ML20002C784
| ML20002C784 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/11/1974 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8101100859 | |
| Download: ML20002C784 (3) | |
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Docket 50-155 Mr. Angelo Giambusso Deputy Director for Reactor Profects License DPR-6 Directorate of Licensing Big Rock Point Plant ATWS US Atomic Energy Commission Washington, DC 205h5
Dear Mr. Giambusso:
Consumers Power Company (CP Co) stated in our October 1, 197h letter to you that a report concerning Anticipated Transients Without Scram (AT4S) for the Big Rock Point Plant would be delayed in submission beyond the October 1, 1974 due date. This report, as required by WASH-1270,
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" Technical Report on Anticipated Transients Without Scram for Water-Cooled Power Reactors," would be in two parts. The first part would be a review of the reactor shutdown system with a consideration of com::en mode failures.
The second part would be an analysis of AT4S consequences.
The first part of the ATdS Report is a document entitled, " Big Rock Point Reactor Protection System Common Mode Failure Analysis," NEDC-20640.
This document was prepared by General Electric Company (GE) and was received on September 27, 1974. After review by CP Co, a meeting was held with GE on October 3, 197h to revise and update the report. Copies of the revised report vill be transmitted to you in a few days.
With regards to possible ATWS consequences analysis, GE has in-formed us that the earliest possible date by which such analyses could be completed is April 1, 1976. GE pleads that manpower and resources are limited to handle its customer-related licensing issues. 'Specifically on the basis of potential impact on plant operation and public safety issues, GE has ranked ATWS last in priority behind ECCS - Appendix K models, fuel densification, scram reactivity and GETAB. GE has done no work on ATJS consequence analysis for Big Rock Point and vill not be able to start this work for several months.
Accordingly, CP Co requests an extension until April 1,1976 for submittal of any ATWS consequences analysis. It does not hppear feasible at this time to have a more rapid analysis done by another consultant.
The consequences of the worst ATdS appear to be within the design pressure of the primary coolant boundary. The steam dru= safety relief valves were sized to limit the pressure resulting from a coincident steam shutoff with failure to scram (see Sections 12 5.8, 12.12.6, and Figure f/o//00B'El
Mr. Anghv L. -_ basso 2
Docket 50-155, License DPR-6 Big Rock Point Plant - ATWS 12.10 of the Final Hazards Sinnmary Report for the Big Rock Point Plant).
Starting from operating conditions of 1500 psia and 2k0 MWt, the peak pressure during this transient ranges from 1700 to 1800 psia. The design pressure of the reactor vessel is 1715 psia and the normal operating pres-sure is 1350 psia, instead of 1500 psia. Taking credit for the 150 psi lover operating pressure (1500-1350) would indicate peak transient pres-sures in the range of 1550 to 1650 psia, which is less than the reactor vessel design pressure.
Yours very truly, (C:'
l TWC/ map Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USAEC 1
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