ML17272A141
| ML17272A141 | |
| Person / Time | |
|---|---|
| Issue date: | 09/28/2017 |
| From: | Office of New Reactors |
| To: | |
| Reckley W, NRO/DSRA/ARPB, 301-415-7490 | |
| References | |
| Download: ML17272A141 (48) | |
Text
Public Meeting on Possible Regulatory Process Improvements for Advanced Reactor Designs September 28, 2017 1
Telephone Bridge (888) 793-9929 Passcode: 7223761
Public Meeting
- Telephone Bridge (888) 793-9929 Passcode: 7223761
- Opportunities for public comments and questions at designated times 2
Introductions
Summary of NRC Standards Forum Licensing Modernization Project o
Follow up on PRA Approach Whitepaper o
Safety Classification White Paper Lunch Advanced Reactor Design Criteria Policy Issues o Insurance o Functional Containment Public Comment Period 3
Outline
4 NRC Standards Forum 2017
5 Licensing Modernization Project Follow up on PRA Approach Whitepaper o White Paper - ML17158B543 o NRC staff comments/questions - ML17233A187 Safety Classification White Paper
6 PRA Approach Paper Staff Comments/Questions 1)
NRC staff participating in ASME/ANS Standard for Advanced Non-LWR PRA and planning to review for endorsement 2)
Organization and relationships between PRA and LBE 3)
PRA/LBE white paper relationships to efforts on advanced reactor design criteria (ARCD) 4)
PRA within larger regulatory framework 5)
Usefulness of PRA in design process beyond regulatory role of NRC
7 PRA Approach Paper Staff Comments/Questions 6)
Risk metrics and top level regulatory requirements to align with revisions to LBE white paper 7)
Examples useful but specific discussions may need revised as broader concepts are addressed 8)
Comparison/crosswalk between LWR PRA Standard and Non-LWR Standard would be helpful 9)
Useful to understand role of PRA in broader regulatory framework
- 10) Standard approach for determining risk significance of non-LWR design features
- 11) Guidance for developing site parameter envelopes
8 PRA Approach Paper Staff Comments/Questions
- 12) Operational program for maintaining and updating PRA
- 13) Interactions between reactor and potential portions of facility for fuel/waste processing and storage
- 14) Use of large release frequency (LRF) and consideration of prevention/mitigation in addition to overall risks
- 15) Multi-unit or integrated risk included in ASME/ANS Standard or more immediate issue
- 16) Output Objectives - observations ASME/ANS PRA Standard as vehicle Issues - F/C figure, external events, MST NRC focus - applications and pre-application interactions
9 Licensing Modernization Project Presentations
10
- Updates
- Public Questions / Comments
- Lunch Break o Meeting/Webinar will resume at 1:00pm Public Meeting
11 Advanced Reactor Design Criteria Discussions from Public Meeting
12 Policy Issues Policy Issues - nonLWRs (ongoing)
Prototype Draft issued, discussed Aug 3, plans are to incorporate into revision of roadmap document - topic at Nov meeting Source Term, Dose Calculations, Siting Future discussion of existing Commission Policy on siting in relation to population centers Licensing Modernization Project Key SSC Design Issues Use of PRA Defense in Depth Licensing Basis Events Functional Containment Offsite EP Final regulatory basis document to Commission Insurance and Liability On agenda for November 2 - preliminary discussion to prepare Security October 12 Public Meeting
13 Policy Issues Policy Issues - nonLWRs (ongoing)
Fuel Qualification Discussed Aug 3, plans to interact with technology working groups Increased Enrichments Awaiting paper No current activities Annual Fees Multi-module License Structure Manufacturing License Operator Staffing Process Heat/Industrial Facilities Operational Programs Fuel Cycle Facilities (front end)
Module Installation During Operation Waste Issues (back end)
Decommissioning Funding Aircraft Impact Assessments Research/Test Reactor Guidance Awaiting paper
14 Insurance SECY-10-0034, Potential Policy, Licensing, and Key Technical Issues for Small Modular Nuclear Reactor Designs SECY-11-0178, Insurance and Liability Regulatory Requirements for Small Modular Reactor Facilities Thermal Power vs Electrical Power Multi-module with reactors < 100 Mwe Comparative Analysis NEI Position Paper / ANS Special Committee / Other Assessments Periodic Report to Congress The Commission and the Secretary shall submit to the Congress by December 31, 2021, detailed reports concerning the need for continuation or modification of the provisions of this section, taking into account the condition of the nuclear industry, availability of private insurance, and the state of knowledge concerning nuclear safety at that time, among other relevant factors, and shall include recommendations as to the repeal or modification of any of the provisions of this section.
15 Insurance Problem Statement Interactions between the NRC staff and stakeholders are intended to identify potential issues associated with requirements for financial protection to cover public liability claims for advanced reactor designs, and to subsequently identify relevant information or needed research/studies to resolve those issues. These activities will support developing recommendations for possible modifications, if warranted, to the Price-Anderson Act, NRC regulations or both.
An example of a previous report to Congress is NUREG/BR-6617, The Price-Anderson Act - Crossing the Bridge to the Next Century: A Report to Congress
16 Functional Containment
- SECY Paper for FY 2018
- Identified in previous stakeholder meeting as a high-priority issue
- Outline
- Background/history
- Proposed Approach
- Safety Function
- Physical Building
17 Functional Containment Physical Building Normal Operation Anticipated Events Design Basis Accidents Beyond Design Basis Events Functional Containment (as needed for specific events)
Other Functions
- Decay Heat Removal*
- External Event Barrier
- Security
- Asset Protection Part 20 Part 20, SAFDL/SARRDL 50.34, SAFDL/SARRDL Safety Goal EPA PAGs Reactivity Control Decay Heat Removal Radioisotope Retention Functional Containment Critical Safety Functions Performance Criteria
18 Future Meetings Oct 12 Physical Security Nov 2 Licensing Modernization - topics ?
Insurance Roadmap, SDA, Prototype (draft in mid-Oct)
Functional Containment Dec 14 Licensing Modernization - topics ?
Siting (populations)
Functional Containment
?
TBD Physical Security Feb 1 Mar 22 NEI (Consolidated) RIPB Guidance
19 Public Comments / Questions
Utility-Led Initiative for Licensing Modernization of Technical Requirements for Licensing of Non-Light Water Reactors NRC Review of PRA and SSC White Papers Karl Fleming, LMP Team September 28, 2017
Discussion Topics
- LMP Response to NRC comments on PRA Approach
- Introduction to LMP approach to SSC safety classification and performance requirements 2
NRC COMMENTS AND QUESTIONS ON LMP PRA WHITE PAPER 3
NRC Meeting 9-28-17
NRC PRA Review Topics and LMP Responses
- 1. NRC participation and plan to review and endorse non-LWR PRA standard.
Critical to successful implementation of LMP framework
- 2. Uses of non-DBA LBEs beyond LBE/DBA selection and evaluation Technical basis for the risk inputs to selection of LBEs is integral to the PRA Further analysis of non-DBA LBEs is used in SSC safety classification, DID evaluation, and other RIPB decisions 4
NRC PRA Review Topics and LMP Responses 3.
Interface with ARDC Pending regulatory guide for developing principal design criteria from ARDCs Some guidance for developing reactor and design specific criteria in SSC white paper RIPB process expected to be useful in establishing design-specific PDCs
- 4. Broader use of PRA in RIPB decisions LMP agreement on PRA applications for LBE, SSC, and DID Specific additional applications not considered within LMP scope 5
NRC PRA Review Topics and LMP Responses
- 5. Pre-application interactions including risk-informed design decisions LMP general agreement
- 6. Alignment with LBE paper comments regarding TLRC and risk metrics LMP general agreement
- 7. Limited NRC review of examples LMP general agreement 6
NRC PRA Review Topics and LMP Responses
- 8. LWR/non-LWR PRA standard cross walk Have color codes for existing standard identifying sources of requirements Need to revisit for revised standard
- 9. Role of PRA in broader regulatory framework; Interface with consensus codes and standards LMP objective to identify needs from supporting standards Reliability and Integrity Management approach in ASME Section XI LMP to address PRA role in SSC, DID, and integrated guidance document 7
NRC PRA Review Topics and LMP Responses
- 10. Risk significance of design features and SSCs SSC paper to propose absolute TI risk metrics for this purpose Topic to be addressed in revised non-LWR PRA standard per PRA pilot feedback
- 11. Guidance needed for site parameter envelope Non-LWR PRA standard accommodates external hazard treatment for range of sites
- 12. Guidance needed for PRA maintenance and updates Agree that PRA maintenance and update process will be required Revisit RIPB decisions supported by PRA Some aspects of this process addressed in SSC paper 8
NRC PRA Review Topics and LMP Responses
- 13. PRA and harmonization of non-reactor facilities and worker risk Questions outside scope of non-LWR PRA Standard Best addressed separately
- 14. Risk metrics questions: LRF, risk contributors; evaluation of prevention and mitigation balance SSC paper defines risk significance for SSCs and LBEs LBE, SSC, and DID papers discuss roles of SSCs in prevention and mitigation Need for LRF is preempted by requirements for dose 9
NRC PRA Review Topics and LMP Responses
- 15. Integrated site risk Non-LWR PRA Standard and LMP framework address multi-module plant risk for advanced reactor applicants
- 16. Observations regarding PRA paper outcome objectives LMP acknowledges that full realization of outcome objectives will require resolution of identified issues, successful completion of a revised and endorsed PRA standard 10
LMP SSC SAFETY CLASSIFICATION APPROACH 11
LMP SSC Paper Scope
- Describe proposed approach for defining safety significant SSCs in terms of their risk significance and role in supporting defense-in-depth (DID), and
- Provide guidance for the development of
- functional design criteria (FDC)
- performance requirements for the reliability and capability of SSCs in the prevention and mitigation of licensing basis events (LBEs)
- special treatment requirements 12
SSC Safety Classification Attributes
- Systematic and reproducible
- Sufficiently complete
- Available for timely input to design decisions
- Risk-informed and performance-based
- Reactor technology inclusive
- Consistent with applicable regulatory requirements 13
SSC Approach Highlights
- Proposes criteria for SSC risk significance based on absolute risk metrics
- Incorporates elements from 10 CFR 50.69 and NEI 04 in the context of a forward fit process
- Includes SSC requirements to address single and multi-module risks
- Expands on guidance for special treatment*
requirements beyond that in NGNP SSC white paper
- *Terminology TBD 14
LMP SSC Safety Classification Approach 15 Input from PRA and LBE Evaluation
- 2. Determine required* and safety-significant functions**
3a. SSC selected to meet required safety function?
3b. SSC function is risk significant?
3c. SSC function required for defense-in-depth?
4a. Classify SSC as Safety Related (SR) 4b. Classify SSC as Non-Safety Related with Special Treatment (NSRST) 4c. Classify SSC as Non-Safety Related with No Special Treatment (NST) 5a. Define SR SSC reliability and capability requirements 5b.Determine NSRST SSC reliability and capability requirements 6c. Determine non-regulatory NST SSC design requirements YES YES YES No No No Special Treatment for Safety Significant Functions 6a. Determine SR SSC design criteria and special treatment requirements 6b.Determine NSRST SSC special treatment requirements 5c.Determine user requirements for NST SSC reliability and capability
- Safety-Significant Functions include functions classified as risk-significant or required for defense-in-depth
- Required safety functions are those necessary to meet 10 CFR 50.34 dose limits for DBAs
LMP Proposed SSC Safety Categories Safety-Related (SR):
SSCs selected by the designer to perform required safety functions to mitigate the consequences of DBEs to within the F-C target, and to mitigate DBAs to meet the dose limits of 10 CFR 50.34 using conservative assumptions.
SSCs selected by the designer to perform required safety functions to prevent the frequency of BDBEs with consequences greater than 10 CFR 50.34 dose limits from increasing into the DBE region and beyond the F-C target.
Non-Safety-Related with Special Treatment (NSRST):
Non-safety related SSCs relied on to perform risk significant functions. Risk significant SSCs are those that perform functions that keep LBEs from exceeding the F-C target, or make significant contributions to the cumulative risk metrics selected for evaluating the total risk from all analyzed LBEs.
Non-safety related SSCs relied on to perform functions requiring special treatment for DID adequacy.
Non-Safety-Related with No Special Treatment (NST):
All other SSCs.
16
LMP Proposed SSC Safety Categories 17 SSCs Including Radionuclide Barriers Safety Related (SR)
SSCs Non-Safety Related SSCs with Special Treatment (NSRST)
Non-safety Related SSCs with No Special Treatment (NST)
SSCs selected for required safety functions to mitigate DBEs within F-C Target*
SSCs performing risk significant functions SSCs performing functions required for defense-in-depth SSCs performing non-safety significant functions SSCs selected for required safety functions to prevent high consequence BDBEs from entering DBE region beyond F-C target Risk Significant SSCs Non-Risk Significant SSCs
SSC Risk Significance A prevention or mitigation function of the SSC is necessary to meet the design objective of keeping all LBEs within the F-C target.
The LBE is considered within the F-C target when a point defined by the upper 95%-tile uncertainty of the LBE frequency and dose estimates are within the F-C target.
The SSC makes a significant contribution to one of the cumulative risk metrics used for evaluating the risk significance of LBEs.
A significant contribution to each cumulative risk metric limit is satisfied when total frequency of all LBEs with failure of the SSC exceeds 1% of the cumulative risk metric limit. The cumulative risk metrics and limits include:
- The total frequency of exceeding of a site boundary dose of 100 mrem < 1/plant-year (10 CFR 20)
- The average individual risk of early fatality within 1 mile of the Exclusion Area Boundary (EAB) < 5x10 -7/ plant-year (QHO)
- The average individual risk of latent cancer fatalities within 10 miles of the EAB shall not exceed 2x10-6/plant-year (QHO) 18
LMP Frequency-Consequence (F-C) Target 19
Risk Significant LBEs 20
Comparison of LMP and 10 CFR 50.69 SSC Safety Categories 21
- Terminology TBD
Derivation of Special Treatment Requirements
- SR SSCs
- Functional Design Criteria (SRDC) derived from required safety functions
- Lower level design criteria derived from SRDC
- SR and NSRST SSCs
- SSC reliability and capability performance targets
- Focus on prevention and mitigation functions from LBEs
- Integrated decision making process to derive specific special treatment requirements
- Incorporates guidance from 10 CFR 50.69 and NEI-00-04 from existing reactors from a forward fit perspective
- Incorporates Commissions expectations for risk-informed and performance based regulation from SRM to SECY 98-0144 22
MHTGR Representative Functional Design Criteria Required Safety Function Safety Related Design Criteria Retain Radionuclides in Fuel Particles I The reactor fuel shall be designed, fabricated, and operated in such a manner that minor radionuclide releases from the fuel to the primary coolant will not exceed acceptable values.
Control Chemical Attack II The vessel and other components that limit or prevent the ingress of air or water shall be designed, fabricated and operated in such a manner that the amount of air or water reacting with the core will not exceed acceptable values.
Control Heat Generation III The reactor shall be designed, fabricated, and operated in such a manner that the inherent nuclear feedback characteristics will ensure that the reactor thermal power will not exceed acceptable values. Additionally, the reactivity control system(s) shall be designed, fabricated and operated in such a manner that during insertion of reactivity, the reactor thermal power will not exceed acceptable values.
Control Heat Removal IV The intrinsic dimensions and power densities of the reactor core, internals, and vessel, and the passive cooling pathways from the core to the environment, shall be designed, fabricated and operated in such a manner that the fuel temperatures will not exceed acceptable values.
Limit Fuel Oxidation XII The primary system/boundary shall be designed and fabricated to a level of quality that is sufficient to ensure high reliability of the primary system/boundary integrity needed to prevent air ingress during normal and off-normal conditions. The plant shall be designed, fabricated, operated, and maintained in a manner that ensures that the primary system boundary design limits are not exceeded.
23
Roles of SSC Capability and Reliability in Prevention and Mitigation of Accidents 24 F-C Target Yes fie p1 Yes No p2 No 0
dlow dhigh SSC LBEs Function IE 1,2,3 Prevent initiating event 1
Mitigate initiating event 2
Prevent fuel damage 3
Help prevent large release 2
Mitigate fuel damage 3
Prevent Large release SSC2 Capability to limit release from fuel damage Reliability of mitigation function SSC Performance Attribute for Special Treatment Reliability of SSC causing initiating event SSC1 Capability to prevent fuel damage Reliability of mitigation function Reliability of mitigation function LBE-3 3
Fuel Damage w/ large release fiep1p2 dhigh Consequence ------->
LBE-2 2
Fuel damage w/ Limited release fiep1 dlow fiep1p2 Dose Frequency ------ >
fie LBE-1 1
No fuel damage or release fie 0
fiep1 IE, Initiating Event SSC1 Prevents Fuel Damage?
SSC2 Limits Release?
LBE End State Frequency
SSC Classification Summary
- LMP retains the NGNP SSC safety categories of SR, NSRST, and NST
- All safety significant SSCs classified as SR or NSRST
- All SR SSCs are classified as risk significant
- NSRST SSCs include other risk significant SSCs and SSCs requiring some special treatment for DID adequacy
- Specific special treatment for capabilities and reliabilities in the prevention and mitigation of accidents
- Special treatment defined via integrated decision panel using forward fit 10 CFR 50.69 process 25
Questions?
26
BACK-UP SLIDES 27 NRC Meeting 9-28-17
LBEs include all the events used to develop design bases and licensing requirements. They cover a comprehensive spectrum of events from normal operation to rare, off-normal events.
There are four categories of LBEs:
Anticipated Operational Occurrences (AOOs) encompass planned and anticipated events.
The radiological doses from AOOs are required to meet normal operation public dose requirements. AOOs are utilized to set operating limits for normal operation modes and states.
Design Basis Events (DBEs) encompass unplanned off-normal events not expected in the plants lifetime, but which might occur in the lifetimes of a fleet of plants. The radiological doses from DBEs are required to meet accident public dose requirements. DBEs are the basis for the design, construction, and operation of the structures, systems, and components (SSCs) during accidents.
Beyond Design Basis Events (BDBEs) are rare off-normal events of lower frequency than DBEs. BDBEs are evaluated to ensure that they do not pose an unacceptable risk to the public.
Design Basis Accidents (DBAs). The DBAs for Chapter 15, Accident Analyses, of the license application are deterministically derived from the DBEs by assuming that only SSCs classified as safety-related are available to mitigate the consequences. The conservatively estimated dose of each DBA must meet the 10 CFR §50.34 consequence limit at the Exclusion Area Boundary (EAB).
28 Categories of LBEs
Process For Selecting and Evaluating LBEs 29