ML20033D309

Forwards Responses to Hydrologic & Geotechnical Engineering & Structural Engineering Branch Requests Re Flood,Drought & Earthquake Insp Program

ML20033D309
Person / Time
Site:	Clinton
Issue date:	11/30/1981
From:	Geier J ILLINOIS POWER CO.
To:	John Miller Office of Nuclear Reactor Regulation
References
L30-81(11-30)-6, U-0353, U-353, NUDOCS 8112070518
Download: ML20033D309 (5)

Text

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U-0353 ILL/NOIS POWER OOMPANY L30-81 (11-30)-6 iP 500 SOUTH 27TH STREET. DECATUR. ILLINo!S 62575 November 30, 1981 8

/,9 Mr. James R. Miller, Chief Og [/

Standardization & Special Projects Branch

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Dear Mr. Miller:

Clinton Power Station Unit 1

-Docket No.

50-461 Enclosed are four responses to verbal requests by the SEB and HGEB reviewers.

Sincerely, C

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'd.D. Geier Manager, Nuclear Station Engineering Attachments cc:

J.H. Williams, NRC Clinton Project Manager H.H. Livermore, NRC Resident Inspector B. Jagannath, NRC HGEB N. Chokski, NRC '- SEB R. Wescott, NRC - HGEB h.

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Response to verbal question / request by B. Jagganath of NRC-HGEB:

A technical specification will be provided for an inspection program that will include the following provisions:

1) The.cntire UllS shoreline will be inspected for erosion annually, af ter major floods, af ter extreme droughts, and major carthquakes.

l This inspection program will consist of a thorough physical examina-tion after spring run-off, floods, droughts and major carthquakes i

for crosion detrimental to the function of the Ultimate Heat Sink.

j The technical specification will define the flood, drought and l

earthquake levels that will initiate the inspection program and l

will provide details of the inspection program.

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2) Conditions encountered during each inspection will be compared i

l with as-built conditions and previous inspection reports to determine the extent of changes will be used to evaluate the adequacy of slope protection against waves, surface runoff and currents.

3) If any features detected in these annual inspections have degraded l

to the poin' t where they will not provide adequate UHS protection, l

the plant will go into a safe shutdnwn condition and remair. Mdown until necessary repairs have been completed.

The technical:speci-fication will define degradation levels that require plant shutdown.

4) The inspection program will be developed using the guidance provided in ~ Regulatory Guide 1.177, inspection of Water-Control ' Structures

. Associated with Nuclear power Plants.

The FSAR will be amended to discuss the provisions of this inspection ~

program.

A technical specification will be provided to establish a sediment mont-toring and dredging program to assure that:

1) During normal operation, there will be a volume of water in the UHS-below elevation 675 sufficient to a) receive the sediment load from-a once in 25 year flood event and b) still be adequate to maintain i:

the plant in a safe shutdown condition for 30 days under adverse

meteorological conditions as defined in.the Reg.-Guide 1.27.:

'2) If the. volume of water below elevation 675 in the UHS is less than that specified in 1) above, the plant will;go into a safe shutdown

- condition and remain shut down until adequate volume in the UHS'is.

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restored.

The FSAR will be amended to discuss the provi.stonsiof this' technical.

specification, i

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The FSAR will be amended to include the following provisions regaru nj the open excavation adjacent to Unit 1:

1) Backfill behind the walls of Unit 1 in the vicinity of the open excavation will be protected against erosion by the installation of a revetment composed of a grout intiusion blanket similar to

" Fa bri form. "

2) Except for the ramp, a perimeter berm of suf ficient height to divert flood water will be installed around the open excavation of Unit 2.

3) A suitable drainage system with sufficient capacity to handle local intense rainfalls up to and includir7 the PMP without excessive ponding or blockage due to debric or ice will be designed and installed.

4) All openings in the Unit 1 building below grade level that lead into Unit 2 excavation will be closed and water proofed.

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.7 Response to question / request by N. Chokski, SEB Reviewer:

Table 3.8.1.1 of the Clinton project FSAR will be amended to include a Hote f which will read as follows:

I l-f) The 33 /3% increase in stresses l.

allowed by the ASME B & PV Code-l Section III Division 2, CC-342t l

(ACI-ASME 359,1973) for members subject to wind or earthquake shall not be considered.

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I Response to question / request by fl. Chokski, SEB reviewer:

Openings in the Unit 1 - Unit 2 interface walls of Category I buildings will be closed with missle resistant concrete barriers.

These barriers have been designed to resist tornado missles identi-fled in the FSAR.

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