ML19249A255
| ML19249A255 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 08/15/1979 |
| From: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| HOWE-221-79, NUDOCS 7908210477 | |
| Download: ML19249A255 (1) | |
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Stephen H. Howell Senior Vice President
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General Offices: 1945 West Parnall Road, Jackson, Michigan 49201. (517) 788-0453 August 15, 1979 Eeve-221-79 Mr J G Keppler, Regional Director Office of Inspection and Enforcement US Nuclear Regulator;, Com:nission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND NUCLEAR PIANT -
UNIT NO 1, DOCKI7f NO 50-329 UNIT NO 2, DOCKET NO 50-330 SMALL BREAK / REACTOR COOLAITI PIEP OPERATION INTERACTION In accordance with the requirements of 10 CFR 50 55(e), this letter constitutes an interim report concerning a potentially unsafe situation if the reactor coolant pumps are tripped after high system void fractions develop in the loop.
Specifically, for the lov probability events gnvohing a range of en11 reactor coolant system breaks (approximately 0.025 ft to 0.2 ft ), analyses show that a high void fraction vill develop in the primary system during the course of the accident. 10 C7R 50 Appendix K criteria may be exceeded if reactor coolant pu:nps are tripped after creation of this high void condition. ELW, Midland's NSSS Supplier, has been workin6 closely with the NRC staff (Dr Rosztozy) concerning this analysis.
B&W reports that analyses have been perfomed which confirm a safe situation if tl e reactor coolant pems are tripped promptly in the transient prior to establishing a high void fraction. E&W made a reco=nendation to the 1TTFA opercting plants that "Upon receipt of an ESFAS actuation caused by low RC pressure, ell operating RC pumps must be tripped i-adiately." CPCo is con-sidering an automatic /cafety grade trip system to accomplish the recommended action for the Midland Plant.
Another report, either interim or final,, vill be sent ca er before October 19, 1979
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%.s CC: Direr. tor of Office of Inspection and Enforcement Att: Mr Victor Stello, USNRC (15) 7(orNN Director of Office of Mana6ement g
Information and Program Control, U3NRC (1) 2 908 210 7n S
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