ML20009C924
| ML20009C924 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 07/15/1981 |
| From: | Vincent R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20009C925 | List: |
| References | |
| TASK-15-01, TASK-15-03, TASK-15-04, TASK-15-05, TASK-15-07, TASK-15-09, TASK-15-1, TASK-15-3, TASK-15-4, TASK-15-5, TASK-15-7, TASK-15-9, TASK-RR NUDOCS 8107220149 | |
| Download: ML20009C924 (2) | |
Text
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r Consumers POWX company Generen offices: 212 West Michigan Avenue. Jackson, Michison 49201 e (517) 788-0660 July 15, 1981 Q
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Director, Naclear Reactor Regulation hp
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, Att Mr Dennis M Crutchfield, Chie.
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Operating Reactors Branch No 5 l,
US Nuclear Regulatory Commission 8,
,s Washington, DC 20555 g
d DOCKET 50-155 - LICENSE DPR "
BIG ROCK POINT PLANT - SEP DESIGN BASIS EVENT TOPICS XV-1, XV-3, XV-4, XV-5, XV-T AND XV-9 The enclosed report entitled " Plant Transient Analysis of the Big Rock Point Nuclear Reactor", contains Consumers Power Company's evaluation of Systematic Evaluation Program topics XV-1, XV-3, XV h, XV-5, XV-T and XV-9.
Plant specific analyses in' support of these evaluations was performed by Consumers Power Company with the assistance of a consulting fim well known in the field of reactor system transient analysis. The analyses were performed using the Retran computer code developed by EPRI. Although the methods used in the analysis have not been romally reviewed and approved by the NRC staff, Consumers Power Company believes that they conservatively predict reactor sys-tem performance for the events analyzed.
It should be noted that the NRC staff has reviewed and approved a reactor system model of BRP for a 10CFR 50, Appendix K, ECCS analysis which is based on the Relap h computer code, and that Retran was derived from Relap h.
All analyses prc/ided in the report have been performed as prescribed in the NRC Standard Review Plan (S.'lP). In some cases, specific SRP acceptance cri-teria.are not met.
In particular, the criterion that " events of moderate frequency in combination with any single active component failure, or single operator error', should not result in loss of function of any barrier other than the fuel cladding" is nou met in scme cases.
That is, for some moderate frequency events a single operator error, with or without a concurrent single f
failure, could lead to a more serious plant condition involving operation of f 0 the reactor depressurization system (i.e. violation of primary coolant system 3
integrity) and a demand on the core spray system to assure adequate core cooling.
As stated in the report, however, this condition vill not affect the health and safety of the public provided the reactor depressurizaticn and
[g core spray systems and the contain=ent isolation system function as designed.
It should be noted that many of the operator errors identified in this report as being possible causes of a more severe event, were:also identified in the Big Rock Point probabilistic risk assessment (FRA) which was submitted to the 0107220149 810715 PDR ADOCK 05000155-P ppy _
2 HRC in our letter of March 31, 1981.
Consumers Power Company is current 3y considering plant modifications to reduce the likelihood of core damage accident sequences, including sequences of the type described in this report, which were identified in the PPA as being probabilistically signifi-cant. An example of this is the proposed modifications to improve the relia-bility of makeup water to the shell side of the emergency condenser in the event of loss of station power or main feedwater, thus providing added assurance that the event will not degrade further. As discussed in our March 31, 1981 letter, our decision to implement these modifications will b
ont#ngent upon NRC action on the PRA.
I AM7tIL '
c2 k mt ll'2dncnt obert A Vincent Staff Licensing Engineer CC Director, Region III, USNRC HRC Resident Inspector - Big Rock Point I
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