05000245/LER-1982-009, Forwards LER 82-009/03L-0.Detailed Event Analysis Encl

Forwards LER 82-009/03L-0.Detailed Event Analysis Encl

ML20052J037
Person / Time
Site:	Millstone
Issue date:	05/12/1982
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20052J038	List: 05000245/LER-1982-009, Forwards LER 82-009/03L-0.Detailed Event Analysis Encl 05000245/LER-1982-009-03, /03L-0:on 820412,while Performing High Pressure Scram & Containment Isolation Functional Calibr Test, Pressure Switch 2206-1612D Failed to Trip at Desired Setpoint.Caused by Setpoint Drift.Switch Replaced
References
MP-1-2064, NUDOCS 8205240347
Download: ML20052J037 (2)

LER-1982-009, Forwards LER 82-009/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2451982009R00 - NRC Website

text

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P O. DOX 270 HARTFORD. CONNECTICUT 06101 L

L TJ 55'5. 5[b'll.l' May 12, 1982 MP 2064 Mr. Ronald C. Haynes Regional Administrator, Region 1 Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406

Reference:

Provisional License DPR-21 Docket No. 50-245 Reportable Occurrence R0-82-9/3L

Dear Mr. Haynes:

This letter forwards the Licennee Event Report for Reportable Occurrence R0-82-9/3L required to be submitted within 30 days pursuant to the requirements of the Millstone Unit 1 Technical Specifications, Section 6.9.1.9.a.

An additional three copies of the report are enclosed.

Yours truly, NORTHEAST NUCLEAR ENERGY COMPANY A

E. J. Mroczka Station Superintendent Millstone Nuclear Power Station EJM/TST:mo

Attachment:

LER R0-82-9/3L cc: Director, Office of Inspection and Enforcement, Washington, D. C. (30)

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

U. S. Nuclear Regu?atory Conmission, c/o Document Management Branch, Washington, D. C. 20555 8205240347 820512 PDR ADOCK 05000245 Oy S

PDR 05 1

1

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ATTACHMENT TO LER 82-9/3L NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION - UNIT 1 PROVISIONAL LICENSE NUMBER DPR-21 DOCKET NUMBER 50-245 Identification of Occurrence Reactor protection system instrument setting was found to be less conservative than that established by Technical Specifications when a high drywell pressure switch tripped above its allowable setpoint.

Conditions Prior to Occurrence Prior to occurrence the unit was operating at a steady state power level of 100%.

Description of Occurrence On April 12, 1982, at 0925 hours0.0107 days <br />0.257 hours <br />0.00153 weeks <br />3.519625e-4 months <br />, while performing High Pressure Scram and Containment Isolation Functional Calibration Test, pressure switch 2206-1621D tripped at 2.1 psig. Technical Specifications, Table 3.2.1, requires a high drywell trip level setting of less than or equal to 2 psig.

Apparent Cause of Occurrence Failure of the switch to trip at its desired setpoint is attributable to setpoint drift.

Analysis of Occurrence Drywell pressure switch instrumentation detects a loss of coolant and initiates emergency core cooling equipment and a Group 2 isolation. These switches are provided as a backup to the water level instrumentation.

Failure of the switch to trip within its allowable setpoint range did not result in a condition that had not been previously analyzed.

The remaining 3 switches in the one-out-of-two twice logic were available. They would had initiated the required action had an actual high drywell pressure existed.

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Corrective Action

After unsuccessful attempts to recalibrate switch 2206-1621D, the microswitch was replaced. The new switch was calibrated and tested satisfactorily.

The pressure switch is a Bartcp Model 288, with a range of 0-5 psid.

Several similar incidents are Reportable Occurrence 81-36/3L and 79-32/3L.

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