ML19210C783

Forwards Util Final Deficiency Rept Re Svc Water Supply Pressure for Containment Recirculating Air Cooling Units

ML19210C783
Person / Time
Site:	Midland
Issue date:	10/19/1979
From:	Gibbs M ISHAM, LINCOLN & BEALE
To:	Cowan F, Linenberger G, Smith I Atomic Safety and Licensing Board Panel
References
NUDOCS 7911200100
Download: ML19210C783 (1)

Text

' ' '

& 'L & f,w,,,.7 Wu D.i]

- ISHAM, LINCOLN & BEALE

%y y counsacas 4r uw 9

2 g f .pf 7 one riasr mariowas etaza roarv-secono recom cwicaco.itumois socos i, ,jj 4hj retcomoNC 3 2=ssa-7Soo TELCx: 2 S288 p* Y was= =orou ornec

,_ , n ,. . ,, .-

ioso in stocar. .. ..

scvturw rooon

- a ._1, ..,s.,

/ ""'s~%

/ gg 2;gg wasm=orou,o.c.acoa.

October 19, 1979 Ivan W. Smith, Esq. Mr. Gustave A. Linenberger Atomic Safety and Licensing Board Atomic Safety and Licensing Bd. Pane.

U.S. Nuclear Regulatory Ccmmission U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Washington, D.C. 20555 Dr. Frederick P. Cowan Apt. B-125 6152 North Verde Trail Boca Raton, Florida 33433 Re: Consumers Power Company (Midland Plant, Units 1 and 2)

Docket Nos. 50-329, 50-330 Gentlemen:

Enclosed are four S 50.55(e) reports which have recently been submitted by Consumers Power Company to the Nuclear Regulatory Ccmmission.

Very truly yours, OaMQ Martha E. Gibbs MEG:cem cc: Service List Enclosures 1%6 130

, .ron g oo } O C _ _~

,- DTED CORREspgxpg h3 C0!1SUlii8fS Stepha.e H. Howell LooRpAg-ds_ --

Genersl Offices: 1945 West Parnest Road, Jackson, MicMeen 4s201 . (5171 7384453 October 15, 1579 Hove-269-79 m e

Mr J G Keppler, Regional Director -

Office of Inspection and Enforcaeaat I g,$pV dI US Nuclear Regulatory Ccz:: mission S,- g(T -

Region III a p 799 Roosevelt Read c5*V,, ,

Glen Ellyn, IL 60137 MIDLLND NUCLEAR PLANT

%In)j UNIT NO 1, DOCz2r r0 50-329 UNIT I:0 2, DCCKET 20 50-330 SER7 ICE WATER SUPPLY PRESSURE IVR TEE CONTAITiME"l' AIR CCCLERS

Reference:

S H Howell letter to J G Keppler; Midland Nuclear Plant; Unit No 1, Dochet No 50-329; Unit No 2, Docket No 50-330; Service Water Supp4 Pressure for the Contaf n-ant Air Coolers; Serial Ecve-219-79, dated August 7, 1979 The referenced letter was an interi 50 55(e) report regarding the failure to obtain the required design pressure at the ott,let of the contain=ent air coolers. This letter is the final report. Corrective actions and their i=ple=entation dates are provided in the attar b ent.

wRs/tr Attachnent: MCAR-30, Final Report, dated Septe=ber 26, 1979 CC: Director of Office of Inspection and Enforce =e=t Att: Mr Victor Stello, USNRC (15)

Director of Office of Management Infor=ation and Program Control, USNRC (1) 1366 131 ggh

- ._- ysa, go erd

2 .

Have-269-79 BCC: JL3 acon, M-lo8SA WRBird, JSC-2163 LHCurtis, Bechtel AA JLCorley, Midlar.d LADreisbach, Bechtel-Midland MIGibbs, IL&.3 y GS lKeeley, P14 kC83 ShEarguglio, JSC-22CA DBfiller, M.!dland WdorinE, Bechtel AA JFNevgen, Bechtel-Midland JARutgers, Bechtel AA ELTeuteberg, P14 d l8 File: 0.4 9 32 6e 9

e ne 1366 132

Howe-269-79

SUBJECT:

MCAR 30 (issued 7/11/79)

Service Water Supply Pressure for the Containment Recirculating Air Cooling Units FINAL REPORI ,

DATE: September 26, 1979 PROJECT: Consumers Power Company Nid1 = d Plant Units 1 and 2 Bechtel Job 7220 ,

Introduction l

This report is submitted to advise of the status of the project's action

~ ~ ~

relating to the service water supply pressure for the conta"ent recir-culating air cooling units (CRACUs).

Description of Ecficiency During final system flow diagram review, project engineering discovered that the service water supply pressure to the CRACUs following a loss-of-coolant accident (LOCA) or main steam line break (MSL3) is less than the 40 psig (54.7 psia) stated in FSAR Subsection 6.2.2.2.3. The final calculations indicate that the service water pressure at the CRACU outlet could be as low as 13 to 14 psia under emergency operation,-with the ultimate heat sink at its design elevation of 604 feet (see FSAR Subsection 9.2.5). The post-accident environ =ent inside the conta4"-ent reaches approxi=ately 300F and causes service water inside the air-coolers to boil, resulting in reduced perfor=ance of the CRACUs.

Consequently, the CRACUs could not re=ove heat from the containment at the rate described in FSAR Subsections 6.2.2.2 and 9.2.1.3 following an MSL3 or LOCA.

Su=marv of Investiention of the Causes of the Deficiency While conducting the investigation, two principal cire--* ances con-tributing to the deficiency were identified.

A. A review of the prelf i n ry calculations identified several errors and nonconservative assumptions, each of which contributed to the deficiency. ,

1. It was assumed that the cooling pond was at the normal full-operating elevation of 627 feet rather than at the 604-foot initial design elevation of the ultimate heat sink. This assumption resufted in an f available service 1sacer pressure of 23 feet

• e DUPLICATE DOCUMENT Entire document previously entered i to s stem under-ANO No. of pages: