Solubility of plutonium in liquid tin

JOURNALOFNUCLEARMATERIALSl2,No.3

(1964)335-336,NORTH-HOLLANDPUBLISHINGCO.,AMSTERDAM

SOLUBILITY

OF PLUTONIUM

IN LIQUID

JOHN W. WARD and ROBERT University

of California,

Los Ahmos

calorimeter

studies

with

plutonium,

to be quite insoluble

temperatures PuSn,

below

in molten

and,

only very slowly. cible solubility holding

therefore,

must

“C, filtration

and at temperatures

Filtration

tin. At

buttons those

be established

specimens

At 400 “C and aabove, reprodu-

times which

that equilibrium

700”-900 employed

were interpreted

specimens

containing

that

tubes

contained

above

10 at%

solubility

data. The apparatus

silica furnace-tube, was connected vacuum

chromel-alumel

“AC-

the

is shown in fig. 1. A

to a liquid-nitrogen

trapped

were measured

thermocouple

whose

high with a

hot junction

was forced into the melt by the light spring action of the coil of thermocouple talum protection

wire. A thin-walled

tube kept the hot junction

tanfrom

coming into direct contact with the melt. The melting point of a sample of pure tin was used to calibrate the thermocouple.

Since an arrest temperature

of 232.0 “C was found,

which is only 0.1 “C higher

than the reported

literature value, it was assumed

than the thermocouple In

the

temperature

was essentially correct as read. range

300”-600

“C, Pyrex

tubes containing coarse fritted filters were used as the filtration t

tubes.

At higher temperatures,

1000 “C. The

for

latter

plutonium.

data were obtained

heated in a resistance furnace,

line. Temperatures

arc-melted except

as follows:

A

button was placed on top of the frit in the filtration

to indicate

was used in obtaining

B-gram

plutonium,

had been est’ablished. The holding

technique

silica were

above 900 “C, where

were

times needed were quite long. A filtration

of fused

were used.

5 at%

were used

The filtration

for different

UXA

began to react with the silica, tubes

and filters of tantalum

between

New Mexico,

1964

in the present

values were obtained

Los Alamos,

the plutonium

solvent

Plutonium

400 “C, equilibrium

and liquid was not attained

experiments

solution

the

properties of liquid tin were investigated. was found

5 February

of a search for a suitable solvent that

In the course

could be used for making high-temperature

N. R. MULFORD

Scientific Laboratory,

Received

TINT

between

Work done under the auspices of the Atomic Energy

Commission.

Fig. 1.

335

336

JOHN

W. WARD

AND

tube (see fig. 1) and the system was evacuated 1 x 10m6 torr. The furnace on, and the specimen temperature.

After

RORERT

N. R. MULFORD TABLE

to

power was then turned

was heated

suf~eient

to the desired

Temp. “C

time at temperature

had elapsed for the specimen

to have attained,

1

Experimental

data at$/o Pu

rime at temp. hours

i

or

dry argon

300

160

400

30

0.0032

was admit,ted into the tube, te force the liquid por-

402

30

0.0033

tion of the specimen through the filter and into the

499

15

0.0198

lower portion of the filtration tube. The furnace was

498

15

0.0195

601

15

0.0981

601

1.5

0.0976

at least closely approached,

then cooled,

the specimen

equilibrium,

tube removed

from the

0.0084”

system, broken within a glove box, and the solidi-

69St

15

0.290

fied filtrate weighed,

8007

15

0.905

903t

15

2.06

1006tt

8

4.42

1001j.t

8

4.41

1102tt

8

8.21

radiochemical

prior to being analyzed

counting

The number

by a

technique.

of hours that specimens

were held

at 400” and 500 “C was increased, for each succeeding un, until two nearly identical analytical

values

were obtained.

At 500 “C it was found that 15 hours

was adequate

to reach equilibrium.

*

Best value, using 500 “C pre-heat, as described

This length of

t

In fused silica

time was then used for all runs between 500” and

tt

900 “C. For the runs at 1000 “C and above, the time was arbitrarily plutonium

alloy from reacting significamly

with its

ature in “C for each point is shown in parentheses. The straight line drawn through the points between

Equilibrium the specimen

was not attained at 300 “C. Holding for as long as 2 weeks at 300 “C still

left it as an apparently

solid specimen

heating specimens to 500 “C to insure good

diffusion

and then holding

scattered

values,

ton having the composition

IO

-r--i F

1

I

I

t,he melting point of the P&n,

all

pyrometer

was determined

I

1

‘\ I9001

f9OOl

and

h

by

P

into an empt,y l/r6”

El

4

b

O.! 0.05

L

t,emperature of this hole at the moment Duplicate

runs gave ident,ical

results, 1198 ’ k 5 “C ; the uncertainty

is that esti-

and prism absorption

and for

scale uncertaint~y.

Data for the solubility

of plutonium

in molten

tin are shown in table 1. These data are plott.ed as long at y0 plu~~um vs. 1000/T,

/

11000)

block.

hole drilled next to tjhe sample hole and noting the

for window

/

(11001

s

but,-

The block was heat,ed in a resistance furnace,

t,he sample melted.

I,

M.P P”9nS

PuSn, was powdered and

placed in 1116” diameter holes in s tantalum

pyrometer

es

high.

sighting an optical

in t,he

i

To extend the solubilit,y data, an arc-melted

black-body

30

t,hem for as long as a

at’ 300 “C, produced

good consistaney

reported values.

which

involved

apparently

400” and 900 “C indicates

which had

not, wett’ed the conta.iner. Another procedure,

mated

Melting point of PuSn, = 1198 “& 5 “C

shortened to 8 hours to prevent the

container.

week

In tantalum

“K, in fig. 2. The approximate

temper-

10001TPK)

Fig. 2.