ML21172A215
| ML21172A215 | |
| Person / Time | |
|---|---|
| Issue date: | 06/21/2021 |
| From: | Joseph Sebrosky NRC/NRR/DANU |
| To: | |
| Uribe J | |
| References | |
| Download: ML21172A215 (20) | |
Text
Technology Inclusive Content of Application Project Workshop June 23, 2021 Microsoft Teams Meeting Bridgeline: 301-576-2978 Conference ID: 395 169 492#
Agenda Time Topic*
Speaker 10:00 - 10:10 am Opening Remarks NRC/Southern 10:10 - 11:50 am First Issue - principal design criteria (issue #6 from TICAP workshops)
NRC/Southern 11:50 - 12:00 pm Stakeholder Questions All 12:00 - 1:00 pm Break All 1:00 - 1:10 pm Opening Remarks NRC/Southern 1:10 - 2:50 pm Second issue to be discussed - reliability and capability targets (issue #9 from TICAP workshops)
NRC/Southern 2:50 - 3:00 pm Stakeholder Questions All 3:00 - 3:30 pm Continuation of Discussion NRC/Southern 3:30 - 3:45 pm Stakeholder Questions All 3:45 - 4:00 pm Next Steps and Closing Remarks NRC/Southern
- Note that list of topics from TICAP workshops including status of the items is available from the May 26, 2021, TICAP workshop meeting summary (see:
https://www.nrc.gov/docs/ML2115/ML21158A223.pdf) 2
TICAP Workshop - Continued 3
The purpose of this meeting is to discuss with the nuclear industry issues related to the draft guidance document for Safety Analysis Report (SAR) content for an advanced reactor application based on the licensing modernization project Key documents associated with the workshop are referenced in the meeting notice and include:
Industry-developed draft TICAP guidance document (ADAMS Accession No. ML21106A013)
Continuation of TICAP workshops held in May of 2021 May 26th meeting summary includes a table with the status of the workshop items up to the date of that meeting (ADAMS Accession No. ML21158A223)
Additional Background Available on NRC ARCAP/TICAP public webpage (see: https://www.nrc.gov/reactors/new-reactors/advanced/details.html#advRxContentAppProj)
ARCAP and TICAP - Nexus
- Additional contents of application outside of SAR are still under discussion. The above list is draft and for illustration purposes only
Principle Design Criteria 5
- Principle Design Criteria (PDCs) are required by regulations: 10 CFR 50.34; 10 CFR 52.47, 52.79, 52.137, and 52.157 General Design Criteria (GDCs) in 10 CFR Part 50, Appendix A are applicable to LWRs (minimum requirements)
GDCs in 10 CFR 50, Appendix A are not applicable to non-LWRs, therefore, non-LWR applicants would not need to request an exemption from the GDC in 10 CFR Part 50 when proposing PDC for a specific design.
RG 1.232 provides guidance for developing PDCs for non-LWR advanced reactors
Principle Design Criteria 6
Applicant must provide supporting information that justifies to the NRC how their design meets the proposed PDC and how the proposed PDC demonstrate adequate assurance of safety ARDCs developed by the NRC staff are intended to provide insight into the staffs views on how the underlying safety bases for the GDC could be applied to address non-LWR design features; however, these are not considered to be final or binding regarding what may eventually be required from a non-LWR applicant ARDCs are an important first step - NRC recognizes the future benefits to risk informing the non-LWR design criteria to the extent possible NRC recognizes that the LMP process provides a risk-informed, performance-based approach to developing proposed PDCs
Principle Design Criteria 7
NRC recognizes that using the LMP process may not address all aspects considered necessary for demonstrating adequate assurance of safety (e.g., normal operations, subcriticality, etc.) and is interested in how these would be proposed to be addressed via the TICAP guidance.
Example:
The LMP design process is focused on off-normal events from AOOs to BDBEs and identifies the design features, performance and special treatment needed to keep those events within the F-C curve and cumulative individual risk targets. Dose at the EAB and cumulative individual risk are the only measures used as acceptance criteria.
However, LMP does not address other concerns associated with the normal operation portion of the design basis, prevention of severe accidents, recovery from off-normal events or non-reactor on-site hazards.
Principle Design Criteria 8
Examples:
- ARDC 26 - specifies that a means be provided to shutdown the reactor and maintain a safe shutdown condition after postulated accidents (DBAs). LMP does not require safe shutdown, only that the dose at the EAB not exceed 25 rem. Safe shutdown is required to terminate the event and provide for refueling, inspections, and/or repair of the facility. Terminating the event is an essential part of safety.
ARDC 62 - addresses the prevention of criticality in fuel storage and handling. LMP does not address criticality prevention. Such events can result in doses to the public.
Principle Design Criteria 9
Examples:
ARDC 10 - protects against fuel damage during normal operation, including AOOs (SAFDLs). This allows continued operation and prevents contaminating the primary coolant system during events which may occur multiple times during the plant lifetime. Such contamination and failed fuel generate additional waste to be disposed of and provide additional radiation hazard to operating personnel. Minimizing waste is a requirement in 10 CFR 20.1406.
LMP does not address this concern. Its also noted that a SAFDL limit could be a surrogate for the dose criteria.
Principle Design Criteria 10 Examples:
ARDC 35 - specifies that during and following postulated accidents (DBAs), fuel and clad damage do not interfere with effective core cooling. LMP does not require effective core cooling during or after DBAs, only that the dose at the EAB not exceed 25 rem. In effect, LMP would allow a DBA to result in a severe accident as long as the dose does not exceed 25 rem. Loss of effective core cooling should be prevented in the DBE/DBA region to be consistent with the current LWR safety philosophy (as expressed in the LWR regulatory requirements).
Principle Design Criteria 11 NRC recognizes that the LMP process assigns special treatments to several design attributes (e.g., quality assurance, protection from external hazards, testability, inspectability, etc.) that are addressed in specific and cross-cutting ARDCs and is interested in how the TICAP guidance could address these (e.g., applicant justifies or demonstrates that these design attributes are integral to LMP-based design process and specification through determination of special treatments based on defense-in-depth adequacy assessment).
Examples:
Various ARDCs (39 & 40 as examples) include requirements that the design of certain SSCs accommodate the capability for their inspection and testing. These kinds of considerations should be included when translating SSC special treatments into associated PDCs, where applicable.
Placeholder slides for TICAP Team PDC Discussions 12
Reliability and Capability Targets 13 Summary of TICAP Workshop #3 discussion held May 26, 2021:
NRC staff noted that the reliability and capability targets were not proposed to be captured in the safety analysis report (SAR) contrary to guidance in NEI 18-04, Section 4.1, Task 7.
From the NRCs perspective the SAR should describe reliability and capability targets and performance requirements used as input to the PRA and for SR and NSRST SSCs that were used to develop the selection of special treatment requirements (i.e., programmatic actions used to maintain performance within the design reliability targets).
The NRC noted that this information is important to capture in the SAR and in some cases will be used as input to technical specification requirements.
Reliability and Capability Targets 14 Additional observations from the LMP Lessons Learned Report:
(see table of reports under Industry-led Licensing Modernization Project on NRC's public website:
https://www.nrc.gov/reactors/new-reactors/advanced/details.html#modern)
When the SSC safety classification steps of the LMP are applied, reliability and capability targets are set for the safety significant SSCs.
These targets consider how reliable and capable the SSCs were assumed to be when assessed in the PRA, including how much the performance may deviate without adversely impacting the risk significance of LBEs and SSCs relative to Frequency-Consequence Target (F-C Target) and cumulative risk targets.
All safety significant SSCs, which include SR and NSRST SSCs, will have performance targets for reliability and capability. These targets are set as part of the DID adequacy evaluation.
The DID baseline is developed as part of the plant license application.
Reliability and Capability Targets 15 The maintenance of a DID baseline is a necessary component of the design and licensing process and supports plant changes (design or operations) throughout the plant lifetime that may impact nuclear safety. The change management of the DID baseline begins following the submittal of the license application. (See NEI 18-04 Section 5.9.7.)
In response to SSCQ7 on the availability of guidance on how to set reliability and capability targets for safety significant SSCs the concept of using the Reliability and Integrity Management (RIM) was discussed (ref. Section 3.5.1 in the LMP report on SSC safety classification and performance requirements). In the RIM program, the allocation of reliability targets starts at the plant level, which in the LMP methodology is represented by the F-C Target and the cumulative risk targets. SSC level targets are then set based on controlling the frequencies and consequences of the LBEs within those targets.
Reliability and Capability Targets 16 The NRC is interested in how the TICAP guidance proposes to address the documentation of reliability and capability targets (e.g.,
through the SAR or other documents submitted with the application or auditable, inspectable owner-controlled documents/programs)
The guidance must take into consideration that any of the reliability/capability target information and resulting LBE margins relied upon by the NRC in making its safety findings must be docketed information Examples for discussion:
How would the reliability and capability targets be documented?
in the SAR in the DID baseline document in the RIM program in the Technical Specification are there other potential approaches
Reliability and Capability Targets 17 Examples for discussion:
How would achievement of the reliability and capability targets be demonstrated?
use the Maintenance Rule (10 CFR 50.65) program?
What if a reliability or capability target is not achieved (Tech Spec completion times including RICTs, ROP and SDP, use of fleet-wide or industry-wide reliability data such as EPIX, appropriate and timely enforcement actions, etc.)?
Placeholder slides for Reliability and Capability Target Discussions 18
Timeline for Technology Inclusive Content of Application Project (TICAP) Guidance and Advanced Reactor Content of Application Project (ARCAP) Guidance (rev 6/23/2021)
Legend Industry Action NRC Staff Action Industry/NRC Joint Action 2022 Jan Mar May Jul Sep Nov 2022 Mar Southern Revision B of TICAP Guidance Document 4/15/2021 Southern Revision C of TICAP Guidance Document 7/16/2021 NEI Revision 0 of TICAP Guidance Document 8/27/2021 NEI Revision 1 of TICAP Guidance Document 1/19/2022 NRC Comments based on TICAP Workshops 6/10/2021 NRC TICAP Regulatory Guide (Draft) 9/10/2021 NRC TICAP Regulatory Guide 3/25/2022 NRC/Industry update ACRS Subcommittee on status of ARCAP/TICAP guidance documents 7/21/2021 NRC/Industry brief ACRS Subcommittee on ARCAP/TICAP guidance documents (NEI, Rev0 and Staff Draft RG) 10/12/2021 NRC/Industry brief ACRS Subcommittee on final ARCAP/ TICAP guidance 2/9/2022 NRC/Industry brief ACRS Full Committee on final TICAP guidance 3/3/2022 ARCAP Application Outline Updated to be Consistent with TICAP outline 1/30/2021 Draft ARCAP Roadmap ISG, ARCAP ISG for "Site Information," and ARCAP Chapters 9, 10, 11, and 12 issued 9/10/2021 2/1/2021 TICAP Tabletop Exercises 4/2/2021 5/2/2021 TICAP Workshops 5/26/2021 19
Next Steps - Future Milestones TICAP Near-Term Milestones Target Date Southern Revision C to TICAP Guidance Document mid July 2021 ACRS Future Plant Subcommittee Meeting providing status of ARCAP and TICAP Guidance Documents mid July 2021 NEI Revision 0 of TICAP Guidance Document August 2021 ACRS Future Plant Subcommittee Meeting on ARCAP/TICAP Guidance Documents October 2021 20