ML20090E514

RO 84-2:on 840528,erratic Performance of Reactor Servo Control Not Noted in Log.Caused by Personnel Error.Operator Cautioned to Be More Observant While Taking Log Readings

ML20090E514
Person / Time
Site:	05000128
Issue date:	06/11/1984
From:	Willits R TEXAS A&M UNIV., COLLEGE STATION, TX
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
RO-84-2, NUDOCS 8407190493
Download: ML20090E514 (2)

Text

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TEXAS ENGINEERING EXPERIMENT STATION THE TEXAS A&M UNIVERSITY SYSTEM COLLEGE S14 TION, TEXAS 77843-3575 #

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11 June 1984 NUCLEAR SCIENCE CENTER 409/845-7551 32@ MOWS  %

Mr. E. Johnson Office of Inspection and Enforcement Region IV )( JUNI5 W U.S. Nuclear Regulatory Commission ,

p 611 Ryan Plaza Drive, Suite 1000 . . . - . ~ _ _ .

Arlington, Texas 76012

Dear Mr. Johnson:

I am forwarding the final report of the reportable occurrence of 28 May 1984.

This report is being submitted in accordance with NSC Technical Specification requirements Section 6.6.2 of the Nuclear Science Center Reactor, License R-83, Texas A&M University.

Respectfully, b

BarryWilli]ts, Manager Reactor Operations BW/ym Enclosure F

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ESEARcy EVELopy, FOR y,Nk/Ng l l a 1

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Reportable Occurrence iP84-2 Operation of the NSCR in Violation of the Technical Specification Limiting Conditions for Operation Reportable Occurrence On 28 May 1984 at-approximately 2202, it was not noted while completing log readings, that the reactor servo control was performing erratically. The operator noted that reactor power had increased slightly by observing the Safety Channel. The Linear Power Level Channel indication was noted to be low at this time, and the operator selected a lower scale setting observing that the signal to this instrument had apparently failed. The Senior Reactor Operator commenced a reactor shutdown in accordance with Standard Operating Procedure 50P III-C, while monitoring reactor power on the Log Power and Safety Channels of indication.

The Manager of Reactor Operations was informed of the situation and directed an investigation into the cause of the failure. The operators noted in the subsequent investigation that the high voltage power supply for the Linear Power Channel was switched off. The power supply was re-energized and the Linear Channel indication was observed to be normal. It is apparent that the high voltage power supply was inadvertantly de-erergized by the Senior Reactor Operator as his hand brushed across the power switch while taking the pool and instrumented fuel element temperature ieadings. The thermocouple selector switch for these temperatures is located just above the high voltage power supply switch in question.

Since th'e experiments under irradiation were essentially completed at the time of shutdown, the operators were directed to secure the reactor. On 29 May 1984, the Linear Power Channel was satisfactorily checked for proper operation during a pre-startup check, and the reactor was returned to normal operation.

Corrective Action This incident is being reported as a reportable occurrence since section 3.2.1 of the NSC Technical Specifications' states that the reactor will not be operated without the Linear Power Channel being operable. The operator acted properly in shutting the reactor down and informing NSC Management.

Though he stated that he does not recall de-energizing the high voltage power supply, and since only he and the reactor operator were in the facility and noting the proximity of the power supply switch to the temperature selector, any other explanation of how the power supply was de-energized is highly improbable. The operator was cautioned in being more observant while taking log readings. Since this is the first incidence of this or any similar occur-rence it is the determination of NSC management that no further action is necessary concerning this incident.

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