ML20196A278
| ML20196A278 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 11/23/1998 |
| From: | Hannon J NRC (Affiliation Not Assigned) |
| To: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| Shared Package | |
| ML20196A283 | List: |
| References | |
| TAC-MA3965, NUDOCS 9811270104 | |
| Download: ML20196A278 (3) | |
Text
_
t Mr. G. R. Horn Novembsr 23, 1998 1
Sr. Vice Presidsnt of Ensrgy Supply Nrbraska Public Powar District 141415th Street i
Columbus, NE 68601 l
SUBJECT:
COOPER NUCLEAR STATION: FLAW EVALUATION OF CORE SPRAY PIPING (TAC NO. MA3965) l
Dear Mr. Horn:
i l
By letter dated November 6,1998, the Nebraska Public Power District (NPPD) submitted a flaw l
evaluation related to the flaw indications found in the core spray piping welds A-1 and A-21 at l
Cooper Nuclear Station (CNS). The flaw indications were first detected in 1995 by ultrasonic l
(UT) examination, and the fracture mechanics evaluation for these flaws using the methodology l
and the acceptance criteria of the American Society of Mechanical Engineers (ASME) Code l
was approved by the Nuclear Regulatory Commission. In the current submittal, the NPPD compared the detected flaw length from the 1998 UT results to the allowable flaw length established in the 1995 fracture mechanics analysis to demonstrate that the unit can be operated without repair for another fuel cycle.
We have completed our review and find that the licensee's flaw evaluation meets the rules of the ASME Code. Since the predicted flaw length at the end of the next fuel cycle is less than the critical flaw length with an adequate margin, the staff concludes that CNS can be operated without repair for one more fuel cycle. We have also evaluated the heat transfer capab!!ity of the core spray piping with calculated leakage flows and have concluded that CNS meets the requirements of 10 CFR 50.46.
The NPPD has requested the review and approval of a new fracture mechanics evaluation which would be applicable to Cycles 20 and 21. That review has not been completed at this l
time. Until the new evaluation is approved, continued operation beyond the next fuel cycle should be supported by the satisfactory results of reexamination or repair of the subject piping welds in accordance with the Code requirements.
Sincerely, ORIGINAL SIGNED BY:
John N. Hannon, Director Project Directorate IV-1 9811270104 981123 PDR ADOCK 05000298 Division of Reactor Projects Ill/IV P
PDR Office of Nuclear Reactor Regulation
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l Docket No. 50-298 I
Enclosure:
Safety Evaluation Iffg/
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UNITED STATES NUCLEAR REGULATORY COMMISSION j
WASHINCTON, D.C. 20066 4 001 Nr*. *G. R. Hom November 23, 1998 Sr. Vice President of Energy Supply Nebraska Public Power District 141415th Street Columbus, NE 68601
SUBJECT:
COOPER NUCLEAR STATION: FLAW EVALUATION OF CORE SPRAY PIPING (TAC NO. MA3965)
Dear Mr. Hom:
By letter dated November 6,1998, the Nebraska Public Power District (NPPD) submitted a flaw evaluation related to the flaw indications found in the core spray piping welds A-1 and A-21 at Cooper Nuclear Station (CNS). The flaw indications were first detected in 1995 by ultrasonic (UT) examination, and the fracture mechanics evaluation for these flaws using the methodology and the acceptance criteria of the American Society of Mechanical Engineers (ASME) Code was approved by the Nuclear Regulatory Commission. In the current submittal, the NPPD compared the detected flaw length from the 1998 UT results to the allowable flaw length established in the 1995 fracture mechanics analysis to demonstrate that the unit can be operated without repair for another fuel cycle.
We have completed our review and find that the licensee's flaw evaluation meets the rules of the ASME Code. Since the predicted flaw length at the end of the next fuel cycle is less than the critical flaw length with an adequate margin, the staff concludes that CNS can be operated without repair for one more fuel cycle. We have also evaluated the heat transfer capability of the core spray piping with calculated leakage flows and have concluded that CNS meets the requirements of 10 CFR 50.46.
The NPPD has requested the review ar,d approval of a new fracture mechanics evaluation which would be applicable to Cycles 20 and 21. That review has not been completed at this time. Until the new evaluation is approved, continued operation beyond the next fuel cycle should be supported by the satisfactory results of reexam;nauon or repair of the subject piping welds in accordance with the Code requirements.
Sincerely, John N. Hannon, Director Project Directorate IV-1 Division of Reactor Projects ill/IV Office of Nuclear Reactor Regulation Docket No. 50-298
Enclosure:
Safety Evaluation cc w/ encl: See next page
Mr. G. R. Horn Nebraska Public Power District Cooper Nuclear Station ec:
Mr. John R McPhail, General Counsel Lincoln Electric System Nebraska Public Power District ATTN: Mr. Ron Stoddard P. O. Box 499 1040 0 Street Onlumbus, NE 68602-0499 Box 80869 Lincoln, NE 68501 Nebraska Public Power District ATTN: Mr. J. H. Swailes MidAmerican Energy Vice President of Nuclear Energy ATTN: Dr. William D. Leech, Manager-Nuclear P. O. Box 98 907 Walnut Street Brownville, NE 68321 P. O. Box 657 Des Moines, IA 50303-0657 Randolph Wood, Director Nebraska Department of Environmental Nebraska Public Power District Control ATTN: Mr. B. L. Houston, Nuclear P. O. Box 98922 Licensing & Safety Manager Lincoln, NE 68509-8922 P. O. Box 98 Brownville, NE 68321 Mr. Larry Bohlken, Chairman Nemaha County Board of Commissioners Nemaha County Courthouse 1824 N Street Auburn, NE 68305 Senior Resident inspector U.S. Nuclear Regulatory Commission P. O. Box 218 Brownville, NE 68321 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 Ms. Cheryl Rogers, LLRW Program Manager Division of Radiological Health Nebraska Department of Health 301 Centennial Mall, South P. O. Box 95007 Lincoln, NE 68509-5007 Mr. Ronald A. Kucera, Department Director of Intergovernmental Cooperation Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102