05000219/LER-1981-017, Forwards LER 81-017/03L-0.Detailed Event Analysis Encl

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Forwards LER 81-017/03L-0.Detailed Event Analysis Encl
ML19347F635
Person / Time
Site: Oyster Creek
Issue date: 05/14/1981
From: Finfrock I
JERSEY CENTRAL POWER & LIGHT CO.
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19347F636 List:
References
NUDOCS 8105220283
Download: ML19347F635 (3)
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LER-1981-017, Forwards LER 81-017/03L-0.Detailed Event Analysis Encl
Event date:
Report date:
2191981017R00 - NRC Website
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text

OYSTER CREEK NUCLEAR CENERATING STATION

'c%"*%<,%'AM (609)693-6000 P.O. BOX 388

  • FORKED RIVER
  • 08731

" C*"4" vue s,vem 14 May 1981

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Mr. Boyce H. Grier, Director

,'2 Office of Inspection and Enforccment

[-

!y /,I/iY 2 1 g I ' b Region I i-United States Nuclear Regulatory Ccumission O' u.s,gM,3Dron R3 631 Park Avenue co King of Prussia, Pennsylvania 19406 N

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Dear Mr. Grier:

SUMECT: Oyster Croek Nuclear Generating Station Docket No. 50-219 Licensee Event Report Reportable Occurrence No. 50-219/81-17/3L This letter forwards three copies of a Licensee Event Report to report Reportau e Occurrence No. 50-219/81-17/3L in carpliance with paragraph 6.9.2.b.1 of the Technical Specifications.

Very trul vours, n.

u van R. F Jr.

ice President JCP&L Director - Oyster Creek IRF:dh Enclosures cc: Director (40 copies)

Office of Inspection and Enforcment United States Nuclear Regulatory Ocmnission Washington, D.C.

20555 Director (3)

Office of Managenent Infor: ration and Program Control United States Nuclear Pegulatory Ccmnission Washington, D. C. 20555 NFC Resident Inspector (1)

Oyster Creek Nuclear Generating Station Forked River, N. J.

M 8105220 283

EYSIER CREEK NUCEAR GENERATING STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/81/17/3L Report Date May 14, 1981

_ Occurrence Date April 15, 1981 Identification of Occurrence Limiting cordition for operation per Technical Soecifications section 3.4.C.3 when containment spray System I was considered inoperable for a period of approximately twenty (20) minutes. The associated emeuJency service water system loop was rendered inoperable when the water level in the intake structure dropped below the puup suctions.

'Ihis event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.b (2).

Conditions Prior to Occurrence

'Ihe plant was operating at steady state power.

Major plant parameters at the time of occurrence were:

Power:

Oore 1430 Mit Electrical 407 Mie 4

Flow:

Becirculation 12.2 x 106 gpn i

Feedwater 4.95 x 10 lb/b Description of Occurrence On April 15, 1981, during normal plant operati n, an " Intake Screen High aP" alarm was received in the control rocm at 1602 hours0.0185 days <br />0.445 hours <br />0.00265 weeks <br />6.09561e-4 months <br />. Operators were innediately sent to investigate the cause for the alarm. At 1607 hours0.0186 days <br />0.446 hours <br />0.00266 weeks <br />6.114635e-4 months <br />, the two traveling screens (41 and #3), operating in the north side of the intake structure, tripped.

i l

Upon investigation, it was discovered that the traveling screens on the north side of the intaka structure had become clogged by sea lettuoe. 'Ihis caused the water level in that half of the intake structure to drop when sufficient flow could not be maintained through the screens to supply the running circulating t

water puup (#2) on that side. 'Ihe screen wash pump lost suction and the water level was also cbserved to be below the level of the energency service water pung suctions which are approximately 6.5 feet above the circulating water puup suction.

I

_. ~ _ _.

asportable Occurrence Page 2 h

Report No. 50-219/81/17/3L n

1 j

At 1619 hours0.0187 days <br />0.45 hours <br />0.00268 weeks <br />6.160295e-4 months <br /> 42 circulating water pmp was ei.va.d.

The water level in the north side of the intake structure returned to normal almost 4===Mately.

The screen wash pm p and #1 traveling screen were then returned to service. The south side of the intake structure, with all three traveling screens-ard both circulating water pups in operation, was unaffected.

i Apparent cause of occurrence 1

j A naHNation to the intake system, which coumenced several years ago, was never j

ccupleted in that the new high pressure screen wash pmps and associated piping.

were not installed, thus reducing trash removal capacity.

j Environmental ~ studies were in progress on April 15 and observations made at the time revealed that, due to strong north-northwest winds, unusually large amounts of Ulva (sea lettuce) were collecting at the neuth of Forked River. Observations i

made at the mouths of Oyster Creek (plant discharge south of Forked River) and l

Cedar Creek (north of Forked River) did not indicate any unusual amounts of sea i

i lettuoe. Ibwever, the mouth of Forked River was reported to be thick with sea I

lettu:e frm the water surface to the river bottcm.

The sea lettuce apparently was carried into the intake canal and 3rpinged on the intake screens. Due to circulating currents at the intake structure, most of the l

material is carried into the north side of the intake. The traveling screens and screen wash system were unable to keep up with the amount of sea lettuce i

deposited on the screens. This restricted the flow of water across the screens resulting in the circulating water pmp lowering the~ water level in the north side of the intake structure to below the Emergency Service Water pmp suctions.

l Analysis of Ocet m ace The auergency Service Water Syst=.1 provides cooling to the contaiment spray heat exchangers and, therefore, is required to provide the ultimate heat sink for the energy release in.the event of a loss of coolant accident. The contain-l ment spray system removes the heat energy frm the contairnent. Each of the two i

loops cont:ains two energency service water pmps, two containment spray pmps and two heat exchangers. The flow frcm one pmp in either loop is more than anple to provide the required heat removal capability.

In addition, the intake structure is divided into north and south halves by a t

j concrete dividing wall. Each half houses three traveling screens, two circulating water pmps and the two emergency service water pups from one loop and other couponents. Since the south half of the intake structure was unaffected, and since the redundant contalment spray and emergency service water loops were available and operable, the safety significance is considered mmimal. Had the con-.

tainment spray system been required for an accident, the operator could have tripped j

the circulating water punps to restore emergency service water flow.

Corrective Action

The circulating water pmp was stopped which allowed the water level in the intake structure to rise back above the pmp suctions. The screen wash pmp and one of the traveling screens were' returned to service. In addition, an engineering

(

request has been subnitted to upgrade the material, used in and inprove the trash l

removal capacity of the traveling screens, trash rake and screen wash system.

Cathodic protection of the screens is planned for installation in the sumer of 1981.

1 The installation of the new high pressure screen wash pmps is scheduled for ccm-i pletion during the November 1981 refueling outage.

.-..,___...,___._._...._.____._______,-.______...,___.m_

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