ML20072R137

RO 83-09:on 830326,plant Process Computer,Which Provides Indication of Linear Heat Rate w/in-core Detectors, Determined Inoperable.Power Reduced to 86%.Cause Unknown

ML20072R137
Person / Time
Site:	Millstone
Issue date:	03/28/1983
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
MP-4843, RO-83-09, RO-83-9, NUDOCS 8304050464
Download: ML20072R137 (1)

Text

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March 28, 1983 MP-4843 Mr. Ronald C. Ilaynes, Regional Administrator Region 1, U. S. Nuclear Regulatory Comission 631 Park Avenue King of Prussia, PA 19406

Reference:

Facility Operating License No. DPR-65 Docket No. 50-336 Reportable Occurrence RO 50-336/83-09

Dear Mr. Haynes:

This letter provides notification of Reportable Occurrence 83-09, pursuant to the requirements of Millstone Unit 2 Appendix A Technical Specifications, Section 6.9.1.8.b. This report concerns operation of the unit with a limiting condition for operation in a less conservative condition than is established in Technical Specifications. The limiting condition for operation affected was under the Power Distribution Limits section for linear heat rate, Section 3.2.1.

Specifically, Section 3.2.1 requires that the linear heat rate be monitored by the incore detector monitoring system or by the excore detector monitoring system. During steady state operation on March 26, 1983, the plant process computer which provides indication of linear heat rate with incore detectors was determined to be inoperable and power was reduced to 86% in accordance with action b for the Excore Detector Monitoring System power level limits.

Further review of the computer failure revealed it had been out of service for l nearly 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and that the plant had been operating for more than I hour in excess of the 89% power level limit as shown in Figure 3.2-2 under Section 3.2.1.

Further information will be provided in the two week report.

Yours truly, NORTHEAST NUCLEAR ENERGY COMPANY

w E. Mroczka 8304050464 830328 - -

Station Superintendent PDR ADOCK 05000336 S PDR Millstone Nuclear Power Station EJM/RWB: plt ,

cc: Director, Office of Management and Program Control, Washington, D. C. (3)

U. S. Nuclear Regulatory Comission, c/o Document Management Branch, Washington, D. C. 20555