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MONTHYEARNMP1L3482, License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2022-12-15015 December 2022
License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b
Project stage: Request
NMP1L3484, Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Reatment of Structures, Systems and Components for Nuclear Power Reactors2022-12-15015 December 2022
Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Reatment of Structures, Systems and Components for Nuclear Power Reactors
Project stage: Request
ML23019A3092023-01-19019 January 2023
Acceptance Review Determination License Amendment Request to Adopt 10 CFR 50.69 Categorization Process
Project stage: Acceptance Review
ML23019A3032023-01-19019 January 2023
Acceptance Review Determination License Amendment Requets to Adopt TSTF-505
Project stage: Acceptance Review
ML23025A3862023-01-31031 January 2023
Regulatory Audit Plan in Support of License Amendment Requests to Adopt TSTF-505, Revision 2, and 10 CFR 50.69
Project stage: Other
ML23033A0142023-02-0202 February 2023
E-mail Dated 2-2-2023 from R.Guzman to R.Reynolds Correction to Error in NMP1 TSTF-505 and 50.69 Audit Plan
Project stage: Other
ML23118A3882023-04-28028 April 2023
Regulatory Audit Questions TSTF-505 and 50.69 (E-mail Dated 4/28/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
ML23142A0222023-05-22022 May 2023
Regulatory Audit Questions (PRA) TSTF-505 and 50.69 (E-mail Dated 5/22/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
ML23149A0012023-05-29029 May 2023
Audit Agenda TSTF-505 and 50.69 (E-mail Dated 5/29/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
ML23209A7672023-06-13013 June 2023
Share File Observations on Response to Question 06 and 22 TSTF-505 and 50.69 (E-mail Dated 6/13/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
ML23209A7692023-06-14014 June 2023
Draft Audit Results File TSTF-505 and 50.69 (E-mail Dated 6/14/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Draft Other
ML23205A2422023-07-11011 July 2023
NRC Staff Follow-up Comments on Audit Questions 17 and 19 TSTF-505 and 50.69 Regulatory Audit (E-mail Dated 7/11/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
ML23205A2412023-07-11011 July 2023
NRC Staff Follow-up Comments on Audit Questions 6a, 6b, and 6c TSTF-505 and 50.69 Regulatory Audit (E-mail Dated 7/11/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
ML23205A2432023-07-19019 July 2023
NRC Staff Follow-up Question on Audit Question 18 TSTF-505 and 50.69 Regulatory Audit (E-mail Dated 7/19/2023) (EPIDs L-2022-LLA-0185 and L-2022-LLA-0186)
Project stage: Other
NMP1L3545, Supplemental Information Letter to Adopt TSTF-505, Provide Risk- Informed Extended Completion Times - RITSTF Initiative 4b, Revision 2 and 10 CFR 50.69, Risk-informed Categorization and Treatment of Structures, Systems .2023-08-0404 August 2023
Supplemental Information Letter to Adopt TSTF-505, Provide Risk- Informed Extended Completion Times - RITSTF Initiative 4b, Revision 2 and 10 CFR 50.69, Risk-informed Categorization and Treatment of Structures, Systems .
Project stage: Supplement
ML23250A0822023-09-19019 September 2023
Regulatory Audit Summary Regarding LARs to Adopt TSTF-505, Rev. 2, and 10 CFR 50.69
Project stage: Approval
ML23289A0122023-12-0606 December 2023
Issuance of Amendment No. 250 Regarding the Revision to Technical Specifications to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b
Project stage: Approval
ML23291A4642023-12-0707 December 2023
Issuance of Amendment No. 251 Regarding the Adoption of Title 10 the Code of Federal Regulations Section 50.69, Risk-Informed Categorization and Treatment of SSC for Nuclear Power Plants
Project stage: Approval
ML24008A0592024-01-0808 January 2024
E-mail Dated 1-8-2024 from R. Guzman to R. Reynolds Correct TS Page 204 for License Amendment No. 250 Adoption of TSTF-505
Project stage: Other
2023-05-22
[Table View] |
Text
From:
Richard Guzman To:
Reynolds, Ronnie J:(Constellation Nuclear)
Subject:
FW: SHARE file Observations on Response to Question 06 and 22.pdf Date:
Tuesday, June 13, 2023 12:15:00 PM Attachments:
SHARE file Observations on Response to Question 06.pdf Ron - see notes attached per the high-level observation discussion from Todd Hilsmeier.
- Thanks, Rich
Staff Observations on Response to Questions 06 & 22 (FLEX credit)
[6.a, 22.a - describe and justify approach]
Response did not justify NMP1s approach for FLEX failure rates (i.e., 2x permanently installed failure rates):
Response did not provide a basis for the 2x factor (value seems arbitrary)
PWROG-18042 (where FLEX failure rates are based on industry experience and vetted by industry and approved by NRC) suggests the 2x factor is too low.
Response primarily focused on questioning PWROG-18042 (i.e., its too conservative), which doesnt validate NMP1s approach.
Response seems ok with FTS failure rates in PWROG-18042, and these FTS failure rates are 10-16x larger than the permanently installed SSCs. This suggests the 2x factor used by licensee is too low.
NMP1s approach (or justification of approach) does not consider available generic or plant-specific FLEX data.
Doesn't meet Conclusion 6 of NRC Memo dated May 6, 2022 (ML22014A084) which states, "should not use failure rates for permanently install equipment."
Response states that DG FTR probability in PWROG-18042 is biased to failing within the first hour (i.e., short FLEX run times). However, from PWROG-18042, early DG FTR events (before reaching stable conditions) are counted as FTS.
[6.c, 22.c - provide updated uncertainty analysis]
Response states FLEX failure probability uncertainty has a minor impact on RICT results (i.e., not a key source of uncertainty).
However, for LCOs 3.6.3.C and 3.6.3.H in Table 6c-3, the impact of FLEX failure probability uncertainty is significant (i.e., impacts RICT by 50% or more).
FLEX failure probability is a key source of uncertainty.
Response mentions one RMA to address FLEX uncertainty (i.e., dedicating the N+1 FLEX generator during AC or DC RICT). It is unclear what this RMA represents:
- Describe RMA in more detail?
- How does this RMA reduce risk (i.e., how credited in PRA sensitivity study)?
- Is there sufficient time to credit a spare FLEX DG?
- Since FLEX uncertainties primarily impact fire CDF sequences, what fire-specific RMAs can be implemented?
