ML19332A080
| ML19332A080 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 09/02/1980 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8009100573 | |
| Download: ML19332A080 (2) | |
Text
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Generet Offices: 212 West MacNeon Avenue. Jacuson Macn6een 49201 * (517) 788-C550 September 2, 1980 Director, Nuclear Reactor Regulation Att Mr Dennis M Crutchfield, Chief Cperating Reactor 3 ranch No 5 US Nuclear Regulatory Commission
'4ashington, DC 20555 DCCKET 50-155 - LICENSE DPR 3IG ROCK POINT PLANT - PROPOSED PRO 3A3ILISTIC RISK ASSESSMENT:
ADDITIONAL INFORMATICN FOR NRC RE7II'!
37 letter dated August 25, 1980, Consumers Power Ccmpany provided information relative to emergency diesel generator (IDG) periodic testing. A discrepancy has been noted affecting the proposed increase in EDG start time acceptance criteria. This discrepancy involves the bases on which the required EDG start time is derived. The 3ig Rock Point LOCA-ECCS Analyses establish recuired EDG start times based on MAPLHGR limits associated with the dr/ out time "of the core.
The current Technical Specifications MAPLEGR limits assume time to rated ECCS spray flow during a D3A is 20.k seconds. The resulting required EDG start time is 13.9 seconds. The most recent MAPLEGR analysis which provides the basis for Consu=ers Power Ccmpany's Technical Specifications change request dated February 25, 1980 assumed rated ECCS spray flov is provided h6.2 seconds after the DBA. "his analysis also assumes that the core spray system (ECCS) provides the rated spray flow in 15 seccnds after actuation (actual rated spray flow occurs approximately o.5 seconds after actuation). '-'herefore, EDG start time of 31.2 seconds er less is required to provide rated spray flov.
Until February 25, 1980 Technical Specifications change request is approved, two EDG scarc time acceptance criteria vill be use?. to fulfill Technical Speci-fications reporting criteria and EDG testing critel'.a.
Technical Specifications reporting vill be based on a 13.9 second start time to satisfy currently appreved MAPLEGR li=its. For the purposes of failure rate determination in accordance with Regulatory Guide -.C8, a 31.2 seccad start time vill be used as described in cur letter dated August 25, 1960.
It is requested that the Co==ission continue its review and provide approval of cur Febr ary 25, 1980 Technical Specifications change request. Plant power levele a-= ---~'y administrc.tively limited by the lov reactor level (LRL) trip set j
point as described in our Technical Specifications change request dated August 2",
1980. Upcn approval of this request, cur ent MAPLHGR limits vill restrict power of s
/ D 8 00910 g$7 3 p
,g,,-.
Propo:ed Probabilistic Risk Assessment -
September 2, 1980 operation to 220 :#,,, (approximately 67.W, gross) vhich correlates to an approximate 2 IN, nit derate below the neret most restrictive fuel themal-
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hydraulic limit. Therefore, approval of the February 25, 1980 Technical Specifications change request vill allow the 31.2 second EDG start time to be used for both reporting and failure rate determination, and vill provide an increase in power output assuming approval of the August 25, 1980 Techn-nival Specifications change request.
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David ? Hoffman Nucleer Licensing Administrator CC JGKeppler, USURC NRC Resident Inspector - Big Rock Point l
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