ocr/ORNL-CF-60-12-111.txt

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OAK RIDGE NATIONAL LABORATORY
~ Operated by

Diisenof Union Caride Crpretion ORNL
Post ? BoxX . | CENTRAL FILES NUMBE_R
GO~ 12 - 11

Oak Ridge, Tennessee
s S | | External Distribution Authorized
I“ - . DATE:  December 13, 1960 =~ copv'No.égy/
2 SUBJECT: Homogeneous Molten Balt Reactors '

 

 

 

 

 

TO: Distribution
FROM: C. W, Néstor, Jr.

Z‘-‘ | . SUMMARY ‘_t

’Multigroup one-dimensional calculations were done recently to obtain
estimates of critical masses, power density distributions and fission=-
ing spectra for some homogeneous molten salt reactors having outer
reflectors and central "islands," placed inside the currently proposed
MSRE vessel. For a 5-inch-thick outer reflector and a l-ft-diameter
island, both beryllium, the calculated critical mass is 108 kg;
40 percent of the fissions occur at thermal, and the maximum power |
density of 3.9 times the core mean power density occurs at the island-
salt interface. If the reflector thickness is increased to 10 inches,
the critical mass is reduced to 34 kg; 67 percent of the fissions
occur at thermal, and the peak power density of twice the core mean
again occurs at the core island=-salt interface. }

g

NOTICE
A This document contains information of a preliminary nature -
- : _ o . and was prepared primarily for internal use ot the Ock Ridge
P National Laboratory. It is subject to revision or correction
’” o : _ and therefore does not represent a final report. The information
- is not to be abstracted, reprinted or otherwise given public

o : dissemination without the approval of the ORNL patent branch,
. o | . Legal and Information Control Department. -

 
 

-

A

v

 

HOMOGENEQUS MOLTEN SALT REACTORS

- C. W, Nestor, Jr.

Multigroup ohe-dimensional calculations were done recently to obtain
estimates of criticel masses, powef.density_distributions-andfissioning
spectra for*éame homogeneous molten salt reactors having outer reflectors
and central“islands,“ placed inside the currently proposed'MSRE véssel as
shown in Fig. 1;_ The salt camposition, listed in Teble l, is that of the |
Current MSRE mixture.l

Results of these calculations are given in Tﬁble 2,with earlier results
for the cgrrent.MSRE.and some results for bare hOmogeneous molten salt re-
actors,2 Included for cbmparison..waerdenéity shapes for the reflected

reactors are plotted in Figs. 2,'3,7h, and 5.

Teble 1. Selt Composition

Compound =~ : - Mole %

LiF | | | T0
Be32 . | 1 : - 23
UEh o . . . " ad (&s required for

criticality)

 

1w R. Grimes, letter of Aug. 23, 1960.

2 7. A. Lane, H. G. MacPherson and F. Maslan, eds., Fluld Fuel Reactors,

Addison-Wésley, 1958

 
 

 

“y

Island and

reflector
material

C
Be

BeO

Island and
reflector

material

C .

Be

BeO

Reflector'_

material
Cc
Be

BeO

..Reflector_ ,

material
C.
Be
Beof

Tgble 2

5" reflector thickness, 1 £t island diemeter

- | ' '~ Percent

Mole % Core critical thermal
uranium mass, kg ~ fissions
- 0,90 . 206 | ) 13.2
Ry - 168 | ':  ho.2
0.54 24 - 32.8

10" reflector thickness, 1 £t islend dismeter

Peréent

 

Mole % Core critical ‘thermal
uranium | mess, kg fissions
- 0.67 . 93 - 332
0.2 3 6T.3
0.28 39 62.0
5" reflector thickness, no island
- ' - o Pgrcent
Mole % Core critical thermal -
uranium _mass, kg fissions
.06 25 4.6
0,76 - 186 - 16.0
“10" reflector thickness, no islend
- Percent
Mole ¥ Core criticel  thermal
uranium mess fissions
085 130 20.6
0.43 65 k6.5

0.46 n k1.5

Median
fissioning
energy, ev
100-150
Te5~ 10

20 - 25

MEdian.'

fissioning

energy, ev
20 - 25

thermal

thermal

Median

fissioning

ener ev
150-400 -
50~ 65

- 80~ 90

Median
fissioning

- ener ev

65-80
- 008'1 ..h-
7 . 5"10 ’

 

 
 

Current MSRE (12 volume percent fuel salt, 88 volume percent graphite)

 

| | |  Median
Mole %. Core critical ‘Percent thermal fissioning
~uranium mass, kg fissions L energy, ev

0.27 13 | oLk o thermal

Bare molten salt reactor

(5 £t diameter sphere, 30 mole % L]3<~3F2 + 68 mole % LiF + 1 mole % ThF; + ~l mole % UFA)

 

_ : ' . - Medlan
Mole % - Core critical Percent thermal fissioning
- uranium ___Dass, kg ~ fisslons ‘ energy, €V
0.94 ' 239 . . 0.040 425

 
 

MIDPLANE

{

 UNCLASSIFIED
ORNL-LR-DWG. 64772

 

 

¢
(OR 18")
ISLAND CORE

 

 

33" (HALF-HEIGHT)

 

 

 

‘L—-G"‘—-h*—-—.—— '3" MM '0“ _—-’-

(OR 5")

REFLECTOR

 

 

 

 

~ Fig. 1. Reacfpf:Mbdél.:_

 
 

POWER DENSITY/AVERAGE POWER DENSITY

UNCLASSIFIED
ORNL-LR-DWG. 54773

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ISLAND - e _ CO'RE g REFLECTO&_'
4.0
Be
BeO
C
3.0
2.0
1.0
o l— . — _ ' a_—
o . - 10 B ‘ 20 _ : -~ 30

| ~ RADIUS, in.
Fig. 2. Po'wer-Dje_nsH:y Disiribuﬂoné Associated
‘with a 6" Island and a 5" Reflector.

 
POWER DENSITY/AVERAGE POWER DENSITY

0.5

3.0

2.5

2.0

1.5

1.0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RADIUS, in.

o Fig. 3. Power D'\ensii‘y Disiribuiions Associated
With a 6" Island and o 10" Outer Reflector.

UNCLASSIFIED
ORNL-LR-DWG. 564774
tseano | CORE o REFLECTOR
c
Bel \
BeO |
o 10 20 30

 
 

- POWER DENSITY/AVERAGE POWER DENSITY

UNCLASSIFIED
ORNL-LR-DWG. 54775

 

 

 

 

 

 

L b CORE sl REFLECTQR
2.0 7

I
1.5 l

 

 

 

 

 

 

 

 

 

 

Be
BeO | \ | BeO
o _ ' f AVERAGE |—
o= W
e | _ -
0.5 ' 8 S —
o 10 | 20 30

RADIUS, in.

Flg 4, Power Denssty Dlslributions Associoied

th a 24" Core cmd a 5" Reflecior

 
 

POWER DENSITY/AVERAGE POWER DENSITY

©

N

o

-
-

UNCLASSIFIED

ORNL-LR-DWG, 54776

 

m .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

e
yBeO
0
0 AVERAGE
8= =
5 .
0 10 20

RADIUS, in.

. Fig. 5. Power Density Distributions Associated
~ With a 19" Core and a 10" Reflector. o |

30

 
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33,
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Distribution

Alexsnder
Beall
Benson
Bettis
Bettis
Blankenship
Boch '
Bolt
Briggs
Bruce -
Burke
Campbell
Chambers
Charpie
Cobb
Conlin
Cook
Cristy
Crovley
Dougles
Ergen
Fraas
Frye
Gabbard
Gall
Grimes
Hise
Howell

‘Jordan

Kasten
Kedl
Kinyon

» Jandin

‘MacPnerson
Manly

~ Mann

McDonald

| McGlO'th.a.n

39.
Lo,
41,
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46,

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59.
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654
66.
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- 70

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72-
73-
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- 81-83.
e
85-99.

He
D.

R. L. Moore

J«. C. Moyers

D. J. Murphy
C. W. Nestor

T, E. Norbhup
L. F. Parsly
P. Patriarca
H. R. Payne

R. C. Robertson
H. W. Savage
Scott

P, Self

N. Smith
Spiewak

A. Swartout
A. Taboada

We G. Ulrich
D. C. Watkin
D. C. Watkin
A. M. Weinberg
Je. H. Westsik
C. H. Wodtke
L. L. Bennett
R. D. Cheverton
H. C. Claiborne
T. B. Fowler
M. P. LiE‘bZke .
B. E. Prince
M. Tobias

D. R. Vondy

D. We Vroom

Je. We Miller

R. VanWinkle
D, E. Ferguson
M. J. Skinner
C. E. Winters
REED Library
Central Res. Library
Document Ref. Library
Laboratory Records
ORNL-RC N
TISE, AEC

F.
A.
I.
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