ML20197F665

Summary of 810925 Meeting W/Util Re Various Approaches Available to Resolve UHS Intake Structure Flood Protection Concerns

ML20197F665
Person / Time
Site:	Diablo Canyon
Issue date:	10/14/1981
From:	Fliegel M Office of Nuclear Reactor Regulation
To:	Lear G Office of Nuclear Reactor Regulation
Shared Package
ML20197F583	List: IA-86-679, Sser Re Effect of Breakwater Damage on Saltwater Intake Structure ML20197F580 ML20197F595 ML20197F598 ML20197F605 ML20197F645 ML20197F665 ML20197F676 ML20197F712 ML20197F813 ML20197F901 ML20215D900 ML20215D909
References
FOIA-86-679 NUDOCS 8110280734
Download: ML20197F665 (2)

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11Ef10RATIDllM FOR: George Lear, Chief RO

!!ydrologic and Geotechnical Engineering .

Branch [' /cbi 9, Division of Engineering FR0ft: flyron Fliegel, Leader, !!ydrologic Engineering Section I!ydrologic and Geotechnical Engineering Cranch Division of Engineering

SUBJECT:

!!EETIriG UITil APPLICAtlT TO DISCUSS DN1 AGED BREAKUATER Plant ilame: Diablo Canyon fluclear Power Station, Units 1 & 2 Licensing Stage: OL A meeting was held with the applicant, Pacific Gas and Electric Company -

(PG& E), on September 25, 1931 to discuss various approaches available to resolve the soff's concerns relating to the flood protection of the Ultimate lleat Sink intake structure. The staf6 concerns are a result of damage incurred by the breakwater during severkwave attack in January,1931.

In our safety evaluation, credit was taken for the protection afforded by the breakwater to the intake during the postulated design flood event. Because of the damage sustained by the breakwater, its ability to provide protection to the intake structure has been questioned by the staff.

The following agreements, understandings and conclusions were reached at the meeting.

1. PG&E's analysis of design flood effects on the intake will take credit for the protection afforded by a " degraded" breakwater. PG&E will '

provide documentation, for f4RC review, to show that if left unrepaired after assumed further wave damage, the breakwater would not completely erode. Rather it would degrade to approximately the i1LUl level at which elevation it would not sustain further wave degradation.

2. PGLE will analyze the effects on the intake structure of the design flood event. Credit for the breakwater in the degraded condition as agreed to by fiRC after evaluation of the material provided as per item 1. above can be taken. Results of the tests performed on the physical model can be used by PG&E. In addition to inundation effects, wave forces on the intake structure will be addressed.

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George Lear CCT I 4198;

3. In order to detemine the design flood event the following combinations will be investigated and documented by PG&E:

a. A Probable Maximum Tsunami combined with stom waves of annual severity and high tide with anomaly.

b. A l',aximum Credible Wave Event combined with high tide with anomaly.

Several approaches to detemining the !!aximum Credible Wave Event were discussed.

4. PG&E will address other potential consequences of a degraded breakwater including ship collisions and tribar impacts on the intake.

5. PG&E will provide documentation, to NRC, in the fom of a report (s),

on the above items.

G. NP,C staff and consultant will visit the physical model in order to observe it during tests. Another meeting with PGSE will be held at that time to review progress in resolving this item.

Original Signed by

' yron H. 711egel J

Myron Fliegel, Leader l{ydrologic Engineering Section flydrologic and Geotechnical Engineering Branch Division of Engineering cc: R. Vollmer J. Knight B. Buckley M. Fliegel DISTRIBUTION Docket File llGEB Reading orncr> h.

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NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY