SSHAC Level 1 and 2 Studies: Procedures and Potential ...
Transcript of SSHAC Level 1 and 2 Studies: Procedures and Potential ...
SSHAC Level 1 and 2 Studies: Procedures and Potential
ApplicationsJon Ake
U.S. Nuclear Regulatory CommissionKevin CoppersmithCoppersmith Consulting
Miriam JuckettJohn Stamatakos
Center for Nuclear Waste Regulatory AnalysesJulian J. BommerImperial College London
DOE Natural Phenomena Hazards Meeting, October 18‐19, 2016
Overview of Presentation
• SSHAC goals and concepts• Participants in SSHAC Level 1 and 2 projects• Workflow and attributes of SSHAC Level 1 and 2 projects
• Potential applications and uses
SSHAC Guidelines and Guidance
NUREG‐2117 SSHAC Implementation Guidelines
Goal of a SSHAC Process“The fundamental goal of a SSHAC process is to properly
carry out and completely document the activities of evaluation and integration, defined as:
• Evaluation: The consideration of the complete set of data, models, and methods proposed by the larger technical community that are relevant to the hazard analysis.
• Integration: Representing the center, body, and range of technically defensible interpretations [CBR of the TDI] in light of the evaluation process (i.e., informed by the assessment of existing data, models, and methods).”
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NUREG‐2117
Key SSHAC ConceptsThese five features are essential for all SSHAC hazard studies regardless of the SSHAC Level and distinguish SSHAC studies from non‐SSHAC studies• Clearly defined roles for all participants, including the responsibilities and
attributes associated with each role.• Objective evaluation of all available data, models, and methods that could
be relevant to the characterization of the hazard at the site. • Integration of the outcome of the evaluation process into models that
reflect both the best estimate of each element of the hazard input with the current state of knowledge and the associated uncertainty. This distribution is referred to as the Center, Body, and Range of Technically‐Defensible Interpretations, or the CBR of the TDI.
• Documentation of the study with sufficient detail to allow reproduction of the hazard analyses.
• Independent participatory peer review is required to confirm that the evaluation did consider relevant data, models, and methods, and that the evaluation was conducted objectively and without bias. The peer review is conducted following a “participatory” or continual process throughout the entire project.
CBR of the TDI
SSHAC Level 1 Participants
Note: Multiple roles may be played by the same person
SSHAC Level 2 Participants
Note: Multiple roles may be played by the same person
SSHAC Level 1 Workflow
Role of PPRP in SL1 Studies
SSHAC Level 2 Workflow
Attributes of SL1 and SL2Level 1 Level 2
Peer Review At least two reviewers; Communication with PPRP during evaluation and integration
Two or more reviewers; Feedback on preliminary models
Technical Integration Team
Small TI Team (depending on nature and complexity of issues)
Small TI Team; possibly multiple teams (e.g., seismic source characterization and ground motion characterization)
Evaluation Sensitivity analysis to identify significant issues; Systematic review of literature
Outreach to proponents and resource experts (e.g., phone interviews)
Integration Develop models that capture the CBR of the TDI
TI Team interaction and hazard feedback during model‐building
Enhancements to SL2 StudiesLevel 1 Level 2 Level 2
EnhancementsLevel 3
Peer Review At least two reviewers; Communication with PPRP during evaluation and integration
Two or more reviewers; Feedback on preliminary models
One or more PPRP representative(s) observes: working meetings, TI Team interactions with external experts, and/or workshops
Ideally five reviewers; Engagement during evaluation and integration process; PPRP briefing of final model
Technical Integration Team
Small TI Team (depending on nature and complexity of issues)
Small TI Team; possibly multiple teams (e.g., seismic source characterization and ground motion characterization)
Larger TI Team Five or more TI Team members
Evaluation Sensitivity analysis to identify significant issues; Systematic review of literature
Outreach to proponents and resource experts (e.g., phone interviews)
Add Workshop #1, #2, or hybrid that includes resource experts and/or proponents
Two workshops with resource expert and proponents; Data summary tables
Integration Develop models that capture the CBR of the TDI
TI Team interaction and hazard feedback during model‐building
Add Workshop #3 with feedback from PPRP
PPRP briefing
*All attributes are cumulative moving from left to right on the table; Level 4 is essentially the same as Level 3 with respect to these attributes.
Uses of SL1 and SL2 Studies
• Site specific refinements to existing regional SL3 projects
• Applications for facilities with lower risk significance and lesser need for regulatory assurance
• Updating decisions regarding the hazard impact of new information
Potential Applications: Updating Existing PSHA
Next slide
Use of SL1 for Updating Decisions
Conclusions• All SSHAC Levels share common goals and basic processes
• Attributes and essential steps in SL1 and SL2 are defined and provided in the update to NUREG‐2117
• SL2 studies can be enhanced depending on project‐specific needs
• Applications include updating decisions:– See talks by Kammerer et al. and Payne et al. for actual applications at INL for several facilities
– See talk by Juckett et al. on update to NUREG‐2117