ML17058B794

Advises of Results of Evaluation of NRC Staff Action 2.c Resulting from NRC IIT Investigation of Event at Plant on 910813.Staff Concluded That Failure of RPI May Complicate Plant Recovery & Result in Unnecessary Operator Actions

ML17058B794
Person / Time
Site:	Nine Mile Point
Issue date:	06/08/1993
From:	Wermiel J Office of Nuclear Reactor Regulation
To:	Tully C BWR OWNERS GROUP, SOUTHERN NUCLEAR OPERATING CO.
References
NUDOCS 9306150299
Download: ML17058B794 (8)

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UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 June 8, 1993 Hs. Cynthia L. Tully, Chairperson BWR Owners Group c/o Southern Nuclear Operating Company P.O.

Box 1295, Bin B052 Birmingham, Alabama 35201

SUBJECT:

CLOSURE OF NRC STAFF ACTION 2.c RESULTING FROH INVESTIGATION OF THE AUGUST 13,

1991, EVENT AT NINE HILE POINT NUCLEAR STATION, UNIT 2 (NUREG-1455)

The purpose of this letter is to advise the BWROG of the results of the evaluation of NRC Staff Action 2.c resulting from the NRC Incident Investigation Team's (IIT's) investigation of the event at Nine Hile Point Nuclear Station, Unit 2, on August 13, 1991.

A common-mode loss of five uninterruptible power supplies resulted, in part, in the loss of rod position indication (RPI) during that event.

The IIT observed that the loss of RPI required the operators to enter the anticipated transients without scram contingency procedures and complicated their response to the event.

Staff Action 2.c was established as a result of this observation and required the staff to evaluate the need for alternate RPI or for providing safety-grade power for the existing RPI for BWRs.

The staff met with the Regulatory Guide 1.97 Committee of the BWROG on December 9,

1992, in an effort to obtain the indust} y's position on the need for alternate RPI or for providing safety-grade power for the existing RPI for BWRs.

By letter dated February 24, 1993, the BWROG subsequently provided the staff with a report, GENE-637-02-0292, "Position on Use of the Rod Position Information System for Post-Accident Honitoring," for the staff's use in addressing Staff Action 2.c.

On Hay 24,

1993, the staff completed its evaluation of Staff Action 2.c.

We concluded that failure of RPI and the Neutron Honitoring System may complicate plant recovery and result in unnecessary operator actions.

However, the staff agreed with the BWROG that the current Emergency Procedure Guidelines provide adequate guidance for incorporation in the Emergency Operating Procedures to direct the operator to take appropriate action without compromising plant safety.

The staff also concluded that it would not be appropriate to require 9306i50299 930608 PDR ADDCK 050004%0 P

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Hs. Cynthia L. Tully 0une 8, 1993 We appreciate the BWROG's assistance in providing input for our consideration in addressing Staff Action 2.c.

Sincerely, Jared S. Wermiel, Chief Instrumentation and Controls Branch Division of Reactor Controls and Human Factors Office of Nuclear Reactor Regulation

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Ms. Cynthia L. Tully 3une 8, 1993 We appreciate the BWROG's assistance in providing input for our consideration in addressing Staff Action 2.c.

Sincerely, Original Signed By:

Jared S. Wermiel, Chief Instrumentation and Controls Branch Division of Reactor Controls and Human Factors Office of Nuclear Reactor Regulation DISTRI BUTION:

Central File NRC PDR PDI-1 Reading THurley/FHiraglia, 12/G/18

WRussell, 12/G/18

JPartlow, 12/G/18

BBoger, 10/H/5 SVarga JCalvo RACapra CVogan JMenning

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'6 /8/93 OFFICIAL RECORD COPY FILENAME: G: iNMP2iNH2BWROG. LTR

scen.mmTE oocnvmm" OrST UTrOx SYSTEM REGULAT INFORMATION DISTRIBUTIO STEM (RIDS)

ACCESSION"NBR:9306080229 DOC.DATE: 93/05/28 NOTARIZED: YES DOCKET N

FACIL:50-410 Nine Mile Point Nuclear Station, Unit 2, Niagara Moha 05000410 AUTH.NAME AUTHOR AFFILIATION TERRY,C.D.

Niagara Mohawk Power Corp.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Forwards request for schedular exemption from requirements of App J to 10CFR50 re periodic Type B leakage testing. Since penetrations open to free space of containment, any leakage, due to expansion, accounted for in ILRT.

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Append J Containment Leak Rate Testing NbTES:

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1 6

6 1

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1 RECIPIENT ID CODE/NAME MENNING,J OC FMB REG FILE Ol RES%DSTR SAIB NSIC COPIES LTTR ENCL 2

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TOTAL NUMBER OF COPIES REQUIRED:

LTTR 16 ENCL 15

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