ML17037C480

Letter Transmitting ACRS Report Dated September 10, 1974, on the Application for Conversion of the Provisional Operating License to a Full-Term Operating License for the Nine Mile Point Nuclear Station Unit

ML17037C480
Person / Time
Site:	Nine Mile Point
Issue date:	09/13/1974
From:	Lear G US Atomic Energy Commission (AEC)
To:	Raymond P Niagara Mohawk Power Corp
References
Download: ML17037C480 (10)

Text

DISTRIBUTION'EC PDR VAMoore Local PDR DJSkovholt DMuller SEP l3 1974 Docket ORB83 Rdg RMaccary Docket No. 50-220 KRGoller RTedesco GLear HDenton CJDeBevec VStello Iintzing SATeets Niagara I fohawk Power Corporation LVGossick GErtter (DR-7674)

NTN: Mr. Philip D. Raymond. SHanauer MGroff Vice President - Engineering ECase EHughes 300 Erie Boulevard Nest FSchroeder EPeyton York 13202 DKnuth Syracuse, New HKShapar Gentlemen: LRouse, E5M RCDeYoUng The Advisory Committee on Reactor Safeguards has issued their report dated, September 10, 1974, on the applicatian for conversion of the provisional operating license to a full-term operating license for the Nine Mile Point Nuclear Station Unit l. A copy of the report is enclosed for your information.

Sincerely, Original Signed George Lear, Chief Operating Reactors Branch 83 Directorate of Licensing

Enclosure:

ACRS Report dtd September 10, 1974 cc: See next page ORB83 ORBP3 ORB/ 3 dURNAMEW SATee CJDeBevec GLear DATE~ 9/ I /74 ,.9/...lw...,/.74,... 9L.....,...../7.4...,..........

Form hRC-318 (ReT. 9.3 3) 'hECM 0240 Q U, dr oOVERNMENT PRINTINO ORRICEI 1074 52d 1dd

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Mr. Philip D. Raymond <<2-cc: 'l0/ enclosure Mr. jrvin E. Upton, Esquire LeBoeuf, Lamb, Leiby 5 MacRae 1757 N Street, N. N.

Washington, D. C. 20036 Mr. Robert P. Jones, Supexvisor Town of Scriba R. D. 84 Oswego, New York 13126 Miss Juanita Kersey, Librarian Oswego City Library 120 E. Second Street Oswego, Nmr York 13126 Dr. Nilliam E.'Seymour Staff Coordinator New York State Atomic Energy Council New York State Department of Commerce 99 Washington Street Albany, New Yoxk 12210 CPPICC ~

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Form,AC.3j8 (Rcv. 9 53) LCM 0240 N U, 8 4OVRRNMRNT PRINTINO CPPICRI 1474 524 144

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~ 0 ADVISORY COMMITTEE ON REACTOR 'SAFEGUARDS UNlTED STATES ATOMlc ENERGY COMMJSSJON WASH l NOTON. D.C. 20545 C)

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September 10, 1974 C) m.

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Honorable-Dixy Lee Ray Chairman U. S. Atomic Energy Commission m Washington, D. C. 20545

Subject:

REPORT ON NINE MILE POINT NUCLEAR STATION UNIT 1

Dear Dr. Ray:

At its 173xd meeting, September 5-7, 1974, the Advisory Committee on Reactor Safeguards completed a review of the application by the Niagara Mohawk Power Corporation for conversion of its Nine Mile Point Nucleax Station Unit 1 provisional operating license to a full-texm opexating license. The "appli-cation also was considered at a Subcommittee meeting in Washington, D. C; on July 29, 1974. During its review, the Committee had the benefit of discus-sions with representatives of the Niagara Mohawk Power"Corporation, General Electric Company, and the AEC Regulatory Staff. The Committee also had the of the documents listed. The Committee previously discussed this 'enefit pxoject in an operating license report of Apxil 17, 1969 and in subsequent reports dated June 16, 1970 and February 6, 1:971.

In its review, the Committee evaluated the operation and performance of this unit with particular emphasis on the response of the applicant to past recommendations for impxovements in safety related systems.

Unit 1 is a non-jet pump boiling water reactor of 1850 MW(t) rated power level. Commercial power operation of the plant was begun in December, 1969.

The operating history of the unit has been generally satisfactory. However, a number of operating problems or design deficiencies have been encountered during the approximately five year period of power operation. Included among these are: cracking of a core spray nozzle safe end; development of cracks in the steam dryer assembly; control rod scram sluggishness; failure of some control rods to remain fully inserted after scram; increased control xod operating restrictions 'found necessary to assure protection for a pos-tulated rod 'drop accident; feedwater control deficiency, with resultant flooding of steam lines; torus baffle dislocation by relief valve steam discharge into the torus; and, failure of a'elief valve to reclose. All of these deficiencies appear to have been satisfactorily corrected. Reactor availability has averaged approximately 66'/..

Honorable Dixy Lee Ray September 10, 1974 Difficulty also has been experienced in respect to repeated occurrences of excessive leakage rates of the main steam isolation valves under test The applicant now proposes to remachine the valve seats and plugs con-'itions.

to an improved configuration and believes that this, together with the probable low levels of residual stresses now existing in these valves, will enable maintenance of acceptable leakage rates in the future. This matter should be followed closely by the Regulatory Staff. 1 A number of design improvements have been accomplished or committed to since operation began. Among the most significant of these from the point of view of safety are the following. The feedwater system has been modified also to serve as an additional emergency core cooling system for small breaks; emergency power for this system is supplied by an offsite source of hydro-electric power. A fuel cask drop protection system has been designed and approved, and installation will be completed before shipment of spent fuel is undertaken. A containment atmosphere dilution (CAD) system for combustible gas control will be installed and available for operation in 1976. An ad-ditional primary pressure boundary leak detection system has been added, and position indication in the control room for the containment vacuum breaker valves has been provided.

Approximately one-fifth of the reactor 7x7 fuel bundles have been replaced with 8x8 fuel; through additional reloads, the core eventually is to consist entirely of 8x8 fuel.

Because of the relatively limited accessibility for in-service inspection of the reactor pressure vessel, the Committee wishes to emphasize again its belief that additional means for assuring continued vessel integrity, in-cluding possible improvement in accessibility, should continue to be actively studied and implemented to the degree practical.

The Committee recommends that the Regulatory Staff and the applicant give further consideration to the possible advisability of additional backfitting of Unit 1 where significant and practical safety improvements can be made.

The Committee believes that, in view of the generally satisfactory operating experience to date and the improvements made in the plant as noted herein, and subject to the above comments and those in previous ACRS reports on this plant, there exists reasonable assurance that the Nine Mile Point Nuclear Station Unit 1, can continue to be operated at power levels up to 1850 MW(t) without undue risk to the health and safety of the public. The Committee concurs in conversion of the present provisional operating license to a full-term operating license.

Sincerely yours, W. R. Stratton Chairman

References:

See Page 3

4' Honorable Dixy Lee Ray 3A September 10, 1974 Referencesi

1. Niagara Mohawk Power Company Technical Supplement to Petition for Conversion from Provisional Operating License to Full-Term Operating License dated July 1972.

2. Applicant'-s Environmental Report, Operating License Stage, Conversion to Full-Term Operating License, June 1972.

3. Amendments 1 through 3 to Application for Full-Term Operating License.

4. Directorate of Licensing Safety Evaluation Report dated July 3, 1974,

5. Directorate of Licensing letter dated July 3, 1974 concerning list of outstanding items in connection with their review of application for Full>>Term Operating License,

6. Niagara Mohawk Power Corporation letter dated November 20, 1972 con-cerning Fuel Densification and'its Effect on Reactor Operation Including Transients and Postulated Loss-of-Coolant Accident.

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