ML17056C324
| ML17056C324 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 03/24/1993 |
| From: | Brinkman D Office of Nuclear Reactor Regulation |
| To: | Sylvia B NIAGARA MOHAWK POWER CORP. |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, TAC-M69461, NUDOCS 9303300278 | |
| Download: ML17056C324 (8) | |
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l UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001
>larch 24, 1993 Docket No. 50-220 Hr.
B. Ralph Sylvia Executive Vice President, Nuclear Niagara Hohawk Power Corporation 301 Plainfield Road
- Syracuse, New York 13212
Dear Hr. Sylvia:
SUBJECT:
RESPONSE
TO REQUEST FOR ADDITIONAL INFORMATION REGARDING SUPPLEMENT 1
TO GENERIC LETTER (GL) 87-02 NINE MILE POINT NUCLEAR STATION UNIT NO.
1 (TAC NO. H69461)
By letter dated September 18,
- 1992, Niagara Mohawk Power Corporation (NMPC) submitted its response to Supplement 1 to GL 87-02, "Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating
- Reactors, Unresolved Safety Issue (USI) A-46," for Nine Mile Point Nuclear Station Unit No.
1 (NMP-1).
The NRC staff provided its safety evaluation (SE) regarding this submittal in an enclosure to a letter dated November 17, 1992.
The NRC staff's SE concluded in part that the NHPC submittal of September 18,
- 1992, did not provide sufficient information regarding the development of the ground response spectrum (GRS) and the in-structure response spectra (IRS).
Therefore, NHPC was requested to provide certain additional information that was identified in the SE.
NHPC responded to this request for additional information (RAI) by letter dated January 22, 1993.
The NRC staff has reviewed NMPC's January 22,
- 1993, response to the RAI.
We have determined the following as a result of this review:
1.
NHPC developed a
new seismic GRS for NHP-1 in 1984.
The new GRS was based on a NUREG/CR-0098, "Development of Criteria for Seismic Review of Selected Nuclear Power Plants,"
50th percentile spectrum anchored at a
peak ground acceleration of 0. 13g.
NHPC stated that the new GRS enveloped the original licensing basis five percent damped GRS.
The GRS was increased by a factor of 1.5 to serve as an in-structure response spectrum for equipment located less that 40 feet above grade.
2.
For equipment located above 40 feet, NHPC generated new IRS for the NHP-1 reactor building and turbine building.
The new IRS were developed using four sets of artificial time histories.
Each set consisted of three statistically independent components (two horizontal and one vertical).
The average of the calculated ground response spectra from the four sets of time histories enveloped the original licensing basis GRS.
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Hr. B. Ralph Sylvia Ifarch 24, 1993 3.
Three-dimensional lumped mass stick models were used to generate the IRS.
The motions in the three directions were applied simultaneously.
Four IRS were generated for each of the four sets of time histories.
At each frequency, the four individual IRS were averaged to produce a single averaged spectrum.
The single in-structure response spectrum was peak broadened by plus/minus 15 percent to produce a design in-structure response spectrum.
A seven percent structural damping value was used in the analysis.
4.
No soil-structure interaction was considered since the reactor and turbine buildings are founded on bedrock.
5.
No torsional effects in the dynamic analysis were considered.
Based on our review of the NHPC response of January 22,
- 1993, and the NRC staff positions delineated in Supplemental Safety Evaluation Report No.
2 that was transmitted by GL 87-02, we have concluded that the procedure used to generate the IRS is adequate and acceptable.
- However, we note that the IRS presented in the NNPC submittal should be treated as median-centered response spectra primarily due to the use of a NUREG/CR-0098 50th percentile spectrum as a basis for the development of the new GRS.
The NRC staff may elect to audit the procedures used in generation of the floor response spectra to verify they correctly reflect the licensing basis.
Therefore, please maintain this information in a readily accessible status.
Sincerely, cc:
See next page Donald S.
Brinkman, Senior Project Nanager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Hr.
B. Ralph Sylvia Niagara Mohawk Power Corporation 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 Hr. Neil S.
Cams Vice President Nuclear Generation Niagara Mohawk 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 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 Nine Mile Point Nuclear Station Unit No.
1 Hr. Kim Dahlberg Unit 1 Station Superintendent Nine Mile Point Nuclear Station Post Office Box 32
- Lycoming, New York 13093 Mr. 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
0
Hr. B. Ralph Sylvia larch 24, 1993 3.
Three-dimensional lumped mass stick models were used to generate the IRS.
The motions in the three directions were applied simultaneously.
Four IRS were generated for each of the four sets of time histories.
At each frequency, the four individual IRS were averaged to produce a single averaged spectrum.
The single in-structure response spectrum was peak broadened by plus/minus 15 percent to produce a design in-structure response spectrum.
A seven percent structural damping value was used in the analysis.
4.
No soil-structure interaction was considered since the reactor and,turbine buildings are founded on bedrock.
5.
No torsional effects in the dynamic analysis were considered.
Based on our review of the NHPC response of January.22,
- 1993, and the NRC staff positions delineated in Supplemental Safety Evaluatio'n Report No.
2 that was transmitted by GL 87-02, we have concluded that the procedure used to generate the IRS is adequate and acceptable.
- However, we note'hat the IRS presented in the NHPC submittal should be treated as median-centered response spectra primarily due to the use of a NUREG/CR-0098 50th percentile spectrum as a basis for the development of the new GRS.
The NRC staff may elect to audit the procedures used in generation of the floor response spectra to verify they correctly reflect the licensing basis.
Therefore, please maintain this information in a readily accessible status.
Sincerely, Original signed by:
Donald S. Brinkman, Senior Project Manager Project Directorate I-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation cc:
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