ML17261B059

Advises That No Interlocks Required for RHR motor-operated Valves 701 & 720 Based on Present Arrangement.Listed Failures Would Have to Occur in Order for Potential Overpressurization of RHR Sys to Occur

ML17261B059
Person / Time
Site:	Ginna
Issue date:	04/17/1990
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	Andrea Johnson Office of Nuclear Reactor Regulation
References
TASK-05-11.B, TASK-5-11.B, TASK-RR GL-89-10, NUDOCS 9005020083
Download: ML17261B059 (4)

Text

ACCELERATED DISTjUBUTION DEMONSHRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9005020083 DOC.DATE: 90/04/17 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION MECREDY,R.C. Rochester Gas 6 Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R. Project Directorate I-3

SUBJECT:

Advises that no interlocks are required for RHR valves MOV 701 6 MOV 720 at plant,per NRC SER for SEP Topic V-ll.B.

DISTRIBUTION CODE, AEOID TITLE: Correspondence re COPIES RECEIVED,LTR SEP Topics 2 ENCL 0 SIZE.

S NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244,

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~ lizsiiriziz iYKYR ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE, ROCHESTER, N K 14649 0001 April 17, 1990 YCLKPHONE KDKK COOK YYO 546.2700 U.S. Nuclear Regulatory Commission Document Control Desk Attn: Allen R. Johnson Project Directorate I-3 Washington, D.C. 20555

Subject:

Lack of Interlocks on RHR Valves MOV 701 and. MOV 720 R.E. Ginna Nuclear Power Plant Docket No. 50-244

Dear Mr. Johnson:

In the NRC's Safety Evaluation Report for SEP Topic V-11.B, "RHR Interlock Requirements", dated September 29, 1981, it was determined that the lack of interlocks on RHR MOVs 701 and MOVs 720 was acceptable. Several reasons were stated for this, as follows:

~ The RHR valves are designed such that they are physically unable to open against a differential pressure greater than 500 psi

~

By administrative procedure, the RHR valves are key-locked closed, with power removed

~ A relief valve, set at 600 psig, is available in the RHR system.

In the course of RG&E's implementation of our MOV testing program, using the guidance of Generic Letter 89-10, it has been determined, that MOVs 701 and 720 will open against a differential pressure of greater than 500 psi.

Nonetheless, RGGE considers that, with the present arrangement, no interlocks are required for these valves. In order for a potential overpressurization of the RHR system to occur, the following set of failures would have to occur: (Note: a. schematic of the RHR system is shown on UFSAR Figure 5.4-7.)

1. Power would. have to be deliberately restored at the breaker, in violation of procedure A-52.2

2. The key-locked switch would have to be enabled, and the valve opened, in violation of normal alignment procedures

3. The interlocked in-board valves (MOV 700 or MOV 721) would have to fail to allow significant leakage. This is considered of low probability, since these valves are in the Ginna Pump and Valve Inservice Testing Program, and are leak-tested on an annual basis usin g p rocedure PT-8.

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Relief valve RV-203, with a capacity of 70,000 lb/hr, would have to fail. This relief valve has been tested annually (RSSP-12) for seat leakage and setpoint verification.

Thus, it is considered that the capability of MOVs 701 and 720 to open against a differential pressure of greater than 500 psi, without the availability of interlocks on these valves, remains acceptable, and does not have a significant implication for public health and safety.

This information will be reflected in the next revision of the Ginna Station UFSAR.

Very truly yours, Robert C. Mecred Division Manager Nuclear Production GJWN099 xc: Mr. Allen R. Johnson (Mail Stop 14D1)

Project Directorate I-3 Washington, D.C. 20555 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road".

King of Prussia, PA 19406 Ginna Senior Resident Inspector