ML19294B733

Forwards Suppl to 791226 Ltr Re 791219 Ao.Encl,Minutes of 800109 Radiation Use Committee,Contains Actions & Recommendations to Correct Deficiency of Preliminary Rept

ML19294B733
Person / Time
Site:	05000142
Issue date:	01/11/1980
From:	Oneill R, Wegst W CALIFORNIA, UNIV. OF, LOS ANGELES, CA
To:	Reid R Office of Nuclear Reactor Regulation
References
NUDOCS 8003050439
Download: ML19294B733 (3)

Text

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UNIVERSITY OF CALIFORNIA, LOS ANGELES ,7 UCLA

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ggp sCHou 0F ENGINEERING AND APPLIED $CIENCE IJh ANGELES. CALIFOhNIA vsc4 January 11, 1980 Mr. Robert W. Reid, Chief Operating Reactors Branch #4/NRR U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Docket No: 50-142 License R-71

Dear Mr. Reid:

This letter is to supplement our letter of 26 December 1979 that reported an abnormal occurrence. That preliminary report by the staff has now been reviewed by our Radiation use Committee. The attached " Minutes" of the review meeting indicate that the preliminary report was accepted by the Comittee as accurate, but incomplete in regard to recomendations and actions to be taken to preclude a recurrence. The " Minutes" contain both actions and recom-mendations that are to correct the deficiency of the preliminary report.

Sincerely, k -

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R.R. O'Neill, Dean School of Engineering and Applied Science Reviewed and Approved by RR0/NC0/j cc: I. Catton, Director, NEL ff '. (d f !! Se /

T. Collins. Assistant Dean, SEAS W. Wegst, Director.

J. Evraets, RSO Research and Occupational Safety J.W. Hobson, Vice Chancellor R.H. Engelken, Director, USNRC Region V S

///

Nt'CLE \H ENERGY LABORATORY IV AN CATTON. DIRECTOR 3 8coaoso ,

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MINUTES RADIATION USE COMMITTEE 9 JANUARY, 1980 Members Present: Guests:

I. Catton N. Ostrander J. Hornor W. Wegst

9. Pomraning A. Zane Members Absent:

V. Dhir Professor Catton called the meeting to order and stated that the sole purpose of the meeting is to critique and amend a staff report of an abnormal occurrence. The event occurred on 12/19/79, and the staff provided a prelimi-nary report to the Nuclear Regulatory Commission by a letter dated 12/26/79.

That letter stipulated a more complete report, including a review by the Radiation Use Committee, on or before, January 15, 1980.

G. Pomraning noted that there were several typographical errors in the preliminary report. The Comnittee accepted the preliminary analysis of the event. I. Catton summarized the cause as arising from three contriuutory factors: (1) operator error, (2) training inadequacy, and (3) control cir-cuit deficiency. The contributing factors were acknowledged without attempt to order or weight the significance of each. It was noted that the operator error is irretrievable, and that attention should focus upon training and instru-mentation review.

The Committee agreed to changing the name of the linear recorder to " Power Recorder-Controller" . Monthly meetings of reactor operators were recommended, with the suggestion that such meetings review any procedural changes, and that brief quizzes be given to appriase operators of appropriate responses to hypo-thetical situations. The Reactor Supervisor was instructed to examine the possibility of using st:h meetings as a means of accomplishing the operator requalification program.

The Committee recommended the installation of an interlock between the instrument power switch and the scram circuit to force scram if power is removed from the controller. A. Zane, as Reactor Superviso" was instructed to deter-mine an appropriate method of implementing this interlock.

The Committee questioned whether other instrumentation could similarly cause an uncontrolied change in reactivity.

Dr. Wegst asked about the period meter and its inter-ties with the scram and inhibit circuitry. A. Zane responded that the period meter would demand

" inhibit" if the period fell below 6 seconds and " scram" at 3 seconds. He also remarked that " inhibit" would drop out the automatic power level controller.

Dr. Wegst ques ;ioned the logic of this coupling. He offered a scenario in which a rabbit of sufficient negative reactivity could be fired out of the reactor and thereby initiate " inhibit". The auto-controller would drop-out, and the reactor restored to " manual" with excess positive reactivity.

2 Mr. Hornor noted that a rod limit switch could also initiate inhibit, and

. that the real question was whether an operator would perceive the auto-controller drop-out. Although there are visual indications (auto versus manual lights, and a period-inhibit light), an operator could be engaged in normal duties such as log entries or chart marking, and fail to see the indications.

Dr. Catton suggested adding an audible signal and a timer that would initiate scram if the operator failed to acknowledge within a specified time interval.

Dr. Wegst reiterated his feeling that automatic drop-out of the controller is not the best logical response to " inhibit", and suggested that a more favor-able response might be a slow, controlled down-drive of the reg rod. By impli-cation, this might be accomplished by introducing a bias signal on the Wheatstone bridge of the controller until the inhibit condition is cleared.

Mr. Ostrander noted that this was a safety-related matter, and that a decision could not be made at the present meeting. Mr. Zane should examine the possibilities and provide a design change that would be submitted to the Committee for approval.

The meeting was adjourned. ,

A. Zane, Secretary Radiation Use Comittee Management Sumary Management will implement the recomendations of the Radiation Use Committee by the following actions:

1. A. Zane is instructed to initiate monthly meetings of reactor operators, and is to determine the feasibility of combining these meetings with the operator requalification program.

2. A. Zane will submit within 30 days, a plan for interlocking the recorder-controller power switch with the scram circuitry.

3. A. Zane is to examine thepossibility of revising the inhibit circuitry to effect down-drive of the reg red with a concurrent audible signal.

A progress report within 30 days is requested.

I i. .

N.C. Ostrander, Manager Nuclear Energy Laboratory