ML092300025
| ML092300025 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/18/2009 |
| From: | Richard Guzman Plant Licensing Branch 1 |
| To: | Belcher S Nine Mile Point |
| Guzman R, NRR/DORL, 415-1030 | |
| References | |
| TAC ME0993 | |
| Download: ML092300025 (4) | |
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Mr. Samuel L. Belcher Vice President Nine Mile Point Nine Mile Point Nuclear Station, LLC P.O. Box 63 Lycoming, NY 13093
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING NINE MILE POINT NUCLEAR STATION, UNIT NO.1, RELATING TO RELIEF REQUEST, 11SI-003, ASSOCIATED WITH THE FOURTH 10-YEAR INSERVICE INSPECTIOI\\I INTERVAL (TAC NO. ME0993)
Dear Mr. Belcher:
By letter dated March 16, 2009, Nine Mile Point Nuclear Station, LLC, submitted for Nuclear Regulatory Commission (NRC) staff review and approval, relief request 11SI-003, proposed alternative in accordance with paragraph 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations and authorization for implementation of a risk-informed/safety based inservice inspection (lSI) program based on the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code Case N-716 for the fourth 1O-year lSI interval for Nine Mile Point Nuclear Station, Unit NO.1.
The NRC staff is reviewing the information provided in that letter and has determined that additional information is needed to support its review. Enclosed is the NRC staff's request for additional information (RAI). The RAI was discussed with your staff on August 18, 2009, and it was agreed that your response would be provided within 45 days from the date of this letter.
Sincerely, Richard V. Guzman, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-220
Enclosure:
As stated cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION (RAI)
NINE MILE POINT NUCLEAR STATION, UNIT NO.1 FOURTH TEN-YEAR INSERVICE INSPECTION PROGRAM PLAN DOCKET NO. 50-220 The Nuclear Regulatory Commission (NRC) staff is reviewing the Nine Mile Point Nuclear Station (NMPNS) submittal dated March 16, 2009. The NRC staff has determined that additional information requested below will be needed to support its review.
- 1.
In Section 3.0 of 11SI-003 you state that there were no deviations to the process described in Code Case N-716. Code Case N-716 dated April 19, 2006, does not include the guidance that any segments with a large early release frequency (LERF) greater than 10-7 per year should be assigned as high safety significant (HSS). In Section 3.1, however, you state that a LERF greater than 10-7 per year was also used to determine high safety significance. Please identify all differences between the guidance in N-716 and your analysis (i.e., even if the differences are not proposed deviations, state the differences which involve the use of additional guidance from N-716).
- 2.
Section 1.2 states that the updated probabilistic risk assessment (PRA) model meets the Capability Category II (CCII) supporting requirements (SRs) and combined CCII and CCIII SRs where both requirements are equivalent. The NRC staff has concluded that additional work may be needed beyond CCII in order for the PRA technical adequacy to be consistent with that determined to be acceptable for PRAs which supported the Electric Power Research Institute TR-112657 RI-ISI process. Please explain how the following three issues are addressed.
- Supporting requirement IF-C3 (IFSN-A6) identifies the failure mechanisms that shall be evaluated to determine the susceptibility of each structure, system, and component (SSC) in a flood area to flood-induced failures. CCII identifies failure modes by submergence and spray as requiring identification but may not require assessment. CCIII requires identification and assessment of all failure modes including submergence, spray, jet impingement, pipe whip, and humidity, condensation, and temperature concerns. Risk Informed Inservice Inspection (RI-ISI) methods require that all SSC failures induced by a pipe break be considered. Please demonstrate that all SCCs failures that are induced by a pipe break are adequately assessed in your analysis.
- Supporting requirement IF-D3a (IFEV-A3) Category II permits grouping or subsuming flood initiated scenarios with existing plant initiating event groups. A Category III analysis which does not permit grouping is more consistent with previous RI-ISI analyses. If grouping of flood scenarios with other initiating events groups was done, please confirm that the subsumed flooding scenarios were identified during the flooding analysis and extracted during the RI-ISI analysis in order to insure that their contribution to the RI-ISI analysis was properly included.
Enclosure
- 2
- Supporting requirements IF-C6 (IFSN-A14) and IF-C8 (IFSN-A16) permit screening out of flood areas and sources respectively based on, in part, the success of human actions to isolate and terminate the flood before equipment is damaged. RI-ISI methods require determination of the flood scenario with and without human intervention which corresponds to the capability Category III, i.e. scenarios are not screened out based on human actions. Therefore, a Category III analysis is more consistent with previous RI-ISI analyses. If capability Category II is used, high reliability of the human actions relied upon to screen out scenarios should be demonstrated using methods consistent with the supporting requirement IF-E5 (IFQU-A5) in the standard. Please re-evaluate the credit given to human actions to provide confidence that scenarios that might exceed the quantitative guideline are identified.
- 3.
Please explain the difference between the "estimated" and "upper" bound values in Table 3.5 and how each is used. The explanation should clarify the differences between the 3E-2 "upper" value for "FWLOCA-OC" and the other "upper" bound values; and the difference between the "estimated" 3.4E-4 and the ''upper bound 2E-3 values for "Class 2 EC."
- 4.
Applying an upper value of conditional core damage probability/conditional large early release probability (CCDP/CLERP) when adding an inspection to a location previously uninspected may result in an overestimate of the risk decrease associated with the new inspection. Please demonstrate that this nonconservative approach, if corrected in the evaluation of your proposed program, would not cause the delta risk guidelines to be exceeded.
- 5.
Please discuss your internal events PRA Peer Review Findings and Observations that are not resolved to date and may affect the planned RI-ISI Program.
August 18, 2009 Mr. Samuel L. Belcher Vice President Nine Mile Point Nine Mile Point Nuclear Station, LLC P.O. Box 63 Lycoming, NY 13093 SUB~IECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING NINE MILE POINT NUCLEAR STATION, UNIT NO.1, RELATING TO RELIEF REQUEST, 1ISI-003, ASSOCIATED WITH THE FOURTH 10-YEAR INSERVICE INSPECTION INTERVAL (TAC NO. ME0993)
Dear Mr. Belcher:
By letter dated March 16, 2009, Nine Mile Point Nuclear Station, LLC, submitted for Nuclear Regulatory Commission (NRC) staff review and approval, relief request 11SI-003, proposed alternative in accordance with paragraph 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations and authorization for implementation of a risk-informed/safety based inservice inspection (lSI) program based on the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code Case N-716 for the fourth 10-year lSI interval for Nine Mile Point Nuclear Station, Unit NO.1.
The NRC staff is reviewing the information provided in that letter and has determined that additional information is needed to support its review. Enclosed is the NRC staff's request for additional information (RAI). The RAI was discussed with your staff on August 18, 2009, and it was agreed that your response would be provided within 45 days from the date of this letter.
Sincerely, Ira!
Richard V. Guzman, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-220
Enclosure:
As stated cc w/encl: Distribution via Listserv DISTRIBUTION:
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