ML17059A027
| ML17059A027 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/26/1993 |
| From: | Brinkman D Office of Nuclear Reactor Regulation |
| To: | Sylvia B NIAGARA MOHAWK POWER CORP. |
| References | |
| TAC-M85003, NUDOCS 9309090364 | |
| Download: ML17059A027 (12) | |
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Docket No. 50-220 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 26, 1993 Hr. B. Ralph Sylvia Executive Vice President, Nuclear Niagara Mohawk Power Corporation 301 Plainfield Road
- Syracuse, New York 13212
Dear Mr. Sylvia:
SUBJECT:
RE(VEST FOR ADDITIONAL INFORMATION REGARDING REREVIEW OF NINE NILE POINT NUCLEAR STATION UNIT NO.
1 TORUS LOAD REDUCTION SUBMITTAL OF HAY 14, 1991 (TAC NO. M85003)
By letter dated Hay 14, 1991, Niagara Mohawk Power Corporation (NHPC) submitted a request to reduce the condensation oscillation (CO) loads in the Nine Mile Point Nuclear Station Unit No.
1 torus and thereby justify a reduction in the minimum allowable wall thickness requirements of the torus.
The NRC staff, with assistance from its contractor, Brookhaven National Laboratory (BNL), reviewed the Hay 14, 1991, submittal and issued its safety evaluation on August 25, 1992.
By letter dated November 23,
- 1992, NHPC responded to the NRC staff's August 25, 1992, safety evaluation and stated that NHPC had determined that the NRC staff's evaluation of the Hay 14,
- 1991, submittal was inconsistent with NHPC's method of analysis.
The November 23, 1992, letter also requested that the NRC rereview the Hay 14, 1991 submittal in conjunction with additional information attached to the November 23, 1992, letter.
In a March 23, 1993, meeting (meeting summary issued April 9, 1993), the NRC staff agreed to rereview the NHPC methodology.
The NRC staff, with assistance from BNL, is in the process of rereviewing the NMPC methodology.
- However, we have determined that additional information, as identified in the enclosure, is required for us to complete our review.
Therefore, NMPC is requested to respond to this request for additional information within 30 days of receipt of this letter in order for us to complete our review in a timely manner.
As previously discussed with Hr. David Baker of your staff, we are also in the process of performing an independent confirmatory analysis of the CO load reduction.
Mr. Baker has suggested a meeting to discuss this confirmatory analysis.
We propose that such a meeting be held after we receive NHPC's response to this request for additional information at which time we will discuss both the confirmatory analysis and NHPC's responses to this request for additional information.
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Mr. B. Ralph Sylvia August 26, 1993 This requirement affects one respondent and, therefore, is not subject to Office of Management and Budget review under P.L.96-511.
Sincerely,
Enclosure:
Request for Additional Information Donald S. Brinkman, Senior Project Manager Project Directorate I-l Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation cc w/enclosure:
See next page
1
Hr. B. Ralph Sylvia Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Unit No.
1 CC:
Hark J. Wetterhahn, Esquire Winston
& Strawn 1400 L Street, NW Washington, DC 20005-3502 Supervisor Town of Scriba Route 8, Box 382
- Oswego, New York 13126 Vice President Nuclear Generation Niagara Mohawk Power Corporation Nine Nile 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 Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, New York 13202 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 Hs.
Donna Ross New York State 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 Hr. Paul D.
Eddy State of New York Department of Public Service Power Division, System Operations 3 Empire State Plaza
- Albany, New York 12223
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 ENCLOSURE RE UEST FOR ADDITIONAL INFORMATION REGARDING REREVIEW OF MAY 14 1991 TORUS LOAD REDUCTION SUBMITTA NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION UNIT NO.
1 DOCKET NO. 50-220 In Section 3.3. 1 of the Nine Mile Point Plant-Unique Analysis Report of the Torus Suppression Chamber (Teledyne Engineering Services TR-5320-1; October 5,
1983), it is stated that controlling load combination for the torus shell is that which combines DBA CO with the DBA hydrostatic pressure (P),
dead weight (W) and the OBE (Case 20).
The NRC staff requests the following additional information and/or clarification with respect to this statement:
1.
What fraction of the total shell stress (membrane, local, etc.) derives from the CO loading2 From the P loading? Etc.
2.
After Case 20, what load combination involving CO loads induces the next highest stress in the torus shell?
What percentage of the total stress is due to CO?
3.
What is the worst case load combination involving both CO and SRV loads2 What are the stress levels and their split for this case?
4.
What is the worst case load combination for the torus shell that does not involve CO?
How are the stresses for that case affected by the thinning of the torus shell?
How do they compare with the Case 20 stresses'2 Referring now to Section 5.3 of Teledyne Engineering Services TR-7353-1 (April 22, 1991), provide the following information/clarification:
5.
Is the statement that "...Event Combination 20...is controlling" valid for both 8 and 4 downcomer bays?
How is this established2 6.
What shell thickness is used to calculate each of the "actual" stress levels tabulated in this section?
7.
Is the split in stresses due to the various contributing loads identical for the thinner shell case?
If it is not, state the fractional distribution.
J' 1'
8.
Is the split in stresses due to the various contributing loads identical for the 4 downcomer bay cases'f it is not, state the fractional distributions 9.
Provide the equivalent response to questions 2 and 3 for the 4 downcomer bays.
Hr. B. Ralph Sylvia August 26, 1993 This requirement affects one respondent and, therefore, is not subject to Office of Management and Budget review under P.L.96-511.
Sincerely, Original signed by:
Enclosure:
Request for Additional Information cc w/enclosure:
See next page Donald S. Brinkman, Senior Project Manager Project Directorate I-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation DISTRIBUTION:
Docket File PDI-1 Reading JCalvo CVogan OGC
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