ML14042A321
| ML14042A321 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 02/11/2014 |
| From: | Andrew Hon Plant Licensing Branch II |
| To: | Cleary T, Hess T Tennessee Valley Authority |
| Andy Hon | |
| References | |
| TAC MF3354 | |
| Download: ML14042A321 (4) | |
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ADAMSAccessionNumber:
Dear Mr. Cleary:
Hon, Andrew Tuesday, February 11, 2014 2:36 PM tpcleary@tva.gov; Hess, Thomas A (tahess@tva.gov)
Arent, Gordon (garent@tva.gov); Kulesa, Gloria; Rezai, Ali; Quichocho, Jessie WATTS BAR NUCLEAR STATION, UNIT 1-REQUEST FOR ADDITIONAL INFORMATION RELATED TO REQUEST FOR ALTERNATIVE NUMBER ISPT-02 REGARDING SYSTEM LEAKAGE TEST OF REACTOR PRESSURE VESSEL HEAD FLANGE SEAL LEAK-OFF PIPING (TAC MF3354)
SUBJECT:
WATTS BAR NUCLEAR STATION, UNIT 1 -REQUEST FOR ADDITIONAL INFORMATION RELATED TO REQUEST FOR ALTERNATIVE NUMBER ISPT-02, REGARDING SYSTEM LEAKAGE TEST OF REACTOR PRESSURE VESSEL HEAD FLANGE SEAL LEAK-OFF PIPING (TAC MF3354)
By letter dated January 10, 2014, TVA submitted the subject request for alternative.
The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is shown below. The proposed questions were discussed by telephone with your staff on February 11, 2014. Your staff confirmed that these questions did not include proprietary or security-related information and agreed to provide a response by February 19, 2014 to this request for additional information (RAJ).
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The NRC staff considers that timely responses to RAis help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-8480 or via e-mail Andrew.Hon@ nrc.gov.
Docket No. 50-390 Accession No. ML14042A321 Sincerely, RIA Andrew Hon, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 2
REQUEST FOR ADDITIONAL INFORMATION REQUEST FOR ALTERNATIVE NUMBER ISPT-02 REGARDING SYSTEM LEAKAGE TEST OF REACTOR PRESSURE VESSEL HEAD FLANGE SEAL LEAK-OFF PIPING TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT (WBN), UNIT 1 DOCKET NO. 50-390 By letter dated January 10, 2014 (Agencywide Documents Access and Management Systems (ADAMS)
Accession No. ML14013A302), Tennessee Valley Authority (the licensee) submitted for the U.S. Nuclear Regulatory Commission (NRC) approval request for alternative (RFA). The licensee proposed an alternative to a certain requirement of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI. RFA ISPT-02 relates to the inservice inspection (lSI) requirement of IWC-5221 for the system leakage test of the reactor pressure vessel (RPV) head flange seal leak-off piping.
The NRC staff requests the following additional information.
- 1. The NRC requires deviations from the ASME Code,Section XI, in accordance with Title 10 of the Code of Federal Regulations (1 0 CFR) 50.55a(a)(3)(ii) be pre-approved. RFA ISPT-02 was submitted for the second 1 0-year lSI interval which commenced on May 27, 2007, and will end on May 26, 2016, for Watts Bar, Unit 1. The RPV flange leak-off piping is subject to system leakage test every inspection period in accordance with the ASME Code,Section XI, IWC-2500, Table IWC-2500-1, Examination Category B-P, Item No. C7.10.
Discuss whether the system leakage test was performed in the previous inspection periods (i.e., the first two periods) of the second 1 0-year lSI interval in accordance with IWC-5221 as specified in Table IWC-2500-1. If the answer is No, discuss the reason(s) for not obtaining the NRC prior authorization for deviation from the ASME Code requirements for the system leakage testing in the previous inspection period(s). If the answer is Yes, discuss why the required system leakage test in accordance with the ASME Code cannot be performed in the upcoming inspection period (the third period) of the second 10-year lSI interval.
- 2. Discuss whether the subject piping can be pressure tested in accordance with the ASME Code in the beginning of a refueling outage before removing the RPV head. If yes, the proposed relief request would not be needed. If no, discuss the hardship and potential personnel radiation exposure including an estimate for person-roentgen equivalent man (rem) exposure with consideration of as low as reasonably achievable (ALARA) for the system leakage test performed in accordance with IWC-5221 before removing the RPV head.
- 3. On page 2 of Enclosure 1 of RFA ISPT-02, the licensee stated, in part, "... Purposely failing the inner 0-ring to perform the ASME Code required test would require purchasing a new set of 0-rings, additional time, and radiation exposure to de-tension the RPV head, install the new 0-rings, and then reset and re-tension the RPV head."
Provide an estimate for radiation exposure (i.e., person-rem exposure if the test in accordance with IWC-5221 is performed after the RPV head and new 0-rings are installed).
- 4. Provide materials of construction for the RPV flange leak-off piping. Discuss operating experience (e.g., plant-specific, fleet, and industry) regarding potential degradation of the subject leak-off piping and its associated welded connections due to any known degradation mechanisms that would lead to leakage.
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- 5. What is the proposed test pressure (i.e., the numerical value for the static head pressure developed from water level above the vessel flange when the reactor cavity is flooded) for the proposed system leakage testing of the subject leak-off line piping?
- 6. Discuss leakage detection capabilities at the plant, or any measure(s) taken, to monitor and identify leakage in an unlikely event of a through wall leak in the RPV flange seal leak-off line piping concurrent with leak or failure of the RPV flange inner seal during normal operation.
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