ML17059B444
| ML17059B444 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 03/03/1997 |
| From: | Hood D NRC (Affiliation Not Assigned) |
| To: | Sylvia B NIAGARA MOHAWK POWER CORP. |
| Shared Package | |
| ML17059B445 | List: |
| References | |
| TAC-M90102, NUDOCS 9703060307 | |
| Download: ML17059B444 (8) | |
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t UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Inarch 3, 1997 Mr. B. Ralph Sylvia Executive Vice President Generation Business Group and Chief Nuclear Officer Niagara Mohawk Power Corporation Nuclear Learning Center 450 Lake Road
- Oswego, NY 13126
SUBJECT:
MODIFICATIONS TO CORRECT CORE SHROUD REPAIR DEVIATIONS, NINE MILE POINT NUCLEAR STATION, UNIT NO.
1 (TAC NO. M90102)
Dear Hr. Sylvia:
During the 1995 refueling outage for Nine Mile Point Nuclear Station, Unit No.
1 (NHP-1), Niagara Mohawk Power Corporation installed four core shroud stabilizer assemblies consisting of tie rods, brackets,
- springs, and other parts.
This repair measure was implemented to ensure the structural integrity of the core shroud with respect to the function of the circumferential welds that experienced cracks in some boiling water reactors (BWRs) as discussed in NRC Generic Letter 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors,"
and other communications.
The 1995 shroud repair was designed as an alternative to the requirements of the American Society of Mechanical Engineers (ASHE) Boiler and Pressure Vessel Code pursuant to 10 CFR 50.55a(a)(3)(i),
and was approved by the NRC staff by letter dated March 31, 1995.
As discussed in your letters dated March 23,
- 1995, and April 30, 1996, the post-installation inspection of the shroud repair revealed conditions that differed from the intended design.
Therefore, in Hay 30 and August 14,
- 1996, letters, you described plans for two modifications to the stabilizer assemblies during the March 1997 outage.
One modification will replace the tie rod and spring assembly with one having the spring on the opposite side of the tie rod because the lower spring currently bears, in part, on the blend radius of the recirculation nozzle.
The other modification will add a U-shaped extension piece such that the lower spring contact for the 90', 166',
and 350 stabilizer assemblies will extend beyond the H6A weld, as original1y intended.
The replacement assembly at 270'ill also extend beyond the H6A weld.
As discussed in the enclosed safety evaluation (SE), the NRC staff has reviewed the proposed modifications and finds that they adequately restore the
/
stabilizer assemblies to the intended function previously approved by the NRC
- staff, and the loads and displacements at critical locations will be within allowable values specified in the design specifications.
The modifications are, therefore, acceptable.
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B. Ralph Sylvia March 3, 1997 This completes the NRC staff's efforts under TAC No. M90102. If you have questions, contact me by phone at (301) 415-3049 or by electronic mail at dsh8nrc.gov.
Sincerely,
/s/
Enclosure:
SE Docket No. 50-220 cc w/encl:
See next page Darl Hood, Senior Project Manager Project Directorate I-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation DISTRIBUTION:
Docket File PUBLIC PDI-1 Reading SVarga JZwolinski SBajwa SLittle DHood THarris (E-Mail TLH3)
OGC ACRS CCowgill, RI JRajan KManoly RWessman DOCUMENT NAME: NM190102. LTR To receive a copy of this document, indicate in the. boxI "C" = Copy without attachment/enclosure "E" = Co y with attachment/enclosure "N" = No co y OFFICE NAME DATE PM:PDI-1 DHood:nw 03/
/97 E
LA:PDI-1 SLittlo 03/
/97 D:PDI-1 SBajwa 03/
/97 0
icosa Recor Copy 03/
/97 03/
/97
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B. Ralph Sylvia This completes the NRC staff's efforts under TAC No. N90102.
If you have questions, contact me by phone at (301) 415-3049 or by electronic mail at dsh8nrc.gov.
Sincerely, Gwz~
Darl Hood, Senior Project Nanager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
SE Docket No. 50-220 cc w/encl:
See next page
B. Ralph Sylvia Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Unit No.
1 CC:
Mr. Richard B. Abbott Vice President and General Manager-Nuclear Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Hr. Hartin J.
McCormick, Jr.
Vice President Nuclear Safety Assessment and Support Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Hs. Denise J. Wolniak Manager Licensing Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Hr. Kim A. Dahlberg General Manager - Projects Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Hr. Norman L. Rademacher Plant Manager, Unit 1
Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident Inspector U.S. Nuclear Regulatory Commission P.O.
Box 126
- Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New Yor k, NY 10271 Hr. Paul D.
Eddy State of New York Department of Public Service Power Division, System Operations 3 Empire State Plaza
- Albany, NY 12223 Hr. F. William Valentino, President New York State
- Energy, Research, and Development Authority Corporate Plaza West 286 Washington.Avenue Extension
- Albany, NY 12203-6399 Mark J. Wetterhahn, Esquire Winston
& Strawn 1400 L Street, NW Washington, DC 20005-3502 Gary D. Wilson, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, NY 13202 Warren Bilanin, EPRI Task Manager 3412 Hillview Ave.
Palo Alto, CA 94303 Robin Dyle, Technical Chairman BWRVIP Assessment Task Southern Nuclear Operating Company Post Office Box 236 40 Inverness Center Parkway Birmingham, AL 35201 Supervisor Town of Scriba Route 8, Box 382
- Oswego, NY 13126