ML17249A779

Responds to NRC 800211 Ltr Re Addl Info on Containment Purge & Vent Sys.Existing Sys Being Modified Per NUREG-0578 to Require Individual Resetting of Any Containment Isolation Valve Required to Open When Initiating Signal Present

ML17249A779
Person / Time
Site:	Ginna
Issue date:	03/17/1980
From:	WHITE L D ROCHESTER GAS & ELECTRIC CORP.
To:	ZIEMANN D L Office of Nuclear Reactor Regulation
References
RTR-NUREG-0578, RTR-NUREG-578, TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8003240381
Download: ML17249A779 (6)

Text

REGULATORY ORMATION DISTRIBUTION SYS 9 (RIDS)ACCESSION NBR t 8003240381 DOC~DATE;80/03/17 NOTARIZED!

NO DOCKET FACIL;50 204 Robert Emmet Ginna Nuclear Planti Unit li Rochester G 05000244 AUTH, NAME AUTHOR AFFILIATION WHITE,L,D, Rochester Gas 8 Electric Corp.RECIP NNAME.RECIPIENT AFFILIATION ZIEMANNiD~L, Operating Reactors Branch 2

SUBJECT:

Responds to NRC'00211 ltr re addi info, on containment purge 8 vent sysExisting sys being modified per NUREG 0578 to.require individua'1 resetting of any conta,inment isolatiop-valve required toI open when initiating signal presents 1 DISTRISUTION CODE: ASSES COPIES RECEIVED:LTR l ENCL-4 SIZE I-~----TITLE: SEP Topics NOTES: JQ~+Ag+J1 E~R.+AC~--'ECIPIENT COPIES RECIPIENT~COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL'CTION:

19 BC Og8 INTERNAL: REG R 10 TA/EDO-13 ENGR BR 15 PLANT SYS BR 17 EFFT TRT" SYS EXTERNAL: 03 LPDR 23 ACRS 1 16 02 NRC PDR 08 ISE il CORE PERF BR 14 REAC SFTY BR-16 EEB STS GROUP LEADR 07 NSIC 1 2 1 1'1 1 MAR S5 1980 TOTAL NUMBER OF-COPIES REQUIRED: LTTR~ENCL P~'

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SZu ROCHESTER GAS AND ELECTRIC CORPORATION J"'gw IIAtt o,89 EAST AVENUE, ROCHESTER, N.Y.14649 LEON D.WHITE, JR.VICE PRESIDENT TELEPHONE ARE*CDDE TIE 546.2700 March 17, 1980 Director of Nuclear Reactor Regulation Attention:

Mr.Dennis L.Ziemann, Chief Operating Reactors Branch No.2 U.S.Nuclear Regulatory Commission Washington, D.C.20555

Subject:

SEP Topic VI-4, Containment Isolation System R.E.Ginna Nuclear Power Plant Docket No.50-244

Dear Mr.Ziemann:

This letter is in response to your February ll, 1980 letter, which requested the following additional information concerning the Ginna containment purge and vent systems.1.The overriding of one type of safety actuation signal should not cause the blocking of any other type of safety actuation signal to the isolation valves.The Ginna plant engineered safety features apparently have several overrides that block even manual actuation.

Response: As stated in our letter to you on the subject system, dated December 14, 1979, the containment purge system has been designed to provide purging capability following a LOCA, when high containment radiation and SI signals may be present, to limit potential hydrogen concentrations in containment during the post accident period.In order to perform this safety function, the reset system is designed to override all containment isolation initiating signals as long as any actuating signal is present.The existing reset with Section 2.1.4 require individual valve which may be signal is present.actions, including system is being modified in accordance and Appendix A 2.1.4 of NUREG 0578, to resetting of any containment isolation required to open while a C.I.initiating At least three deliberate operator operation of the containment isolation 80032408'I Jl ROCHESTER GAS AND ELECTRIC C P.DATE March 17, 1980 To Mr.Dennis L.Ziemann,-Chief SHEET NO.key switch, must be performed by the operator before any two redundant isolation valves (potential release path)are opened (e.g., purge exhaust).This virtually precludes inadvertent violation of containment, isolation.

Procedures require extensive review of plant conditions before initiating any action which would require the opening of an isolation valve after an event which has caused containment isolation.

If it were decided to perform a containment purge during accident conditions, great care would be taken during this operation.

The personnel performing this safety function would be aware of the significance of the action, and would be prepared to close the valves if necessary for any reason.Re-establishing containment isolation would be a quick, simple process (closing the appropriate valve switches).

It is not considered that.this process requires any further simplification (such as having a system-level manual isolation switch).Another set of circumstances wherein the containment ventilation isolation valves are blocked from closing upon receipt of a safety actuation signal is described in our December 14, 1979 letter on this subject.In the event these valves are open, and high activity (but no SI signal)is present, administrative procedures ensure that the reset will not be used until the high activity alarm has been cleared.The SI signal will thus no longer be blocked, and be capable of effecting valve closure.2.The system level annunciation of the overridden status should be provided for every safety system impacted when an override is active.The Ginna plant apparently does not have this capability.

Response: As noted in our response to item (1)above, the reset panel matrix clearly displays any isolation valve which is in a reset status.The requirement referred to for system level annunciation of overridden status of safety systems is contained in Regulatory Guide 1.47, B assed and Ino erable Status Indication for Nuclear Power Plant Safet S stems which was z.ssued zn May 1973.The extent to which plants, such as R.E.Ginna, which were designed and constructed prior to the issuance of this Regulatory Guide, are required to implement its requirements is currently the subject of generic review under the SEP program and TMI related NRC staff programs.It is our position that status monitoring modifications should only be made on an integrated basis for all safety systems in accordance

'with careful consideration of the man-machine interface.

T , ROCHESTER GAS AND ELECTRIC C P.DATE March 17, 1980 To Mr.Dennis L.Ziemann, Chief SHEET NO.Treating individual systems, such as containment isolation, without regard to maintaining a consistent=

status monitoring approach to all safety systems could lead to operator confusion and error.3.The instrumentation and control systems provided to initiate engineered safety features should be designed and qualified as safety grade equipment.

Discuss the qualification of the isolation channel and radiation channel equipment.

in this regard.Response: The containment isolation system, including the actuating channels, was designed and constructed as a Class IE system.Qualification of electrical and ISC equipment has been described in our report to A.Schwencer, dated February 24, 1978, on the subject."Environmental Qualification of Electrical Equipment, R.E.Ginna Nuclear Power Plant Unit No.1".This topic is currently being reviewed generically under the SEP program.4.The overriding or resetting of the isolation actuation signal should not cause the automatic motion of any Engineered Safety Feature valve.Your letter of October 17, 1979 and November 19, 1979 indicate that a modification is planned for the upcoming March refueling outage.Describe how the modification will prevent automatic valve position changes on resetting of isolation logic, including schematic diagrams or sketches as necessary.

Response: The detailed design of the containment isolation modification which requires individual reset for each isolation valve is being reviewed as part of the Short-Term Lessons Learned Program.Very truly yours, L.D.Whi e, Jr.LDW:np