ML20011E178
| ML20011E178 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 02/01/1990 |
| From: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Reed C COMMONWEALTH EDISON CO. |
| Shared Package | |
| ML20011E179 | List: |
| References | |
| GL-84-15, NUDOCS 9002080387 | |
| Download: ML20011E178 (2) | |
Text
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Docket'No. 50-295-Commonwealth Edison Company L ATTN: Mr. Cordell Reed Senior Vice President Post Office Box'767
' Chicago, IL-60690 Gentlemen:
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SUBJECT:
ENFORCEMENT DISCRETION REGARDING DIESEL GENERATOR OPERABILITY' REQUIREMENTS - ZION STATION, UNIT 1 We have reviewed your letters of January 30 1990, and January 31, 1990, documenting your January.30,1990, verbal' request that NRC exercise =
. Discretionary Enforcement from the requirements of a February 29, 1980, Confirmatory Order regarding diesel generator operability requirements at Zion, Unit-.1. The January 31, 1990, submittal was necessary to supplement your. original January 30, 1990, request. Copies of your letters are
. attached for reference.
The Confimatory Order stipulates allowable outage times dependent on the number of-diesel generator failures.in the prior 100 tests. The Unit I diesel generators had experienced four-failures which corresponded to an allowable outage time of 32 ~ hours. At 12:37 p.m. on January 29, 1990, the Unit 11, IB Diesel Generator was Ceclared. inoperable due to a failure of the air start system. This was the fourth failure in 100 tests. Therefore, at 8:37 p.m. on January 30, 1990, Unit I would be required to be in hot shutdownLwithin 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in cold shutdown within the fol10 wing.30: hours.
On January 30, 1990, you requested a 40-hour extension of the allowed outage' time to. complete the repair to the air start system and to perform the required operability run of the IB Diesel Generator. Your January 31, 1990 supplement also indicated that each ESF bus is capable of being powered from the System Auxiliary Transformer supplied by the offsite distributions system, the Unit Auxiliary Transformer powered from the main generator or offsite power when in a backfeed configuration, a reserve feed from the opoosite i
. units 4 ky' bus, and the diesel generator assigned to the associated ESF bus.
We understand that the ESF bus associated with Diesel Generator IB will have all the available power sources except that provided by the diese!.
In addition, we note that during this requested extension of time two diesel generators for Unit 1 (five diesels total for both units) will remain operable and absent a loss of cooling event, only one diesel generator is needed to place the plant in hot shutdown.
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We note that the requested 40-hour extension is consistent with the current NRC position as reflected in the Westinghouse Standard Technical Specification 72-hour allowed outage time.. Based on the additional knowledge of and changes in the regulatory position concerning diesel ger.erator surveillance testing and reliability (as reflected in the Standard Technical Specifications and Generic Letter GL 84-15), and based on the information you provided in your January 31, 1990, submittal regarding the reliability of the Zion diesel generators including the stability provided with six incoming lines to.the switchyard ring bus, I have concluded that an extension of time is appropriate to permit the necessary repairs and testing. Discretionary Enforcement is granted for a period of 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> beginning at 8:37 p.m. on January 30, 1990, until 12:37 p.m. on February 1,1990.
We understand, as described in your original January 30, 1990 request, that if the diesel generator is still inoperable at the end of the 40-hour extension, Unit 1 will be shut down in an orderly fashion.
Sincerely, ORIGINAL SIGNED BY A. BERT DAVIS A. Bert Davis Regional Administrator Attachments: As stated cc w/ attachments:
T. J. Maiman, Vice President, PWR Operations T. Kovach, Nuclear Licensing Manager T. Joyce, Station Manager DCD/DCB(RIDS)
Licensing Fee Management Branch Resident Inspector, RIII Richard Hubbard J. W. McCaffrey, Chief, Public Utilities Division Mayor, City of Zion Chandu Patel, Project Manager, NRR e
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