ML19305D665

Interim Deficiency Rept Re Safe Shutdown Boration Capability.Conceptual Design Completed for Emergency Boration Sys,Containing Sufficient Boron to Independently Maintain Shutdown Margin & Transition

ML19305D665
Person / Time
Site:	Midland
Issue date:	04/11/1980
From:	Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
References
HOWE-73-80, NUDOCS 8004150356
Download: ML19305D665 (2)

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1 POW 8f Stephen H. Howell

'.' (QQpQg Senior Ywe President oeneral O ffices: 1945 West Pernell Road. Jackson, Michigen 49201 * (517) 788 4453 April 11, 1980 Hove-73-80 .

Mr J G Keppler, Regional Director Office of Inspection and Enforcement US Nuclear Regulatory Co:::missica Regien III 799 aoosevelt Road Glen Ellyn, IL 60137 MIDLAND NUCLEAR PLANT UNIT NO 1, DOCKET NO 50-329 UNIT NO 2, DOCKET NO 50-330 SAFE SHUTDOWU BORATION CAPABILITY

References:

S H Howell letters to J G Keppler; Midland Nuclear Plant; Unit No 1, Docket No 50-329; Unit No 2, Docket no 50-330; Safe Shutdown Boration Capability;

1) Serial Hove-283-79; dated October 31, 1979

2) Serial Hove-308-79; dated December 6,1979 This letter, as were the referenced letters, is.an interim 50.55(e) report regarding safe shutdown capability assuming a most restrictive core ecndition and the control rod of highest worth stuck out .cf the core.

The Architect-Engineer on the Midland Plant (Bechtel) has ccripleted the conceptual design of a system to increase the safety grade

• boratien capability for the plent. This system vill be separate frcm the existing beration systems and contains sufficient boren to independently maintain the 1% A k/k chutdevn margin and the transiticn to cold shutdown.

The design criteria for the system design are delineated below:

a. The emergency boration system (EBS) shall be designed to prc' tide the boric acid needed to maintain.the reactor at 15 A k/k suberitical during hot shutdown and the transition to cold shutdown (assuming the contraction volume makeup sources have a minimum boric acid concen-tration) with the highest reactivity worth control rod stuck in the ccnpletely withdrawn position with no xenon in the core.

b. The EBS system shall be designed so that any single active failure shall not affect its design function.

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c. The system shall be designed to remain functional after a safe shutdown earthquake (SSE) and shall be protected against the postulated effects of flooding, pipe whip, jet impingement, and missiles.

d. The system shall be designed so that active components can be tested during normal plant operation,

e. The system shall be designed to allow for in-service inspection of its canponents in accordance with ASME Boiler and Pressure Vessel' Code,Section XI.

f. The system shall be designed.for local manual alignment of the valves and remote manual initiation of the equipment necessary for operation.

g. Piping and valves in the safety-related portions of the emergency boration system shall be designed to the requirements of the ASME Boiler and Pressure Vessel Code,Section III.

The details of the system design are being reviewed by CPCo, Bechtel, and B&W, and are expected to be coupleted within the next few weeks.

Another report, either interim or final, vill be sent on or before July 31, 1980.

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GRE/1r CC: Director of Office of Inspection & Enforcement Att Mr Victor Stello, USHRC (15) rector, Office of Management .

Informaticn & Program Control, USNRC (1) i l

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