ML20267A442
| ML20267A442 | |
| Person / Time | |
|---|---|
| Issue date: | 09/29/2020 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| Nathan Siu | |
| References | |
| Download: ML20267A442 (15) | |
Text
Enhancement of PRA Technology for Applications:
A Regulatory Research Perspective*
Nathan Siu and Mehdi Reisi Fard Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission IAEA Technical Meeting on the Enhancement of Methods, Approaches and Tools for Development and Application of Probabilistic Safety Assessments September 29-October 2, 2020
- The views expressed in this presentation are not necessarily those of the U.S. Nuclear Regulatory Commission
2 Outline
- Role of regulatory research at NRC
- Comments on potential PSA technology*
enhancements
- Dynamic PSA
- Combinations of hazards
- Portable equipment
- Development of SAMGs
- Level 3 PSA
- Software reliability and modelling
- Incorporation of ageing aspects
- Treatment of uncertainties**
TM Organizer Questions Why it is important to consider the subject from a PSA research perspective?
What is the current national/international status of practice/experience?
What are the current challenges and open issues?
- In this presentation Technology = {methods, models, tools, data}
- Added to organizer list
3 ROLE OF REGULATORY R&D
4 NRC Regulatory R&D:
Purpose and Considerations NRC/RES TSOs Universities Industry Other Agencies International Technical analyses Technology development Tests/experiments Surveys/reviews
Adapted from NUREG-2150 Resources
- People
- Funds
- Infrastructure
- Information R&D needs, wants, priorities Multiple Stakeholders Multiple Actors Multiple Products Multiple Uses Ultimate Purpose Role of Regulatory R&D Methods, Models, Tools, Databases, Standards, Guidance, (T)
Foundational Knowledge (K)
Analyses (A)
Technology (capabilities)
Applications (incl. reviews)
Context
5 NRC Regulatory R&D: More Considerations Role of Regulatory R&D Multiple regulatory functions (and decision types)
Risk-informed decision making Current Trends Near Term (User Need)
Long Term (Future-Focused)
Time Scale Not just reactors
6 Photo courtesy of NEA Halden Reactor Project Some Trends
- Market forces
- Increased number of applications
- Increased credit for capabilities (e.g., FLEX)
- Greater role in design (e.g., LMP)
- Novel designs, technologies, and operational concepts
- Improving analysis capabilities
- Computational resources
- Smart technologies (e.g., content analytics)
- Changing workforce (KSAs, preferences)
Role of Regulatory R&D Challenge :
Be Ready!
7 COMMENTS ON POTENTIAL PRA TECHNOLOGY ENHANCEMENTS
- Why it is important to consider the subject from a PSA research perspective?
- What is the current status of practice/experience?
- What are the challenges and open issues?
T: Technology K: Knowledge A:
Analyses Analyses (for application)
Technology (provides capability)
Knowledge (provides context)
8 Long history (starting with fast rx)
J.M. Lanore, et al, Progress in Methodology for Probabilistic Assessment of Accidents: Timing of Accident Sequences," ANS/ENS Intl Mtg Probabilistic Risk Assessment, Port Chester, NY, 1981.
A. Amendola and G. Reina, Event Sequences and Consequence Spectrum: A Methodology for Probabilistic Transient Analysis," Nuclear Technology, 77, 297-315(1981).
Dynamic PSA Importance (Benefits)
Analyses (anticipated, potential)
Advanced reactor design approvals Operating reactor risk-informed applications (e.g., FLEX, security)
External hazards scenarios (e.g., flooding)
Severe accidents Technology Improved realism (fewer modelling approximations)
Reduced completeness uncertainties (e.g., EOCs, passive systems)
Improved synergy (other fields, educational trends)
Knowledge Improved insights Current status U.S.
Technology development Multiple demonstrations International: some applications Challenges Communication and perception Investment requirements, cost/benefit Cultural resistance See also draft white paper (ML19066A390) and presentation from 2019 IAEA workshop (ML19248C656)
Not always complicated T. J. McIntyre and N. Siu, "Electric Power Recovery at TMI-1, A Simulation Model," ANS/ENS Intl Topical Mtg Thermal Reactor Safety, San Diego, California, February 2-6, 1986.
TAF Computational capabilities + investments (e.g.,
DOE, TSOs, universities) => time to reap benefits?
9 Combination of Hazards Importance (Benefits)
Analyses (ongoing)
Current risk-informed applications (specific combinations)
Technology Improved realism (correlation of hazards)
Reduced completeness uncertainties Improved synergy with natural hazards community Knowledge Additional/improved insights Current status (U.S.)
Some methods developed and used, included in PRA standards and guidance Participation in international activities Challenges Efficient identification and prioritization Data augmentation (simulation?)
Communication (discipline-specific frameworks -
what is a hazard? Area of responsibility when performing analyses?)
https://commons.wikimedia.org/wiki/File:Storms_Lothar_and_Martin_december_1999.png Treatment of consecutive events (and pre-conditioning)?
Hurricane tracks adapted from University of Wisconsin-Milwaukee (https://web.uwm.edu/hurricane-models/models/archive/)
Emergency response based on data from National Hurricane Center:
(https://www.nhc.noaa.gov/1992andrew.html)
Role of stochastic simulation?
10 Portable Equipment Importance (Benefits)
Analyses (ongoing)
FLEX applications Other non-safety related equipment Technology Improved HRA for ex-MCR activities (possibly including task-based simulation)
Improvements (practice, methods?) in constructing informed priors (potential)
Knowledge Improved insights Current status (U.S.)
Strong interest, many applications (e.g., NOED, CRM, SDP, licensing actions, NTTF 2.1 seismic PRA)
Further applications being developed Improved HRA demonstration (IDHEAS)
Challenges Reliability data HRA (e.g., granularity/aggregation, quantification)
See also presentation from 2019 IAEA workshop (ML19248C655)
M.T. Lawless, K.R. Laughery, and J.J. Persensky, Using Micro Saint to Predict Performance in a Nuclear Power Plant Control Room: A Test of Validity and Feasibility, NUREG/CR-6159, 1995.
S. Fogarty, Approaches and Tools to Quantifying Facility Security Risk, INMM Workshop on Risk-Informed Security, Stone Mountain, GA, February 11-12, 2014.
Task-Based Simulation: Old Idea, Recent Applications
11 Development of SAMGs Importance (Benefits)
- Technology
- Improved HRA for post-core damage
- Severe-accident induced cascading failures
- Knowledge
- Additional/improved insights (e.g., to prioritize severe accident R&D)
Current status (U.S.)
- Some changes identified during FLEX implementation Challenges
- Multi-source dependencies
- Appropriate realism (scope, avoiding Game Over)
D. Collins, et al., Modeling Potential Reactor Accident Consequences, NUREG/BR-0359 Rev. 1, 2012. (ML12347A049)
SOARCA Assessment of B.5.b Measures
12 Level 3 PSA Importance (Benefits)
Analyses Demonstration of LMP for operating plants Regulatory analysis guidance revisions (potential)
Technology Developments in selected areas (e.g., multi-source PRA)
Knowledge Improved insights regarding safety margins Improved insights for performing analyses (risk, feasibility of and benefits from future Level 3 studies)
Improved staff capabilities for performing and reviewing PRAs Current status (U.S.)
Reference plant state-of-practice study ongoing Challenges Broad scope Integration across all sources, hazards Resources Level 3 PRA Project Scope
13 Software Reliability and Modeling Importance (Benefits)
Analyses Licensing digital upgrades Approving new designs Technology Improved hazard identification Reduced completeness uncertainties Improved synergy with I&C community Knowledge Improved insights Current status U.S.
Technology development (e.g., integration of STAMP/STPA with conventional PRA)
International Activities include WGRISK benchmarking study Challenges Software CCF Data M. Porthin, et al., Comparative application of digital I&C modeling approaches for PSA, International Topical Meeting on Probabilistic Safety Assessment (PSA 2019), Charleston, SC, April 28-May 3, 2019.
WGRISK Benchmarking Study
14 Incorporation of Ageing Aspects Importance (Benefits)
Technology Capabilities should regulatory need arise Knowledge Improved insights Current status (U.S.)
Long history of R&D, no recent work Challenges Data Physics of failure modeling Other trends, e.g.,
Technology (NDE, prognostics, )
Workforce Fleet (unique reactors)
Incorporation in PRA Standards As good as new Analysis technology exists D. Rudland and C. Harrington, xLPR Pilot Study Report, NUREG-2110, 2012. (ML12145A470)
Blending mechanistic and statistical perspectives changes PRA approach?
Importance of burn-in?
15 Treatment of Uncertainties Importance (Benefits)
Analyses All risk-informed applications (operating reactors and new designs)
Technology Improved characterization methods Improved synergy with other technical communities Knowledge Improved insights Current status (U.S.)
Established methods and guidance Improvements being considered in R&D planning Challenges Quantitative assessment (model and completeness uncertainties), particularly for new designs Communication Model uncertainties can be characterized; consensus approach for quantification?
Adapted from NUREG-2156 From static (handoff) to dynamic (interaction)?