ML20082B993

Discusses from DD Ebert of Univ of Maryland Re Operational Aspects of Fuel Temp Meter That Is Being Replaced & Which Did Not Have Cold Junction to Compensate for Room Temp Changes.Concurs W/Conclusions

ML20082B993
Person / Time
Site:	University of Maryland
Issue date:	07/03/1991
From:	Asmussen K GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER
To:	Alexander Adams NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
38-67-1765, NUDOCS 9107170251
Download: ML20082B993 (2)

Text

_ _ - _ _ _ _ _ - .

w

.- .. ~

\

\

• h C:N:RAL ATOMIC 3 July 3,1991 38/67-1765 Document Control Desk ATTN: Mr. Alexander Adams, Jr.

Non Power Reactor, Decommissioning and Environr' ental Project Directorate Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

TRIGA Reactor Fuel Temperature Monitoring

Reference:

Ebert, David D. (Reactor Director, University of Maryland at College Park) letter to Alexander Adams, Jr . dated May 8,1991.

Dear Mr. Adams:

During my visit to your office on May 23, 1991, you shared with me a letter (Reference) you had received from David Ebert, the Reactor Director at the University of Maryland at College Park. The letter discusses operational aspects of a fuel temperature meter that is being replaced and which did not have a cold junction to compensate for room temperature changes. General Atomics (GA) has reviewed the letter and concurs with the conclusion that at no time did the situation constitute a safety concern; it simply is a non-problem.

Dr. Carriveau, Director of GNs TRIGA Reactors' Product Division, offers the following observations regr.rding this type of fuel temperature monitoring device installed in GNs very early console systems:

1) To the best of GNs knowledge, a temperature monitoring device which did not include a room temperature compensation circuit was provided on a small number of the early console systems prior to 1970. GA contacted all of the current owners and users and has determined that they have either replaced this device with one containing a compensation circuit, or that they are operating in a manner similar to that described in the referenced letter. Please note that when these systems were first installed, they were calibrated at

,he room temperature at that time, so that they would indicate a correct temperature over their full scale range. The only error that would then be introduced would occur when the room temperature changed i

9107170251 910703 POR ADOCK 07000734 C PDR  ;

e O GENEllAL. ATO4ttCS CJJRT, SAN DIEGO CA 9/121 M94 PO BOX 85608, SAN Dl!GO. CA92186-9784 161% 455 3000 f

f'

4 .. -

Mr. Alexander Adams, Jr., U.S. NRC July 3,1991 38/67 1765 page 2 significantly. GA felt that this change (anticipated to be on the order of 5*C) would introduce an error of no more than 1% of full scale at the trip l' point. This is, of course, far smaller than the 50*C bias implemented by the

- University of Maryland.

2) General Atomics-initially provided the instrumentation console to the )

University of Maryland for use with their plate fuel (non TRIGA) core. This fuel did not have provisions for temperature monitoring. When General Atomics provided the core upgrade to TRIGA fuel. it was not in the scape of work to add temperature monitoring cepabilities.

3) General Atomics does not consider the small variations in the indicated fuel temperature that may occur through changes in the room temperature, to be

. a safety problem. Note that this condition may cccur only in a vety limited number of the older consoles. To the best of GA's knowledge, the current owners have changed the circuitry or have changed the temperature scram

- point. The more modern instrumentation provided in the past twenty years contains compensation circuitry to mitigate any influence that a change in room temperature could possibly introduce.

4) Finally, note that severallow power (s250 kW) steady state TRIGA reactors operate without fuel temperature monitors because the maximum fuel temperature is so low (=150 C) compared to the typical license limit of 400"C for such steady state reactors.

GA hopes this information assists in the understanding of this situation. If you should have any questions regarding the above, please contact me at (619) 455-2823 or Dr. Gary Carriveau at (619) 455 3569.

Very treif yours, Keith E. Asmussen, Manager Licensing, Safety and Nuclear Compliance KEA:shs -

cc: Mr. John B. Martin, Regional Administrator, NRC Region V Dr. D. D. Ebert, U. of Maryland at College park