ML19305D989

Interim Deficiency Rept Re Safe Shutdown Boration Capability Assuming Restrictive Core Condition.Delineates Ae Design Criteria for Separate Sys to Increase safety-grade Boration Capability.Addl Rept Will Be Submitted by 800731

ML19305D989
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 8004170083
Download: ML19305D989 (2)

Text

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O CORSumBIS bi C 1l POVlBf Stephen H. Howell (QlQ%Qf Senior Vice President General Of ficos: 1945 West Pernell Road, Jackson, Michigen 49201 * (517) 7884453 April 11, 1980 Howe-73-80 Mr J G Keppler, Regional Director Office of Inspection and Enforcement US Huclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND HUCLEAR PLANT UNIT NO 1, DOCKET NO 50-329 .

UNIT NO 2, DOCKET NO 50-330 SAFE SHUTDOWN 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 Howe-283-79; dated October 31, 1979

2) Serial Howe-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 ccadition and the control rod of highest worth stuck out of the core.

The Architect-Engineer on the Midland Plant (Bechtel) has canpleted the conceptual design of a system to increase the safety grade' boration capability for the plant. This system will be separate fran the existing boration #

systems and contains sufficient boron to independently maintain the le A k/k shutdown margin and the transition to cold shutdown.

The design criteria for the system design are delineated below:

a. The emergency boration system (EBS) shall be designed to provide the boric a-id necded to maintain the reactor at 1% A k/k suberitical during hot atdown and the transition to cold shutdown (assuming the contractic tolume makeup sources have a minimum boric acid concen-tration) with the highest reactivity worth control rod stuck in the 4 conpletely withdrawn position with no xenon in the core.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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Howe-73-80

c. The system shall be designed to remain functicnal 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 ccruponents 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, will bo sent on ol- before July 31, 1980.

- y A A.A.

GRE/1r CC: Director of Office of Inspection & Enforcement-Att Mr Victor Stello, USNRC (15)

Director, Officc of Menagement Informaticn & Prc, gram Control, USNRC (1) e-