05000219/LER-1983-010, Forwards LER 83-010/01T-0.Detailed Event Analysis Encl

Forwards LER 83-010/01T-0.Detailed Event Analysis Encl

ML20072U336
Person / Time
Site:	Oyster Creek
Issue date:	03/23/1983
From:	Fiedler P GENERAL PUBLIC UTILITIES CORP.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20072U337	List: 05000219/LER-1983-010, Forwards LER 83-010/01T-0.Detailed Event Analysis Encl 05000219/LER-1983-010-01, /01T-0:on 830307,design Deficiency Discovered When Standby Gas Treatment Sys (SGTS) II Racked Out for Maint. SGTS II Inlet & Outlet Valves Opened,Allowing Recirculation During Sys I Operation.Procedures Revised
References
NUDOCS 8304110280
Download: ML20072U336 (3)

LER-1983-010, Forwards LER 83-010/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
2191983010R00 - NRC Website

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GPU Nuclear Q

g7 P.O. Box 388 Forked River, New Jersey 08731 609-693-6000 Writer's Direct Dial Number:

March 23, 1983 Mr. Ronald C. Haynes, Mministrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

Dear Mr. Haynes:

Subj ect: Oyster Creek Nuclear Generating Station Docket No. 50-219 Licensee Event Report Reportable Occurrence No. 50-219/83-10/0lT This letter forwards three copies of a Licensee Event Report (LER) to report Reportable Occurrence No. 50-219/83-10/0lT in compliance with paragraph 6.9.2. A.9 of the Technical Specifications.

Very truly yours, A

(

Peter B. Fiedler Vice President and Director Oyster Creek l

l PBF:jal l

Enclosure s cc: Dire ctor (40 copies)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.

20555 Dire c tor (3)

Of fice of Management Information and Program Control U.S. Nuclear Regulatory Commission Was hington, D.C.

20555 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, NJ 08731 l

F304110280 830323 PDR ADOCK 05000219 l

S PDR l

GPU Nuclear is a part of the General Public Utikties System ggt

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OYSTER CREEK NUCLEAR GENERATING STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No 50-219 /83-10/OlT Report Date March 23, 1983 Occurrence Date March 7, 1983 Identification of Occurrence Discovery of a design deficiency which resulted in not meeting a Limiting Condition for Operation as defined in the Technical Specifications, paragraph 3.5.B.

This event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.A.9.

Conditions Prior to Occurrence Mode Switch Refuel Thermal Power 0 MWt Generator Load 0 MWh 0

Reactor Coolant Temperature dL212 F Description of Occurrence On Monday, March 7,1983, the circuit breaker for System II of the Standby Gas Treatment System (SGTS) was " racked out" for system maintenance. Plant operations personnel later recognized a system design deficiency.

When the circuit breaker is " racked out", the control power transformer (connected to the primary side of the circult breaker) de-energizes. When control power is lost to the solenoid valves, air supply to the diaphragm operated inlet and outlet valves is vented of f.

Since these diaphragm valves

.are " air to close" and fail open on a loss of air, this results in the af fected system being lef t unisolated.

If one (1) SGTS is out of service, by " racking out" the circuit breaker, and the remaining system is initiated under an accident condition, some portion of the discharge from the operating system would recirculate through the out of service system as the SGTS trains are situated in parallel and share a common discharge duct.

Licensee Event Report Page 2 Reportable Occurrerce No. 50-219/83-10/0lT Apparent Cause of Occurrence The apparent cause of the occurrence is attributed to the removal of an exhaust fan circuit breaker which unexpectedly removed control power from the inlet and outlet solenoid valves, resulting in the diaphragm valves failing open.

This occurrence is attributed to a design deficiency.

Analysis of Occurrence The Standby Gas Treatment System is provided to filter Reactor Building atmosphere to the stack in the event of certain accident situations, in order to minimize the release of radioactive materials to the environment.

The SGTS consists of two parallel full-flow systems of filters and fans, capable of maintaining a negative building pressure (-0.25" H O) and retaining 2

radioactive iodines and particulates that may be present in the Reactor Building during and af ter an accident.

For the condition presented in this occurrence, recirculation could possibly reduce the operating system's ability to provide sufficient system flow and suf ficient negative pressure in the Reactor Building.

Corrective Action

Immediate corrective action was to place the System II exhaust fan breaker back in service, which closed the inlet and outlet valves, allowing System I to operate independently.

Additional corrective action will be to add precautions and limitations to SGTS related procedures which will maintain operability of the redundant system when one system is removed from service.

Caution tags will be placed on the control switches and circuit breakers to alert the operator of this problem.

The SGTS control circuitry will be reviewed to determine if an improved methodology of maintaining continuous control power to the solenoid valves is prac tical.