ORNL-5176.txt

BNE Issuep  FEB o ORNL-5176

@I

Engineering Tests of the Metal Transfer
Process for Extraction of Rare-Earth
Fission Products from a Molten-Salt

Breeder Reactor Fuel Salt

H. C. Savage
J. R.

Hightower, Jr.

OAK RIDGE NATIONAL LABORATORY

OPERATED BY UNION CARBIDE CORPORATION FOR THE ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION

Printed in the United States of America. Available from
National Technical Information Service
U.S. Department of Commerce
5285 Port Royal Road, Springfield, Virginia 22161
Price: Printed Copy $4,50; Microfiche $3.00

This report was prepared as an account of work sponsored by the United States
Government. Neither the United States nor the Energy Research and Development
Administration/United States Nuclear Regulatory 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.

S TEEE T v

-

Crmww TS T T

ORNL-5176
Dist. Category UC-/6

Contract No. W-7405-eng-26
CHEMICAL TECHNOLOGY DIVISION

ENGINEERING TESTS OF THE METAL TRANSFER PROCESS FOR EXTRACTION OF
RARE~EARTH FISSION PRODUCTS FROM A MOLTEN-SALT
BREEDER REACTOR FUEL SALT

H. C. Savage
J. R. Hightower, Jr.

Date Published: February 1977

0OAK RIDGE NATIONAL LABORATORY
Oak Ridge, Tennessee
operated by
UNION CARBIDE CORPORATION
for the
ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION

-iii-

TABLE OF CONTENTS

Page
ABSTRACT . & v & v v v & o o o 4 o e e e e e s e e e e e 1
1. INTRODUCTION . & & v 4« v v v v o o e e v e e e e e e e a1
2. METAL TRANSFER PROCESS . . . « . « & v « & & v v o « « « o 3

3. DESCRIPTION OF METAL TRANSFER EXPERIMENTS MTE-3 AND MTE-3B. 6

3.1 Process Vessels and Equipment . . . . . . . . . « . . b
3.2 Experimental Procedures . . . . . . . . . « + .« « .« « 11
4. ANALYSIS OF DATA + & v & v o o & v o & o o o o o o o« « « 14
5. EXPERIMENTAL RESULTS . . + + v « « & & & ¢ « o + « « « « « 18

5.1 Overall Mass-Transfer Coefficients and Equilibrium

Distribution Coefficients for Neodymium . . . . . . . 19
5.2 Entrainment Studies in Experiment MTE-3B . . . . . . 36
5.3 Neodymium and 147Nd Inventory in Experiment MTE- 3B . . 38
5.4 Lithium Reductant in the Bismuth Solutions in the

Contactor and Stripper . . + . + « « « « « « « « « « « 40

5.5 System Performance . . . . . « « « .+ & .+ o« « « . . 42

6. DISCUSSION OF RESULTS . . « + « & + v v v & o « o « o« o« « . 44
7. CONCLUSIONS . &+ & v & & v v & o & « o & o« & o o« o o & s« « » 51
8. ACKNOWLEDGMENTS . . . & v « o v « & « &« o o« « « « « o « « « 53
9. REFERENCES . . +« v v & « & « & « « o o & « o« o« o « « « « . 54

APPENDIX + v « v v v « 4 4 & 4 s & s s & & & + o w o « s« o s+ « « 56

t
|
}
|
ENGINEERING TESTS OF THE METAL TRANSFER PROCESS FOR EXTRACTION OF

| RARE-EARTH FISSTION PRODUCTS FROM A MOLTEN-SALT
BREEDER REACTOR FUEL SALT

’ H. C. Savage
J. R. Hightower, Jr.

} ABSTRACT

[ In the metal transfer process for removal of rare-earth

| fission products from the fuel salt of a molten—-salt breeder

reactor (MSBR),the rare earths are extracted from the molten

fuel salt into a molten bismuth solution containing lithium and

thorium metal reductants, transferred from the bismuth into

| molten lithium chloride and, finally, recovered from the

| lithium chloride by extraction into molten bismuth containing
Tithium reductant.

| Engineering experiments using mechanically agitated, non-
| dispersing contactors with salt and bismuth flow rates [V 1% of
P those required for processing the fuel salt from a 1000-MW(e)

| MSBR] have been conducted (1) to study this process, () to measure

| the removal rate of a representative rare-earth fission product

f (neodymium) from MSBR fuel salt, and (3) to evaluate the mechanically
agitated contactor for use in a plant processing fuel salt from

a 1000-MWw(e) MSBR.

The experimental equipment and procedures are described.
l Results obtained during five experiments in which the rare earth
neodymium was extracted from MSBR fuel salt are presented.
i Removal rates and mass-transfer coefficients between the salt and
bismuth phases were determined for neodymium and are discussed in
terms of the processing requirements for a 1000-MW(e) MSBR.

1. INTRODUCTION

The Oak Ridge National Laboratory has been engaged in developing

23 233
4 molten-salt breeder reactor that would operate on the 2Th— U

fuel cycle to produce low-cost power while producing more fissile

salt mixture as the fuel and graphite as the moderator. In order for
the reactor to be operated as a breeder, it would be necessary to

remove the rare-earth fissicu products on a 25~ to 100-day cycle and

23

material than is consumed. The reactor would use a molten fluoride
isolate 3Pa from the region of high neutron flux during ite decay
i

23 . . .
to 3U. Thus an on~-site processing plant that continuously removes

che protactinium and rare earths is required for the reactor to
perform as a breeder.

The fuel salt for a single~fluid MSBR
71.67-16-12-0.33 mole 7% LiF—BeFZ—ThF4~UF4 and contains 233PaF4 and

rare-earth fluoride fission products. In the reference flowsheet

1 has the composition

for the processing plant, fuel salt is removed from the reactor at
a rate of about 0.9 gpm. The salt is first fed to a fluorinator
where about 997 of the uranium is removed as UF6. The salt stream
leaving the fluorinator is contacted with bismuth that contains
lithium and thorium reductants in order to extract protactinium and
the remaining uranium. The salt stream, essentially free of uranium
and protactinium but containing the rare-earth fission products, is
then fed to a rare-earth removal system where the rare-earth fission
products are extracted before returning the fuel salt to the reactor.
The equilibrium concentration of the rare earths in the salt from
the reactor is about 100 ppm for a 1000-MW(e) MSBR; rare-earth
removal times range from 25 to 100 days.

Engineering experiments to study a recently developed rare-earth

removal system, ’

called the metal transfer process, have been
conducted over the past several years. In this method, the rare earths
are extracted from the fuel salt into bismuth containing lithium and
thorium reductants, transferred from the bismuth into molten lithium
chloride and, finally, recovered from the lithium chloride by
extraction into molten bismuth containing lithium reductant.
Mechanically agitated salt-metal contactors have been investigated4’5
for use in the MSBR processing systems based on reductive extraction.
This type of contactor is of particular interest for the metal transfer
process since adequate mass-transfer rates may be possible without
dispersal of the salt and bismuth phases. Eliminating phase dispersal
considerably reduces the problem of entrainment of bismuth in the
processed fuel carrier salt and subsequent transfer to the reactor,
which is constructed of a nickel-base alloy that is subject to damage
by metallic bismuth. The bismuth in this type of contactor would be
a near-isothermal, internally circulated, captive phase that would

minimize the occurrence of mass-transfer corrosion. Also, it is believed
L

-3-

that a processing system employing this type of contactor can be more
easily fabricated of graphite, which is required for bismuth containment,
than one using packed columns.

Operation and test results of engineering-scale experiments,
utilizing the metal transfer process and mechanically agitated contactors,
are described in this report. These experiments incorporated all the
steps in the metal transfer process using salt flow rates that were
about 1% of those required for processing the fuel salt from a 1000-
MW(e) MSBR. The goals of the experiments were (1) to study the various
steps of the process, (2) to measure the rate of removal of representative
rare-earth fission products from the molten-salt reactor fuel, and (3)
to determine the suitability of mechanically agitated contactors for

this process. For this evaluation, mass-transfer coefficients between

the salt and metal phases in the system were determined using representative

rare-earth fission products.

2. METAL TRANSFER PROCESS

In the metal transfer process, fluoride fuel salt that is free
of uranium and protactinium is first contacted with molten bismuth
containing lithium and thorium as reductants at concentrations of
about 0.002 and 0.0025 m.f., respectively. The rare earths are
extracted into the bismuth. The bismuth that contains the rare earths
and thorium is then contacted with molten lithium chloride; and,
because of highly favorable distribution coefficients, the rare
earths distribute selectively, relative to thorium, into the LiCl.
The final step of the process consists of extracting the rare earths
from the LiCl by contact with molten bismuth containing lithium
reductant at concentrations of 5 to 50 at. %.

The chemical reactions that represent each step of the process
are given below, using a trivalent rare earth as an example:

Reductive extraction: (1)

[ . . Uo i .+ .
Re3+(fue1 salt) + 3Li(Bi)Bl 0.2 at. £ L1, 3Li (fuel salt) + RE(Bi):

Transfer to LiCl: (2)
+ LiCl 14
RE(Bi) + 3Li (LiCl) -—— 3Li (Bi) + RE (LiCl);

Stripping into Bi-Li: (3)

i==> at. 2 Li, 41.%1ic1) + RE(B1).

REST(LiC1) + 3Li(Bi) B

The equilibria for these reactions have been measured and expressed
as distribution coefficients for the rare earths between the fuel
carrier salt and bismuth containing lithium as a reductant and as
distribution coefficients of thorium and rare earths between lithium

’

chloride and bismuth containing lithium. The distribution

coefficient is defined as

“u

D, = (4)

M XMXn ,

)
il

distribution coefficient,

mole fraction of metal M in the bismuth phase,

=8

XMXn = mole fraction of the metal halide in the salt phase.
Under conditions of interest, the distribution coefficients have

been found to be dependent on the lithium concentrations as follows:

%*
log Dy =nm log X ; + log Ky (5)

where

+
n = valence of metal M" in the salt phase,
X i " mole fraction of lithium in the bismuth phase,

KM = constant at a given temperature.

Calculated values of rare earth--thorium separation factors
between the bismuth and LiCl salt range from about 104 to 108 for
divalent and trivalent rare earths based on the measured distribution
coefficients.

One version of a flowsheet for removing rare earths from MSBR
fuel salt using the metal transfer process is shown in Fig. 1. Using
this method, uranium- and protactinium-free fuel salt from the
protactinium removal step is fed to a series of contactor stages
through which bismuth containing dissolved reductant is circulated.
The bismuth in each of these fuel-salt contactor stages also circulates
through a corresponding lithium chloride contactor stage within a
series of contactors through which a lithium chloride stream flows.

This lithium chloride stream, in turn, circulates through a single

ORNL DWG 76-885

U,Po-FREE SALT LITHIUM
FROM Po-REMOVAL STEP CHLORIDE

T0
HYDROFLUORINATOR >

STRIPPER

NN\m

/ 7 B
l ; |
i | 3ISMUTH - LITHIUM
g, N, | STRIPPER
| 7 7 | SOLUTION
S V0 o : |
/ : i
<} J / -
PROCESSED SALT L RECIRCULATING
TC FUEL : 31SMUTH
SECONSTITUTION STREAM
sTEP

N - o . . A AT ) PR g e s N e
Fi?,» 1. Motal transier process using TML;.Ltlp¢€ ."‘ILE“;"""“LVPQ ccritaciLors.,

—6—

contactor, where the lithium chloride is contacted with a bismuth-
lithium stripper solution,

An advantage of this arrangement is that the fuel salt--bismuth
contactors and the lithium chloride--bismuth contactors can be
constructed contiguous to one another, and the bismuth can be made
to flow between the two by the pumping action of the agitators (described
in experiments MTE-3 and MTE-3B in Sect. 3). Thus in this method, the
need for external bismuth pumps is eliminated. Another advantage is
that the bismuth is this type of contactor would be a near-isothermal,
captive phase that would minimize the occurrence of mass-transfer
corrosion,

Although other variations can be synthesized, the removal rates
of neodymium measured in experiment MTE-3B are discussed in terms of
processing requirements for a 1000-MW(e) MSBR using the flowsheet

shown in Fig. 1.

3. DESCRIPTION OF METAL TRANSFER EXPERIMENTS MTE-3 AND MTE-3B

3.1 Process Vessels and Equipment

The basic equipment used in the experiments (shown diagrammatically
in Fig. 2), consisted of three carbon steel vessels: (1) a l4-in.
(0.36-m)-diam fluoride salt reservoir containing the fuel carrier

salt (72-16-12 mole % LiF-BeF -ThFa), a 10-in. (0.25-m)~-diam salt-

2
metal contactor, and a 6-in. (0.15-m)-diam rare-earth stripper. A
photograph of the process equipment is shown in Fig. 3. The salt-
metal contactor is divided into two equal compartments by a carbon
steel partition that separates the fluoride and LiCl salts. A 1/2-in.
(13-mm)~high slot at the bottom of the partition interconnects

the captive pool of bismuth-lithium-thorium solution in the contactor.
Mechanical agitators in both compartments of the contactor and in the
stripper were used to improve contact between the salt and bismuth
phases. Four-bladed turbines, 2-7/8-in. (73 mm) in diameter and having
a pitch of 45°, were located in each phase. A photograph of the
agitators is shown in Fig. 4. The blade mounting and shaft rotation
were such that the salt and bismuth flows were directed toward the

interface. The engineering drawings used in the construction of the

metal transfer experiments agre listed in Table 1.

ORNL -DWG-71-147-R|

AGITATORS
VENT LEVEL
ELECTRODES LEVEL
/ ELECTRODES
FLUORIDE
+ SALT PUMP VENT

—
J

ARGON
SUPPLY

L

_

ARGON
SUPPLY

1.25
\ ~Y -~ 11 D /.

7
X

N
7
Y
IV
N
ANY

72-16-12 mole % Bi-Th N - Li-Bi
LiF -BeF,- ThF,
FLUORIDE SALT- METAL RARE EARTH
SALT CONTACTOR STRIPPER
RESERVOIR

Fig. 2. Flow diagram for metal transfer experiment MTE-3.

e —==® PHOTO NO. 2706-74 A

:
/

-
SALT-METAL
CONTACTOR

FLUORIDE - SALT §
RESERVOIR

.\

RARE-EARTH STRIPPER mesm s

-
.-u“‘\
-

: "-’5,, '

. :
d- L

Fig:. .Js Photograph of processing vessels for metal transfer experiment
MTE-3B with heaters and thermocouples installed.

e e e

Fig. 4.

Photograph of agitators used for promoting mass transfer
between the salt and bismuth solutions in metal transfer
experiments MTE-3 and MTE-3B.

PHOTO 1829-71

~10-

Table 1. Engineering drawings used in construction of the metal transfer

experiment

Drawing number

Description

F-12172-CD-116E
M-12172-CD-025D
26D

27E
29E
30E
31D
32E
33D
34D
35E
36D
37D
38D
39D
46D
47D
48E
49C
51D
52E
53C
M-12053-CD~-83C

Flowsheet
Fluoride salt tank

Details of pump nozzle, viewing port, salt funnel
and drain

Agitator details of assembly

Contactor vessel assembly

Contactor vessel plan view

Contactor vessel sections

Contactor vessel detail sheet 1

Contactor vessel sampler details

Thermowell details

Acceptor vessel assembly

Acceptor vessel sections A-A, B-B, and C-C
Acceptor vessel details

Transfer line isolation flange assembly and details
Details for brazing copper sheath to steel pipe
Heat transfer line subassembly

Agitator blades assembly and details

Vessel stand and mounting details

Samplers

Details of salt transfer line piping

Fluoride salt pump assembly and details

Sample ladle body detail

Salt and bismuth filter

-11-

The outside surfaces of the carbon steel vessels were coated with
v 0.015-in. (0.4-mm)-thick chromium~--nickel--67% aluminum oxidation-
resistant material (METCO* No. P443-10) using a plasma spray gun. This
prevented air oxidation of the carbon steel vessels at the operating
temperature of v 923 K.

Fuel salt was circulated between the fluoride salt reservoir and
one side of the contactor by means of a specially designed gas-operated
pump utilizing molten bismuth check valves. Lithium chloride was
circulated between the stripper and the other side of the contactor by
alternately pressurizing and venting the stripper vessel. The bismuth
phase in the contactor was circulated between the two compartments in
the contactor by the action of the agitators, and no direct measurement of
this flow rate was made during experiments, However, measurements made in
a mockup using a mercury-water system indicated that the bismuth flow
rate between the two compartments would be high enough to cause the rare-
earth concentrations in the compartments to be essentially equal.

The salt flow rates used were about 1% of those required for processing the
fuel salt from a 1000-MW(e) MSBR.

Approximate quantities of salt and bismuth used in the experiment
were the following: (1) 110 kg of fluoride salt and 64 kg of bismuth-
lithium-thorium (containing about 0.0018 atom fraction lithium and
0.0014 atom fraction thorium) in the contactor, and (2) 10 kg of lithium
chloride and 44 kg of bismuth-lithium (containing 0.05 atom fraction

lithium) in the stripper.

3.2 Experimental Procedures

Procedures for the makeup, purification, and addition of the
salt and bismuth phases to the process vessels were designed to minimize
contamination of these materials with oxide (air, water, and any oxides
present in the carbon steel process vessels). Prior to the addition of
the salts and bismuth, the internal surfaces of all vessels were treated
with hydrogen at 923 K to reduce residual iron oxides. (Most of these
oxides had been removed by sandblasting during fabrication.) After
this treatment, a purified argon atmosphere (v 0.1 ppm of HZO) was

maintained in the vessels to preclude further oxidation.

*METCO, Inc., 1101 Prospect Avenue, Westburg, Long Island, N.Y.

The salt and bismuth solutions were made up in auxiliary vessels (also
treated with hydrogen) at v 923 K to remove oxides). The bismuth was
hvorogen treated atr v 923 K, while the fluoride salt and LiCl salt
were contacted with hismuth containing thorium for oxide removal. After
makeup and purification, all solutions were filtered by passing through a
cintered molybdenun tileter (v 30-4 pore-diameter) during transfer
from the auxiliary vessels into the process vessels. After the process
vessels had been charged with the salt and bismuth solutions, the entire
svstem was maintained at temperatures above the liquidus temperature
(> 890 K) of the solutions.

The experimental procedure was essentially the same for each run.

The rare earth for which the mass transfer rate and overall mass transfer
coefficients were to be measured was added to the fluoride salt, the
agitators were started and adjusted to the desired speed, circulation

ofF the fluoride salt and LiCl was started, and the salt and bismuth phases
were periodically sampled during the run period and analyzed for rare-

carth content., In each run, trace quantities of a radioactive isotope

were inciuded in the rare-earth addition, and counting of the radio-
activity of the samples was used to follow the transfer rate.
Samples of the salt and bismuth phases were taken using a small
(v O.4—cm3) stainless steel sampling capsule with a sintered metal
filter (v 20-u pore—diameter). A 1/16-in. (0.16-mm)-diam capillary
tube attacned to the capsule was used for inserting it into the solution
to be sampled (see Fig. 5). During insertion, the capsule was
continuously purged with purified argon gas until it was positioned in
the solution. The Flow of purge gas was then stopped, and a sample was '
taken by applying a vacuum to the capsule. When the molten salt or
bismuth solution reached the upper, cool section of the capillary tube, it
solidified. The sample was then withdrawn into the sample port and
1llowed to cool under an argon atmosphere before removal. |
All runs in the second experiment, MTE-3B, were made using the rare
sarth neodymium. In these runs, trace amounts (50 to 150 mCi) of 147Nd
were inciuded in the neodymium added to the experiment. Neodymium
concentration in each phase was determined by counting the 0.53-MeV

l'47Nd in the sample. In addition, the total

gamma emitted by the
seodymium contents of selected samples were determined by an isotopic

dilution mass spectrometry technique. This proved to be a valuable means

]

-13~

PLASTIC TUBING ——T0 ARGON AND VACUUM SUPPLIES

SAMPLERS

TEFLON PLUG

.......

Ve

AN

VENT PURGE
SAMPLE HOLDER
=]
/‘////ABALL VALVE
Top OF vesseL 04T
A i
A
N | N
Y
N N
‘3143}$‘ . w-= - SALT LEVEL
N § |
i:jizw.
N o o
ol
s = N T Bz - Bi LEVEL
Bk
N P
- - u:@‘;‘- T— i
IE N e
- T [N -
Fig. 5.

experiment MTE-3B.

ORNL DWG NO. 72-10408

1716 1n. STAINLESS STEEL
CAPILLARY TUBING - 40 in. LONG

TYPICAL SAMPLER

///"3’15 in. ORILL

14 in. DIAM
STAINLESS STEEL ROD

POROUS METAL FILTER,
20u PORE SIZE,
347 STAINLESS STEEL

Schematic diagram of sample capsule and sample port used in

~1d4~

of checking on the tracer counting results and was especially useful
for those samples with very low neodymium concentrations (< 1 ppm) ,
where counting techniques were inadequate.

For runs in the initial experiment MTE-3, in which the rare earths
europium, lanthanum, and neodymium were used, counting of the 1.28-MeV
gamma emitted from the 154Eu tracer was used to follow the transfer
rate, and the lanthanum concentration was determined by neutron activation
and subsequent counting of the 140La produced.

This report primarily describes the results obtained using the rare
earth neodymium in the second metal transfer experiment, MTE-3B. The
first experiment, MTE-3, was conducted by others and reported

>

previously; results are summarized for comparison with MTE-3B

results.

4., ANALYSIS OF DATA

Experiment MTE-3B involved the successive transfer of rare earth
from a fluoride salt to a bismuth-lithium-thorium pool, to a lithium
chloride salt, and, ultimately, to a bismuth-lithium pool. The rate at
which the rare earth was transferred through the several contactor stages
was governed by the equilibrium distribution coefficient of the rare
earth, the salt and bismuth flow rates, and the mass—-transfer
coefficients. The determination of these mass-transfer coefficients was
one of the major requirements for meeting the objectives of the experiment.

An idealized sketch of the contactor arrangement for the experiment is
shown in Fig. 6.

From a rare-earth material balance in each of the seven regions
indicated in Fig. 6, the following equations governing the movement of

rare earth through the regions were derived:

dxl

Vi ge T Fi(x - x), (6)
dx2 x3

Vo gt T F1(x) - x9) - KA (%, - '13;;)’ (7)
dx3 x3

Via e T KA (g - ‘D;) - Fylxy - %), (8)

ORNL DWG 76-716

FLUORIDE LiCl
X2 xs/

—> —» | Xg L

F1 F:3 ] T
X T R jp—— JE——— g— S

! = = | = || = = | | =+—Li-Bi
—3— —_\ )24_1 )27_ o
J(

\BISMUTH

Idealized diagram of the metal transfer experiment showing

the regions used for mass transfer calculations.

Fig. 6.
4
Vo ¢ T Fal¥g = %) = KAy (xy - Dpxo), (9)
dx5
Vs qr = Kofp(xy — Dgxs) - Falxg - xp), (10)
dx6 X5
V6 9 = FZ(XS X6) K3A3(X6 D—C), and (11)
dx X
V7 dc T Kahglxg DC)’ (12)
where
t = time, sec,
x .= molar concentration of rare earth in region i, i = 1,2,...7
i
V.= volume of fluid in region i, i = 1,2,...7, cm3,
i
Fl = flow rate of fluoride salt, g-moles/sec,
F2 = flow rate of bismuth between contactor compartments, g-moles/sec,
F3 = flow rate of lithium chloride between the stripper and the

contactor, g-moles/sec,

D, = equilibrium distribution coefficient for the rare earth
between fluoride salt and bismuth-lithium-thorium, g-mole/g-mole,

DB = equilibrium distribution coefficient for the rare earth between
bismuth~lithium-thorium and lithium chloride, g-mole/g-mole,

DC = equilibrium distribution coefficient for the rare earth between
lithium chloride and bismuth-lithium stripper solution, g-mole/
g-mole,

A1 = interfaéial area between fluoride salt and bismuth-lithium-
thorium, cm2,

A2 = interfacjial area between bismuth-lithium-thorium and LiCl.
2

cm”,

A3 = interfacial area between LiCl and bismuth-lithium
stripper alloy, cm2,

K, = overall mass-transfer coefficient at the fluoride salt--
bismuth~lithium-thorium interface (based on concentration in
the fluoride salt phase), cm/sec,

K, = overall mass. transfer coefficient at the bismuth-1ithium-

thorium--LiCl interface (based on concentrations in

the bismuth phase), cm/sec,
~17-

K3 = overall mass-transfer coefficient at the LiCl--
bismuth-lithium interface (based on concentrations in the
lithium chloride phase), cm/sec.
The overall mass~transfer coefficients are dependent on the
individual mass-transfer coefficients for each phase and the equilibrium
distribution coefficients for the rare earth between the salt and bismuth

solutions. They are expressed as follows:

' 1

T (13)
1 2 37A

D

-, (14)
2 4 5

1 1 1

K, "k, "D, (13)
3 6 7°C

where
koo« ks = individual mass transfer coefficients for each region in

the contactor and stripper vessels (subscripts correspond
to the numbers assigned to each phase in Fig. 6).
Overall mass-transfer coefficients for each run were calculated by

selecting values for K and K3 which resulted in the best agreement

10 Koo
between calculated time-dependent concentrations for each region and the
experimentally measured time-dependent concentrations.

The appropriate known values for the initial concentration in each
region, X453 the fluid volume of each region, Vi; the area of each of the

three interfaces, A A and A and the three equilibrium distribution

1’ 72’ 3°
coefficients, D,, Dy, and D, were substituted into Egs. (6)-(12). Initial
estimates of Kl, K2, and K3 were also substituted into these equations,
which were then solved using a computer program. The calculated results
were subsequently compared with the measured results, new estimates for
Kl’ K2, and K3 were chosen, and these were substituted into the
differential Eqs. (6)~-(12). This process was repeated using adjusted
until the calculated results reproduced satis- |

values for K K and K

1’ —2 3
factory measured results. The values for Kj, KZ’ and K3 determined in
this manner were taken as the experimentally prevailing overall mass-

transfer coefficients.
18-

5. EXPERIMENTAL RESULTS

Four runs (Nd-1, -2, -3, and -~4) using the rare earth neodymium as
a representative fission product were completed in metal transfer
experiment MTE-3B. Neodymium was chosen as the representative rare-
earth fission product for the studies in MTE-3B for several reasons:

1. Neodymium is one of the more important trivalent fission

products to be removed from a molten-salt breeder reactor
fuel salt.

2. The use of 147Nd tracer with its relatively short half-life (11
days) would prevent excessive levels of radiocactivity in the
experiment (additional neodymium, containing 147Nd tracer, was
added during the studies).

3. Results could be compared with those obtained using neodymium
in the first experiment, MTE-3.

Data from Nd-1, -3, and -4, were analyzed, and overall mass-transfer
coefficients at the three salt-metal interfaces were determined. Mass-
transfer coefficients were not determined in experiment Nd-2 due to
unexpected entrainment of fluoride salt into the LiCl in the contactor.
Entrainment of fluoride salt into the LiCl affects the equilibrium
distribution coefficients of the rare earths and thorium between the
LiCl and bismuth phases such that thorium is transferred into the LiCl.ll
Entrainment also occurred during run Nd-1; however, the amount of fluoride
salt entrained was relatively small (v 1.3 wt % F in the LiCl1), and the
distribution coefficients measured at the end of run Nd-1 were near the
expected values. During run Nd-2, the cumulative amount
of fluoride salt entrained (Vv 3 wt %) became significant. The
distribution coefficients (particularly for thorium at the LiCl-bismuth
interface in the contactor) were reduced, and a significant quantity of
thorium was transferred into the LiCl and was subsequently circulated into
the stripper, where it reacted with the lithium reductant in the Bi-Li
solution., This reaction continued until most of the lithium reductant
was lost from the stripper and the neodymium was no longer extracted
into the Li~Bi in the stripper, Extraction of neodymium stopped after
about 50 hr of operation of run Nd-2; thus no determination of mass-

transfer coefficients could be made.
-

~19-

Because of the entrainment of fluoride salt into the LiCl during runs
Nd-1 and Nd-2, it became necessary to remove both the LiCl from the
contactor and stripper and the bismuth--5 at. %Z Li from the stripper
after run Nd-2. Fresh LiCl and bismuth-lithium solution were charged to
the system before starting run Nd-3.

5.1 Overall Mass-Transfer Coefficients and Equilibrium
Distribution Coefficients for Neodymium

Operating conditions and system parameters for runs Nd-1 through Nd-4
in metal transfer experiment MTE-3B are shown in Table 2. Results of
the determinations of overall mass-transfer coefficients for the rare earth
neodymium for runs Nd-1, -3, and -4 in metal transfer experiment MTE-3B
are given in Table 3. Values for the equilibrium distribution
coefficients for neodymium measured at the completion of each run,
during periods of no salt circulation, are shown in Table 4.

Previously reported values for overall mass-transfer coefficients for
europium, lanthanium, and neodymium obtained in the experiment, MTE-3,
are shown in Table 5 for reference.

Values for overall mass-transfer coefficients for neodymium at the
three salt-bismuth interfaces in metal transfer experiment MTE-3B (Table 3)
were obtained by selecting values for the mass-transfer coefficients which
resulted in a "best fit" between the experimentally obtained concentrations
during each run and the calculated concentrations as discussed in Sect. 4.
The experimentally measured values for the equilibrium distribution coefficients
for neodymium between the salt and bismuth solutions were used in calculating
the "best fit'" case.

Results are shown in Figs. 8-18. 1In these figures, the experimental
data points are indicated for each solution, and the line shown represents
the "best fit'" for the calculated concentrations during each run. Excellent
agreement was obtained for the fluoride salt solution and the bismuth--5
at. % lithium solution in the stripper for each run. For these solutions,
the data obtained by counting the 0.53-MeV gamma emitted by the 147Nd
tracer (with results expressed in disintegrations per minute per gram)
were used. Equally good agreement was obtained for the data obtained by
analysis for total neodymium in these two phases. The results obtained
by total neodymium analysis (pg/g) are shown for the bismuth-~thorium-

lithium solution in the contactor and the LiCl in the contactor and stripper.

~20~

Table 2. Operating conditions for runs Nd-1 through
Nd-4 in metal transfer experiment MTE-3B

Run number 1 2 3 4
Run time, hr 140% . 138 165.2° 165%
(115.7) (107.8)P (109.5)b
Agitator speed, rps 5.0 5.0 4.17 1.67
Fluoride salt circulation 5.8 x 10/ 5.8 x 10/ 0 0
rate, m3/sec
. . , -5 -5 -5 -5
LiCl circulation rate, 2.0 x 10 2.0 x 10 2.0 x 10 2.0 x 10
m~/sec
Average temperature, K 923 923 923 923
Quantities of Salt and Bismuth (g-moles)
Fluoride fuel salt in 1535 1535 1535 1535
reservoir®
Fluoride fuel salt in 161 161 161 161
contactor
Bi-Li-Th in fluoride salt 132 132 129 132
compartment of con-
tactord
Bi-Li-Th in LiCl salt 161 161 156 156
compartment of con-
tactor
LiCl in contactor® 101 101 101 101
LiCl in stripper 132 132 114 114
Bi--5 at. % Li in stripper’ 190 190 190 190

a . . . ) . 1t
Total time of fluoride salt and/or LiCl salt circulation plus equilibrium
time with agitation but no salt circulation.

Time of fluoride salt and/or LiCl salt circulation.

“Mole wt = 42.4 gy p = 1.48 g/cm3; u = 0.016 P at 923 K.12
dMole wt = 63.2 g; p = 3.30 g/cm3; u = 0.0088 P at 923 K.13
®*Mole wt = 209 g; p = 9.66 g/cm3; u = 0.016 P at 923 K.14
Mole wt = 199 g5 o = 9.28 g/em>; 1 = 0.0094 P at 923 K.
-2]1-

Table 3. Overall mass~transfer coefficients? for neodymium in metal
transfer experiment MTE-3B

Agitator Run Overall mass transfer
Run speed time coefficients (mm/sec)b
number (rps) (hr) Kl K2 K3
Nd-1 5.0 116 0.006 0.20 0.06
Nd-3 4.17 108 0.018 0.030 0.035
Nd-4 1.67 110 0.0040 0.020 0.0055

a ..
The mass-~transfer coefficients Kj and K3 are based on the rare-earth
concentration in the salt phase, and K, is based on the rare earth con-

centration in the bismuth phase.

bDefined by Eqs. (13)-(15).

Table 4. Neodymium equilibrium distribution coefficientsa’b

Run UA DB

number Calculated Experimental Calculated Experimental Calculated Experimental
Nd-1© 0.03° 0.027 1.67¢ 0.94 3.5 x 104 >1 x 107
Nd-3¢ 0.017f 0.022 0.94f 0.98 3.5 x 104 >1 x 103
Nd~4°€ 0.017f 0.027 0.94f 1.0 3.5 x 10°

Eu-6, -79  0.0088P 0.012 0.49 0.30 3.5 x 10 2 x 100

neodymium in bismuth, m.f.

aCoefficients are defined as follows:

]

o)

o
H

“Experiment MTE-3B.

dExperiment MTE-~3.

neodymium in salt, m.f.

®Based on 60 ppm of lithium in bismuth.

fBased on 50 ppm of lithium in bismuth.

gBased on 5 at. % lithium in bismuth.

h

Based on 40 ppm of lithium in bismuth.

equilibrium-distribution coefficients between phases (A) bismuth-thorium/fluoride salt,
(B) bismuth-thorium/LiCl, (C) bismuth--5 at. % lithium/LiCl.
Table 5. Overall mass-transfer coefficients? for lanthanum,
europium, and neodymium in metal transfer experiment MTE-3

Agitator Run . . b
Run Rare speed time Ove;all mass transfe; coefficient (mmésec)
number earth (rps) (hr) 1 2 3
La-1 La 2.50 15.2 0.0014 0.0011 0.12
La-2 La 3.33 15.4 0.002 0.0013 0.2
Eu-1 La 1.67 14.3 0.0006 0.00039 0.062
Eu 0.001 0.000015 0.011 |
N
()
Eu-2, -3 La 3.33 15.0 0.002 0.0013 0.2 j
Eu 0.003 0.000048 0.033
Eu-4,5 -5 La 3.33 12.2 0.002 0.020 0.2
Eu-6 La 3.33 64.6 0.002 0.020 0.2
Nd 0.002 0.065 0.2
Eu-7, -8 La 5.0 15.4 0.0026 0.032 0.2
Nd 0.0032 0.11 0.2

a . . .
The mass-transfer coefficients K; and K, are based on the rare-earth concentration in the salt phase, and
K, is based on the rare-earth concentragion in the bismuth phase.

bSee footnote (b) in Table 3.

“After argon sparging in the LiCl side of contactor (bismuth-thorium/LiCl phases, KZ)'

ORNL DWG 76-8T78
2.0 T T I T T

%,
l
|

(dpm/qg x 10-6)
o

0.5 e -RESERVOIR -

A - CONTACTOR

147TNd CONCENTRATION

] I 1 1 |
OO 20 40 60 80 100 120
TIME (hr)
Fig. 7. Neodymium concentration in the fluoride salt in the reservoir

and contactor during run Nd-1.

ORNL DWG 76-881

[ | | [ I I
N , STOPPED
o LiCl IN THE CONTACTOR FLUORIDE STOPPED
:5 LiCl INT T SALT LiCl
1 ‘ HE STRIPPER CIRCULATION CIRCULATION
= 0.60 _
Z ® A 1
o
'_
<
(o'l
—
< 040 .
s
S e 2
=
D 0.20 _
= e = CONTACTOR
o a = STRIPPER
Wl
=

0 1 | | |

0 20 40 60 80 100 120

RUN TIME (hr)

Fig. 8.
stripper during run Nd-1.

Neodymium concentration in the LiCl in the contactor and
ORNL DWG 76-882

0.40

0.30

0.20

0.10

NEODYMIUM CONCENTRATION (ug/q)

S
CIRCULATION CIRCULATION

T I T I T T
STOPPED
FLUORIDE STOPPED

LiCl

b

° s
o4 T
A A
¢ ® —
A
A e =FLUORIDE SALT SIDE OF CONTACTOR
a=LiClI SIDE OF CONTACTOR
| | ] l ] |
20 40 60 80 100 120
RUN TIME (hr)
Fig. 9. Neodymium concentration in the bismuth-thorium in the

contactor during run Nd-1.
'47 Nd CONCENTRATION (dpm/g x 1073)

Fig.

10.

-7~

ORNL DWG 76 -899

. J J (& ¢ ¢ ¢ J ] |

20 40 60 80 100 {20
TIME (bhr)

Neodymium concentration in the bismuth-5 at. 7 lithium in
the stripper during run Nd-1.
'47Nd CONCENTRATION (dpm /g x 10-6)

ORNL DWG 76-350 R2

5.0
I D D R R A
4 0 | STOPPED FLUORIDE STOPPED LiCl ]
: SALT CIRCULATION CIRCULATION
3.0 ~© 1 l _—

N S O N T O O O

20 40 60 80 100 120 140 160

TIME ( hr)

Fig. 11. Neodymium concentration in the fluoride salt in the
contactor during run Nd-3, MTE-3B.
NEODYMIUM CONCENTRATION (ug/qg)

ORNL DWG 76-884

0.5 T 1 I T T I I
STOPPED
o LiCl
0.4} CIRCULATION —
A -~
// \‘
,/
0.3 _
®
&
o
0.2~  gsToPPED * ] o
FLUORIDE °
) SALT
CIRCULATION a
0.4 ¢ A —~
* e:FLUORIDE SALT SIDE
a=LiCl SIDE
i | I 1 1 I 0
20 40 60 80 100 120 140 160 180
RUN TIME (hr)
Fig. 12. Neodymium concentration in the bismuth-thorium solution in

the contactor during run Nd-3.

NEODYMIUM CONCENTRATION

(pg/q)

ORNL DWG 76-911

2.5 T T l I T T I T
= CONTACTOR
= STRIPPER
2.0} -
STOPPED
STOPPED FLUORIDE . LiCl
SALT CIRCULATION CIRCULATION
A
1.5 —
[ )]
. &
///’ ° °
®
/
CXS——/ A —
/A
o | | | I ] I 4 I
0 20 40 60 80 100 120 140 160 180

RUN TIME (hr)

Fig. 13. Neodymium concentration in the LiCl in the contactor and
stripper during run Nd-3.

'47Nd CONCENTRATION (dpm /g x 107°)

4.0

3.0

2.0

ORNL DWG 76-35t R2

STOPPED FLUORIDE 0] © ©
SALT CIRCULATION T

l ;

STOPPED LiCl

CIRCULATION N
—
ole N S I N O B
0 20 40 60 80 100 120 140 160
TIME (hr)

Fig. 14. Neodymium concentration in the bismuth-5 at. % lithium in
the stripper during run Nd-3, MTE-3B.

147TNg  CONCENTRATION (dpm/g x 1076)

ORNL DWG 76-352Ri

>0 T T 1T T T T T T T T T T 1
— Ba—
STOPPED FLUORIDE STOPPED LiClI
4 Ol— SALT CIRCULATION CIRCUIATION |
3.0 —]
4@"-0-(}_@ ] n
) ©° % ow O——0— ©
2.0*"— 0 © o
!
'—— R —
o]
|.O— —
ol | [N VN S S I I O N N N B
0] 20 40 60 80 100 120 140 160
TIME (hr)
Fig. 15. ©Neodymium concentration in the fluoride salt in the contactor

during run Nd-4, MTE-3B.

...-Z E—
ORNL DWG 76-917

1 l | ] | | I |
STOPPED FLUORIDE STOPPED LiCl
SALT CIRCULATION SALT CIRCULATION
—~ 05 - ® = FLUORIDE SALT SIDE —
2 A = LiCl SIDE
o
3
-~ o
5 0.4 (— A . .
2 A e
3 Py A ®
= 7”7
& 0.3 A o o —
3 / . ,
A w
(S}
5 / i
=) —
s 0.2
)—
O
o
w
=z
0.1 —
o | | | l | | ] l | |
0] 20 40 60 80 100 120 140 160 180

RUN TIME (hr)

Fig. 16. Neodymium concentration in the bismuth-thorium in the
contactor during run Nd-4.

NEODYMIUM CONCENTRATION

2.0 T T T I I ] T T
e - CONTACTOR
STOPPED FLUORIDE a = STRIPPER
SALT CIRCULATION
15 —
STOPPED LiCl
/_NCULATION
, | ,
t.oF / —
[ ] /
/ .
0.5 "_/ ‘ ‘ @ ]
;o : :
o L | { 1 1 1 s | i
0 20 40 60 80 100 120 140 160

ORNL DWG 76-896

RUN TIME (hr)

Fig. 17. Neodymium concentration in the LiCl in the contactor and

stripper, run Nd-4.

180
ORNL DWG 76-353RI

SO 7171 T T T T T T T T T T T T T 1

147Ng CONCENTRATION (dpm /g x 10-5)

|
2.0+ — v
STOPPED FLUORIDE STOPPED LiCl ‘
| SALT CIRCULATION CIRCULATION _
1.0 -
o [ i | | N T R R R e | l i L]
o) 20 40 60 80 100 120 140 160
TIME ( hr)

Fig. 18. Neodymium concentration in the bismuth-5 at. %Z lithium in the
stripper during run Nd-4, MTE-3B.

~36—

More scatter and fewer points appear in these data. However, it is felt
that the figures for the total neodymium content more nearly represent the
true concentration in these solutions since the results obtained by the
counting of samples from these solutions were unrealistically high (by a
factor of 3). The difficulty seemed to be a bias in the counting data
at these very low neodymium concentrations (< 1 ppm).

Tabulations of the concentrations of 147Nd tracer and the total

neodymium for all samples removed during runs Nd-1 through Nd-4 are included

in the Appendix.
5.2 Entrainment Studies in Experiment MTE~3B

Based on previous studies in awater-mercury system,15 it was
concluded that entrainment of fluoride salt into the bismuth and LiCl phases
in the mechanically agitated contactor would occur if the agitators were
operated at speeds of 5.0 rps or higher. However, in the first metal
transfer experiment, MTE-3, entrainment was not observed at 5.0 rps but
was seen at 6.7 rps.l6

Since fluoride salt entrainment occurred at an agitator speed of 5.0
rps in experiment MTE-3B, a series of tests were made to determine the
maximum allowable agitator speed that could be used in experiment MTE-3B
without entrainment. The tests were conducted by operating the agitators
in the contactor at several different speeds (3.3, 4.6, and 5.0 rps) for
time periods ranging from v 50 to v 140 hr. During each test at
constant agitator speeds, samples of the LiCl salt were removed from the
contactor and analyzed for fluoride content. An increase in fluoride ion
concentration would indicate entrainment of fluoride salt into the LiCl.
Figure 19 shows the fluoride ion concentration in the LiCl as a function
of time for each agitator speed. The initial concentration of fluoride
ion of Vv 4 wt % represents the amount of entrainment that occurred over
a period of v 250 hr during runs Nd-1 and Nd-2. The sequence of agitator
speeds shown in Fig. 19 represents the order in which the tests were run.
An increase in the fluoride ion concentration is clearly indicated in the
v 50~-hr test at 5.0 rps. At agitator speeds of 3.3 and 4.6 rps, no
entrainment (within experimental limits) appears to have occurred over the

v 200-hr combined test periods at these two speeds.

.

ION

FLUOQRIDE
CONCENTRATION (wt %)

280

ORNL DWG 76-349RI
I l | | l
{
© 5@ © °© o

’ ©
4— .

e— 5 Orps »¢— 3 3rps M¢———--—— 4.6rps ———¥
X 1 | | | | |

0 40 80 120 160 200 240

TIME (hr)

Fig. 19. Results of tests to determine the entrainment rate of fluoride
salt into LiCl as a function of agitator speed, MTE-3B.

~38—

These results indicated that experiments could be carried out at
agitator speeds up to about 4.5 rps without entrainment,and experiments
Nd-3 and Nd-4 were conducted using agitator speeds of 4.2 and 1.67 rps.
It was also concluded that rapid determinations of fluoride ion concentration
in the LiCl during experiments were needed to verify that no entrainment was
occurring. For this purpose, an Orion Model 801A pH/mV meter* equipped with

specific ion (fluoride) electrodes was obtained for rapid analyses of LiCl

samples. The mV meter could also be used to continuously measure and
record the emf between the two bismuth phases in the contactor and
stripper vessels that contained different concentrations of lithium
reductant (0.0015 and 0.050 atom fraction lithium). A change in emf would
indicate a change in the lithium concentration ratio in these phases
(Sect. 5.3) with a resultant change in the equilibrium distribution
coefficient for neodymium and thorium between the salt and bismuth phases.

5.3 Neodymium and 147Nd Inventory in Experiment MTE-3B

Weighed amounts of neodymium, as NdF3, containing 147Nd tracer were

added to the fluoride fuel salt in the fuel salt reservoir on three
occasions during operation of metal transfer experiment MTE-3B. The NdF

and 147Nd tracer were prepared by the Isotopes Division of ORNL. The

3

NdF3 containing the tracer was placed in a specially designed charging
capsule used to add the neodymium to the fuel salt (Fig. 20). The
capsule was sealed by a spring-loaded disc which was soldered to the
capsule. When inserted into the molten fuel salt (Vv923 K), the solder
melted and opened the capsule, allowing the NdF3 to disperse into the
fuel salt. Capsules were inspected after each addition to ensure that
all of the neodymium had been transferred into the fuel salt.

147Nd and total neodymium inventory during each run in metal
transfer experiment MTE-3B was followed by both counting and chemical
analyses of samples of the salt and bismuth phases. The concentration of
147Nd was determined by counting the 0.53-MeV gamma emitted, while the
concentration of the total neodymium was determined by an isotopic dilution

mass~spectrometry technique.

*0rion Research, Inc., Cambridge, Mass.
-39~

RN WG 76-874

N L -0.Dx0028 WALL 316
ud/ STAINLESS STEEL TUBING
© il
N WELD TUBE TO CAP
ik /
i
é I
10
(e
Eod
o
i | 'flc
: [
71
w/: ¥ A4—
T A 3
G
N
\ N -1 -20 THREAD
ALL DIMENSIONS N \\
IN INCHES \ | STAINLESS STEEL SINTERED
METAL FILTER
nl© Ry N
~N .
N
N N — STAINLESS STEEL SPRING
"IN COMPRESSION
\ b
N N
N N
_JZiil_,J,_fifi /e
WELD SPRING TO TUBE * |

N 1-THICK CARBON STEEL DISC.
SOLDER TO TUBE USING
50-50 LEAD-TIN SOFT SOLDER

WALL AND DISC

Fig. 20. Capsule used to add neodymium containing lA?Nd tracer
to the fuel salt in experiment MTE-3B.

~40-

Table 6 compares the neodymium and 147Nd inventory in metal
transfer experiment MTE-3B based on the amounts added to the system and
those calculated from the concentrations in all phases determined by
sampling. As seen in Table 6, the inventory of neodymium and 147Nd tracer
determined by sampling was in good agreement with the amounts added,
varying between 84 and 1007 for each of the four runs,

These results indicate that (1) the losses of neodymium were
insignificant, (2) the neodymium remained dispersed in the salt and bismuth
solutions, and (3) the sampling procedures provided samples that adequately
represented the concentrations of neodymium in the salt and bismuth
solutions.

5.4 Lithium Reductant in the Bismuth Solutions in the
Contactor and Stripper

The equilibrium distribution coefficients for neodymium (and other
rare earths) between the salt and bismuth solutions in the metal transfer
process are dependent on the lithium reductant concentrations in the
bismuth solutions (Sect. 2). Therefore, mass-transfer coefficients for
the rare earths are dependent on these equilibrium distribution
coefficients.

During the runs in experiment MTE-3B, the concentrations of lithium
reductant in the bismuth solutions were known initially. The relative
concentrations of lithium in the bismuth in the contactor (v 0.0015 m.f.)
and in the stripper (v 0.05 m.f.) were determined during the experiments
by measuring the emf between these two bismuth solutions. The contactor
and stripper vessels are electrically isolated from each other by an

' and the bismuth solutions

electrically insulated "isolation flange,'
are connected by the molten LiCl that circulates between the contactor
and stripper. The relative concentrations of lithium in the bismuth

solutions can be calculated from the emf measurement by the following

equation:

emf = -RT/nF 1n C,/C,, (16)
where

emf = emf developed between the two solutions, V,

n = valence,

R = gas constant = 1.987 cal/mole"-K,
F = Faraday = 23,050 cal vL (g-equiv)'l,
Table 6. Neodymium and 147Nd inventory and mass balance in metal transfer experiment MTE-3B

Nd by sampling (%)

Nd added to system Nd determined by sampling Nd added
Run Total Nd Nd-147 Total Nd (g) Nd-147 (mCi) Total Nd Nd-147
number (g) (mCi) Start End Start End Start End Start End
1 2.24 71.4 2.10 2.11 63.1 59.9 93.7 94.2 88.4 83.
2 4,61 83.5 4.10%9 - 73.0% —- 88.9 — 87.4 —
3 5.91 148.9 4.98 5.03 144.1 144.1 84.3 85.1 96.8 96.
4 5.91 148.9 5.12 5.32 150.9 131.5 86.6 90.0 100.3 88.

a,. . . ) .
Final inventory not determined due to fluoride salt entrainment.

42

Cl’ C2 = concentrations of lithium in the two bismuth solutions.
For the concentrations of lithium reductant in the bismuth phases
in experiments conducted in MTE-3B, the expected emf was "v 275 mV.

Measurements of emf taken intermittently during runs Nd-1 and Nd-2
gradually decreased from ~ 300 mV to v 25 mV near the end of run Nd-2,
indicating loss of lithium reductant in the stripper (see Table 7).

(This loss of lithium in the stripper was caused by the entrainment of
fluoride fuel salt into the LiCl and by subsequent reaction of the
thorium in the fuel salt with the lithium. It resulted in no further
extraction of neodymium as was observed.)

In the final two experiments, Nd-3 and Nd-4, the emf between the
contactor and stripper was followed continuously by using a recording
millivolt-meter. No entrainment of fluoride fuel salt occurred during
these runs,and the emf between the bismuth solutions remained essentially

constant at v 250 mV, indicating no significant change in the

concentrations of lithium reductant.
5.5 System Performance

Installation of metal transfer experiment MTE-3B was essentially
complete in February 1975. During March 1975, the process vessels were
pressure tested (both at room temperature and at an operating temperature
of v 923 K); and the intermal surfaces of the process vessels and
charging vessels were hydrogen treated at v 923 K to remove residual
oxides. After the hydrogen treatment, all vessels were maintained under
purified argon (v 0.1 ppm of H20) to prevent oxidation. The addition of
all salt and bismuth solutions to the process vessels was completed during
May 1975 with the system at the operating temperature of " 923 K.

The initial experiments (Nd-1 and Nd-2) were carried out in June
1975, and, after removal of the LiCl from the contactor and stripper
and the removal of the bismuth-~-5 at. % lithium from the stripper, fresh
LiCl and bismuth--5 at. % lithium were added to the system. The final
two experiments (Nd-3 and Nd-4) were conducted during January 1976.

The system was not cooled to room temperature until the first week of
April 1976; thus the system was maintained at the operating temperature
of v 923 K for about 11 months. The three agitators in the contactor

and stripper vessels were operated for about 700 hr at speeds ranging

-

Table 7. Measurements of emf between the bismuth solutions in the
contactor and stripper vessels during runs Nd-1 and Nd-2
T in metal transfer experiment MTE-3B

| Calculated lithium concentration

} Run time® emf Li-Bi in stripper
| (hr) (mV) (atom fraction)
; Run Nd-1
} 0 300 0.052
6.8 225 0.020
| 18 200 0.015
| 49 200 0.015
71 195 0.014
‘ 108 195 0.014
| Run Nd-2
:
. 0 165 0.0095
| 11.5 165 0.0095
30.8 155 0.0084
48.1 124 0.0057
63.6 100 0.0042
78.1 88 0.0036
100.1 25 0.0016

a . , \ . ,
Run time = time from start of fluoride salt circulation.

bBased on the assumption that the initial concentration of lithium
~ (0.0012 at. %) in the bismuth-thorium phase in the contactor
remained constant throughout runs Nd-1 and Nd-2. The initial
concentration of lithium in the bismuth-lithium alloy in the
stripper was "~ 0.050 at. Z%.
4l ~

between 100 and 300 rpm (1.67 to 5.0 rps) during this period. The
fluoride salt pump was in operation for ~ 295 hr, and LiCl circulation was
maintained for v~ 475 hr. With the exception of one of the agitator seals
which developed a leak and allowed inleakage of argon buffer gas into the
system shortly after terminationof the last run (Nd-4), all equipment
functioned without incident throughout the life of the experiment.
Specifically, no heater, thermocouple, or control system malfunctions
occurred. Also, no leakage of salt or bismuth from the system was
observed. The outside surfaces of the carbon steel process vessels were
inspected after shutdown to determine the effectiveness of the oxidation-
resistant spray coating (METCO No. P443-10) in protecting these surfaces
against oxidation at the operating temperature. The outside surfaces
were found to be in excellent condition, with only a small amount of
oxide present.

During the four runs conducted in metal transfer experiment MTE-3B,
807 samples of the salt and bismuth solutions were taken for analyses.
As discussed above, the sampling procedures adequately obtained

representative samples of the process solutions.
6. DISCUSSION OF RESULTS

The objectives of metal transfer process experiments MTE-3 and
MTE-3B were to measure the rate of removal of representative rare-earth
fission products from a molten-salt breeder reactor fuel salt and to
evaluate the suitability of mechanically agitated contactors for the
metal transfer process. Thus it was necessary to determine the overall
mass-transfer coefficients for rare earths at the three salt-bismuth
interfaces in the system and to study the effect of agitation on the
transfer coefficients in stirred contactors.

In metal transfer process experiments MTE-3 and MTE-3B, only the
overall mass-transfer coefficients were measured, as discussed in Sect. 4.
Results of individual mass-transfer coefficients in stirred contactors in

5, 18-20 In

which the phases are not dispersed have been reported.
these studies, mass-transfer coefficients in organic-water, mercury-water,
and LIF—-BeFZ—ThF4 salt~bismuth systems were determined, and correlations

were developed which relate the individual mass-transfer coefficients for
F

~45-.

each phase to the properties of the solutions and system parameters such
as the size and speed of the stirrer. The reported dependence of the
mass~transfer coefficient on the agitator speed varied widely.

The overall mass-transfer coefficients obtained for neodymium
at the three salt-bismuth interfaces in the five runs in experiments
MTE-3 and MTE-3B at agitator (stirrer) speeds ranging from 1.67 rps to 5.0
rps are shown in log-log plots in Figs. 21-23. Direct correlation of the
effect of agitator speed on mass-transfer coefficients cannot be made
because other system parameters — particularly the equilibrium
distribution coefficients for neodymium — were not the same for all rums.
Also, since the overall mass-transfer coefficients were determined by
simultaneous solution of seven differential equations to determine mass
balance, precise values for the three coefficients calculated for each
run are not possible.

Although there is a great deal of scatter in the data shown in Figs.
21-23, the overall mass—~transfer coefficients generally increase with
increasing agitator speed as predicted. Direct comparison of selected
values from those runs in which only the agitator speed was changed
(e.g., runs 3 and 4) clearly shows an increase in the overall mass-
transfer coefficients when the agitator speed was elevated from 1.67 to
4,17 rps. Similarly, a comparison of runs 6 and 7 (conducted in a
previous experiment MTE-3) shows an increase when the agitator speed was
elevated from 3.33 to 5.0 rps. A dashed line of slope 1 is included on
these figures for reference purposes only. Various correlations developed
in the cited references indicate that mass-transfer coefficients are
proportional to agitator speed raised to a power between 0.9 and 1.65.

The overall mass-transfer coefficients for rare earths across the
salt and bismuth phases determined in experiments MTE-3 and MTE-3B were
only about 1 to 50% of those that would be predicted by currently
available correlations, with the largest discrepancy occurring at the
lithium chloride--bismuth interfaces. Further studies are required in
order to obtain correlations that would reliably predict the overall mass-
transfer coefficients for stirred contactors if this type of contactor is
to be used in a full-scale processing plant to remove the rare-earth
fission products. In addition to the influence of agitator speed and
physical properties of the several solutions, the effect of scale-up

to larger processing equipment requires further investigation.

46~

ORNL DWG 76-883

-2 100 150 200 250 300

10 I T T I I |
’.-
Z
w
o
T

(3)
o "
o
o —
uw 9o /
v 2 -3 —
2\10 [ _— ]
< E —
xo -
- —
7] —
wn - [ |
q —
3 —
{4) -
2 !L,”/
_
@ - [ |
w
>
o (6)
[ ]
10° | ] | | ] |
1.9 2.0 2.1 2.2 2.3 2.4 2.5
LOG AGITATOR SPEED (rpm)

Fig. 21. Overall mass-transfer coefficients for neodymium at the

fluoride salt-bismuth interface at agitator speeds of
100-300 rpm. Numbers in parentheses refer to run numbers.
The dashed 1ine of slope 1 shown for reference purposes
only.
47—

ORNL DWG 76-879

AGITATOR SPEED (rpm)

1 100 150 200 250 300
| 1 ] 1 ! |
(1)
[
E: -
L140° 2 P -
E il
U -
= (6) _—"
- —
z —
w —
— /
(&) —_—
w -
w //
wl // (3)
S - ]
-
T é (4)
™y »
w
2
a
@
’_
0 1073 .
<
-
.|
-
a
@
w
>
o
10-4 | I ] i ] |
1.9 2.0 2.1 2.2 2.3 2.4 2.5
LOG AGITATOR SPEED (rpm)
Fig. 22. Overall mass-transfer coefficients for neodymium at the

lithium chloride-bismuth interface in the contactor at
agitator speeds of 100-300 rpm. Numbers in parentheses
refer to run numbers. The dashed line of slope = 1 is
shown for reference purposes only.
~48—

ORNL DWG 76-877

AGITATOR SPEED (rpm])

10 -1 10C 150 200 250 200
| | 1 ] !
m (6) |(7)
@
€
~ 1072 =
/
- —
—
5}
o ’/,f” m (1
w —
W
: —
// | ] (3)
o //
tI.‘l.LJ —
n -
4 //
L= ¢ |~
s 4
—
v
w
<
=
L1073 —
4
<
@x
5
o m(4)
10-4 1 ] | 1 1 |
19 2.0 21 2.2 2.3 24 25

LOG AGITATOR SPEED ( rpm)

Fig. 23. Overall mass-transfer coefficients for neodymium at the
lithium chloride/bismuth--5 at. % lithium in the stripper
at agitator speeds of 100-300 rpm. Numbers in parentheses
refer to run numbers. The dashed line of slope = 1 is
shown for reference purposes only.
~4,9—

An important feature of the metal transfer process is the selective
separation of thorium from the rare earths at the bismuth--1ithium

chloride interface. Rare earth-thorium separation factors, defined as

Som = DTh/D (17)

RE’
have been determined to be in the range of 164 to 108 for the trivalent and
divalent rare earths.® Thus negligible loss of thorium from the fuel
salt occurs in the process. Because of entrainmment of the fluoride salt
into the LICl in experiment MTE-3B, it was not possible to determine the
separation factor. However, during studies in the first experiment
MTE-3, in which the rare earths europium, lanthanum, and neodymium were
used, the separation factors were estimated based on the total amount of
thorium (% 10 wt ppm) found in the bismuth--5 at. 7 lithium alloy in the
stripper after about 400 hr of operation. Separation factors
DTh/DRE for these rare earths in the order of lO4 to 106 were indicated.
Preliminary calculations, using a computer code developed by W. L.
Carter2l at ORNL, have been made to estimate the contactor size and
operating conditions that would be required in order to remove the
rare—-earth fission products at the design rate22 from the reference MSBR.
For these calculations, the rare earth neodymium was chosen as a
representative example. The design removal rate of neodymium is ~ 1.2 g-
moles (v 174 g) per day for a breeding ratio of 1.06. (Note: Reducing
the rare-earth removal rate would not have a prohibitive deleterious effect
on the breeding ratio — a threefold reduction would lower the breeding
ratio by about O.Ol.)23 In these calculations, the effects of several
parameters (mass-transfer coefficients, interfacial area, salt and
bismuth flow rates, and number of extraction stages) on the removal rate
of neodymium were evaluated, and a combination of parameters that would
be required to meet the design removal rate was determined.
Results of these calculations are summarized in Table 8. The
cases shown were selected to indicate the effect of several variations on
neodymium removal rates. The fuel-salt flow rate of 0.9 gpm (5.7 x 10_5
m3/sec) was held constant for all cases since it is the design fuel-salt
flow rate for the reference processing plant. Three contactor stages

were used for all but one case since this seemed to be a reasonable compromise

based on preliminary calculations. For case 1, the values of overall mass-
-50-

transfer coefficients at the three salt-bismuth interfaces (Kl’ KZ’ K3)
are representative of those obtained in our experimental studies. The
area of 1 ft2 (0.093 m2) per stage, the bismuth flow rate of 3 gpm

(1.9 x lO-4 m3/sec), and the LiCl flow rate of 30 gpm (1.9 x lO_3
m3/sec) were chosen as a basis for further extrapolation. As seen in
Case 1, the neodymium removal rate of 0.003 g-mole/day is about a
factor of 400 below the design value of 1.2 g-moles/day. Increasing
overall mass-transfer coefficients at the LiCl-bismuth interfaces

in the contactor and stripper by a factor of 5 (case 2) increased the
removal rate by about a factor of 4. The effect of increasing the
interfacial contact areas to 10 and 20 fr2 (0.94 and 1.9 mz) is seen in
cases 3 and 4, and the effect of increasing the number of stages

from 3 to 6 is seen by comparing 4 and 5. The results from increasing
the bismuth and LiCl flow rates to 6 gpm (3.8 x lO_4 m3/sec) and

60 gpm (3.8 x 10_3 m3/sec) is seen in cases 7 and 9. 1In case 8,

the overall mass-transfer coefficient, K, at the fluoride salt--bismuth
interface is increased by a factor of 10.

Finally, the desired removal rate is reached by use of the parameters
shown in case 11. For the choices made, a neodymium removal rate of 1.3/
g-moles/day is indicated for the following system:

salt and bismuth interfacial areas/stage = 20 ft2 (1.86 mz),

fluoride salt flow rate = 0.9 gpm (5.7 x lO_5 mz/sec),

bismuth flow rate = 18 gpm (1.1 x 10—3 mzlsec),

LiCl flow rate = 60 gpm (3.8 x lO_3 mz/sec),

K1 = 0.16 mm/sec, Ky, = 1.0 mm/sec, and K3 = 4.0 mm/sec.

The values for Kl and K2 at the fluoride fuel salt--bismuth and LiCl--
bismuth interfaces in the contactor (case 11) are about a factor of

10 higher than those observed in metal transfer experiments. Results
from studies in the water-mercury contactors indicate that an increase
of about a factor of 10 in the mass~transfer coefficient might be
expected with increased agitator turbine diameter over those used in the
metal transfer experiments (1.4 m vs 0.073 m).24 The value for Ky at
the interface between the LiCl--bismuth and the 5 at. % lithium in the
stripper (case 11) is about a factor of 100 higher than that observed in

metal transfer experiments. This large increase would likely require

; -51-

increased agitation to the point of some degree of dispersion of the

salt and bismuth in the stripper; however, this would probably be

acceptable since the likelihood of bismuth entrainment back into the

fuel salt is minimal in the stripper vessel.

Other combinations of the various parameters could be used to achieve

the required removal rate of neodymium. Calculated results, shown in

| Table 8, are intended to indicate the effect of several parameters on
the removal rate in a full-sized multistage metal transfer process for the
removal of rare-earth fission products (using neodymium as an example)

from a 1000-MW(e) MSBR.

7. CONCLUSIONS

The objectives of the metal transfer process experiments were (1)
to study the various steps in the process, (2) to measure the rate of
removal of rare-earth fission products from the molten-salt reactor fuel,
and (3) to evaluate the suitability of a mechanically agitated contactor
for use in the process.

Conclusions relating to these objectives are as follows:

1. During 15 experiments in engineering-scale process

equipment, representative rare-earth fission products

| (europium, lanthanum, and neodymium) were extracted from
molten-salt breeder reactor fuel salt (72-16-12 mole 7
LiF—BeFZ—ThF4) and transferred into bismuth-lithium alloy in
the stripper vessel.

2. 1In those experiments in which entrainment of fluoride salt into
the LiCl salt did not occur, the rare earths were selectively
transferred (with respect to thorium) into the bismuth-lithium
alloy. Separation factors of about 104 to 106 estimated in
these experiments compare favorably with predicted values of
about 104 to 108 for trivalent and divalent rare earths. Thus
negligible loss of thorium from the fuel salt would occur in thz

| process.

3. Overall mass-transfer coefficients measured at the three salt-
bismuth interfaces (fuel salt-bismuth, bismuth-LiCl, and LiCl~--
bismuth~lithium) in the process were lower than would be required

for full-scale metal transfer process equipment of reasonable size.
Table 8.

on neodymium removal rate in the metal transfer process

using mechanically agitated contactors

Summary of calculations on the effect of various parameters

Nd removed

Salt and Bi flow (m3/sec)

Mass transfer coef.

Area
DSSEZI (gigoiEZ) £:§i Bismuth Licl Ky (mmézeC) K3 (mz/stage) oguzgz;es
1 0.003 5.7 x 10° 1.9 x 100% 1.9 x 10> 0.016 0.030  0.040 0.093 3
2 0.013 5.7 x 107° 1.9 x 1004 1.9 x 107> 0.016 0.15 0.20 0.093 3
3 0.11 5.7x10° 1.9 x 1004 1.9 x 102 0.016 0.15 0.20 0.93 3
4 0.18 5.7x10°° 1.9 x 100% 1.9 x 107> 0.016 0.15 0.20 1.86 3
5 0.24 5.7 x 10° 1.9 x 10°% 1.9 x 1072 0.016 0.15 0.20 1.86 6
6 0.37 5.7 x10° 1.9 x 1004 1.9 x 107> 0.016 0.75 1.0 1.86 3
7 0.55 5.7 x 102 5.7 x 1004 1.9 x 107> 0.016 0.75 1.0 1.86 3
8 0.67 5.7 x 1000 5.7 x 100" 1.9 x 1070 0.16 0.75 1.0 1.86 3
9 0.61 5.7 x10° 5.7 x 10" 3.8x10° 0.016 0.75 1.0 1.86 3
10 1.05 5.7 x 10° 5.7x10°% 3.8 x10°  0.16 1.0 40.0 1.86 3
11 1.37 5.7 %x 10° 1.1 x10°° 3.8x 10> 0.16 1.0  40.0 1.86 3

_.53_

4. The overall mass-transfer coefficients increased with
increasing agitation (agitator speed) as expected, but
meaningful correlations were not possible with the
limited data obtained.

5. 1In the equipment used in these experiments, the degree
of agitation (agitator speed) was limited by entrainment
of fluoride salt into the LiCl in the contactor. This
would require further evaluation and careful design of
mechanically agitated contactors for use in the metal

transfer.

The effect of increased equipment size (diameters of the process
vessels and agitator paddles) on the overall mass—-transfer coefficients
and rate of removal for the rare earths was not studied and need addi-

tional investigation.

8. ACKNOWLEDGMENTS

The authors gratefully acknowledge the assistance of many Oak Ridge
National Laboratory staff members during the course of the two metal
transfer process experiments. The design, installation, and operation of
of the first experiment MTE-3, together with the analysis of the results,
were done by E. L. Youngblood, L. E. McNeese, W. L. Carter, and W. F.
Schaffer, Jr. The following members assisted greatly with the second
experiment MTE-3B: J. Beams, C. H. Brown, Jr., R. M. Counce, R. B.
Lindauer, and R. O. Payne, experimental operation; W. R. Laing, H. A.
Parker, and R. L. Walker, chemical analyses; and W. L. Carter and E. L.

Youngblood, data analysis and interpretation. The secretarial assistance

of Carol Proaps is greatly appreciated.

10.

11.

12.

13.

14.

15.

~54—

/. REFERENCES

R. C. Robertson (ed.), Conceptual Design Study of a Single-
Fluid Molten-Salt Breeder Reactor, ORNL-4541 (June 1971).

L. E. McNeese, Engineering Development Studies for Molten-Salt
Breeder Reactor Processing No. 5, ORNL/TM-3140, pp. 2-15 (October
1971). :

U. S. Patent No. 3,853,979 (Dec. 1974).

L. E. McNeese, Engineering Development Studies for Molten-Salt
Breeder Reactor Processing No. 9, ORNL/TM-3529, pp. 196-215 (December
1972).

C. H. Brown, Jr., et al., Measurement of Mass~Transfer Coefficients
in a Mechanically Agitated, Nondispersing Contactor Operating with a

Molten Mixture of LiF‘Ber‘ThE4 and Molten Bismuth, ORNL-5143
(November 1976).

L. M. Ferris et al., "Distribution of Lanthanide and Actinide
Elements Between Molten Lithium Halide Salts and Liquid Bismuth
Solutions,” J. Inorg. Nucl. Chem. 34, 2921 (1972).

L. M. Ferris et al., "Equilibrium Distribution of Actinide and
Lanthanide Elements Between Molten Fluoride Salts and Liquid Bismuth
Solutions, J. Inorg. Nucl. Chem. 32, 2019 (1970).

L. E. McNeese, Engineering Development Studies for Molten Salt
Breeder Reactor Processing No. 10, ORNL/TM-3352, pp. 57-59 (Dec. 1972).

E. L. Youngblood et al., in MSBR Semiannu. Progr. Rept. Aug. 31, 1972,
ORNL~4832, pp. 168-71.

Chem. Tech. Div. Annu. Progr. Rep. Mar. 31, 1973, ORNL-4883, pp. 23-25.

L. M. Ferris et al., "Distribution of Lanthanide and Actinide Elements
Between Liquid Bismuth and Molten LiCl-LiF and LiBr-LiF Solutions,"
J. Inorg. Nucl. Chem. 34, 313 (1972).

G. J. Janz et al., Molten Salts: Vol. 1, Electrical Conductivity,
Density and Viscosity Data, NSRDS-NBS 15 (October 1968).

MSRP Semiannu. Progr. Rep. Aug. 31, 1969, ORNL-4449, Tables 13.12,

13.13, p. 146 (February 1970).

R. N. Lyon (ed.), Liquid Metals Handbook, NAVEX0OS P-733,
Office of Naval Research (June 1, 1950).

L. E. McNeese, Engineering Development Studies for Molten-Salt
Breeder Reactor Processing No. 10, ORNL/TM-3352, pp. 53-57

(December 1972).

16.

17.

18.

19.

20.

21.

22.

23.

24,

—55—

Chem. Tech. Div. Annu. Progr. Rep. Mar. 31, 1973, ORNL-4883, p. 25.

D. D. Sood and J. Braunstein, "Lithium-Bismuth Alloy Electrodes
for Thermodynamics Investigation of Molten LiF-BeF., Mixtures,"
Flectrochem. Soc. 121 (2) 247 (February 1974).

J.

J.

D.

W.

W.

W.

B.

R.

J.

L.

L.

Lewis, Chem. Eng. Sci. 3, 248 (1954).

Olander, Chem. Eng. Sci. 18, 123 (1963).

McManamey et al., Chem. Eng. Sci. 28, 1061 (1963).
Carter, ORNL, personal communication.

Carter and E. L. Nicholson, Design and Cost Study of a

Fluorinator-Reductive Extraction-Metal Transfer Processing

Plant for the MSBR, ORNL/TM-3579 (May 1972).

L. E. McNeese and M. W. Rosenthal, "MSBR: A Review of Its Status and
Future," Nucl. News 17 (12), 52-58 (September 1974).

J. R. Hightower, Jr., Engineering Development Studies for Molten-

Salt Breeder Reactor Processing No. 24, ORNL/TM-5339 (in preparation).

56—

APPENDIX A: SAMPLE ANALYSES FOR EXPERIMENT MTE-3B

14
The concentrations of 7Nd tracer and total neodymium in each of

the seven salt and bismuth phases in metal transfer experiment MTE-3B

during runs Nd-1 through Nd-4 are tabulated in Tables A-1 through A-8.

14 .
The 7Nd tracer concentrations were determined by counting the 0.53-MeV

gamma emitted by the 147Nd tracer. Values are corrected for decay during

the run (t = 11 d). Results for total neodymium were obtained by

1/2
chemical anglyses using an isotopic dilution mass spectrometry procedure.
All samples were counted for 147Nd contents. Analyses for total
neodymium were done on a limited number of representative samples (1) to
establish that the 147Nd—tracer data represented the total neodymium
concentration, (2) to verify the adequacy of the sampling procedure, and
(3) to check on the accuracy of the inventory of the neodymium in the

system.
-57—

1
Table A-1. Concentrations of 47Nd in the salt and bismuth phases?
during run Nd-1,° MTE-3B

Run 147Nd concentration (dis min_l g_l)C
time FSV FSC BTF BTC CSC CSS BLS
(hr) x 10 x 10° x 104 x 104 x 10% x 10% x 107
f
0 1.37 0 0 0 0 0 0
1.6 1.31 0.60 1.40 0.63 1.12 0.68 0.044
4.8 1.18 1.05 1.93 1.20 2.41 2.42 0.17
6.8 1.20 1.14 2.26 1.20 3.36 2.57 0.29
9.6 1.15 1.13 2.11 1.30 0.77 2.84 0.48
12.6 1.23 1.18 1.96 1.37 3.42 2.42 0.53
15.6 1.21 1.13 1.53 1.28 3.41 2.92 0.85
18.1 1.18 1.13 1.03 0.93 4.08 2.61 1.0
22.6 1.22 1.17 1.59 1.29 2.09 2.28 1.13
25.6 1.27 1.18 2.50 1.29 4.57 2.97 1.19
29.1 1.18 1.11 1.50 1.12 2.95 2.93 1.50
33.1 1.25 1.22 1.76 0.99 2.82 4.13 1.71
37.1 1.19 1.11 1.66 1.53 2.32 3.84 1.63
41.1 1.14 1.12 1.87 2.34 3.52 3.08 1.81
45.1 1.20 1.17 0.99 1.24 3.97 2.21 1.68
49.1 1.16 1.18 1.52 1.29 3.50 2.84 2.35
55.8 1.20 1.17 1.95 1.53 5.11 —- 2.68
61.6 1.16 1.12 2.33 1.75 3.35 2.40 2.94
71.6 1.16 1.15 2.10 1.47 4.02 2.82 3.60
79.6 1.10 1.09 2,19 1.66 3.78 2.81 3.45
85.8 1.03 1.06 1.84 1.41 4.85 2.87 3.58
96.8 1.07 1.07 1.16 2.28 3.98 1.80 4.35
96.9 Stopped fluoride salt circulation
98.8 1.09 1.03 1.78 0.98 2.19 2.39 4.60
100.8 1.04 0.94 0.91 1.20 4.26 2.05 6.50
103.8 1.08 0.93 0.93 1.16 3.12 <6.79% 4.66
106.8 1.11 0.84 1.42 1.25 3.24 <5.27% 4.66
108.8 1.01 0.78 1.80 0.83 2.24 <15.8% 4.92
112.8 1.23 0.71 0.91 1.08 <6.59%  <1B.4% 5.45
115.8 1.16 0.71 1.52 0.93 <7.31*% <14.8% 5.06
115.8 Stopped LiCl circulation
A® 1.05 0.62 1.04 0.93 <12.9% <h.T4* 5.18
B 1.01 0.63 0.56 0.47 T<4,11% <2.11% 4.56
C 1.02 0.56 0.77 0.57 8.98%* <0.25% 5.13
aFSV = fluoride salt in the reservoir; FSC = fluoride salt in the contactor;
BTF = bismuth-thorium in the fluoride salt side of the contactor; BTC =

bismuth—thorium in the LiCl side of the contactor; CSC = LiCl in the con-
tactor; CSS = LiCl in the stripper; BLS = bismuth-lithium in the stripper.

b, .

Agitator speed = 5.0 rps.

Co. . \ - .

Disintegrations per minute per gram of solution corrected for decay.
d . . . . .

Run time = time elapsed after start of fluoride salt circulation.

eEquilibrium conditions with no salt circulation.
. .. -1 -1

fThis value is read as 1.37 x lO6 dis min ~ g .

*These values are questionable due to use of different procedure and counting

equipment.
—58-

Table A<2. Neodymium concentrations in the salt and bismuth phases?
during run Nd~1,b MTE-3B

Run Neodymium concentration (Lg/g)
time FSv FSC BTF BTC CSC CSS BLS
(hr)©
0 21.6 0 0 0 0 0 0
9.6 17.8 0.15 0.15 0.14 0.03 0.11
18.1 17.6
22.6 17.9 0.91
25.6 0.36 0.06 0.57
29.1 0.25
33.1 16.5 18.3 0.35 0.57 1.96
41.1 0.27
49.1 17.6 0.27
55.8 16.9 0.17 0.11 0.14 2.24
79.6 17.2 21.3 0.10 0.38 0.25 5.04
96.8 Stopped fluoride salt circulation
100.8 0.31
103.8 15.8
106.8 16.7 0.10 0.11 0.32 0.31
115.8 16.1 0.08 3.22
115.8 Stopped LiCl circulation
d 17.4 9.2 0.08 0.17 0.78 <0.01 3.36

8FSV = fluoride salt in the reservoir; FSC = fluoride salt in the contactor;

BTF bismuth thorium in the fluoride salt side of the contactor; BTC = bismuth-
thorium in the LiCl side of the contactor; CSC = LiCl in the contactor; CSS =
LiCl in the stripper; BLS = bismuth--5 at. % lithium in the stripper.

bAgitator speed = 5.0 rps.
“Run time = time elapsed after start of fluoride salt circulation.

d i L . . .
Equilibrium conditions with no salt circulation.
-59-
Table A-3. Concentrations of 147Nd in the salt and bismuth phases?
during run Nd-2,P MTE-3B
Run 147Nd concentration {(dis min'—l g-l)c
time FSV FSC BTF BTC csc CSS BLS
hr)d  x 10° x 10° x 104 x 104 x 10% x 10 x 10
0 1.61f 0.058 0.12 0.11 <0.56 <0.38 0.56
2.2 1.48 1.02 1.92 1.03 "4.92 T 1.41 0.53
7.0 1.43 1.26 2.96 1.88 8.54 1.68 0.89
11.0 1.47 1.44 2.82 1.62 6.01 3.29 1.16
15.0 1.38 1.35 1.73 0.89 4.82 2.68 1.49
19.0 1.41 1.35 0.98 0.89 5.53 4.40 1.80
23.0 1.35 1.38 1.76 1.41 7.01 5.16 2.21
27.0 1.36 1.30 3.61 1.39 7.10 4,27 2.57
31.0 1.35 1.26 2.05 1.38 8.01 4.86 2.78
35.8 1.41 1.27 2.68 1.45 7.30 3.12 3.29
42.1 1.37 1.34 2.35 1.47 11.8 4.09 3.87
49.0 1.31 1.22 1.49 1.45 6.82 3.81 5.02
57.0 1.27 1.22 2.50 2,14 7.25 5.22 4.90
63.3¢ 1.25 1.19 2.19 1.42 11.1 9.42 6.42
70.8 1.28 1.25 2.35 1.78 14.0 14.1 5.98
78.8 1.31 1.43 3.48 2.37 35.1 44.6 5.39
87.3 1.19 1.52 3.45 2.60 44,8 50.3 1.65
94.5 1.37 - 2.98 2.48 29.7 28.2 0.57
102.5 1.26 1.34 2.23 1.95 19.1 20.3 0.43
110.8 1.38 1.39 2.05 1.34 20.4 22.4 0.46
121.3 1.35 1.22 3.70 1.78 20.8 21.7 0.42
130.3 1.40 1.36 2.43 2.33 21.8 22.6 0.46
138.3 1.36 1.44 2.45 1.95 19.9 19.8 0.39
139.0 Stopped fluoride salt and LiCl salt circulation
146.8 1.47 1.42 2.13 2.08 22.1 22.4 0.39
145.1 1.39 1.51 2.04 1.85 55.6 21.9 0.44
164.0 1.42 1.42 1.16 2.02 21.0 20.7 0.40
171.0 1.61 1.53 2.29 1.71 17.4 23.5 0.46
Apgy = fluoride salt in the reservoir; FSC = fluoride salt in the contactor;
BTF = bismuth-thorium in the fluoride salt side of the contactor; BIC =

bismuth-thorium in the LiCl side of the contactor; CSC = LiCl in the contactor;
CSS = LiCl in the stripper; BLS = bismuth--5 at. % lithium in the stripper.

bAgitator speed = 5.0 rps.

Coi: . . . . .
Disintegrations per minute per gram of solution corrected for decay during
run.

time from start of fluoride salt circulation.
147

Run time =
Nd in LiCl indicated loss of reductant in stripper.

-1

e .
Increase 1n

. <1
fThis value is read as 1.6l X 106 dis min = g

-60-

Table A-4. Neodymium concentrations in the salt and bismuth phases?
during run Nd-2,P MTE-3B

Run

time Neodymium concentration (ug/g)

(hr)c FSV FSC BTF BTC CSC CSS BLS
0 30.4 9.2 0.08 0.17 0.34 <0.01 3.36
2.2 0.55
7.0 7.8

11.0 0.34

15.0 33.6 32.9 0.21 0.10 11.9
19.0 1.33 0.42

35.0 29.1 0.03 0.06 0.92 0.32 7.6
42.1 29.7 26.3 0.06 0.88 0.71 15.1
57.0 0.25

78.84  41.2 33.6 0.45 32.8

102.5 36.0 47.6 0.32 0.03 8.0 0.59

130.3 35.4 1.09 5.3 0.83

138.3 0.27

139.0 Stopped fluoride salt and LiCl circulation

146.8 7.6

171.0 35.4 0.32 0.07 8.0 1.01

182.0 37.0

8FSV = fluoride salt in the reservoir; FSC = fluoride salt in the contactor;

BTF bismuth-thorium in the fluoride salt side of the contactor; BTC =
bismuth-thorium in the LiCl side of the contactor; CSC = LiCl in the contac-
tor; CSS = LiCl in the stripper; BLS = bismuth--5 at. Z lithium in the stripper.

bAgitator speed = 5,0 rps.

“Run time = time elapsed after start of fluoride salt circulation.

Increase in the neodymium concentration in the LiCl in the stripper and
decrease of the neodymium concentration in the Bi--5 at. %Z lithium in the
stripper indicated loss of lithium reductant in the stripper.
—61-

|
| Table A-5. Concentrations of 147Nd in the salt and bismuth phasesd

during run Nd-3,b MTE-3B

Run 147Nd concentration (dis min 1 g_l)d
; e FSV FSC BTF BTC csC css BLS
| time 6 6 4 4 4 4 5
| (hr) x 10 x 10 x 10 x 10 x 10 x 10 x 10
|
: e
‘ 0 3.67 0 0 0 0 0 0
| 1.5 3.05 1.88 3.55 1.94 0.7 0.7 0
4.3 3.27 3.07 4,22 3.62 3.63 1.35 0
11.5 2.99 3.00 4.85 2.50 3.87 3.33 0
| 18.8 ———— Stopped Fluoride Salt Circulation
| 19.8  2.88 2.78 4.55 3.21  21.7 9.84 0.052
| 27.0 - 2.77 4 .04 2.56 26.6 40.1 0.16
| 35.7 - 2.52 4.20 3.01 19.4 19.3 0.66
43.8 —- 2.26 2.71 2.49 13.7 22.4 0.80
51.0 - 2.29 3.53 2.03 16.7 24,4 1.23
59.5 - 1.99 3.38 1.96 21.0 23.6 1.62
E 68.0  3.02 1.90 2.39 1.84  12.0 13.5 1.92
% 74.8 —- 1.84 2.62 1.63 22.4 24.1 2.11
| 83.5 —- 1.63 3.73 1.52 12.5 8.3 2,62
r 92.0 - 1.49 2.53 1.54 9.3 8.7 2.65
| 99.0 - 1.48 3.00 2.26 11.8 7.1 2.86
| 107.5 —- 1.31 1.46 1.08 7.4 9.8 3.26
| 107.8 Stopped LiCl Circulation
| 115.6 — 2.01 5,33 1.54 16.4 2.1 3.16
| 139.5 — 1.24 —- 1.24 15.5 <0.9 3.13
s 165.2 3.31 1.26 1.36 1.44 12.0 <0.8 3.15

contactor; BTF = bismuth-thorium in the fluoride salt side of the

i
r
]
E 4FSV = fluoride fuel salt in the reservoir; FSC = fluoride fuel salt in the
i
l contactor; BTC = bismuth-thorium in the LiCl side of the contactor; CSC =

| LiCl in the contactor; CSS = LiCl in the stripper; BLS = bismuth--5 at. 7%

' lithium in the stripper.

]

bAgitator speed in the contactor and stripper was 4.17 rps.

“Run time = time elapsed after the start of fluoride salt circulation.
dDisintegrations per minute per gram of solution corrected for decay.

6 -1 ‘

€This value is read as 3.67 x 10° dis mim'—1 g
—62-

Table A-6. Neodymium concentrations in the salt and bismuth phases,?
during run Nd-3,b MTE-3B

Run

time© Neodymium concentration (ug/g)

(hr) FSV FSC BTF BTC CSC CSS BLS
0 47.3 34.2 0.28 0.15 0.34 0.34 0.56
1.5
4.3 44.7 0.32 0.36 1.20 0.46 0.53

11.5

18.8 Stopped Fluoride Salt Circulation

19.8 47.7 46.3 0.42 0.59 2.24 0.56
27.0

35.7 40.9 0.08 0.34 1.67 1.53

43.8

51.0 35.7 2.27

59.5

68.0 30.7 0.11 0.25 1.08 1.82 4.34
74.8
83.5 26.5 5.05

92.0

99.0

107.5 21.7 0.20 0.14 0.71 0.50 5.17

107.8 Stopped LiCl Circulation

115.6 0.85

139.5 22.3 0.18 0.85 0.03

165.2d 47.2 20.7 0.17 0.10 0.03 7.28

Apsy = fluoride salt in the reservoir; FSC = fluoride salt in the
contactor; BTF = bismuth-thorium in the fluoride salt side of the
contactor; BTC = bismuth-thorium in the LiCl side of the contactor; CSC
LiCl in the contactor; €SS = LiCl in the stripper; BLC = bismuth—--5 at. %
lithium in the stripper.

i

bAgitator speed = 4.17 rps.
“Run time = time elapsed after start of fluoride salt circulation.

d s . . .
Equilibrium conditions with no salt circulation.

R g

. e o g TR T TR T T R e T T

—63—

Table A-~7/. Concentrations of 147Nd in the salt and bismuth phases?

during run Nd-4,b MTE-3B

RUD 147Nd concentration (dis min g:})d
. FSV FSC BTF BTC CSC CSS BLS
fime 6 6 4 4 4 4 5
(hr) x 10 x 10 x 10 x 10 x 10 x 10 x 10
0 3.31% 1.26 1.36 1.44 12.0 0.08 3.15
4,2 2.80 2.75 4.63 2.20 8.32 7.92 3.36
14.0 2.73 2.67 3.32 2.45 6.16 6.74 3.24
21.0 2.76 2.72 4,49 3.22 10.5 7.92 3.34
21.3 Stopped Fluoride Salt Circulation
28.3 - 2.77 3.98 2.67 8.93 1.58 3.35
36.8 -— 1.88 3.30 2.16 5.96 4.74 3.43
45.3 -- 2.39 2.84 2.30 6.35 7.72 3.57
52.3 —-= 2.38 5.42 2.49 8.83 11.4 3.62
60.8 - 2.23 3.37 2.49 7.22 5.50 3.59
69.0 2.59 2.28 3.76 2.19 7.11 8.69 3.68
76.3 - 2.47 5.69 2.47 7.86 6.17 3.78
84.8 - 2.36 3.01 2.51 11.0 11.3 3.91
93.2 - 1.88 7.37 2.31 8.04 9.80 3.87
100.5 - 2.21 2.59 2.25 5.72 21.7 4,12
109.4 - 2.12 3.03 2.61 5.15 10.3 3.89
109.5 Stopped LiCl circulation
117.0 - 2.34 3.62 2.59 11.4 <3.3 4.15
135.8 -- 2.37 3.30 2.41 20.8 2.3 4.06
165.9 - 2.35 4.55 2.25 29.2 <2.2 4.27

4rsy = fluoride fuel salt in the reservoir; FSC = fluoride fuel salt in the |
contactor; BTF = bismuth-thorium in the fluoride salt side of the contactor; |
BTC = bismuth~-thorium in the LiCl side of the contactor; CSC = LiCl in
the contactor; CSS = LiCl in the stripper; BLS = bismuth--5 at. 7 lithium
in the stripper.

bAgitator speed in the contactor and stripper was 1.67 rps.
“Run time = time elapsed after the start of fluoride salt circulation.

dDisintegrations per minute per gram corrected for decay.

-1

®This value is read as 3.31 x 106 dis min—1 g

6~

Table A-8. Neodymium concentrations in the salt and bismuth phases?
during run Nd—4,b MTE-3B

Run

time® Neodymium concentration (ug/g)

(hr) FSV FSC BTF BTC CSC CSS BLS
0 47.2 20.7 0.17 0.10 0.85 0.03 7.28
4.2

14.0 43,7 0.36 7.73

21.0 0.36 0.48
21.3 Stopped Fluoride Salt Circulation
36.8 0.42 0.39 4.27

45.3 41.6 0.35

52.3 0.38 0.45 9.13

60.8 40.2 0.35

69.0 47.3 0.46 0.63

76.3 0.29 7.46
84.8 37.2

93.2 37.8 0. 34 0.36 6.58

100.5 0.25 1.96 6.50

109.4 36.1 0.35

109.5 Stopped LiCl Circulation

135. 84 34.7 0.29 1.05 0.11 8.54

165.9¢ 36.0 0.34 0.85 0.03 8.40

262,04 36.1 0.29 0.25 1.34 0.03 9.24

4FSV = fluoride salt in the reservoir; FSC = fluoride salt in the contactor;
BTF = bismuth-thorium in the fluoride salt side of the contactor; BTC =

bismuth~thorium in the LiCl side of the contactor; CSC = LiCl in the
contactor; €SS = LiCl in the stripper; and BLS = bismuth--5 at. %
lithium in the stripper.

bAgitator speed = 1.67 rps.

CRun time = time elapsed after start of fluoride salt circulation.

quuilibrium conditions with no salt circulation.

co~Novin B~ Wk

= b= = = =
rLONRF O

=
o W

17-20.

NN
N

52.
53.
54,
55.
56.

57.

58.

59-60.

61-~172.

—65-

ORNL-5176
Dist. Category UC-76

Internal Distribution List

Brooksbank
Brown, Jr.
Burch

. Carter

Counce

Culler

. Dale

Daley
DiStefano
Egli, ERDA~ORO
Engel

. Ferguson
Ferris

Grimes

Glass

Hibbs
Hightower, Jr.
. Kee

Kelmers

OGRS PG OGHGENE SO0
UESWwHSOREREHRBCO O RERE O T

23.
24,
25.
26.
27.
28.
29.
30-32.
33.
34.
35.
36-39.
40.
41.
42,
43,
4.
45-46.
47.
48-50.
51.

Laing

Lenhard, ERDA-ORO
Leuze

MacPherson

. Malinauskas

. Matthews, ERDA-ORO
. McCoy

. McNeese

Newman

Postma

W. Rosenthal

C. Savage

D. Scott

F. Schaffer, Jr.
B

G

L

mECoHEP R

. Trauger

. Wymer

. Youngblood

Central Research Library
Document Reference Section
Laboratory Records
Laboratory Records (LRD-RC)

OO ZO0oOD 2o T O N0 G

Consultants and Subcontractors

W. K. Davis

E. L. Gaden, Jr.
C. H. Ice

R. B. Richards
D. 0'Boyle

External Distribution

Research and Technical Support Division, Energy Research and
Development Administration, Oak Ridge Operations Office, P. O.

Box E, Oak Ridge, TN 37830

Director, Reactor Division, Energy Research and Development
Administration, Oak Ridge Operations Office, P. 0. Box E, Oak

Ridge, TN 37830

Director, Division of Nuclear Research and Applications, Energy
Research and Development Administration, Washington, D. C. 20545
For distribution as shown in TID-4500 under UC-76, Molten-Salt

Reactor Technology

v U.S. GOVERNMENT PRINTING OFFICE: 1977-748-189/166