas is the fluorinating
agent.

The direct fluorination was carried out at a rate of about 20 grams of
uranium converted per hour. This rate was controlled quite easily by regu-
lating the fluorine flowrate. There was little or no reaction noted between
uranium metal and fluorine at temperatures helow 300°C, and additional heat
was needed at the end of the reaction to fluorinate the last traces of

uranium metal and intermediate fluorides to UF6°

5.0 Adsorption of Fission Products and Plutonium

 

Since PuFg has almost the same vapor pressure as UFéh), its separation
from uranium by fractiomal distillation would be difficult and some other

method; such as adsorption; for effecting the separation would prove to be

e ————
w—— -12- ORNL- 980

 

Adgorption of Fission Products and Plutonium (continued)

of sconsidersble value. Previous work showed that plutonium hexafluoride is
less stable than UFg since the plutonium plated out on copper connecting
lines in the experimental apparatus(5). Adsorption on copper and Alundum
were tested and copper was found to be partially effective and Alundum com-
pletely satisfactory for removing plutonium from UFg. Neither the copper nor
the Alundum removed enough of the Gross B activity from the UF6 to be of
value for a deconmbamination procedure.

Graphite and activated c¢alcium sulfate were found to react with UFg at
100°C and so were mot tested further. Sodium fluoride and UFg form an inter-
molecular compound which decomposes to give fluorine when heated. Since UFg
camniot be remcved frem this compound by sublimation, sodium fluoride was not

soneidered as an adsorbing medium to remove the plubtonium.

5.1 Adsorption on Copper

 

Three types of copper traps were used to adsorb plutonium: (1)
a coil of 1/4 inch tubing 3 feet long, (2) a "U" tube 9 inches high made
from 1-1/8 inch dismeter tubing and packed with copper turnings, (3) cylin-
ders 2 inches in diameter and from 3 to 15 inches long (Figure 3). The
gtream of gaseous uranium hexafluoride from the reactor was passed through
these vessels which were heated to 70-80°C in & water bath. After the ex-
periments were completed,; the traps were washed with diluté nitric acid to
removed the plutonium, uranium, and fission products.

o
S -13- ORMNL- 980
Adsorption on Copper (comtinued)

The three feet of copper tubing removed 27% of the plutonium while the
trap packed with copper turnings removed 70% of the plutonium,

In the experiments using the 2 iuch diameter copper traps, the amount
of plutonium held up was proportiomal to the length of the traps (Teble 2)..
This increase of adsorption may be due to the increase of surface area,
increase of comntact time, or both. The plutonium hold up for the 3-1/h inch
trap was 21%, for the 7-1/2 inch trsp was 57%, for the 9 inch trap was 98.7%,
and for the 15 inch trap was 92.2%. The high value for the 9 inch trap is
not explained. The results indicate that thé last trace of plutonium may be
difficult to remove by mears of adsorption on copper.

The fission product decontamination factor over these traps was negli-
‘gible (gbout 1.1). The uranium hold up waa small (£0.3%) except when the
copper adsorption was preceded by condensation and resublimation as in
Experiment 12. This high loss of 8% may either be due to reduction of UFg
during the first condensation or to an inadequate sweep out of the equipment

after resublimation.

5.2 Adsorption on Alundum
Chips from Alundum crucibles were placed in a nickel tube 1 inch
in diameter and 9 inches long (Figure 4). The bed was heated to 100°C in
a tube furnace, and the gaseous UFg stream from the fluorinator was passed
through the Alundum. For analytical purposes the plutonium, wanium, and

fission products were removed from the Alundum by elution with 30% nitric acid.

e ————
— -1l - ORNL- 980

 

Adsorption on Alundum (continued)

The Alundum bed removed 92-99% of the plutonium (Table 3). The plu-
tonium passing through was thought to be non-volatile since it could be
easily removed by filtration (Experiment 22, Table 4) or by resublimation
of the UFg (Experiments 20 to 21, Table 5). The uranium loss on the
Alundum was 1-3%, and the fission product decontamination factors were only

about 1.k4.

6.0 Filtration of Uranium Hexafluoride

 

Durlng early experiments a considerable quantity of fission products
was carried over from the fluorinator to the cold trap. This suggested
that solid particles wers entrained in the gas since all the fission pro-
ducts present formed non-volatile or only slightly volatile fluorides.
Barrier backing tubes were used as & laboratory tool in determining whefher

or not the activity and plutonium carry-over was due to entrainment.

6.1 Filtration Equipment and Procedure

 

A nickel, barrier backing filter tube 1/2 inch in diameter and 5
inches long was fitted with nickel ferrules. One end of the tube was closed
and the other end was flanged. This assembly was sealed into a nickel tube
(1"D x 8") by the use of heavy flanges and a double gasket arrangement
(Figure 5). A thermocouple well extended through the end plate flange %o
the center of the barrier backing tube. The inlet and outlet for the f£il-
ter consisted of 1/4 inch brass tube fittings silver soldered into the ends

of the case.
T
] -15- - CRNL- 980
Filtration Equipment and Procedure (continued)

Uranium hexafluoride was passed through the barrier backing at 70 - 225°¢,
After filtration was complete, the barrier backing and ferrules were dissolved
in concentrated nitric acid, and the case was washed with dillute nitric acid.

Theses solubions were analyzed for gross B, plutonium, and uranium.

6.2 Filtration Results and Discussion
When the ursnium hexafiuoride came directly from the fluorinator,

the plutonium hold up on the filter was 30 - 75% and was not a function of
temperature in the range of T0°C to 230°C (Teble 4). Omly 0.01 - 0.15% of
the uranium remained on the filter. The high value of 3.7% in Experiment
14 may have been caused by incomplete nitrogen sweeps of the equipment after
the reaction was completed. The gross P decontamination factor was 103 when
the filter was operated at 70°C and 300 When the temperature vas 220 - 240°¢.
The only individual fission product decontamination factor tha;h wag sub-
gtantially affected by temperature was that for ruthenium. At 70°C, the Rug
decontamination factor was 200-500, and at 225°C it was only 15. In general,
the decontamination factors for Csp, Sr3, and TRER were slightly greater
than 103,

When filtration was preceded by resublimation, the filtration showed
little improvement in decontamination since the activity was too low for

accurate analysis (Exp. 19).
SlaRE -16- ORNL-980
Filtration Results and Discussion (continued)

When the filter was used after an Alundum adsorber (Experiment 22), <1
Pu o ct/m/mg U passed through the filter and<T.0l%f the uranium stayed on
the filter. The fission product decontamination factors were of the same
order as for filtration of uranium hexafluoride coming directly from the
fluorinator.

Since no way is known to removed plutonium, uranium, and fission pro-
ducts from the bar:ier backing except by washing,; it is recommended that fil-
tration of this type be used only as a laboratory tool and not be considered
for large scale operation. After washing barrier backing, it is very dif-

ficult to dry it thoroughly enough to pass UFg and F, through it again.

T.-0 Resublimation of Uranium Hexafluoride
Simple batch sublimations were made to determine their effectiveness in

further decontaminating UFg from fission products and plutonium.

7.1 Subliimation Equipment and Preocedure
Uranium hexafluoride was condensed in copper traps of various sizes,

the trap most used being a cylinder 3 inches in diameter and 12 inches high.
To carry ofit a resublimation; the trap containing uwranium hexafluoride was
Placed in a water bath and heated to 90°C. The uranium.hexafluoridglwas
volatilized and passed through a copper conmmecting line to a similar trap
placed in a bath of dry ice-trichloroethylene. A reasonable length of time
was allowed for the sublimstion to take place, since there was no convenient

method of determining when it was complete. No nitrogen or fluorine sweeps
ey
SRy -17- ORNL- 980

 

were made to remove the last traces of UFS.

T.2 Resublimation Results and Discussion
The results for batch resublimation varied considerably for two
reasons: (1) the resublimation was crude and often incomplete, and (2)
the previous treatment of the uranium hexafluoride varied widely.

The only fission products present form non-volatile fluorides which
must have been carried into the cold trap by entrainment. The resublimation
should serve primarily to remove the uranium hexafluoride gas from these
solids. Sinece the distillations were crude, the amount of solid entrain-
ment varied and gave s wide range of decontamination faetors. Gross B
decontamination factors were 12-330 (Table 5). For resublimation preceded
by filtration, the amount of activity present was so small that the gross
B decontaminstion factors could not be determined.

Plutonium decontamination factors over the resublimation step were
probably dependent upon both the entraimment phenomenon agd the adsorption
of the volatile plutonium on the copper walls., Resublimation removed 80-
100% of the plutonium.

Uranium losses varied widely due to incomplete sublimation and sweep

out of the equipment.

8.0 Overall Results

 

Fluorination, copper adsorption, Alundum asdsorption, filtration, and
resublimation procedures were combined in various ways to study the separation

SRR
] -18- ORNL-980

 

Overall Results (continued)

 

of plutonium sund fission products from uranium metal irradiated 335 days
in the ORNL pile and cocled 30 months. The overall procedure and results
for various experiments are given in Table 6. Purities of the uranium
hexsfluoride products are given in Table 7.

The most effective removal of fission products was made in the ex-
periments involving a filtration step. The overall gross 3 decontamination
factors varied from 3 x 103 to greater than 10‘1'F and the products contained
1 - 50 B cts/m/mg U. Experiments containing a resublimation but no fil-
tration were less effective in removing fission products. Gross B decon-
tamination factors were 230 to 1.4 x 103 with a corresponding higher activi-
ty in the product. The one experiment (No. 1) which used only fluorination
and copper adsorption gave a gross B decontaminetion factor of only 12.

The most effective and only satlsfactory removal of plutonium was
made in experiments using Alundum adsorption. In these experiments (Nos.
20, 21, 22) the plutonium decontemination factors were 6 x 103 4o 6 x 10*
and the uranium product cowtained< 0.5 plutonium ct/m/mg U. In all the
other experiments,plutonium decontamination varied widely; however, large
copper adsorbing surfaces tended to increase the decontamination factors.

Uranium losses for all the experiments were quite high. These losses
were explained under the variocus sections in this report dealing with the
individual operatioms. It may not be possible to reduce the uranium loss
of 1 - 3% on the Alundum adsorber; however, by improved operating technigues

the other losses can be reduced to <0.1%.
i,
ey -19- ORNL-~ 980

vt —le 3

9.0 Recommendations

The results of the experiments presented in this report serve primarily
a8 a gulde to further investigations. There are many problems remaining to
be solved and the following recommendationsg deal only with those which

should te studied in the immediste future.

9.1 Preparation of Uranium Hexafluoride
A thorough investigation of various methods of converting uranium
metal to UFg 1s peeded. From this study should come the optimum procedure

from the view point of safety, ease of operation, and economics.

9.2 Adsorptlon Techuiques

 

A more complete survey of adsorbing media for removing plutonium
and of elution methods is needed. Design information should be obtained

for the most promising adsorbers.

9.3 Distillation Studies

 

A program to determine the relative volatilities of various fission
product fluorides is now in progress. Determination of the optimum distil-

lation methods, and testing on a laboratory scale should be carried out.
SRR -20- ORNL- 980

9.4 TPhase Diagram

Solubilities of the fission product fluorides in uranium hexa-
fluoride should be obtained. Phase diagrams involving BfiF3, C1F3, and
HF will also be needed if these materials are to be used in the fluoride

process.

9.5 Filtration
At present, filtration seems to be valuable only as a laboratory
tool. Filtration in large scale operations is not desirable due to dif-
ficulties of washing the filter free of plutonium and fission products and
then drying so it can be reused. At this time no further work need be

done on this procedure.

9.6 Equipment Development
Special equipment and samplers are needed to study all of the
previously mentioned problems. Development and testing of this equipment
can best be carried out along with the investigations for which the‘equtp;

ment is needed.
Rl

~-21- ORNL- 980

10 o O BibliQE E Lh 2

1.

20

Anderson, H. L., and Brown, H. S., Report CN-362, Liquid UF
Plant for the Production of Element 94k, November 27, 10L2.

Barry, L. A., Montillon, G. H., and Van Winkle, R., Report
K-548, Fluorination of Uranium Pile Slugs with Elemental
Fluorine, Carbide and Carbon Chemicalg Corporation, K-25,
December 30, 1949,

Bernhardt, H. A., Gustison, R. A., Kirslis, 5. S., and
Wendolkowski, W. S., Report K-345, Hydrofluorination of Massive
Uranium Metal to Uranium Tetrafluoride, K-25 Laboratory Division,
February 1, 1949.

 

Florin, A., Dry Fluoride Meeting at Argomne National Laboratory,
September 8, 1950.

 

Seaborg; G. T., Williard, J. E., et al, Report CN-696, Chemical
Research-Production and Extraction of Plutonium, Metallurgical
Laboratory, Report for May 16-31, 1943.

Webster, D. S., Report CN-1206 (A-1686), Engineering Studies
of Dry Fluoride Process, Clinton Laboratories, January 10, 19hkh.

 

 
g

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

" -D0. ORNL- 980
Table T |
Removal of Plutonium and Figsion Products from Uranium by Fluorination
Conditions:
(1) Reactor: 1-1/2" OD nickel tube 2 inches deep
(2) Uranium metal irradiated 335 daye in the ORNL pile and cooled 30 months.
(3) Reaction temperature: 250-6000C
(k) Reaction pressure: most experiments started under vacuum and gradually
increased to one atmosphere
(5) Fluorine flowrate: started at 20 ml/min and increased to >200 ml/min.
xperiment| Uranium Feed| % Hold up in Fluorinator Decontamination Factors
Number (grams) Uranium Plutonjum| Pu«a | Gross ¥ [Gross 8 | Rup [ Cs B Sr 8 | TRE B
18 35.0 1.698 27 1.5 10 10 7 11 6 10
2P b1 0.300 46 2.0 16 o7 23 21 29 | 27
3P 64.1 0.080 h1 2. | 15 20 15 13 18 | 25
4¢ 16.0 <0.002 12 1.5 7
54 36.1 £0.002 19 2,2 4
6 27.0 <0.060 17 1.2 6
7° 57.5 0.050 33 1.4 7 5 4 5 I 5
8 45.8 0.005 8 1.2 5 5 6 3 b 6
9 50.8 <0.005 5.1 1.2 3 3 I 3 2 3
10 418.0 0.080 8. 1.4 5 T 10 5 L 7
11 41.0 <0.006 5.4 1.4 T T 13 6 5 T
12 72.2 <0.00k T 1.1 L 5 L 3 L 6
13 T5.5 0.01 14 1.6 3 3 6 3 2 3
148 75.8 1.81 Lo 1.9 3 L 7 3 4 5
15 76.0 0.020 19 L.k 4 L 10 3 3 b
16° 2L5,0 0.0006 31 1.5 3 L 6 3 3 L
1gf 50.0 0.070 31 1.9 L
188 37.8 0.03% 10 1.2 3
19 73.3 <0.00k 4,0 1.1 5 T 11 4 5 14
(continued)

 
=23~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

i ORNL- 980
Teble I (continued)
Experiment ‘Uranium,Feed % Hold up in Fluorinator Decontamination Factors
Numbex: (grams) Uranium Tlotonium | PuQ | Gross ¥ |Gross 8 | Rupg [Cs p | Sr B |TRE B
20 21’;07 anog 7 100 '102 }-j'
21 39.9 <0.002 10. 1.3 5
op 48,2 <0.002 15 1.k 5
a A larges reschbor was used 2'D X 67, Temperasture not uniform throughout reactor.
A larger reachtor was used 2'D X 12", Temperature not uniform throughtout reactor.
s Flaowlnstion carvied out at 20-26" wacuum.
4 TFluoriostlen caxrled out at 4 - 7 psig.
e Fluowinabion started with atmosphers of nitrogen in fluorinator.
£ Startad under nltrogen sbmosphere. 30%'N2 - T% Fo fluorinating gas.
g Staried under vacuwn. 55% Np - 45% Fp fluorinating gas.
L. Tnsufficlent heating period after reaction subslded.

 
ORNL=~ 980

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

e -2k~
Table 2
Removal of Plutonium and Fisslon Products from Gaseous UFg by Adsorption on Copper
Conditions:
(1) Equipmfib as noted
(2) Uranium irradiated 335 days and cooled 30 months
(3) Temperature of trap T0-80°C
(4) Previous process steps as noted
- ' % of Pu
% of Original Charge to trap Decontamination Factors
Experiment| Previous Process | Copper Trap Held up in Copper | held-up Gr@ssF Gross|
Number Stepa Degeription 0 Pa | in trap |Puca ¥ B |[Ru p| Cs BlSr B|TRE B
1 Fluorination 3! of 1/4" 0.2k 19 27 1.k | 1.2 1.2 |2 1.1 |L.1 1.1
tubling ) !
7 Fluorination 1-1/8"D x 9" 0,30 53 70 L I>5 4 1.5 |& |5 |4
U tube packed 1 '
with Cu twrn-
ings '
8 Fluorination 2" x 3-1/4" £0.01 18 21 1.3 ] 1.03 §1.03 |1.03] 1.03 _]..oh 1.0’4
S Fluorination 2™ x T-1/2" {0.01 ko 57 2 1.2 1.2 1.7 |1l.2 J1.1 }1.2
10 Fluorination 2D x 9" - 71 99 Th 1.2 1l.2 |i.3 |1l.2 j1.2 (1.2
11 Fluorination 2"D x 15" £0.01 66 92 13 1.1 Ji.07 j1.2 | 1.071.07|1.07
12 Fluorinstion 2"p x 15" 8.1 0.07 19 1.1 Pl 1.2 [1.00}1.7 | |1.7
Resublimation Co-

 

T AR——

 
-0 ORNL-980

Table 3

Removal of Plutonium and Fission Products from Gaseous UFg
by Adsorption on Alundum i

Conditions:
(1) Ca 100 grams of chipped Alundum in a nickel case
1%?D x 9?5

(2) UFg prepared by direct reaction of fluorine and
. uranium irradiated 335 days and cooled 30 months
(3) Temperaturs of Alundum bed: 95 - 115°C

 

 

 

 

 

 

 

 

 

 

 

% of Original Charge | % of Pu entering Decontamination
Bxperiment | held up in Alundum Alundum which was . Factors
Number Uranium Plutoniim held up in the Alundum| Pu Q_ Gross B
20 3.3 T5 92 13 1.3
21 1.3 81 99 96 1.4
22 2.4 T0 98 58 1.3

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SEonEN -26- ORNL-980
Table 4
Removal of Plutonium end Fission Products from Gaseous UFg by Filtration
Conditionss
(1) Filter - nickel barrier backing tube 5/8"0D x 5" in a nickel case
i"p x 10" |
(2) Uranium irradiated 335 days and cooled 30 months
{3) Temperature of filter as noted |
(4) Previous process steps as noted -
% of Pu i
to the Fil- |
% of Original Charge|ter held up __D.osonbamins..ou Faghors
[Experiment | Previcus Process |Filter Temp. | Held up on Fliter on Gross|Gross|
Nunih=r Stepsa og - Pu Filter Pu o ¥ B8 |Ru B] =3 |Sr B|TRE B
i3 Fluorination 220-240 0.01 19 29 1.6 | 190 | 310 | 13 | 430 {1200 930
1% 185-203 3.69 27 53 2,1 | »90 | 410 | 17 pe8oo |1800|1400
15 TO=90 0.001 27 38 1.6 | D40 {1100 |220 |2200 |2600|1800
15 65-85 0.009 20 30 1.5 | >80 | 870 |40 {8300 |3800{1200
1y 87-105 0.022 32 61 3 1400
1» | 85-110 0.070 57 75 4 920 L
i §9 Fluorination 75-85 0.120 0,85 65 3 >0 | >8 | >2| >k |>80[>100
Regublimation ' —
22 Fluorination 102-110 <0,01 1,15 o7 30 810
Alundum .
Adscrption\

 

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SRR ORNL-980
Table 5
Removael of Plutonium snd Fission Products from UFg by Batch Sublimation
Conditionss (1) Copper and stainless steel cold traps of various sizes were used.
(2) The trap containing UFg wes placed in a water bath at 90°C
(3) Previous treatment as noted.
(4) Uranium was irradiated335 days in the (RNL pile and cooled 30 months
Experiment R % of Original Charge Decontamination Factors
Number Previous Process Steps | Held up in Still Pot Pu ¢ Gross 7 |Grosge Bl Ru pB |Csp | Sr 8 |TRE B
U Pu
2 Fluorination 0.9 48 19 > 6 L6 5 190 70 140
3 1.6 Lo 100 >25 20 8 27 20 21
i 1.1 68 95 33
5 ,9 43 >2000 330
G 10.8 84 290 320
6 Fiuorination 11.5 0.06 v 1.3 >
Resublimetions (2) J‘Z'Ll
7 Fluorination 0.30 5.5 .- > 2 12 > 3 140 0 G0
3 Copper Adsorption 5.9 52 5 >32 250 60 310 [340 280
9 2.3 35 21 >3k 100 5 260 600 310
10 0.08 0.58 5 >55 120 37 140 [50 140
11 2.5 4.5 D 213 80 18 80 70 100
12 Fluorination 16.2 T7 160 w50 70 o 240 60 210
Resublimation :
, Copper Adsorption -
13 Fluorination 0.16 43 19 2100 8 18 |[>10 p10 >24
14 Filtration 2.1 2l 30 > 2 >6 20 w6 30 v 39
15 0.15 Wy 90 >2 >2 |22 >3 |»l.3 > 1.k
16 1.k 39 6 >1.1 >21.2]1>21.7 ] >1.5121.k 1> 1.2
19 Fluorination 1.2 86 66 31 100 32 220 ]110 50
50 Fluorination Alundum | 17.8 8.2 1600 ' 0 |
21 Adsorption ' 23.8 0.84 > 50 100
22 Fluorination Alundum 2.9 0.04 >30 > 2
Adsorption Filtration

 

 

 

 

 

I

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Saeme -28- ONRL- 980
Table 6
Overall Results for Dry Processing
Conditions: (1) Uranium irradiated 335 days in the ORNL pile and
cooled 30 months
(2) Procedure as listed
Uranium |% of Pu in Decontamination Factors
Experiment Loss Product \ Gross p[RupB | Ce B | Sr B | TRE B
 Number _ Prozess Staps(®) % UF4 Py g |seoss v] z10°3 | x10-3] x10-3| x10-3] x10-3
1 Fluorination 1.93 50 2 1L 0.012 | 0.013}) 0.013 | 0.007} 0.01L
Copper Adsorphion
2 Fluovination 1.20 Do Tl 36 L0 1.3 0.11 | 4.3 2.0 4.0
3 Resuyhlimation 1.60 Q.41 240 2380 o4l 0.12 | 0.37 | 0.37 | 0.5k
b 1.10 0.73 140 .23 |
5 o )} | 1,90 £0.02 1600 1.4
& Flucrinsgtion 20,3 0,023 430 T.0
Resublimstias (2)
7 Fluorination 0.45 15.5 7 »160 o 24 0.015] 3.0 2.2 1.3
8 (‘opper Adsorption 5086 13.7 T »150 1.3 0.35 | 0.90 | 1.4 1.7
G Resublimation 2,31 1.79 60 »L30 » 34 0.037] 0.70 | 1.6 1.1
10 0.93 0.01% T00 >370 1.0 0.50 { 1.0 0.79 | 1.2
11 L 2.52 1.13 90 > 90 50 0.28 | 0.48 | 0.40 | 0,70
iz Fluorination 2h .3 0.290 210 »220 AT 0.037[ 1.2 PpP2.0 ] 2.0
Resublimation | ,
) Copper Adsorption _
13 Fluoriuation | 0.19 2.50 41 >1000 T7-0 1.2 Ppi5. 20. P60a
L Filtration 7.60 0.83 120 |>420 }]1i1.0 2.6 Pp50. FR00. 00.
15 Resublimation 0.17 0.49 200 | >330 8.0 L6 behk. P 9.0 PP10s
16 1.43 T.66 13 |>»260 | 3.9 4.8 PB3k pPlo. 6.
17 0.09 20.1 5 6.0
18 0.10 18.7 5 3.0
(continued)

————————————-

 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

pmer— -29- ORRL- 980
Table 6 (continued)
Uranium |% of Pu in Decontamination Factors
Txperiment ( L.oss Product Gross B] Ru B Cs B | Sr B |TRE B
Number Process Steps a) % UFg Pu o | Gross ¥ x10“3 x10-3 | x10-3 x10-3 |x10-3
19 Fluorination 1.3 0.46 220 [»2,900 5.5 | 0.70 11. |[»50. Pp8o.
Resublimation,Filtration |
20 Fluorination 1 21.1 £0.001 360,000 1.0
21 Alundum Adsorption 25.1 4£0.01 56 ;000 60
Resublimation
22 Fluorination 53 € 0.001 0,000 »10.0
Alundum Adsorption
Filtration Resublimation _

 

 

(al

For mors dabailsd procsdurs, see tables describing each operation.

 
-30-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

S ORNL- 980
Table 'Z
Purity of UFg After Dry Processing
Conditions:
(1) Uranium irradiated 335 days in the ORNL pile and cooled 30 months
(2) Procedure as listed
Experiment o ets/m/mg U in Product
Nunber Process Steps(a) Pu O ] Gross ¥ Gross 5 Ru B Cs B Sr B TRE B
1 Fluorination 1.1 x 105 9 1.1x10% 410 2.25105 | 2.7x103 | 7 x 103
Copper Adsorption
2 Fluorination 60 £0.9 100 50 6 9 19
3 Resublimation S < 0.3 300 Ll T0 b7 140
L 15 600
5 o < 0.6 90
& Fluorination 6 25
2 Resublimations :
T Fluorination 330 < 0.7 500 510 6 T 80
8 Copper Adsorption 300 < 0.8 120 25 21 11 T0
g Resublimation L <1 500 270 30 12 120
10 <3 < 0.3 130 11 27 21 60
11 25 <1l - 290 31 40 39 140
12 Fluorination 10 < 0.5 300 220 15 T 148
Resublimation | '
Copper Adsorption o _
13 Fluorination 60 < 0.2 w12 < 5 < 2 < 0.9 < 1
14 Filtration 17 < 0.2 < 1 < 2 < 0.5 < 0.1 < 0.3
| | Resublimetdnn ... 1 . .. e L e
15 C | 10 <U.3 <9 <1 C1 w2 w6
16 160 <0.4 15 <l < 0.7 1 12
17 €00 26
18 €00 48
(continued)

 
 

 

 

 

 

S -31- ORNL- 980
Table T (continued)
Txperiment cts/m/mg U in Product )
Nunber Process Steps(a) Pu O Gresg 7 Gross P Ru B Cs B Sr B i P
19 Fluorination 11 < 0.1 31 14 < 0.4 1.9 1.5
Resublimation
Filtration —
20 Fluorination < 0.05 150
21 Alundum Adsorption < 0.5 240
Resublimation
22 Fluorination < 0.03 v 1h
Alundum Adsorption
Filtration
Resublimatlion

 

 

 

 

 

 

 

 

 

(%) For more detailed procedure, see tables deseribing each operation.

 

I

 
 

 

 

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S‘O{m O H o A

 

-32- ORNL-980

Dwg.#10639
FIGURE 1
Vent to'

 

 

=

o

'O @ 3

Hood

 

Soda Lime

TT?P“‘~\\

  

 

 

 

 

 

 

 

 

 

 

‘W - , : To
~Alundum Bed, _ - Vacuum
Copner Trap | | Pump
: or Y .
Barrier Backing|
Filter

   

 

 

 

 

Cold

Trap—’)’

 

 

 

 

 

 

 

 

 

Fluorinator ' o |

2-7-5/
Z B
 

©33=
FIGURE 2 ORNL-98
- - " t 1 - o
FLUCRIHATLR.ASEFmflLY Dwg.# 10640

 

 

Fluorine Inle UFg Qutlet
Stainlass Stesl
Fleage 5" QD x
1.9" 1D

Fluorinator Too
1/32" sheet nickel

Alunminum Wire
Gaslet — -

Fluorinator

1 1/2" dia, x
2" long nickel
tube

 

 

 

 

 

 

Thzrmocouple

 

Steinless Steel

  

2 Fl?’*fflg‘fi 5" 0D »
Conical Electric & A S 1.3" Ip
fleater = =/ ;s (AR _

 

oy L

 

Insulation

1/4" p

[
]

e fers

E-6-5/
dam eon ORIL- 980
| COFTER ADSORPTICN TRAP

Dwg. #10641

   
   

l/@" Copper
Tubing

 

2 1/8" Copper
Tubing

 

 

 

 

 

 

 

 

Note -

Length varied
frem 3" to 15",

All joints
Silver solderad.

 

 

 

 

 

 

 

 

 

 

 

 

 

1 1.

 

 

 

 

 

 

 

 

 

 

 

 

Z-E-5/

EZ v VSR
        
       
 

4 N ¢ s
. ~35- ORNL-~980
Dwg. # 10642
FIGURE 4
ALIWNDIM ADSORETTON PED
Aluminum Wire
Gaslket
1" dia. Nickel Tube hipred Alundum 1/4" Tube
g 1/2" long
1/4" Tute \

Fitting,
Mtting,

Fress

Thermocouple el
1/4" Nickel Tube

Note:

All materisl Wigke; ~xcept where noted.
All joints silver ¢l Cered.

2-8-57
XEw
ORNL-980
Dwg.# 10643

FIGURE 5

FILTRATION ASSEMRLY

  
   

Wickel Flange

4" dia. x1/2" thiclk Aluminum Wire
Nickel Thermocouple Gasket

Well, 1/4" dis,| x 4"long

Nickel Rarrier

Backing, 1/2" gdia

X 5" lon

End drilled &
Nickel Flange and taspped for
" el x 1/2" thick 1/2" nipe to

1/4" tube fitting.

 
 
 
 
 
  
  
 

   

     
  
 
        

 
 

: Nickel Flange |
Crilled ¢ Tappad 2 3/8" dia, x 1/32n Nickel Tube
for 1/8" pipe to 1/4¢ thick ‘

: 1" dia. x 10" long
tube fitting

£-& 5/
BEHW,