ML20238B638

Special Rept 87-15:on 870625,listed Carbon Dioxide Zones Inoperable.Caused by Sys Isolation at Sys Manual Isolation Valve.Fire Watch Established for Listed Inoperable Sys in Accordance W/Tech Spec 3.14.4.2

ML20238B638
Person / Time
Site:	Rancho Seco
Issue date:	08/21/1987
From:	Andognini G SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V), Office of Nuclear Reactor Regulation
References
87-15, GCA-87-497, NUDOCS 8709010323
Download: ML20238B638 (4)

Text

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SPECIAL REPORT NUMBER 87-15 ISOLATION OF ENTIRE CO2 SYSTEM l

Date of Rep.att August 18, 1987 Date of Occurrence:

July 8, 1987 l Plant Conditions Prior to Occurrence 1 The plant has been in a major outage with the reactor in cold shutdown.

Identification of Occurrence The following carbon dioxide (C02). fire suppression systems were not restored to operable status within 14 days as specified in Technice.1 Specifications Section 3.14.4.2:

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• 11 40 12 41 14 *53 15 *54 16 75 17 76 19 77 i 36 78 37 *79 38 *80 39

• Technical Specification required per Proposed Amendment 137. I Description of Occurrence s

On June 25, 1987, the above identified CO2 zones were rendered inoperable du'e j to the entire C02 system being isolated at the system manual isolation valve. '

The system was isolated due to spurious actuations which occurred immediately following the performance of a C02 concentration verification test for Zone

76. The concentration test on Zone 76 revealed potential ventilation system N problems which prevented the required CO2 concentration levels from being achieved within the design time interval Zone 76 C02 system has been technically inoperable since May 16, 1987. This zone was impaired on May 16, 1987 due to two gage calibrations being overdue j as reported in Special Report No. 87-12. The gages were recalibrates on June 17, 1987. On June 14, 1987 a problem was discovered with the Zone 76 alarm circuitry during the first attempt to conduct Zone 76 CO2 system j concentration test. The alarm circuitry problem was corrected on July 9, 1987. 1 i

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_2 Corrective Actions Taken A fire watch was established for each inoperable C02 system listed above in ,

accordance with Technical Specifications 3.14.4.2. The installation of'a new  !

master. selector valve and adjustments made to individual zone selector and -l' solenoid valves resolved the spurious actuation condition. All CO2 zones were returned to operable status on August 8, 1987 except Zone 76. The fire watch for Zone 76 will remain until the system is restored to operable status.

Elans and Schedule A work request has been issued to investigate and correct the ventilation system discrepancies. Further engineering evaluations will be necessary to- ]

accept the overall system performance. The system in question is expected to i be returned to operable status by October 31. 1987. t l

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, SACRAMENTO MUNICIPAL UTILITY DISTRICT O P. O. Box 15830, Sacramento CA 95852-183o,(916) 452-3211 l AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA j l

l l GCA 87-497 l

AUG 211987 U. S. Nuclear Regulatory Commission ,_ l Attn: J. B. Martin, Regional Administrator s Region V [

Office of Nuclear Reactor Regulation gi m m l 1450 Maria Lane, Suite 210 m r

EE Halnut Creek, CA 94596 gh@

V < E Docket No. 50-312 W Rancho Seco Nuclear Generating Station o License No. DPR-54 SPECIAL REPORT NUMBER 87-15 ISOLATION OF ENTIRE CO2 SYSTEM i

Dear Mr. Martin:

In accordance with Technical Specification 6.9.5.E, the Sacramento Municipal l Utility District hereby submits Special Report 87-15. This report is being submitted outside the time frame required in Technical Specification 3.14.4.2. l The District apologizes for any inconvenience this delay may have caused you, l If there are any questions concerning this report, please contact Mr. Bob Little at (916) 452-3211, extension 4477.

Sincerely, f, . Carl$ ##vn Andogfrini Chief Executive Officer, Nuclear Attachment cc w/atch:

G. Kalman, NRC, Bethesda (2)

A. D'Angelo, NRC, Rancho Seco p

.ZG-M RANCHO SECO NUCLEAR GENERATING SfATioN O l'444o Twin Cities Road, Herald, CA 95638 9799;(209) 333-;935

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