ML20005B017
| ML20005B017 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/29/1981 |
| From: | Vincent R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-15-19, TASK-RR NUDOCS 8107060220 | |
| Download: ML20005B017 (4) | |
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Consumem Power Company Geaeral Offices: 212 West Michigan Avenue, Jackson, Michleen 49201 + (517) 788-0550 June 29, 1981 Director, Fuelear Reacter Regulation Att Mr Dennis M Crutchfield, Chief Operating Reactors Branch No 5 US Nuclear Regulatory Con =ission Washington, DC 20555 DOC m 50-155 - LICENSE DPR BIG ROCK POINT PLANT - SEP TOPIC XV-19, LOSS OF COOLANT ACCIDENTS RESULTING FROM SPECTRUM OF POSTULATED PIPING BREAKS WITHIN THE REACTOR COOLANT PRESSURE BOUNDARY (SYSTEMS PORTION)
Attached is the Consumers Power Company evaluation of SEP '"cpic XV-19 (Systems Portion) for the Big Rock Point Plant.
Ct b
Robert A Vincent Staff Licensing Engineer CC Director, Region III, USNRC NRC Resident Inspector-Big Rock Point b
8107060220 810 PDR ADOCK 0500 SS P
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Topic - XV-19: Loss-of-Coolant Accidents Resulting from Speetrum of Postulated Piping Breaks within the Reactor Coolant Pressure Boundary (Reactor System Response Portion)
Background:
A LOCA analyses in compliance with 10CFR50.h6 and Appendix K was submitted for_ Big Rock Point in reference 1.
Reference 1 also contained a request for exemption -from the single fai3 ure criteria as applied to a LOCA caused by a break in one core' spray line vith concurrent failure of a valve in the other core spray line to open.
This exemption request was subsequently expanded to include the requirement that long term recirculation mode cooling be maintain-able despite failure of the on-site diesel generator in the absence of offsite power..By memorandum and order (reference 2) the NRC provided plant-life exemptions from 10CFR50.46 in the two areas noted above. These exemptions were contingent upon a number of conditions including:
1.
providing test data satisfactorily demonstrating adequate core spray distribution of the.ECCS spray nozzle.
2.
modifying emergency procedures to assure that a second emergency diesel generator vill be obtained and can be made fully operational within 2h
' hours of a LOCA.
3.
augmenting surveillance of ECCS availability.
4.
=odifying the fire protection system such that long tem cooling can be accomplished without relying en the undergzeund portions of the fire system.
These conditions, among others, were satisfied as described in references k through 12.
Reference '13 contains the staff SER on the Censumers Power Company i-response to the memorandum and order.
Subsequent to the efforts described above Censumers Power Company was required to perform the following additional work:
1.
To provide an updated ECCS analyses for Exxon fuel which utilized speci-fic blowdown information generated by Exxon approved methodology rather than that generated by the General Electric ECCS evaluation codel.
2.
To provide test data demonstrating adequate core spray distribution of the ECCS ring sparger.
(The sparger is redundant to the spray no::le tested previously. )
Eeferences lk,15 and 18 provided the CPCo response to the first item of addi-tional work listed above. Reference 19 contains the staff SER regarding this item.
Reference 16 provided the CPCo response to the requirement for ring sparger testing and reference 17 contains the staff SER of that report.
Re fer-ence 18 also provided information concerning LOCA vith one reactor coolant pu=p not in service. The staff has not as yet completed its review of this issue however.
I e
2 Evaluation The most recent LOCA analysis (reference 14,15 and 18) considered a complete break spectrum including breaks in the recirculation pump suction and dis-charge piping.
Ioss of offsite power was assumed in the analysis.
Break sizes up to and including the complete severance of the largest pipe in the system were considered. The analyses assumed the worst single fa'. lure of ECCS equipment; i.e. the diesel generator. This failure causes the unavail-ability of the electric fire pump and the core spray nozzle, and therefore only the diesel driven fire pump and the core spray sparger were assumed to
. be available for core cooling. The evaluation model used in the analysis had been previously reviewed and approved by the staff. Results of the analyses show that the ECCS acceptance criteria of 10CFR50.h6 are met; i.e.
peak cladding temperature is predicted to be less than 22000F; the maximum localized clad oxidation is less than 177. of the total clad thickness; the calculated total amount of hydrogen generated by oxidation of cladding does not exceed l. of the hypothetical amount that would be generated if all of the metal surrounding the fuel were to react; and the core is calculated to remain in a coolable geometry. -Long term cooling is provided by injection of fire water through either the core spray sparger or nozzle until the contain-ment water level maches the 587 feet elevation and the operator manually switches to the recirculation mode of long term cooling using the Post Inci-dent System.
Cenelusion The Big Rock Point Plant is in compliance with current NRC criteria for Loss of Coolant Accidents as contained in 10CFR50.h6 and 10CFR50 Appendix K except with regard to the single failure criterion as discussed above. With respect to the single failure criterion, the NRC has granted a plant lifetime exemp-tion to the regulation.
References ( All pertain to Docket DPR-6)
(1) Letter - RBSevell to USNRC dated July 25, 1975 (2) USIGC Memrandum and Order dated May 26,1976.
(3) A=endment No. 10 to Facility Operating License-, June h, 1976.
(h) - Letter to USNRC dated May 11, 1976.
(5) -Letter to USNRC Cated May 20,19T6.
(6) _ Letter to USNRC dated February h,1977 (T) Letter to USNRC dated May 5,1977 (8) Letter to USNRC dated July 26, 1977 (9) Letter to USNRC dated July 28, 1977 (10) Letter to USNRC dated August 9,1977 (11) letter to USNRC dated August 12, 1977 (12) Letter -WSSkibitsky to USNRC dated August 12, 1977 (13) Amendment No. 13 to Facility Operating License, October 17, 1977 (1h) Letter - DPEoffhan to USNRC dated Septe=ber 29, 1978.
(15) Letter - DA31xel to USNRC dated March 7, 1979 (16) Letter - DA31xel to USNRC dated March 28, 1979 (IT) Amendment No. 26 to Facility Operating License, April 10, 1979 (18) Letter - DPRofftan to USNRC dated February 25, 1980.
(19) Amendment No. kh to Facility Operating License, June 9, 1981.
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