ML121080125

Fort Calhoun Station, Unit 1 - Request for Additional Information, Request for Change in Reactor Vessel Surveillance Capsule Removal Schedule (TAC No. ME8219)

ML121080125
Person / Time
Site:	Fort Calhoun
Issue date:	05/03/2012
From:	Wilkins L E Plant Licensing Branch IV
To:	Bannister D J Omaha Public Power District
Wilkins, L E, NRR/DORL/LPL4, 415-1377
References
TAC ME8219
Download: ML121080125 (5)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 May 3, 2012 Mr. David J. Bannister Vice President and CNO Omaha Public Power District Fort Calhoun Station 444 South 16th St. Mall Omaha, NE 68102-2247 SUBJECT: FORT CALHOUN STATION, UNIT NO.1 -REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED CHANGE IN REACTOR VESSEL SURVEILLANCE CAPSULE REMOVAL SCHEDULE (TAC NO. ME8219) Dear Mr. Bannister: By letter dated February 6,2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12040A317), Omaha Public Power District (OPPD), the licensee for Fort Calhoun Station, Unit No. 1 (FCS), submitted a request for authorization to change the schedule for removal of reactor vessel material surveillance capsules associated with FCS. The proposed changes were submitted pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix H,Section III.B.3, which requires that (1) withdrawal schedules be submitted with a technical justification, as specified in 10 CFR 50.4, and (2) the proposed schedule must be approved by the U.S. Nuclear Regulatory Commission (NRC) prior to implementation. The NRC staff has reviewed the information provided in your application and determined that additional information is required in order to complete its review. A draft copy of the enclosed request for additional information was provided to Mr. Bill Hansher of your staff via e-mail on April 9, 2012. On April 13, 2012, Mr. Michael Edwards of your staff indicated that no clarifying telephone call was needed and that the response would be provided within 30 days of receipt of this letter.

D. Bannister -2 If you have any questions, please contact me at 301-415-1377 or via e-mail at Iynnea.wilkins@nrc.gov. Sincerely, lynnea E. Wilkins, Project Manager Plant licensing Branch IV Division of Operating Reactor licensing Office of Nuclear Reactor Regulation Docket No. 50-285 Enclosure: As stated cc w/encl: Distribution via listserv REQUEST FOR ADDITIONAL REACTOR VESSEL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE REVISION OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT NO.1 DOCKET NO. 50-285 By letter dated February 6,2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12040A317), Omaha Public Power District (OPPD), the licensee for Fort Calhoun Station, Unit No.1 (FCS), submitted a request for authorization to change the schedule for removal of the reactor vessel (RV) material surveillance capsules associated with FCS. The proposed changes were submitted pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix H,Section III.B.3, which requires that: (1) withdrawal schedules be submitted with a technical justification, as specified in 10 CFR 50.4, and (2) the proposed schedule must be approved by the U.S. Nuclear Regulatory Commission (NRC) prior to implementation. The NRC staff has reviewed your submittal and has determined that the following additional information is needed for the staff to complete its evaluation. American Society for Testing and Materials (ASTM) E185-82 recommends that for an RV with a five-capsule withdrawal schedule, such as the FCS RV, the fourth capsule should be withdrawn at approximately 15 effective full power years (EFPY) or at a time when the accumulated neutron fluence of the capsule corresponds to the approximate end-of-life (EOL) f1uence at the RV inner wall, whichever comes first. The licensee's proposed schedule for FCS for Capsule W-275S, the fourth capsule for FCS in terms of fluence, calls for the capsule to be withdrawn in 2028 when it has received a fluence of 3.0 x 1019 n/cm2* The licensee also stated that the projected 60-year (48 EFPY) peak RV fluence is 3.5 x 1019 neutrons-per-square centimeter (n/cm2). Therefore, the proposed withdrawal fluence of Capsule W-275S is approximately 86 percent of the EOL RV inner wall fluence. Please provide a technical justification for withdrawing Capsule W-275S at a fluence that is significantly less than the peak projected RV inner wall fluence at EOL The proposed schedule calls for Capsule W-275S to be withdrawn at 47.2 EFPY, corresponding to the year 2028. Table 2 of the submittal provides no lead factor for this capsule (implying capsule fluence is identical to the peak RV inner wall f1uence). The submittal also indicates that Capsule W-275S was inserted at 13.6 EFPY. Therefore, the capsule will have been irradiated for 33.6 EFPY at withdrawal. The average f1uence per EFPY of the peak RV inner wall location should be (3.5 x 1019 n/cm2/48 EFPY) = 7.29 x 1017 n/cm2/EFPY. Based on no lead factor, it would appear the f1uence received by the capsule would be 33.6 EFPY x 7.29 x 1017 n/cm2/EFPY =2.45 x 1019 n/cm2, which is significantly less than the proposed withdrawal fluence of 3.0 x 1019 n/cm2 . Enclosure

-low-leakage core, fluence/EFPY would have been higher earlier in plant life. Also, since the projected EOl EFPY is 48 in 2033, the EFPY value of 47.2 for 2028 appears high unless the FCS RV will receive greater than 48 EFPY in 60 calendar years. Please provide the details of the fluence projection for capsule W-275S.

D. Bannister -2 If you have any questions, please contact me at 301-415-1377 orvia e-mail at Iynnea. wilkins@nrc.gov. Docket No. 50-285 Enclosure: As stated cc w/encl: Distribution via Listserv DISTRIBUTION: PUBLIC LPLIV Reading RidsAcrsAcnw_MailCTR Resource RidsNrrDeEvib Resource RidsNrrDorlLpl4 Resource RidsNrrLAJBurkhardt Resource Sincerely, IRA! Lynnea E. Wilkins, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsNrrPMFortCalhoun Resource RidsOgcRp Resource RidsRgn4MailCenter Resource ..IPoehler, NRRlDE/EVIB CSydnor, NRR/DE/EVIB ADAMS Accession No. ML 121080125 *via memo dated NAME LWilkins JBurkhardt SRosenberg** DATE 4/20/12 4/19/12 3/28/12 OFFICIAL RECORD COpy