ML19270G363

LER 79-032/01T-0 on 790516:sprinkler Hanger Mods Indicated Seismic Design Deficiency for Cable Spreading Room Sprinkler.Caused by Lack of Detailed Seismic Analysis.Analysis & Mods Have Begun

ML19270G363
Person / Time
Site:	Hatch
Issue date:	05/30/1979
From:	Thomas Greene GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19270G361	List: ML19270G360 ML19270G363
References
LER-79-032-01T, LER-79-32-1T, NUDOCS 7906060218
Download: ML19270G363 (4)

Text

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Q l On 5-16-79, at ')0_0__ CST. while reviewino sprinkler hancer modifications proposed by 1

@ l the architect-engineer, it was discovered that such modifications indicated a seis-E I mic dnsign deficiency for the_ Unit 1 and Unit 2 cable spreading room sprinkler sys- I f 1~

Subsequent investigation -

l EI tems per HNP-2-FSAR Section 3.2.1.1 and IEEE 308-1971.

l-All hafSers had b_p_en specified according to seismic l E l_reveale.d_more araas affected. i I

E I guide]_irms assuming _.Wnts1_ case. wet pipe variables so that i_n the isolated dry-pipe  !

(contiayed) J I EI conditions the systems were closer to_s_eismic qualification than . 80 .

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CAUSE DESCRIPTloN AND CORnECTIVE ACTIONS h o l The architect-engineer had submitted approved s_orinkler systen desions to meet NRC I commitments which had not received a detailed seismic analysis. Upon reccanition j ,

yl of the event, the analys'is and modifications were begun immediately on the affected j yl On 5-26-79, modification and qualification of Unit 2 related systems were _]

EI systems.

complete and on 5-29-79, modification of Unit 1 related (continued) l EI '

'silN7s* . roe.E R OTHER STATUS @ C Y DISCOVERY DESCRIPTION @

E [.A.j@ l' 0 0l0l@l N/A I [Dj@lProposed modificatiens indicated orchlem] sa i2 n 44 45 46 A!nviTY COOTEnT LOCATION OF RELE ASE RELE ASED OF HELEASE AMOUNT OF ACTIVITY N/A I E [_7_] @ [Z _j @ l N/A l *

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3. [2j@l , iO Is M NsUg @DtSCHIPflON l N/A 1 l1lll1l1IIII12 68 69 80 E T. V. Greene, Supt. Plt. Eng. Serv. pgong; 912-367-7781 {

NAME OF FHEPAnEH

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Georgia Power Company Plant E. I. Ilatch Baxley, Georgia 31513 Event Description and Probable Consequences (continued) calculations indicated. --

Cause Description and Corrective Actions (continued) -

sytems was begun and is to be completed by the end of the Unit 1 Refuel-ing Outage. l 9

2274 268 f

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llARRATIVE SUPJ!ARY I

LER 1-79-32 i .

In reviewing the Grinnell as-built drawings of new sprinkler systems in-  !

stalled during the first half of 1978, to meet the 1979 due dates, it j was discovered by. the architect-engineer that these fiRC fire protection i commitment related systems had received an inadequate seismic review and that modifications would be recessary to meet the design loads. Upon notification of the proposed modifications the responsible personnel on ,, i site proceeded to obtain details on design bases and additonal systems

• l affected. Pending clarification of the problem, the design deficiency for ,  :

the more critical area, the conmon cable spreading room was reported at both units, and the approved design modifications to this area were begun. 1 At this point it was found that several other systers were seismically in- '

adequate. The affected systems, committed operability date, and modific-  ;

ation schedule are summarized below: i SPRINKLER SYSTEM COMMITMENT DATE MODIFICATIONS AND COMPLETE UNIT 1/ UNIT 2 QUA1.IFICATION BY: (UNIT 1/ UNIT 2)

Intake Structure Jan. 31, 1979 5-25-79; no modifications  !

(common) required  ;

RPS Cabicway Unit 1, 1979 5-26-79 (common) refue) .,

Control Building Unit 1, 1979 5-26-79/5-26-79 Corridor at El. refuel 130' (Units 1

& 2)

Rx. Building HVAC -

Unit 1, 1979 6-30-79/5-26-79 Rooms at El. 164' refuel / Unit 2, (Units 1 & 2) 1980 refuel Cabic Spreading Unit 1, 1979 5-26-79/5-26-79 Room refuel Rad-Waste Dry Waste N/A, 6-30-79 Storage (Unit 1)

Recire. MG Set Jan. 31, 1979 6-30-79 (Unit 1)

East Cableway July 31, 1978 6-30-79 (Unit 1)

HPCI Room May 31, 1978 6-30-79 (Unit 1)

. 2274 269 I

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Those systems already declared operabic were not impaired in their fire protection functions, and degradation of the seismic qualification of systems beneath the sprinkler systems was minimal since the initial designs

.' were based on seismic guidelines assuming a worse case of water being in the piping of the isolated. dry-pipe systems. Final calculations have rev-

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caled further modifications, and both calculations and modifications will be complete fer areas affecting each unit before start-up of that unit.

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