ML20054L802

Responds to NRC Re Violations Noted in IE Insp Rept.Corrective Actions:Std Operating Procedures Revised & Fuel Element Handling Tool Will Be Padlocked & Key Retained by Reactor Supervisor

ML20054L802
Person / Time
Site:	University of California - Irvine
Issue date:	05/07/1982
From:	Mcgaugh J CALIFORNIA, UNIV. OF, IRVINE, CA
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20054L794	List: ML20054L793 ML20054L802
References
NUDOCS 8207080492
Download: ML20054L802 (2)

Text

1 UNIVERSITY OF CALIFORNIA, IRVINE - I?

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42 EXfiCtfD VE VICE CHANCELLOR IltV1N6lCALIFORNI A 92717 May 7th, 1982 U.S. Nuclear Regulatory Commission, Region V, Reactor Operations Projects Branch, 1450 Maria Lane, Suite 210, Walnut Creek, CA 94596 Gentlemen:

Re: Notice of Violation, dated April 15th,1982, received April 20th,1982 We are requested under the terms of this notice to respond to (1) the corrective steps which have been taken and the results achieved; (2) corrective steos which will be taken to avoid further items of noncompliance; and (3) the date by which compliance will be achieved.

Our response is as follows:

Discussion.

Records (reactor log book) for June 8th,1981 indicate the following sequence:

Operator (senior) completed regular start-up, core excess measured at $2.90.

Personnel proceeded to move one graphite element from core position F-7 to core position G-5 and to move one fuel element from storage rack into F-7. The objective was to improve the excess value with pulse rods in core ( so-called

" pulsing excess" ) to a value closer to $3.00, the allowable limit. No notation was made in the log book as to the estimated reactivity change this move would involve, an item required by our Standard Operating Procedures at that time.

According to standard practice, the reactor was then brought critical at 1.5 watts indicated power to measure the excess change. When the operator noted that the reactor was stabilizing at critical with the REG rod at a reading of only 30 units, indicating on an extrapolated rod calibration curve, an excess of $3.75, he immediately scramed the reactor and proceeded to reduce excess by removal of two graphite elements from the G ring to storage. He again brought the reactor critical, obtaining a new indicated excess of $3.35 - a reduction of $0.40 by this measure. Repeating this procedure, two more graphites were -

removed, obtaining $3.12, and finally one more to indicate $3.02. At this time a recalibration run was performed on the REG rod yielding a more accurate excess value ( by period summation method ) of $2.92. He then proceeded to recalibration of other rods, confirming the new excess value.

A recent assessment, via direct comparison measurements (5/1/82) of the change in core excess between the two states:

Fuel in F-7, graphite in G-5 vs Fuel in storage, graphite in G-7 yields a value of +$0.32 for this differential. Thus we estimate that the probable actual core excess achieved on 6/8/81 was only $2.90 + $0.32 = $3.22.

Immediate corrective action was taken in that operation was suspended and excess reduced by removal of reactive elements ( two graphite units). This probably 82070so492 920702 DR ADOCK 05000326 o -

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U.S. Nuclear Regulatory Commission May 7th, 1982 Page 2 reduced the excess level below $3.00. The subsequent removal of three more I

graphite units certainly did so. The fuel change had apparently offset the REG rod calibration by approximately 10%.

Summary Position.

The reactor was operated at a power level of 1.5 watts or less - solely for the purpose of c5taining core excess values - for brief periods of time (less than 10 minutes total) at a maximum excess now estimated to be $3.22.

Immediate corrective action was taken and the excess reduced below the license limit before other operations were carried out. This action consisted in removal of reactive graphite units from core. There was no danger to the reactor or threat to the health and safety of the public or other personnel.

The probable over excess was less than 10% of the value of excess permitted.

Procedures were not correctly followed in that no written estimates of the changes in core reactivity as a result of any of the fuel or graphite element movement were made.

The incident was not treated by the Senior Operator involved, nor by persons who subsequently reviewed the logs as an Abnormal Occurrence and so no notifications to the NRC were made.

Detailed Response.

(1) As a result of discussions with the NRC Inspector involved, we have taken actions as follows:

Standard Operating Procedures have been revised, and the revisions approved by our Reactor Operations Committee:

(a) Wording requiring a record of the estimate of anticipated change in core reactivity prior to taking the reactor critical has been strengthened, and repeated in several sections of the 50P's.

(b) Additional sections have been included to require that written permission, in the reactor log, must be given by the Reactor Supervisor before ANY fuel movements in or out of core may be cormienced.

The above changes have been reviewed with all licensed and trair.ee operators.

(2) The following additional actions are planned:

(a) The fuel element handling tool will be padlocked and the key retained by the Reactor Supervisor, so that his physical involvement is assured before any fuel or graphite element movement can be accomplished.

(b) An additional section for the S0P is being prepared to assist operators in making reactivity change assessments as a result of common core movements.

(c) Discussions will be instituted with NRC personnel to see if wording changes can be proposed for the Technical Specifications which would allow small over-excess measurements to be made which would not automatically bacome Abnormal Occurrences.

(3) The date by which items 2(a) and (b) will be accomplished is June 1st,1982 (including appropriate notification of operators). Item 2(c) will take much longer.

S'ncerely m $yours, h dfG GEM /km/m J!l.McGaugh, Executive Vice-Chancellor