ML15126A484
| ML15126A484 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/06/2015 |
| From: | Richard Guzman Plant Licensing Branch 1 |
| To: | Craft W Dominion Nuclear Connecticut |
| Guzman R | |
| References | |
| TAC MF5096 | |
| Download: ML15126A484 (2) | |
Text
From:
Guzman, Richard Sent:
Wednesday, May 06, 2015 3:32 PM To:
'wanda.d.craft@dom.com'
Subject:
NRC Request for Additional Information - Adoption of TSTF-425 - Relocation of Specific Surveillance Frequency Requirements to Licensee Controlled Program (MF5096)
- Wanda, The NRC staff is reviewing the information provided in the subject license amendment request dated October 22, 2014 (Agencywide Documents Access and Management System Accession No. ML14301A112), and has determined that additional information is needed to complete its review. Shown below is the NRC staffs request for additional information (RAI) questions. This information request was discussed w/your staff on May 5, 2015. As agreed, please provide your formal response by June 5, 2015. Please contact me if you have any questions.
REQUEST FOR ADDITIONAL INFORMATION ADOPTION OF TECHNICAL SPECIFICATION TASK FORCE-425 RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM (TAC NO. MF5096)
- 1. In Gap #1, from the 2000 peer review, related to Supporting Requirements (SRs) AS-10 and sub-element AS-18, the peer review team noticed that there was no modeling of makeup to the condenser when the steam dump valves fail. The licensee dispositioned the finding by performing a sensitivity study that added the steam dump valves as a required support system for the Main Feed Water function until the F&O can be resolved. However, the F&O has been considered unresolved since 2000 with a sensitivity study. The licensee stated in the submittal that they update their PRA model every three to five years. If that is the case, Gap #1 should have a resolution/disposition in place and be closed out per the update process.
Explain how this work will be completed before implementation of the TSTF-425 program.
- 2. In Gap #2, from the self-assessment, related to SR IE-A8, the self-assessment team noted that the interview with plant personnel for potential initiating events has been overlooked by the licensee. In Gap #6, from the self-assessment, related to SRs SY-A4 and SY-C2, the self-assessment team referenced the Individual Plant Examination documentation and interviews with PRA engineers as evidence that the tasks in SY-A4 were completed, but there was no documentation supporting this work. The licensee stated that they conducted interviews with system engineers but would need to conducted interviews with operations personnel and perform walkdowns, in accordance with their procedure, before resolving this documentation F&O. The licensee further stated that these SRs will remain unmet until they perform interviews with the operation
personnel, in accordance with their PRA procedure. The ASME/ANS PRA Standard requires the licensee to interview plant personnel (e.g. operation, maintenance, engineering, safety analysis) to determine if potential initiating events have been overlooked (Gap #2) and that the licensee perform interviews and walkdowns (Gap #6).
The SRs cited are not related to documentation except SY-C2, which was also considered unmet.
Provide justification that the interviews with operations personnel have been conducted or that the system personnel interviewed possessed equivalent knowledge of operations personnel (e.g., former reactor operators, shift technical advisors, etc.) such that there is no impact on the initiating events and the PRA model represents the as-built, as-operated plant.
- 3. In Gap #4, from the self-assessment, related to SR AS-A10, the self-assessment team stated that the licensee did not explain how the differences in system requirements for each initiating event impacted operator actions or system responses. The licensee stated that this F&O is a documentation issue and will not have any impact to the program. The licensee further stated that they will address this as a part of F&O HR-G4-01 (Gap #9) and will remain open until HR-G4-01 is closed. The relationship between Gap #9 and Gap #4 needs clarification as Gap #9 appears to be a HEP timing issue whereas Gap #4 appears to be differences in system requirements for each initiating event that will impact operator actions and system response. The NRC staff notes that, since the cited SR is not part of the documentation HLR, it does not appear be solely a documentation issue, but requires specific action to be met.
Explain how the licensee plans to resolve this F&O and its impact to the TSTF-425 program. If the resolution to the HEP timing issue in HR-G4-01 applies, then the licensee should explain how the resolution to HR-G4-01 applies to Gap #4 and the impact on the application.
- 4. In Gap #9, from the Focused Scope Peer Review, related to SR HR-G4, the peer review team noted that the HEP timing information for HRA event OAADV1 showed two different times associated with the event (30 minutes for General Transient and 11 minutes for Loss of Main Feedwater). The peer review team further stated that the licensee should use 11 minutes since it is limiting and that 30 minutes may be non-conservative. The licensee will keep this F&O open until the issue is addressed and then they plan to perform a sensitivity study with a combination of corrected HEPs. The licensee identified this F&O as risk-significant.
If this gap is risk-significant and important for the application, the F&O should be addressed before implementing the program. Discuss how this will be addressed.
- 5. In Gap #8, from the Focused Scope Peer Review, related to SR HR-G3, the peer review team noted that the HRA calculator worksheets were identified as not being properly filled out (i.e. dependency factors and sigma). The licensee will keep this F&O open until correct the new HRA calculations are included in the model. They also plan to
correct the HRA Calculator entries for dependency factor and sigma and then they plan to perform a sensitivity study with a combination of corrected HEPs. The licensee identified this F&O as risk-significant.
If this gap is risk-significant and important for the application, the F&O should be addressed before implementing the program. Discuss how this will be addressed.
- 6. In Gap #11, from the Focused Scope Peer Review, related to SR LE-F1, the peer review team found that the licensee did not provide a quantitative evaluation and identification of the dominant LERF contributors to LERF by plant damage states. The licensee stated the dominant LERF contributors to LERF need to be presented by plant damage states, which requires enhancements to the CAFTA LERF model, but will not have an impact to the LERF results. The licensee goes on to state that this is a documentation issue and will only provide another way for the licensee to present the results. Capability Category II of this SR requires that the licensee perform the evaluation of the relative contribution to LERF from plant damage states and significant LERF contributors from Table 2-2.8-9.
Both Capability Category I and Capability Category II require consideration of significant LERF contributors. Therefore confirm that the LERF model has considered the significant contribution from Table 2-2.8-9.
- 7. In Gap #14, from the Focused Scope Peer Review, related to SR IFSN-A8, the peer review team found that the licensee did not identify inter-area flood propagation through areas connected via backflow through drain lines involving failed check valves and hatchways, explicitly require by the ASME/ANS PRA Standard. The licensee stated that they would perform a sensitivity study to those two pathways if new propagation or flood pathways were identified.
Since propagation pathways are potentially risk significant, resolve the F&O for the application of the program, or provide justification that the resolution of the F&O is not important for this program.
- Thanks, Rich Guzman Sr. Project Manager NRR/DORL US NRC 301-415-1030