U-602081, Suppls 920706 Response to NRC SE for Station Blackout .Topics Include,Battery Design Margin,Control Room Ventilation & EDG reliability.Heat-up Analysis for Main Control Room Will Be Revised Using Conservative Temp

Suppls 920706 Response to NRC SE for Station Blackout .Topics Include,Battery Design Margin,Control Room Ventilation & EDG reliability.Heat-up Analysis for Main Control Room Will Be Revised Using Conservative Temp

ML20126E635
Person / Time
Site:	Clinton
Issue date:	12/22/1992
From:	Spangenberg F ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
U-602081, NUDOCS 9212290231
Download: ML20126E635 (3)

Text

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U26020813 L37-92(12-22)1.P

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• hknois Power Company :

CMton Power Station P O. Box C78 Clintn, IL 61727 .-

Tel 217 935 6881 P4WWER December 22, 1992 10CFR$0.63-a Docket No. 50 461 i Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555 '

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Subject:

Clinton Power Station (CPS) - Response to Supplemental Safety Evaluation for the Station Blackout (SBO) Rule. 10CFR50.63 _

1

Dear Sir:

1 Illinois Power (IP) aubmitted a letter (U 601998), dated July 6,1992, 4 to the Nuclear Regulatory Commission (NRC) in response to the.NRC-staff's' safety evaluation dated May 29, 1992. . The safety evaluation documented tho NRC's acceptance of CPS's compliance with the -(SBO) rule 10CFR50,63 contingent upon. CPS responding to several recommendations, IP's letter-included responses to the recommendations and the-justifications for IP's position. 9anuse the actions ~ required to-address some of the recommendations were not complete at the time of the July 6 submittal, IP submitted a supplemental letter (U-602062) dated.

October 30, 1992 to provide a status of those incomplete' actions. The--

c purpu;c of this letter is to provide a-response to the staff's rupplemental safety evaluation documented in the letter-dated October-29, 1992', which requested a written responso for= thel concerns not yet addressed from the original or the supplemental safety evaluation. -A description of the concerns c.nd IP's' justifications for resolutions are explained below.

JLatterv a Desinn Marcin: 'l Vith respect to the battery design margin, in letter U-601998, CP5

-justified its use of a. design margin of 1.0 based- on the fact .that the design mars in 1.1 to l.15 stated -in Institute of Electrical: and Electronics Engineers (IEEE) Standard 485 is used for selecting a battery and not to determine the adequacy- of an -existing ' bat.tery. - h ,-

the plant was designed'.and built, the IEEE ' design margin was used, but as loads were addxt,-the. design margin was-reduced. For this reason,

'during the third refueling-:outag- in 1992,' CPS replaced the Division I battery with'a larger capacity battery and-there-are plans.co replace the-Division II battery in rcfueling outage 5'or 6 which will then.

9212290231 921222-PDR f. DOCK'05000461 P pyg . Q- h k,

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to U 602081 restore its original design margin. The NRC concurred with this justification in the supplemental safety evaluation Aated October 29, 1992; however the staff evaluation in the letter states that CPS _should respond, in writing, to the NRC regarding its intentions to maintain a minimum 5% design margin throughout the design life of the station batteries.

The station batteries are periodically tested in accordance with the requirements of the CPS Technical Specifications. This testing consists of a service test every 18 months and a discharge test every 5 years.

(However, the service test is not performed when the discharge test is due.) The service test demonstrates the battery's ability to satisfy the design requirements of the DC system. The discharge test demonstrates the battery's capnbility to meet the original manufacturer --

specifications. This periodic testing provides assurance that the battery is ready to perform its design function.

In a telephone conversation on September 8, 1992, the NRC Clinton Licensing Project Manager was informed that CPS has replaced the Division I battery and there are plans to replace the Division II battery. Presently, the remaining capacity for Division II battery is 17% and Division III battery is 10.1%. The battery remaining capacity was calculated by considering temperature correction, design margin and aging factor.

IP does not plan to maintain a minimum 5% design margin throughout the design life of the station batteries; however, if new loads are being considered to be adood to the batteries (through design changes controlled by the configuration management procedures) the impact of the new loads on the batterier are analyzed to ensure sufficient design margin exists.

Based on this justification, CPS believes that no further action is -

reouired on this issue.

Centrol Rooly Ventiletiont CPS performed main control room heat-up calculation using the initial temperature of 73*F, which is the normal ciarating temperature of the main control room. The NRC questiened the initial temperature of 73*F used in the heat-up calculation insteau of 86*F specified in the CPS-Technical Specifications. There currently are no administrative controls in place to take any action if the temperature goes above 73*F, and the operacor is not required to take Loy corrective action until 78'F when the high temperature alarm actuates.

The NRC evaluation in the letter dated October 29, 1992 states, "The licensee should document the basis and justification for the assumed initial temperature used in heat-up analysis for the control room. The basis and justification should be included in the documentation that 'is

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_, _to U 602081' to be maintained by the licensee in support of the SB0 submittals. If a non-conservative' initial ~ temperature is assumed (in this case, 73*F is non conservative), then administrative procedures or other controls ishould be established to maintain the temperature consistent with the-initial temperature used in_the heat up analysis. However, if a conservative initial temperature is used, then administrative procedures or other controls'for the initial temperature are'not necessary but can- .

be established."

CPS concurs with the NRC evaluation and will revise the heat-up analysis for the main control room by using a conservative initial temperature.

Emergency Diesel Generator (EDC) Reliability:

• In the telephone conversation on September 8,-1992, Clinton Licensing' Project Manager (PM) discussed the CPS's EDG reliability pro 6 ram. He indicated that CPS uses Nuclear Management and Resources Council, Inc.

(NUMARC) 87-00 recemmendations for its EDG reliability program instead of Regulatory Guide 1.155 section-1,2 recommendations. He was informed that the existing EDG ro11 ability program at CPS does include the Regulatory Guide 1.155 recommendations. The PM considered the. item =

resolved, therefore no further action is required on this issue.-

All other NRC recommendations either have been impicmented or resolved by the justifications provided in the letters U-601998 and U-602062 dated July 6, 1992 and October 30, 1992, respectively.

Please contact me should you have any questions on this matter.

Sincerely yours, V

.F. A. Spa genbe

, _III Manager, icensing'and'Sa ety -

SSG/mfm (c .cc: NRC Clinton Licensing Project Manager i

hkC Resident Office g Regional Administrator, Region III..USNRC L Illinois Department of Nuclear Safety

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