05000245/LER-1982-001, Forwards LER 82-001/03L-0.Detailed Event Analysis Encl

Forwards LER 82-001/03L-0.Detailed Event Analysis Encl

ML20041A704
Person / Time
Site:	Millstone
Issue date:	02/10/1982
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20041A705	List: 05000245/LER-1982-001, Forwards LER 82-001/03L-0.Detailed Event Analysis Encl 05000245/LER-1982-001-03, /03L-0:on 820115,while Performing Steam Line High Flow Functional Test,Switches 261-2B & 261-2D Failed to Trip at Desired Setpoint.Caused by Setpoint Drift.Switches Recalibr
References
MP-1-2002, NUDOCS 8202220424
Download: ML20041A704 (2)

LER-1982-001, Forwards LER 82-001/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2451982001R00 - NRC Website

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February 10, 1982 f1P-1-2002 Mr. Ronald C Haynes U

Regional Administrator, Region 1 Q, X Office of Inspection and Enforcement

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Reference:

Provisional License DPR-21 b.N' -

Docket No. 50-245 Reportable Occurrence R0-82-1/3L b ze

Dear Mr. Haynes:

This letter forwards the Licensee Report for Reportable Occurrence R0-82-1/3L 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 E.

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

Attachment:

LER R0-82-1/3L 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 Regulatory Commission, c/o Document Management Branch, Washington, D.C.

20555 8202220424 820210

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Attachment to LER 82-1/3L Northeast Nuclear Energy Company Millstone Nuclear Power Station - Unit 1 Provisional License Number DPR-21 Docket Number 50-245 Identification of Occurrence A primary containment isolation function instrument setting was found to be less conservative than those established by Technical Specification.

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

Description of Occurrence On January 15,1982, at 1615 hours0.0187 days <br />0.449 hours <br />0.00267 weeks <br />6.145075e-4 months <br />, while performing Steam Line High Flow Functional Test, switches 261-2B and 261-2D failed to trip at their desired setpoint. Technical Specification, Table 3.2.1, requires the. main steam line high flow setting to be less than or equal to 120 percent of rated steam flow.

Apparent Cause of Occurrence Failure of the switches to trip at their desired setpoints is attributable to setpoint drift.

Analysis of Occurrence The primary function of the main steam line instrumentation is to detect a break in the main steam line, thus maintaining primary containment integrity by a Group 1 isolation.

For the worst accident, a main steam line break outside the drywell, the trip setting of 120 percent of rated steam flow in conjunction with flow limiters and main steam line closure, limit the mass inventory loss, such that fuel is not uncovered, fuel temperatures remain less than 1500 F and the release of radioactivity to the environs is below guidelines.

Switches 261-2B and 261-2D detect differential pressure on main steam line A and input to Channel B logic. The 2 remaining switches on main steam line A were found to be within their desired setpoint range and would have initiated the required action had an actual break occurred.

Additionally all the switches in main steam line B, C and D were found to be within their desired setpoint range.

Corrective Action

The switches in question were recalibrated to within their acceptable setpoint range and satisfactorily tested.

The switches were manufactured by Barton, Model 278, with a range of 0-200 psid.