ML24144A189
| ML24144A189 | |
| Person / Time | |
|---|---|
| Site: | 99902056 |
| Issue date: | 05/23/2024 |
| From: | NRC |
| To: | NRC/NRR/DNRL |
| References | |
| Download: ML24144A189 (4) | |
Text
From:
Allen Fetter Sent:
Thursday, May 23, 2024 1:23 PM To:
Schiele, Raymond Joseph; Montague, Kelvin Jevon; Klein, Spencer Paul Cc:
ClinchRiver-CPSafDocsPEm Resource; Greg Cranston; Sean Gallagher; Michelle Hayes; Shilp Vasavada
Subject:
Risk Insights Information Needs_Clinch River CPA Readiness Assessment.pdf Attachments:
Risk Insights Information Needs_Clinch River CPA Readiness Assessment.pdf Good Afternoon, As part of NRCs ongoing preapplication readiness assessment for the Tennessee Valley Authority (TVA)
Clinch River construction permit application (CPA), attached are information needs on risk insights and information for the BWRX-300 reactor design that TVA is referencing in the CPA.
NRC can support a clarification call with TVA on any of the items in the attached. If a clarification call is not needed, NRC and TVA should nonetheless have a discussion on a tentative schedule for feedback on the information needs and completion of this part of the readiness assessment.
- Thanks, Allen H. Fetter, Senior Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of New and Renewed Licenses New Reactor Licensing and Infrastructure Branch Washington, D.C.
301-415-8556 (Office) 301-385-5342 (Mobile)
Hearing Identifier:
ClinchRiver_CPSafDocs_Public Email Number:
21 Mail Envelope Properties (MW4PR09MB939603FF9F6B8AC24B835DE685F42)
Subject:
Risk Insights Information Needs_Clinch River CPA Readiness Assessment.pdf Sent Date:
5/23/2024 1:22:46 PM Received Date:
5/23/2024 1:22:49 PM From:
Allen Fetter Created By:
Allen.Fetter@nrc.gov Recipients:
"ClinchRiver-CPSafDocsPEm Resource" <ClinchRiver-CPSafDocsPEm.Resource@nrc.gov>
Tracking Status: None "Greg Cranston" <Gregory.Cranston@nrc.gov>
Tracking Status: None "Sean Gallagher" <Sean.Gallagher@nrc.gov>
Tracking Status: None "Michelle Hayes" <Michelle.Hayes@nrc.gov>
Tracking Status: None "Shilp Vasavada" <Shilp.Vasavada@nrc.gov>
Tracking Status: None "Schiele, Raymond Joseph" <rjschiele@tva.gov>
Tracking Status: None "Montague, Kelvin Jevon" <kjmontague@tva.gov>
Tracking Status: None "Klein, Spencer Paul" <spklein@tva.gov>
Tracking Status: None Post Office:
MW4PR09MB9396.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 941 5/23/2024 1:22:49 PM Risk Insights Information Needs_Clinch River CPA Readiness Assessment.pdf 135251 Options Priority:
Normal Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
1 Information Needs to Leverage Risk Insights for the Tennessee Valley Authority (TVA)
Construction Permit Application (CPA)
Key Messages Collection of available risk insights and information for the BWRX-300 design via TVAs electronic reading room (portal) prior to submittal of the CPA will be mutually beneficial.
o NRR/DRA staff will share this information, as applicable, with the entire CPA technical review team to facilitate (1) understanding of the implementation of the Safety Strategy in the CPA, and (2) grading the teams review.
The NRC staff will not perform a PRA technical acceptability review as part of the pre-submittal collection of risk insights. This will constitute a key assumption for this activity and should not be construed as tacit approval of the technical acceptability of the risk assessments and insights supporting the CPA.
Initial List of Information Requested Risk information and insights CDF and LRF for each hazard category and the total CDF and LRF.
Information, preferably quantitative, of the most impactful design features in terms of impact on risk metrics (CDF and LRF) and risk insights. The staff requests this information to be provided for the following:
o Each hazard for full power mode o Each hazard for low power and shutdown mode o Top 5 design features and human actions resulting in risk increases (CDF and LRF) o Top 5 design features and human actions resulting in risk decreases (CDF and LRF)
Discussion of the use of risk information and insights from the PRA to select design alternatives and operational strategies to reduce risk.
Dominant (e.g., 5% contribution or more) core damage sequences for each hazard and mode with their quantitative contribution to CDF.
Dominant (e.g., 5% contribution or more) large release sequences for each hazard and mode with their quantitative contribution to LRF.
Criteria (e.g., importance measure thresholds) used to determine candidate risk significant SSCs from PRA.
List of candidate risk significant SSCs and human actions for each mode and hazard, including the corresponding:
o Conditional core damage frequency, o Fussell-Vesely (F-V) contribution to core damage frequency, o Conditional large release frequency, o F-V contribution to large release frequency.
List of first-of-a-kind or novel design features and source of failure probability for each identified feature, including common-cause failure (e.g., valves for the isolation condensers).
Seismic fragility for dominant seismic risk contributors.
Key insights from PRA or alternative risk evaluations for non-seismic hazards, including design requirements and mitigation capability (e.g., flood doors for key SSCs).
2 Severe accident sequences selected to represent the full spectrum of conditions for analysis for severe accident mitigation.
Information on design features and strategy for combustible gas control in the RCS and containment.
A summary table of the PRA sensitivity studies, the parameters varied in each sensitivity study, and the corresponding results.
A list of key PRA assumptions.
PRA development Identification of which hazards have been modeled using PRA, non-PRA evaluations, or screened.
Description of the systematic approach used to develop a comprehensive list of potential initiating events for the internal events PRA.
Description of each initiating event modeled in the internal events PRA.
Identification of initiating events that are screened from inclusion in the internal events PRA with basis for screening.
Description of necessary and sufficient equipment (safety and non-safety-related) reasonably expected to be used to mitigate initiators, including simplified drawings of the system.
System dependency matrix for systems modeled in the PRA.
List of sources used for data on failure probability, including common-cause failures.
Process for identifying key PRA assumptions.
Rationale for excluding any design features that are not modeled in the PRA (all hazards, all modes).
Clarification on whether the PRAs have been self-assessed or peer reviewed. If yes, identification of the relevant PRA Standards and a summary of results of the self-assessment or peer review, especially the identified limitations of the PRA model.
Description of the success criteria for each initiating event or initiating event group, including the list of performance requirement (e.g., number of trains required) and operator actions credited in the determination of success criteria.
Overview of Passive Safety System Reliability Analysis.