ML19320A960

Forwards LER 80-014/03L-0

ML19320A960
Person / Time
Site:	Cooper
Issue date:	06/16/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19320A961	List: ML19320A960 ML19320A962
References
NUDOCS 8007080365
Download: ML19320A960 (2)

Text

e o -

o, COOPER NUCLEAR STATION

• p.O. box 9.. BRoWNVILLE, NEBRASKA 6 321 Nebraska Pubh.c Power Distr. t N...

.m

_j OM

~

ic TELE ~oNE c o2> .2s.3.ii CNSS800358 June 16, 1980 Mr. K. V. Seyfrit U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement 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.3 of the Technical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on May 18, 1980. A licensee event report form is also enclosed.

Report No.: 50-298-80-14 Report Date: June 16, 1980 Occurrence Date: May 18, 1980 Facility: Cooper Nuclear Station Brownville, Nebraska 68321 Identification of Occurrence:

Observed inadequacies in the implementation of administrative control of construction activities which threaten to cause re-duction of degree of redundancy provided in engineered safety feature systems.

Conditions Prior to Occurrence:

The reactor was in cold shutdown for refueling.

Description of Occurrence:

During routine surveillance testing of the low voltage relays on the normal 4160 V buses, relay 14A-K2B was found deenergized. This would not allow starting "B" Core Spray Pump in the event the #2 diesel generator and emergency power breakers were racked out.

OoOb 8007080 3[ f g gli

)

Mr. K. V. Seyfrit June 16, 1980 ,

Page 2.-

Designation of Apparent Cause of Occurrence:

An extra contact in the diesel generator output breaker, (52b/EG2) was inadvertently left connected in Core Spray Pump 1B logic cir-cuit after circuits were revised during initial construction. The identical problem was found in the logic circuit for Core Spray Pump 1A. This oversight has been attributed to inadequate super-vision of construction activities.

Analysis of Occurrence:

When Emergency 4160 V Buses IF and 1G are energized from startup or normal transformer, relays 14A-K2A and 14A-K2B are energized. On LOCA these relays permit starting of core spray pumps without delay.

When 4160 V Buses IF and 1G are energized from diesel generators or from emergency transformer, relays 14A-K2A & 14A-K2B are deener-gized and have no function in starting the core spray pump.

The superfluous contacts 52b/EG1 and 52b/EG2 left connected in circuits for relays 14A-K2A and 14A-K2B did not affect normal operation of core spray pumps. However, it could have prevented the automatic start of the core spray pump if diesel generator output breakers and emergency transformer tie breaker were racked out concurrently.

It is believed that Cooper Nuclear Station has never operated with diesel generator output breaker and emergency transformer tie breaker racked out at the same time. Under such condition, reactor

' operation would be permissible only for seven days as per Technical Specification 3.5.F.1.

Corrective Action:

Superfluous contacts 52b/EG1 and 52b/EG2 were disconnected. Cir-cuits for both core spray pumps were checked and verified to agree with elementary diagram. It was ascertained that no similar prob-lem exists in RHR pump circuits.

Sincerely, L. C. Lessor

. Station Superintendent Cooper Nuclear Station l

.LCL:cg Attach.

. _ _ - _ _ _ . .