ORNL-TM-0733REV.txt

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OAK RIDGE NATIONAL LABORATORY
operated by

UNION CARBIDE CORPORATION w
for the

U.S. ATOMIC ENERGY COMMISSION

 

 

ORNL- TM- 733 (Revised)

 

COPY NO. - ég

DATE -  August 3, 1965

MSRE DESIGN AND OPERATIONS REPORT
Part VI

OPERATING SAFETY LIMITS FOR THE MOLTEN-SALT
' REACTOR EXPERIMENT

S. E. Beall
R. H. Guymon

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NOTICE

This document contains information of a preliminary nature and was prepared
primarily for internal use at the Oak Ridge National Laboratory. It is subject
to revision or correction and therefore does not represent a final report. The
information is not to be abstracted, reprinted or otherwise given public dis-
semination without the approval of the ORNL patent branch, Legal and infor-
mation Control Department.

 
 

 

 

LEGAL NOTICE

This report was prepared as an account of Government sponsored work. Neither the United States,

nor the Commission, nor any person acting on behalf of the Commission:

A. Mekes any warranty or representation, expressed or implied, with respect to the accurecy,
completeness, or usefulness of the information contained in this report, or that the use of
any informaotion, apporatus, method, or process disclosed in this report may net infringe
privately owned rights; or

B. Assumes any ligbilities with respect to the use of, or for damages resulting from the use of
any information, apparatus, method, or process disclesed in this report.

As used in the above, "person acting on behalf of the Commission’ includes any employee or

contractor of the Commission, or employee of such contractor, to the extent that such employee

or contractor of the Commission, or employee of such contractor prepares, disseminates, or
provides access to, any information pursuant to his smployment or contraet with the Commission,

or his employment with such contracter.

 

 
~%-

MSRE DESIGN AND OPERATIONS REPORT

Part VI

OPERATING SAFETY LIMITS FOR THE MOLTEN-SALT REACTOR EXPERIMENT

S. E. Beall
R. H. Guymon

This document has been prepared at the request of the U. S. Atomic

Energy Commission to set the limits for various parameters related to the

Molten-Salt Reactor Experiment. In some cases the limits report the level

at which the reactor will be shut down by automatic monitoring devices.

In all cases the reactor operators are obligated to take steps intended to

correct a parameter which is temporarily outside the specified range indi-

cated herein.

1.0 Contaimment

1.1

Leakage from the primary system as indicated by the reactor and
drain-tank-cell air activity will not exceed the equivalent of
4 liters of salt after 120 days of operation at full power, as
estimated in the case of the Most Probable Accident.l Off-gas
activity release will be limited to fission-product concen-
trations averaging less than 1.5 x ZLO-LL uC/CC in the stack.
Fission product release will be monitored by radiation monitors

on the off-gas lines and at the stack.

The cover-gas supply pressure will be kept at 30 psig or greater
and the leak-detector system pressure above 50 psig to help pre-
vent excessive exposure to operating personnel, as specified in

Chapter 0524 of the AEC Manual.5

 

1

S. E. Beall et al., "MSRE Design and Operations Report, Part V,

Reactor Safety Analysis Report," USAEC Report ORNL TM-732, Ozk Ridge
National Laboratory, August 1964.

2Based on 5 x 10"9 uc/cc as permissible concentration at_ground level
downstream of the stack. An atmospheric dilution of 0.5 x 107 is assumed.

5Chapter 052k, "Standards for Radiation Protection.”
1.0

2.0

Containment (continued)

1.3 The radioactivity in the reactor cell service lines will be
maintained at a level sufficiently low to prevent excessive
exposure to personnel, as specified in Chapter 0524 of the

AEC Manual.

1.4 The pressure in the reactor and drain tank cells will be main-

tained below atmospheric pressure during reactor operation.

1.5 The maximum reactor and drain-tank-cell leak rate will not be
allowed to exceed 1% of the cell volume per day, calculated for
the conditions of the Maximum Credible Accident.l The in-

leakage rate will be determined at least once per week.

1.6 The maximum vapor-condensing system pressure (under nonaccident

conditions) will not exceed 3 psig.

1.7 The building high-bay pressure will be maintained at slightly
less than atmospheric pressure (~0.1 in. HBO) during all oper-
ations in which the high bay serves as the secondary contain-

ment.

1.8 The ventilation system filters will be tested at least annually

and after each change of filters.

1.8.1 The measured efficiency of the filters must be greater
than 99.9% for 0.5 p and larger particles, as indicated
by the standard dioctylphthalate test.

Fuel System

2.1 The maximum steady-state power level is 10 Mw (administrative

limit).
2.2 The power level for safety-rcd scram trip is 15 Mw or less.

2.3 The temperature level for safety~rod scram trip is less than
14000F. Adjustment of the trip between 1300 and 1400°F will

require administrative approval.

2.4 The maximum fuel system cover-gas pressure is 50 psig.
2.0

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2.6

2.7

no
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Fuel System (continued)

The maximum salt fill rate while filling the core 1s 1.0 ft5/min.
235

The maximum amount of U which will be added at one time 1is
120 g. During cperation fuel will only be added through the

sampler enricher.

The maximum concentration of fissionable material in the fuel
salt will not exceed by more than 5% the minimum required Tor
full-power operstion at 1200°F with equilibrium xenon and the
control rods poisoning 0.6% Sk/k. The fuel salt will be sampled

and the concentration measured at least once per week.

At no time during critical operation of the reactor will the re-
activity anomaly be allowed to exceed 0.5% $k/k. A "reactivity
anomaly" is defined as a deviation from the reactivity which is
expected on the basis of measured reactor physics constants and

calculated effects of burnup and fission product accumulation.

A positive period of 1 sec or less will cause a safety-rod scram.

Coolant System

3.1

b,1

L, 2

L,z

The maximum coolant system cover-gag pressure is 50 psig.

Control Rods

The normal complement of control rods 1s three, of which two

 

are reguired to scram for safety action.

The maximum scram time (time from initiation of signal until a

rod is on the seat) is 1.3 sec.

The rod speed (motor powered) is 0.5 ! 0.05 in./sec.
This speed permits maximum reactivity additions in "start" of

0.1% $k/k per sec and in "run" of 0.05% S$k/k per sec.

The scram time of the rods will be checked before each fill
with fuel salt.
5.0

7.0

6.

Nuclear Control and Safety Instrumentation

 

5.1

5.2

5.5

5.4

9.5

All nuclear safety instrumentation will be checked for proper

operation before each fill.

A minimum of two safety-level channels will be in service during

reactor operation.

A minimum of two reactor fuel outlet temperature signals will be

in service during reactor operation.

A minimum of one fission chamber with count-rate circuilt must be

in operation during startup filling operations.

A minimum of two positive period safety channels will be in

service during reactor operation.

Personnel Radiation Monitoring

 

6.1

Radiation level monitors

A minimum of two perscnnel radiation monitors will be in oper-
ation at all times, one in the high-bay area and one in the

control-rcom area.
Air monitors

A minimum of two air activity monitors will be in operation at
all times, one in the high-bay area and one in the office—

control-room area.

Personnel and Procedures

 

T.1

Personnel qualifications

The reactor will be operated only by qualified personnel ap-
proved by the Chief of Operations. It will be operated in con-
formance with documented operating procedures which, in no in-
stance, designate authorization to operate the reactor in excess

of any operating safety limits listed above.
7.0

8.0

Personnel and Procedires

 

7.2 The minimum staff requirement for operation during any shift is
that at least orie supervisor and two technicians will be on duty
during reactor operation. The control room will not be left un-

attended while fuel is in the reactor vessel.

Experimental Limits

 

Experiments will be conducted within the limits specified in this
report. Experimental procedures will be approved in advance by the
Head of the Operations Department, Oak Ridge National Laboratory

Reactor Division, or his authorized assistant.
lO.

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Blankenship

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Boch
Borkowski
Briggs
Burger
Cottrell
Crowley
Culler
Engel
Epler
Fraas
Gabbard
Gallaher
Grimes
Guymon
Harley
Haubenreich
Holt
Hudson
Kasten
Krakoviak
Lindauer
Lundin
Lyon
MacPherson

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McDonald

 

ORNL-TM-733%

REVISED
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2. H. McDhuffie

%3%3. C. K. McGlothlan

3h, A, J. Miller

35. R. L. Moore

36. H. R. Payne

3f. A. M. Perry

38. H. B. Piper

39. J. L. Redford

40. H. C. Roller

41. M. W. Rosenthal

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57. G. D. Whitman
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65. Laboratory Records, RC
66. C. E. Larson
67. S. J. Ditto

External Distribution

 

Division of Technical Information Extension, DTIE
D. F. Cope, Reactor Division, AEC, ORO

R. W. Garrison, AEC, Washington
H. M. Roth, Division of Research and Development, AEC, ORO
W. L. Smalley, Reactor Division, AEC, ORO

M. J. Whitman, AEC, Washington