ML17053D969

Forwards Request for Addl Info Needed for NRC Assessment of Reactor Bldg Crack.Meeting on 830725 Would Be Most Expeditious Method of Providing Info & Discussing Problem

ML17053D969
Person / Time
Site:	Nine Mile Point
Issue date:	07/15/1983
From:	Vassallo D Office of Nuclear Reactor Regulation
To:	Rhode G NIAGARA MOHAWK POWER CORP.
References
TAC-69217, NUDOCS 8307290217
Download: ML17053D969 (8)

Text

4 DIST: 'ocket File NRC PDR OELD EJordan RHermann ACRS-10 Gray LPDR SNorris ORB¹2 Reading NSIC Dfisenhut JTaylor Docket Ho. 50-220 JUL 15 lsd Hr. G. K. Rhode Senior Vice President tiiagara fiohawk.Power Corporation 300 Erie Boulevard Hest

Syracuse, New York 13202

SUBJECT:

ASSESSHEHT OF REACTOR BUILDING CRACK Nine flile Point Nuclear Station, Unit Ho.

1 Reference is made to your letter of tiarch 25, 1983 which submitted your evaluation of the crack in the Reactor Building at the facility.

The information was reviewed by our staff and we find that the information identified in the enclosure I-,>>~required to complete our review.

In order to expedite our review, we feel that a meeting on July 25, 1903.

at 10:00 am would be advantageous.

He expect at that time you would formally respond to the enclosed questions and provide any further

~

information you have on your plans for longer-term actions regarding the crack.

This approach has been discussed with and found acceptable to your licensing staff.

The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; therefore, OliB clearance is not required under P.L. 96<<511.

Sincerely, Cdgff5f SjIFIMd)y D B. Va".sath 8~0 >~

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Enclosure:

Request for Additional Information cc ~f/a~closure:

See next page Domenic B. Vassallo, Chief Operating Reactors Branch F'2 Division of Licensing OFFICE II SURNAME/

DATE Q DL:O~RB¹ IYTOl01 S

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NRG FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY USGPO'981~960

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Mr. G. K. Rhode Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station, Unit No.

1 CC:

Troy B. Conner, Jr.. Esq.

Conner 8 Wetterhahn Suite 1050 1747 Pennsylvania Ave.,

NW Washington, D.C.

20006

Director, Technological Development Programs State of New York Energy Office Swan Street Building CORE 1 - Second Floor Empire State Plaza

Albany, New York 12223 Hr. Robert P. Jones, Super visor Town of Scriba R.

D.

F.4

Oswego, New York 13126 Niagara Mohawk Power Corporation ATTN:

Mr. Thomas Perkins Plant Superintendent Nine Mile Point Nuclear Station P.O.

Box 32

Lycoming, New York 13093 John W. Keib, Esquire Niagara Mohhwk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Mr. Jay Dunkleberger Division of Policy Analysis and Planning New York State Energy Office Agency Building 2, Empire State Plaza

Albany, New York 12223 U.S. Environmental Protection Agency Region II Office Regional Radiation Representative 26 Federal Plaza New York, New York 10007 Resident Inspector c/o U.S.

NRC P. 0.

Box 126

Lycoming, New York 13093

4

ENCLOSURE RE/VEST FOR ADDITIONAL INFORMATION DOCKET NO. 50-220 NINE MILE POINT NUCLEAR STATION, UNIT NO.

1 A

Reference:

Niagara Mohawk letter dated March 25, 1983 to D.B. Vassallo with enclosure

'"Analysis. of Reactor Building Wall."

1.

Provide a discussion of the procedures used to evaluate the dynamic lateral earth pressures, the dynamic components of groundwater

loads, and the dynamic component of surcharge load acting on the reactor building wall under seismic conditions.

Specifically, include information related to the method used in estimating the dynamic lateral earthpressure, the soil parameters assigned to the backfill materials adjacent to the wall (i.e., angle of friction of soil, unit weight of soil, coefficient of earth pressure at rest, etc.), height"of backfill material, depth of water table, and horizontal and vertical ground acceleration components used to estimate dynamic lateral earth pressure.

2.

The conservativeness of the assumptions made regarding the use of a non-rigid wall condition active earth pressure loading should be addressed.

3.

5.

6.

The conservatism of neglecting dynamic components of groundwater and surcharge should also be addressed as appropriate.

Provide'a sketch showing the finite element model of the reactor building wall,analyzed by Structural Analysis Program (SAP).

Indicate how the load of 585 kips imposed by the screenhouse wall on the re'actor building wall is obtained.

It is stated that groundwater would tend to reduce the assumed 20'F temperature rise.

of the wall and therefore the load is considered to be conservative.

This may not be true in view of the fact that water tends to lubricate the interface between the screenhouse wall and rock and therefore decreases the friction force.

Furthermore, concrete in contact with water tends to expand

and, as a result, will increase the force.

In view of these considerations the load of 585 kips as calculated by you may not be conservative after all.

A relative deflection of 0.034" has been mentioned in your analysis (Case 3).

Indicate the contributions from the screenhouse and the reactor building respectively.

In Item (b) of Case 3, your reasons for conservatism are described; however, it appears that if you allow rotation around the perimeter, larger deflection should result and thus the relative deflection will be increased.

Therefore, by constraining the finite element model perimeter, it may not be conservastive.

A cl.arification of your reasoning is required.

I

7.

In your discussion on the structural integrity of the reactor building wall'you implied in Item II B that cracking of the wall is due to formation of a very localized plastic hinge and does not constitute a structure failure.

However, in Item III you rely on a

compression block of 3.6 inches deep to maintain thd reactor building boundary.

Specify clearly what the criteria of failure for the reactor building are.

Indicate how 3.6 inches deep compression block is estsblished together with your assumption of the shape of the block.

Please describe how you are assured that the crack is not a through crack.

8.

The rationale of your proposed modification to enhance reactor building integrity is not clear.

Provide an analysis and design of the compression strut and the crushable grout.

In crushing the

grout, a force will be transmitted to the floor slab, which may be damaged as a consequence.

Provide an analysis to indicate the possibility that such occurrence has been considered. in your design.

A