ML17263A948

Informs That NRC Staff Accepts Analytical Approach Re SG Replacment Concurrence on Licensee Planned Reevaluation of Postulated Effects on Reactor Vessel Internals

ML17263A948
Person / Time
Site:	Ginna
Issue date:	02/15/1995
From:	Andrea Johnson Office of Nuclear Reactor Regulation
To:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
References
TAC-M90043, NUDOCS 9502270140
Download: ML17263A948 (7)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 15, 1995 Dr. Robert C. Mecredy Vice President, Nuclear Operations Rochester Gas

& Electric Corporation 89 East Avenue Rochester, NY 14649

SUBJECT:

R.

E.

GINNA NUCLEAR POWER PLANT STEAM GENERATOR REPLACEMENT CONCURRENCE ON LICENSEE'S PLANNED REEVALUATION OF THE POSTULATED EFFECTS ON THE REACTOR VESSEL INTERNALS (TAC NO. M90043)

Dear Dr. Mecredy:

Rochester Gas

& Electric Corporation (RG&E) plans to reduce full-load temperature (T,) in the reactor coolant loop from the present 573.5 F to as low as 559 'F at the Ginna Nuclear Power Plant, following steam generator (SG) replacement in 1996.

This reduced coolant temperature results in a denser fluid and for purposes of post-loss-of-coolant accident inertial loading effects, is nonconservative.

RG&E, therefore, plans to.perform a reevaluation of the effects of a postulated pipe rupture on the reactor vessel internals due to inertial loads.

The consequences from this pipe break are considered to be the most severe in comparison with pipe rupture effects from any other pipe break in a piping system connected to the reactor coolant system (RCS) which has not had an NRC-approved "leak-before-break" safety evaluation.

In accordance with GDC-4, a

double-'ended RCS break is a dynamic effect and may be excluded from the Ginna plant design basis because the analyses submitted to the

NRC, and subsequently approved (References 2, 3, 4, and 5), demonstrated that the probability of a rupture in the RCS piping, pressurizer surge line, and the accumulator lines is extremely low under conditions consistent with.the design basis for the piping..

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February 15, 1995 The NRC staff finds this analytical

approach, as proposed Reference 1 in the enclosed list of references acceptable, and may at its discretion review the analysis related to the pipe break in the 10u residual heat removal line when it is submitted for information under 10 CFR 50.59 as part of the SG replacement documentation.

Sincerely, Docket No. 50-244

Enclosure:

As stated Original signed by Allen R. Johnson, Pr'oject Manager Project<<Director ate I-,3 Division of. React'or Projects - I/II Office of'Nuclear Reactor Regulation cc w/enclosure:

See next page DISTRIBUTION:

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The NRC staff finds this analytical

approach, as proposed Reference 1 in the enclosed list of references acceptable, and may at its discretion review the analysis related to the pipe break in the 10" residual heat removal line when it is submitted for information under 10 CFR 50.59 as part of the SG replacement documentation.

Sincerely, Docket No. 50-244

Enclosure:

As stated Allen R. Johnson, Project Manager Pro 'ect Director te 1-3 Divis of ctor Projects I/II Office of Nuclear Reactor Regulation cc w/enclosure:

See next page

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Dr. Robert C. Mecredy R.E. Ginna Nuclear Power Plant cc:

Thomas A. Moslak, Senior Resident Inspector R.E. Ginna Plant U.S. Nuclear Regulatory Commission 1503 Lake Road

Ontario, NY 14519 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Ms. Donna Ross Division of Policy Analysis 8 Planning New York State Energy Office Agency Building 2 Empire State Plaza

Albany, NY 12223 Charlie Donaldson, Esq.

Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Nicholas S. Reynolds Winston 8 Strawn 1400 L St.

N.W.

Washington, DC 20005-3502 Ms. Thelma Wideman

Director, Wayne County Emergency Management Office Wayne County Emergency Operations Center 7336 Route 31

Lyons, NY 14489 Ms. Mary Louise Meisenzahl Administrator, Monroe County Office of Emergency Preparedness ill West Fall Road, Room ll Rochester, NY 14620

REFERENCES 1.

Letter from Rochester Gas

& Electric Corporation (RG&E) to the NRC seeking concurrence on analytical pipe break approach due to reduction in RCS T, dated August 2, 1994.

2.

3.

Letter from D. Eisenhut (NRC) to All Operating PWR Licensees,

Subject:

Safety Evaluation of Westinghouse Topical Reports Dealing with Elimination of Postulated Pipe Breaks in PWR Primary Main Loops (Generic Letter 84-04) dated February 1,

1984.

Letter from D. DiIanni (NRC) to R. Kober (RG&E),

Subject:

GL 84-04, dated September 9,

1986.

4.

Letter from F. Miraglia (NRC) to All Operating Licensees,

Subject:

Relaxation in Arbitrary Intermediate Pipe Rupture Requirements (GL 87-ll), dated June 19, 1987.

5.

Letter from D. Crutchfield (NRC) to John E. Maier (RG&E),

Subject:

IPSAR Section 4. 13, Effects of Pipe Breaks on Structures,

Systems, and Components Inside Containment for the R.

E. Ginna Nuclear Power Plant, dated June 28, 1983.