ML20004D880

Ro:On 810527,during Preoperational Checkout,Polarizing High Voltage Was Removed from Safety Channel Compensated Ion Chamber Neutron Detector.Caused by Operator Inadvertently Reducing High Voltage Power Supply Output to Zero

ML20004D880
Person / Time
Site:	North Carolina State University
Issue date:	06/01/1981
From:	Bray T North Carolina State University, RALEIGH, NC
To:	John Miller Office of Nuclear Reactor Regulation
References
ADM-1-1-16-1, NUDOCS 8106100260
Download: ML20004D880 (2)

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NORTH CAROLINA STATE UNIVERSITY AT RALEIGH SCHOOL OF ENGINEERING -

Deranruxxx or Nuctura Escmarama Bos 5636 Zir 27650 1 June 1981  %)M h. .

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4 Mr James R. Miller, Chief o M O bn.

Standardization and Special Projects Branch

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Division of Licensing U.S. Nuclear Regulatory Commission

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Docket No.50-297 / /, , , -r(M Washington, D.C. '20555 Facility License 4 R-120 9

Dear Sir:

In compliance with NCSU PULSTAR Technical Specification 6.5.c. and 6.7.2.c. we hereby submit the following report:

During the PULSTAR reactor pre-eperational checkout on 27 May 1981, the m:rning shift reactor operator inadvertently removed the polarizing hl.gh voltage from the Safety Channel compenstced ion chamber nautron d .tector af ter having properly and successfu'.ly completed the channel -

t est on said Safety Power Channel. The operator then performed a r:utine startup and attained a steady power level of 100 kilowatts

( '0*'. of NCSU PULSTAR licensed maximum power) for some routine scheduled ,-

r . actor irradiations for a period of approximately two (2) hours.

J' the erfd of this two (2) hour period, the reactor was shutdown f or t'e lunch .eak.

W.ile performing a " key-on" checkout after lunch, the afternoon shift c:;erator noticed that the high voltage power supplies monitor meter indicated zero in the Safety Channel HVPS check position. At this t :'.me , the reactor operator notified the Designated Senior Operator a:d the Chief of Reactor Maintenance.

It was concluded that the morning shift operator had unintentionally reduced the Safety Chanael HVPS output to zero rather than the test source current power supply. The Safety HVPS shares one half of a standard 19-inch rack space in the reactor console with the channel-test current source occupying the other half. (The current source output is used to chanael-test the Safety Channel and is normally r??2 ed to zero after testing is successfully completed.)

Verbal examination of the morning shift reactor opera tor substanti-ated this conclusion.

Analysis of the subject occurecce in its entirety indicates the cause to be inattention en the part of the reactor operator to the pre-operational checkout procedure details. The occurrence is con-sidered to have been a function of tha operator performance only and hence the result of his own individual inattention to the check- o l i .a t steps being performed. We have performed over 2,000 such y

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pre-operational checklists at this facility and this occurrence is the first, therefore, we consider the console design and instrumen-tation layout net a factor in this event.

Immediataly following the subject occurrence, the Safety Channel HVPS control knobs were taped down to prevent another unintentional operation of the control knobs. A permanent metal shield will be attached over the HVPS knobs in a timely manner to prevent further recurrences of the subject event.

End of Report....

Postscript: We are aware of the change in definition of an "A0" produced by Sec'tioa 208 of the ERA of 1974 (Pub. L.

33 438), howevar, under our present Technical Specifi-cations 1.17.b. and 6.5.c., we are required to report

-the subject event as an Abnormal Occurrence. There exists now, in the planning stage, a proposed change to the NCSU PULSTAR Technical Specification to re-define our "A0s" as necessary to conform to Section 208 of the 1974 Snergy Reorganization Act.

Cnd of Postscript. ..

.Please notify me immediately should yo*u require additional information regarding this report. Telephene (919) 737-2323 or (919) 73 7-2 3 ?'? .

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Thomas C. Bray Acting Nuclear Operations Administrator TC3:Ish cc: M. Caudle Julian USNRC, Region II Dr. R.G. Cockrell NCSU RPC

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