ML17056C193

Recommends That Technical Working Type Meeting Be Held in mid-February to Discuss Details of Util Proposals Re Condensation Oscillation Loads in Plant Torus

ML17056C193
Person / Time
Site:	Nine Mile Point
Issue date:	12/23/1992
From:	Brinkman D Office of Nuclear Reactor Regulation
To:	Sylvia B NIAGARA MOHAWK POWER CORP.
References
TAC-M85003, NUDOCS 9212310074
Download: ML17056C193 (8)

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t UNITED STATES t

NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 December 23, 1992 Docket No. 50-220 Hr.

B. Ralph Sylvia Executive Vice President, Nuclear Niagara Mohawk Power Corporation 301 Plainfield Road

Syracuse, New York 13212

SUBJECT:

CONDENSATION OSCILLATION LOADS IN NINE MILE POINT NUCLEAR STATION UNIT NO.

1 TORUS (TAC NO. H85003)

In combined Inspection Report Nos. 50-220/89-28 and 50-410/89-24 the NRC staff concluded that the minor but ongoing corrosion of the internal surfaces of the Nine Nile Point Unit 1 containment torus would permit the plant to operate safely for one more fuel cycle (cycle now scheduled to end February 19, 1993).

By letter dated May 14,

1991, Niagara Mohawk Power Corporation (NHPC) submitted for NRC staff review, a revised methodology for calculation of unstable condensation oscillation (CO) loads within the torus.

NHPC believes the revised method is a more realistic method for calculation of CO loads than the procedures previously submitted by NHPC in September 1984 and approved by the NRC staff in a letter and enclosed safety evaluation dated January 22, 1985.

The NRC staff reviewed the May 14, 1991, submittal and documented this review in a safety evaluation dated August 25, 1992.

In its August 25,

1992, safety evaluation, the NRC staff found the methodology presented in the Hay 14, 1991, submittal to be acceptable as an alternative to the method approved by 'the NRC staff on January 22, 1985.

In its August 25, 1992, safety evaluation, the NRC staff did not approve the use of both methods to be used in combination.

By letter dated November 23,

1992, NMPC responded to the NRC staff's August 25, 1992, safety evaluation and stated that NMPC had determined that the NRC staff's evaluation of the Hay 14, 1991, submittal was inconsistent with NHPC's method of analysis.

In its November 23, 1992, letter, NHPC requested that the.NRC re-review the Hay 14, 1991, submittal in conjunction with additional information provided in an enclosed Teledyne Engineering Services Report dated November 19, 1992.

The Teledyne Engineering Services Report was provided to support NHPC's contention that both the method presented in September 1984 and the method presented in the Hay 14,

1991, submittal may be combined.

NHPC also proposed to continue to defer implementation of torus modifications and to operate NHPl for at least one more fuel cycle without modifications to the torus.

These proposals were based on an adequate remaining margin in the torus walls and the present corrosion rate of the torus walls.

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Hr. B. Ralph Sylvia December 23, 1992 The NRC staff has performed a preliminary review of the NHPC proposals and has determined that there is nothing in the Hay 14,

1991, submittal that negates our January 22,

1985, approval of the procedures submitted in September 1984.

We have also determined that because of the complexity of the CO phenomena, we will require approximately 12 months to complete the requested re-review.

Therefore, we agree that NHPC may continue to operate NHP1 in accordance with the criteria approved in our January 22, 1985, safety evaluation until we complete the requested re-review provided NHPC also performs the torus monitoring programs outlined in our August 25, 1992, safety evaluation.

We recommend that a technical working type meeting be held in mid-February to discuss the details of NHPC's proposals.

Please contact me on (301) 504-1409 if you have any questions regarding these matters and to arrange the recommended meeting.

Sincerely, cc:

See next page Donald S. Brinkman, Senior Project Hanager Project Directorate I-1 Division of Reactor Office of Nuclear Reactor Regulation Projects - I/II

Mr. B. Ralph Sylvia Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Unit No.

1 CC:

Hark J. Wetterhahn, Esquire Winston 5 Strawn 1400 L Street, NW Washington, DC 20005-3502 Supervisor Town of Scriba Route 8, Box 382

Oswego, New York 13126 Hr. Neil S.

Cams Vice President - Nuclear Generation Niagara Hohawk Power Corporation Nine Mile Point Nuclear Station Post Office Box 32

Lycoming, New York 13093 Resident Inspector U.S. Nuclear Regulatory Commission Post Office Box 126

Lycoming, New York 13093 Gary D. Wilson, Esquire Niagara Hohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202 Regional Administrator, Region I U.S.. Nuclear Regulatory Commission..

475'"Allendal'e Road

'ing of Prussia, Pennsylvania 19406 Hs.

Donna Ross New York Stat'e Energy Office 2 Empire State Plaza 16th Floor

Albany, New York 12223 Hr. Kim Dahlberg Unit 1 Station Superintendent Nine Mile Point Nuclear Station Post Office Box 32

Lycoming, New York 13093 Hr. David K. Greene Manager Licensing Niagara Mohawk Power Corporation 301 Plainfield Road

Syracuse, New York 13212 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, New York 10271 Mr. Paul D.

Eddy State of New York Department of Public Service Power Division, System Operations 3 Empire State Plaza

Albany, New York 12223

Mr. B. Ralph Sylvia December 23, 1992 t'

The NRC staff has performed a preliminary review of the NMPC proposals and has determined that'here is nothing in the Hay 14, 1991, submittal that negates our January 22,

1985, approval of the procedures submitted in September 1984.

We have also determined that because of-the complexity of the CO phenomena, we will require approximately 12 months to complete the requested re-review.

Therefore, we agree that NHPC may continue to operate NHPl in accordance with the criteria approved in our January 22, 1985, safety evaluation until we complete the requested re-review provided NHPC also performs the torus monitoring programs outlined in our August 25, 1992, safety evaluation.

We recommend that a technical working type meeting be held in mid-February to discuss the details of NHPC's proposals.

Please contact me on (301) 504-1409 if you have any questions regarding these matters and to arrange the recommended meeting.

Sincerely, Original Signed By:

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