ML17037C526

Letter Informing That Proposed Request to Install an Access Platform to the Refueling Bridge Does Not Present Significant Hazards Consideration and Grants Request

ML17037C526
Person / Time
Site:	Nine Mile Point
Issue date:	01/21/1974
From:	Skovholt D US Atomic Energy Commission (AEC)
To:	Raymond P Niagara Mohawk Power Corp
References
Download: ML17037C526 (8)

Text

4AM 2"- 1974 Docket Iio. 50-220 Hiagara Hohawk Power Corporation AXTH: Hr. Philip D. Raymond Vice President - Engineering 300 Erie 3oulevard Hest Syx'acuse, Hew York 13202 Gentlemen:

Your letter dated January 11, 1973, with additional infoxmation dated August 27, 1973, described the design of and included a safety analysis for the proposed installation of an access platform to the refueling bridge at your 'Nine ELle Point Unit 1 facility.

be have reviewed the infoxmation you provided and have concluded that the proposed change to the facility does not present a significant hazards consideration and tlmt there is reasonable assurance that the health and safety of the public will not be endangered. Accordingly, you may install the proposed access platform as you describe in your letters and in accordance with paragraph 50.59(a) of 10 CPR Part 50.

Tae results of our review are given in the enclosed Safety Evaluation.

Sincerely, Origin@i si~ned by.

Dennis L. 2!eat.".an Donald J. SI;ovholt Assistant Director for Operating Reactors Directorate of Licensing

Enclosure:

Safety Evaluation cc: See next page

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Magma Mohawk Power Corporation - 2 J. Bruce MacDonald, Esquire Deputy Commissioner and Counsel llew York State Department of Commerce and Counsel to the Atomic Energy Council 99 Washington Avenue Albany, New York 12210 Arvin E. Upton, Esquire LeBoeuf, Lanib, Leiby ItI Mackle 1757 N Street, N. W.

Washington, D. C. 20036 Dr. WiQ.iam Seymour Staff Coordinator Mew York State Atomic Energy Council Hew York State Department of Commerce 112 State Street Albany, New York 12207 Distribution

~ocket File Anthony Z. Roisman, Esquire AEC PDR Berlin, Roisman and Kessler Local PDR 1712 N Street, H. W. RP Reading Washington, D. C. 20036 Branch Reading JRVuchanan, ORNL Oswego City Library TBAbernathy, DTIE VMoore, L:BWR cc w/enclosure and cy of NMP ltrs DJSkovholt, L:OR dtd 1/ll/73 6 8/27/73: TJCarter, LOR Mr. Hans L. Hamester ACRS (16) M ATTN: Joan Sause RO (3)

Office of Radiation Programs OGC Environmental Protection Agency DLZiemann, L:ORB 82 Room 647A East Tower, Waterside ?fa11 CJDeBevec, L:ORB f32 401 H Street, S. W. NDube, L:OPS Washington, D. C. 20460 MJinks, DRA RMDiggs, L:ORB t'/2 Mr. Paul Axbesman SKari, L:RP Environmental Protection Agency PCollins, L:OLB 26 Federal Platen SVarga, L:RP New York, New York 10007 ~

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Form hEC.318 (Rev. 9.33) hECM 0240 OPO C12 10 11405 I 220 254

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UNITED STATES ATOuZC KmRGY ComuSSION SAFETY EVALUATION BY THE DIRECTORATE OP LICENSE DOCKET NO. 50-220 NXAGARA M)HANK POtfER CORPORATXON PROPOSED INSTALLATION OP AN ACCESS PLA1TORf TO THE REHjELING BRIDGE AT NINE 1'ELK POOD UNIT 1 By letter dated January H., 1973, Niagara Eu'hawk pxoposed a change to that described in the CESAR involving the installation of an access platform'to the refueling bridge at Nine IKle Point Unit 1 (%2>>1) ~

The platfoxm will be used to aid in the xeuoval and replacement of the drywall and xcactor vessel heads and in the cleaning of the reactor xefueling cavity walls.

He requested additional information by letter dated July 26, 1973, concerning the structural design methods, loading criteria, hoist and bridge drive design basis, contxol systems and safety intexlodcs, and an overall failure analysis. By letter dated August 27, 1973, Niagara Hohawk provided the xequested additional. information to enable us to complete our review.

The access platform, consisting of a safety platform attached to two telescoping tube assemblies which are secured to the extended top of the refueling bridge structure, provides a movable working platform in the reactor refueling cavity. High pressure spray nozzles are mounted on a vertical manifold assembly and attached to the platform.

The nozzle manifold maintains .the spray nozzles perpendicular to the cavity wall to provide for suitable cleaning action.

The use of the platform wild. simplify access to the reactor cavity and reduce the time requixed to clean the cavity and reduce personnel residence time in the cavity, tnereby resulting in reduction of personnel xadiation exposure.

OPPIC5~

SVRNAMC W DATUM Fosm hEC.318 (Rsv. 9.33) hECM 0240 OPO Cl5 1 ~ 5l 155 I 520.254

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To accommodate the addition of the platform, the gantry refueling bridge structure will be modiHed to provide additional leg spread and stiffer structure, extended cantilever overhang for the suppoxt of the platfoxm, and replacement of the mechanical drive assemblies for the bridge.

Two hoisting winches will be added to raise and lower the platform telescoping supports. Thus, the proposed platform and modified 'bridge assembly wQ.1 be provided with redundant hoists to assure raising and lowering capability even ii one hoist failed. The contxol system will be designed such that inadvertent operation of the system is precluded. The platform will be lacked to the refueling bridge when not in use at an elevation above the operating floor thereby removing the load from the hoist cables.

The licensee used the working stress method of design and finite element methods of analysis. The structures have been analyzed for operating, seismic, and accident conditions. The stresses computed by the licensee are below the allowables as deHned in applicable codes. The licensee concluded, and we agree, that the structures are adequate to carry the operating, seismic, and accident loads.

The proposed modification will be accomplished using acceptable design and fabrication standards and codes. The quality assurance program proposed meets the intent of our regulations, 10 CPR 50, Appendix 3.

The licensee has described a testing pxogram that is to, be accomplished Xn the fabricators shop and after installation in the facie.ty. Visual inspection of the complete system wiD. ba made after the preoperation tests and the first period of operation. Mditional visual inspections will be made prior to each refueling outage.

3ased on our review of the proposed modif.cation, we have determined that the design is acceptable for the operation as described. There-.

fore, we have concluded that, the proposed change to the ?RP-1 facie.ty from that described in the PSAR,does not present a significant hazards consideration and that thexe is reasonable assurance that the health and safety of the public wQ.l not be endangered.

C. J. DeBevec Operating Reactors 3ranch 82 M.rectorate of Licensing Original siGncd bV'ennis L. Ziemnnns Ch<<f a rr

'orricc~ Diroctoxa e of Licensin SVltHAMK96 ,. dAN 21 tg g DA'TE~

Form hXC-315 (Rev. 9.53) hECM 0240 OPO c4$ lo ~ 140$ l $ 20 284