05000298/LER-1979-012, Forwards LER 79-012/03L-0

Forwards LER 79-012/03L-0

ML19224D793
Person / Time
Site:	Cooper
Issue date:	05/30/1979
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19224D794	List: 05000298/LER-1979-012, Forwards LER 79-012/03L-0 05000298/LER-1979-012-03, /03L-0 on 790503:vessel Water Temp Increased to 220 F W/Primary Containment Integrity Not Established.Caused by Omission in Operating Procedures.Setpoint of Interlock Verified & Procedures Revised
References
CNSS790266, NUDOCS 7907170054
Download: ML19224D793 (2)

LER-1979-012, Forwards LER 79-012/03L-0

Event date:
Report date:
2981979012R00 - NRC Website

text

e COOPE R NUCLE AR STATION P.o. 3c x 8, B R OWNVILLE, NE BR ASKA 68321 Nebraska Public Power District ru.En o~E -> us u n

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CNSS790266 May 30, 1979 Mr. K. V. Seyfrit U.S. Nuclear Regulator'; Cocsission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Suite 1000 Arlington, Texas 76011

Dear Sir:

This report is submitted in accordance with Section 6.7.2.B.3 of the Technical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on May 3, 1979. A licensee event report form is also enclosed.

Report No.:

50-298-79-12 Report Date:

May 30, 1979 Occurrence Date: May 3, 1979 Facility:

Cooper Nuclear Station Brownville, Nearaska 68321 Identification of Occurrence:

Observed inadequacies in the implementation of administrative or procedural controls.

Conditions Prior to Occurrence:

Inservice leak test of the reactor pressure boundary.

Description of Occurrence:

During depressurizatiot. of reactor vessel following an in-ervice leak test, vessel water temperature increased to approximatelv 220 F with reactor vessel head vents closed and primary containmeit not established.

Designation of Apparent Cause of Occurrence:

The station operaHng procedure for the reactor vessel in-service leak test did not caution the operator about exceeding 212 F during the hydro operation.

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Mr. K. V. Seyfrit May 30, 1979 Page 2.

Analysis of Occurrence:

The lachnical Specifications require that primary contaittment be established what. the reactor is critical or when the reactor watcr temperature 19 >212 F and fuel is in the reactor vessel.

The temperature 10=1t of 212 F was exceeded for a short time when the operators experienced difficulty resetting the Residual Heat Removal (RHR) pressure interlock at 75 psig when attempting to return to the shutdown cooling mode after the hydro. Although the temper ature limit was exceeded, this event gresented minimal adverse consequences from the standpoint of public health and safety because the reactor was suberitical, secondary containment was established and the Standby Gas ireatrent and Low Pressure Core Standby Cooling Systems were operable.

Corrective Action

The setpoint of the _nterlock was vecified correct. A precaution will be added to thu procedure for '.Fe Reactor Vessel In-service Le?k Test to caution the operator concerning the 212 F limit. The switches are under evaluation. The Technical Specifications are under evaluation to Cetermine whether an exemption to the 212 F limit can be permieted during the in-service leak t,ect.

This event has been discussed with the personnel involved and a copy of the LER will be routed to all licensed operators.

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

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