ML17263A313
| ML17263A313 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 06/08/1993 |
| From: | Andrea Johnson Office of Nuclear Reactor Regulation |
| To: | Mecredy R ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| TAC-M86376, NUDOCS 9307140182 | |
| Download: ML17263A313 (6) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 June 8,
1993 Dr. Robert C. Mecredy Vice President, Nuclear Production Rochester Gas
& Electric Corporation 89 East Avenue Rochester, New York 14649
Dear Dr. Mecredy:
SUBJECT:
APPLICATION OF LEAK-BEFORE-BREAK TECHNOLOGY, R.E.
GINNA NUCLEAR POWER PLANT (TAC NO. M86376)
REFERENCES:
1.
2.
3.
Letter from Rochester Gas
& Electric to the NRC seeking clarification on the applicability of leak-before-break requirements for the design of steam generator internals, dated May 13, 1993.
Nuclear Regulatory Commission, 7590-01, "10 CFR 50 Modification of General Design Criteria 4 Requirements for.
Protection Against Dynamic Effects of Postulated Pipe Ruptures,"
Statement of Considerations.
Letter from D. Di Ianni (NRC) to R.
W. Kober (RG&E), "Docket No. 50-244, (Generic Letter 84-04)," dated September 9,
1986.
This letter is in regard to Rochester Gas and Electric Corporation's (RG&E) replacement of steam generators (SGs) for the R.
E. Ginna Nuclear Power Plant (Ginna).
Pursuant to your request (Reference I), confirmation that the replacement SG internal components can be designed on the basis of the reduced loads resulting from the application of the leak-before-break (LBB) criteria to postulated breaks in the primary reactor coolant loop (RCL) piping, is as follows.
The modification of the 10 CFR Part 50, Appendix A, GDC 4 requirements resulting from the acceptance of the LBB concept are delineated in Reference 2.
The requirement is that, if it can be demonstrated that the probability of pipe rupture is extremely low, the dynamic effects of the pipe rupture (i.e., missile generation, pipe whipping, pipe break reaction forces, jet impingement forces, decompression waves within the ruptured pipe and dynamic or non-static pressurization in cavities, subcorIpartments and compartments) can be excluded from the design basis of the unit.
The statement of considerations specifically excludes the applicability of this aspect of the rule to emergency core cooling systems, containments, and environmental qualification.
By Reference 3, the NRC approved the use of this aspect of the rule for primary system piping for the R.
E. Ginna Nuclear Power Plant.
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Dr. Robert C. Hecredy June 8, 1993 Your proposed interpretation is that the internal components of the replacement SG can be designed on the basis of loads'omputed by taking into consideration the LBB criteria.
Specifically, you contend that the dynamic effects of primary system piping-ruptures need not be included in the design basis of the primary side divider, plate of the SG.
The staff concurs with this interpretation, provided that the LBB considerations are applicable only to the primary RCL piping.
The dynamic effects of breaks in any of the branch lines, e.g.,
the emergency core cooling system, should be included in the design basis.
Furthermore, it is incumbent upon you to demonstrate that the LBB considerations will continue to be valid for the primary coolant loop piping after the new SGs have been installed.
In particular, the cutting and welding of the RCL piping, during the SG replacement process, will not introduce any new pipe break locations which are not covered by the LBB criteria. If any such new locations can be postulated where LBB criteria would not be applicable, then the internals of the replacement SGs must be designed to the full effects of the limiting breaks.
Should you have any further questions regarding this subject, contact James A. Norberg, Chief Mechanical Engineering Branch, Division of Engineering, at (301) 504-3288.
Sincerely,
/s/
Allen R. Johnson, Project Manager Project Directorate I-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation cc:
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Dr. Robert C. Mecredy June 8, 1993 Your proposed interpretation is that the internal components of the replacement SG can be designed on the basis of loads computed by taking into consideration the LBB criteria.
Specifically, you contend that the dynamic effects of primary system piping ruptures need not be included in the design basis of the primary side divider plate of the SG.
The staff concurs with this interpretation, provided that the LBB considerations are applicable only to the primary RCL piping.
The dynamic effects of breaks in any of the branch lines, e.g.,
the emergency core cooling system, should be included in the design basis.
Furthermore, it is incumbent upon you to demonstrate that the LBB considerations will continue to be valid for the primary coolant loop piping after the new SGs have been installed.
In particular, the cutting and welding of the RCL piping, during the SG replacement process, will not introduce any new pipe break locations which are not covered by the LBB criteria.
If any such new locations can be postulated where LBB criteria would not be applicable, then the internals of the replacement SGs must be designed to the full effects of the limiting breaks.
Should you have any further questions regarding this subject, contact James A. Norberg, Chief Mechanical Engineering Branch, Division of Engineering, at (301) 504-3288.
Sincerely, cc:
See next page All n R. Johnson Project Manager Pro 'ect Director te I-3 Dlvis ctor Projects - I/II Office of Nuclear Reactor Regulation
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, New York 14519 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 Ms.
Donna Ross Division of Policy Analysis 5 Planning New York State Energy Office Agency Building 2 Empire State Plaza
- Albany, New Yor k 12223 Charlie Donaldson, Esq.
Assistant Attorney General New York Department of Law 120 Broadway New York, New York 10271 Nicholas S.
Reynolds Winston 5 Strawn 1400 L St.
N.W.
Washington, DC 20005-3502 Ms. Thelma Wideman
- Director, Wayne County Emergency Management Office Wayne County Emergency Operations Center 7370 Route 31
- Lyons, New York 14489 Ms. Mary Louise Meisenzahl Administrator, Monroe County Office of Emergency Preparedness 111 West Fall Road, Room 11 Rochester, New York 14620