05000298/LER-1982-001, Forwards LER 82-001/03L-0.Detailed Event Analysis Submitted

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

ML20041C381
Person / Time
Site:	Cooper
Issue date:	02/17/1982
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20041C382	List: 05000298/LER-1982-001, Forwards LER 82-001/03L-0.Detailed Event Analysis Submitted 05000298/LER-1982-001-03, /03L-0:on 820122,reactor Vessel Level Switch NBI-LIS-72C Failed to Trip at Tech Spec Setpoint.Caused by Misalignment of Switch Mechanism.New Switch Calibr & Installed
References
CNSS820078, NUDOCS 8203010253
Download: ML20041C381 (2)

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

Event date:
Report date:
2981982001R00 - NRC Website

text

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g Mr. John T. Collins, Regional Administrator W

U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.2 of the Technical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on January 22, 1982. A li-censee event report form is also enclosed.

l Report No.:

50-298-82-01 Report Date:

February 17, 1982 Occurrence Date: January 22, 1982 Facility:

Cooper Nuclear Station i

l Brownville, Nebraska 68321 Identification of Occurrence:

A condition which could have resulted in operation in a degraded mode permitted by the limiting condition for operation established in Table 3.2.B of the Technical Specifications.

Conditions Prior to Occurrence:

The reactor was at a steady state power level of 100% of rated power.

Description of Occurrence:

During the performance of a routine surveillance procedure, it was noted that NBI-LIS-72C switch #2 failed to trip until approximately 20 seconds had passed after reaching its Technical Specification setpoint.

Designation of Apparent Cause of Occurrence:

Investigation into the cause of this occurrence indicates that some switch misalignment was present. This resulted in delayed actu-ation of the switch.

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Mr. John T. Collins February 17, 1982 Page 2.

Analysis of Occurrence:

NBI-LIS-72C is a Yarway Model 4418C level indicator. The #2 switch on this level instrument is part of the Level (I) (>-145.5") ADS permissive logic. The switch misalignment was caused by improper technique when setting the switch. Maintenance personnel align the switches and adjust the gap between the magnet and the switch contact. The gap on this switch appeared excessive. The switches in the redundant logic were operable and the ADS permissive would have functioned properly if required.

This occurrence presented no adverse consequences from the stand-point of public health and safety.

Corrective Action

Switches #2 and #3 on NBI-LIS-72C were replaced. The new switches were calibrated and functionally checked. The importance of proper switch alignment has been reviewed with appropriate station personnel.

Sincerely, L. C. Lessor Station Superintendent Cooper Nuclear Station LCL:cg Attach.