ML20134L246

Advises That Listed Valves Can Be Operated from 460-volt Switchgear Room During post-accident Conditions & Indications Exist to Alert Operator of Containment Sys Failure,Per Integrated Assessment of SEP Topic VI-4

ML20134L246
Person / Time
Site:	Oyster Creek
Issue date:	08/27/1985
From:	Fiedler P GENERAL PUBLIC UTILITIES CORP.
To:	Zwolinski J Office of Nuclear Reactor Regulation
References
TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8509030153
Download: ML20134L246 (3)

Text

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GPU Nuclear Corporation Nuclear = = r 388 Forked River.New Jersey 08731-o388 609 971-4000 Writer's Direct Dial Number:

August 27, 1985 Mr. John A. Zwolinski, Chief Operating Reactors Branch No. 5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Oyster Creek Nuclear Generating Station (OCNGS)

Docket No. 50-219 SEP Topic No. VI-4, Containment Isolation System The Containment Spray and Core Spray systems are closed systems and are provided with remote manual isolation valves. Since operator action is required to initiate isolation, if necessary, the operator must know when to initiate isolation. This requires a leakage detection capability and appropriate procedures to indicate under what conditions these valves should be shut. During the integrated assessment of the subject SEP topic, the NRC staff requested GPUN to evaluate the leakage detection provisions, provide appropriate procedures for operator action and relocate the operating station to an accessible area, when necessary, for the following valves:

V-20-3 V-21 -5 Y-20-4 Y-21 -7 Y-20-32 V-21 -9 V-20-33 V-21 -l l V-21 -1 V-21 -15 V-21 -3 Y-21 -18 GPUN has reviewed each of the valves listed above and detennined that all of the valves listed can be operated from the 460 V switchgear room located in the Office Buildi1g which is assessible during post accident conditions.

Should a failure occur in any of the Containment or Core Spray lines outside the containment there are indications to alert the operator. These indications include pressure, flow indications and sump pump running l l

indications. The attached table identifies the specific indications that would be expected for a break in either the Core Spray or Containment Spray systems. Although an excess flow with low dfscharge pressure condition would be observed following a break downstream of the flow element in either system, 0509030153 850827 PDR ADOCK 05000219 P PDR

. I GPU Nuclear Corporation is a subsidiary of the General Pubhc Utihties Corporation

the same indications would be seen when these systems are being utilized to mitigate an accident. Therefore, it is not possible to distinguisn a cause based on these indications. However, both the Core and Containment Spray lines are low energy piping (low pressure and low temperature) and it is highly unlikely to experience a line break between the flow element and the containment wall in conjunction with an accident which requires Core Spray and/or Containment Spray actuation.

Based on the above, sufficient indications presently exist to alert the operator of the need to isolate the affected system in the event of a break between the suppression chamber and the flow elements in both systems (major portion of the piping). As it was stated earlier, all of the valves can be operated from the 460 Y switchgear room which is accessible at all times.

Plant procedures will be revised to incorporate isolation provisions with operator action before restart from the Cycle 11 refueling outage.

Very truly yours, w - x - - n.,,)

P ter' o. riedler Vice President and Director Oyster Creek P8F/YN/ dam Attachment 2187f l

cc: Dr. Thomas E. Murley, Administrator Region I U.S. Nuclear Regulatory Comission 631 Park Avenue King of Prussia, PA 19406 Mr. Jack N. Donohew, Jr. l U.S. Nuclear Regulatory Comission 7920 Norfolk Avenue, Phillips Bldg.

. Bethesda, MD 20014 l Mail Stop No. 314 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, NJ 08731

l M-SYSTEM DISCHARGE LINE BREAK SUCTION LINE BREAX l i I l l l Indication: 1 Indications: 1 I I I I I I I Reduced differential pressure l I I I between tube side and shell of I i l l heat exchangers 1 i l i l IContainment Spray i I I I I I I I -l No flow or very reduced flow, l Temperature elements, TE 408, C l l l low pressure (Break before flow I will show decrease in temperature l l l elements FE IP02A, B) I because of increased cooling due l l l l to reduced flow. I I I I I l l l Sump pump running indication l I I I I I I I I I I Indication: I Indications: l I I I I l Core Spray I Low discharge pressure, no flow I Loss of pressure (break occurs l I l (break before flow elements l before suction pressure indicators l l l FE-RV25A, B) l PI-25A, B, C, 0 - local indicator) 1 I i 1 l l I I I I I I I I i i I

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