ltsp sshac level 3 study - pg&e, pacific gas and electric · 1 pg&e dcpp sshac study ltsp...

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PG&E DCPP SSHAC Study

LTSP SSHAC Level 3 Study Workshop 1 – SSHAC and Workshop Rules

William Lettis November 29, 2011

PG&E DCPP SSHAC Study 2

• What is SSHAC?

- Objectives of the LTSP SSHAC Level 3 Study - Overview of SSHAC Process - SSHAC concept of (1) evaluation and (2) integration: capturing

views of informed technical community (ITC) and technically defensible interpretations (TDI)

- Workshop Structure and Ground Rules - Participant Roles and Responsibilities

SSHAC and Workshop Rules


LTSP SSHAC Level 3 Objectives

(1) Develop fully hazard-informed SSC and GMC models for

update of the Diablo Canyon PSHA

(2) Provide increased regulatory assurance that the PSHA adequately captures uncertainties in data and scientific knowledge

(3) Identify important data needs for reducing uncertainties in significant SSC and GMC parameters that can be fulfilled by the ongoing LTSP field and research programs

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1987-2008


The SSHAC Process

A structured framework and procedure for conducting

multiple-expert assessments of input to PSHA

Procedures defined by the Senior Seismic Hazard

Analysis Committee (SSHAC)


The SSHAC Process Several more recent updates on SSHAC Guidance (1) Hanks et al, 2009, Implementation of the SSHAC Guidelines for Level 3 and 4 PSHAs – Experience Gained from Actual Applications; USGS Open-File Report 2009-1093 (2) Coppersmith, Bommer, Kammerer and Ake, 2010, Implementation

Guidance for SSHAC Level 3 and 4 Processes; June 10, 2010 Probabilistic Safety Assessment and Management Conference

(3) Munson and Ake, 2010, Seismic Considerations for Western U.S. Sites June 16, 2010 ANS Conference (4) NRC, 2011, Practical Implementation Guidelines for SSHAC Level 3 and

4 Hazard Studies; Draft NUREG XXXX


SSHAC Objective

Develop a methodology for obtaining reproducible, stable estimates of probabilistic seismic hazard at a site, including explicit quantification of uncertainty • Focused on Process for assessing uncertainty in the

PSHA model input assessments and for quantifying the uncertainty in PSHA results

• “Stability” is achieved by properly characterizing and quantifying uncertainty

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SSHAC Basic Principles for a PSHA

Principle 1: The goal of a SSHAC is “to represent the center, the body, and the range of technical interpretations that the larger technical community would have if they were to conduct the study”

Termed the “informed technical community” (ITC) by Budnitz et al (1997)

Termed the range of “technically defensible interpretations” (TDI) by NRC (2011, Draft)


SSHAC Basic Principles for a PSHA (continued)

Principle 2: “It is absolutely necessary that there be a clear definition of ownership of the inputs into the PSHA, and hence ownership of the results of the PSHA”

• Ownership means intellectual responsibility • For SSHAC Level 3, Technical Integrator (TI) assumes

ownership – TI Team (Intellectual ownership) – As opposed to Owner/Sponsor (Project owner)


Define specific roles of all participants Develop and disseminate complete database Consider range of TDI in evaluating alternative models and uncertainties Encourage interactive debate and learning in structured setting • Documented Workshops and Information

Build SSC and GMC modes to represent center, body, and range of technically defensible interpretations Provide hazard sensitivity feedback to understand implications of preliminary models and uncertainties Conduct participatory (continual) peer review

Key Features of a SSHAC Process


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Diablo Canyon – SSHAC Level 3 Seismic Source and Ground Motion Characterization Project

Ground Rules for Workshops - The workshops are an opportunity for the TI team to: • Exchange data • Present interpretations • Challenge and defend technical hypotheses • Gain information on the project • Interact and ask questions Therefore, the focus of each workshop is for the TI Team Conduct of the technical discussions at the workshops will be at the highest professional level -Discussions will be among the TI team, Presenters and Experts - No Niggling (petty criticism, unimportant issues) - PPRP observers at Workshops 1 & 2, active participants in Workshops 3 & 4 - Meeting with PPRP at end of workshop for informal comments; to be followed by written comments - TI team runs the workshops and is responsible for keeping schedule, logistics, etc.


Probabilistic Seismic Hazard Analysis (PSHA)

Reiter (1990)

Source Geometry

Earthquake Recurrence

Seismic Source Characterization:

SSC Model

Ground Motion Characterization:

GMC Model


SSHAC Participants and Roles

SSHAC defines several key concepts and roles (Budnitz et al, 1997; NRC, 2011, Draft)

• Project Technical Integrator • Technical Integrator (TI) • Expert roles:

– Evaluator expert – Resource expert – Proponent expert – Hazard analyst – Database manager

• Participatory Peer Review Panel 8


Expert Roles

Project Technical Integrator An individual that serves as coordinator/facilitator of combined

SSC and GMC SSHAC Study; Interface with Project Manager and Project Sponsor

Technical Integrator An individual or small team of evaluator experts that serves as

integrator for the technical assessments Structures and documents information exchanges Stages effective debates and interactions in critical areas Responsible for capturing range of TDI and considering them in

the evaluation process Responsible for documentation Intellectual ownership of final model


TI Team Responsibilities

Evaluation • Identification of important issues and applicable data • Interaction with proponent and resource experts • Evaluate existing data, alternative models and methods from the

larger technical community, and need for additional information

Integration • Develop range of alternative models and uncertainties, given

available data and proponent viewpoints, that represent the center, body, and range of technically defensible interpretations

• Imagine community’s views if they had gone through the same evaluation process


Expert Roles (continued)

Resource Expert Personal knowledge of a particular data set, interpretation and/or hypothesis Active or past participant in research of a particular topic (issue or data set) Participates in professional community through meetings and literature Presents data and information without proponent bias


Expert Roles (continued)

Proponent Expert An expert who advocates a particular hypothesis, interpretation or model Common role in science Peer review in professional meetings and literature Opinions may range from mainstream to extreme (or outlier) views


Participatory Peer Review Panel

Participatory Peer Review Panel (PPRP) Panel of individuals with SSHAC and/or PSHA experience

that provide peer review of the SSHAC implementation process

PPRP need not necessarily have prior technical knowledge of the site but provides technical review of the PSHA input parameters and uncertainties

PPRP assures that the range of TDI is considered and evaluated through implementation of the SSHAC process


PPRP Responsibilities

Continual review of technical and process aspects of the project Technical • Quality of the databases developed or compiled? • Have all data, models, and methods within the techncial community

been considered? • Is the evaluation of the available data reasonable? • Has uncertainty been properly evaluated and captured in the

integration process? • Are models and assessments defensible and justified? Process • Are activities consistent with SSHAC-3 process? • Have available data, models, and methods been considered? • Is documentation complete and clear? Endorsement


Process and Technical R

eview

PPRP

Evaluation of M

odels to Form C

omposite D

istribution

TI Team Hazard

sensitivity calculations

Preliminary database

WORKSHOP 1: Significant Issues, Available Data and

Data Needs Resource Experts

Additional data collection & analysis

WORKSHOP 2: Alternative Models

Resource Experts (?)

Proponent Experts

Final database Preliminary SSC and GMC models

WORKSHOP 3: Presentation of Models and Hazard Sensitivity Feedback

Database C

ompilation

Technical Staff & Contractors

Evaluation Integration Workshop 4: Final Briefing SSC and GMC models, then final hazard

calculations, Documentation of all technical bases


LTSP SSHAC Level 3 Study

Activities Performed to Date Completion of Draft and Final Project Plan - Scope and Schedule - Including PPRP Review and Comment Identification of Project Participants/Contracts Completion of Initial Data Compilation and Sensitivity Analysis Completion of Workshop 0 – “Kickoff meeting, Project Plan and Significant Issues” Preparation for Workshop 1 – “Significant Issues, Available Data and Data Needs” - Document SSC V0 Model and GMC V0 Model - Identify Resource Experts and Discussion Topics - PPRP Review - Convene several SSC and GMC Working Meetings


Diablo canyon SSHAC Level 3 Project Plan

Project Plan includes (1) Formal Structured Workshops with Resource and

Proponent Experts (2) Working Meetings of the SSC and GMC TI Teams (3) Interface opportunities between the GMC and SSC TI

Teams and ongoing DCPP field and research programs (4) Comprehensive documented SSC and GMC database (5) Explicit process of Evaluation and Integration (6) Continual participatory peer review

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LTSP SSHAC Organization


Workshop 0 – Kick-off Meeting, Project Plan, Significant Issues

Workshop 1 – Significant Issues, Available Data, Data Needs - Resource Experts Workshop 2 – Alternative Models and Proponent Interpretations

- Proponent Experts

Workshop 3a, b, c – Preliminary Model and Hazard Sensitivity

Workshop 4 – Final Model Briefing

LTSP SSHAC Level 3 Workshops


LTSP SSHAC Level 3 Study

Workshop 1 – Significant Issues, Available Data and Data Needs • Goals Identify significant technical issues important to hazard Provide an opportunity for the TI team to understand available data

relevant significant technical issues Identify additional data needs or data gaps to address significant

issues or uncertainties

- Presentations of data and interpretations directly from the Resource Experts, including discussion topics requested by the TI team

- Question/answer period

Attendees: TI Staff, Evaluator Team, PPRP, Resource Experts and Hazard Analyst.

Length: 3 days.

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LTSP SSHAC Level 3 Focussed Investigations

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Diablo Canyon SSHAC Level 3 Study

Workshop 1 – SSHAC Training

Questions and Comments?


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LTSP SSHAC Level 3 Study Workshop 0 – Kick-off Meeting, Project Plan and Significant Issues

Goals of the workshop - Introduce participants - Introduce projects goals, expectations, schedule - Review Project Plan - Identify key hazard-significant SSC and GMC issues - Review available data, including availability, formats, quality, and uncertainties - Identify Resource Experts for Workshop 1 and Tentative Proponent Experts for Workshop 2 - Identify the project path forward - PPRP feedback and comments


DCPP SSHAC Level 3 – Project Schedule


Regulatory Basis for SSHAC SSHAC Provides an Accepted Assessment Process

The principal geologic and seismic considerations for site suitability and engineering criteria are given in 10 CFR 100.23 and Appendix S to Part 50. -- 10 CFR 100.23 identifies a PSHA as an acceptable means to address the - uncertainties in determination of the SSE.

Regulatory Guide 1.208 provides more detailed guidance on: - Investigations and applications of PSHA and development of the ground motion

response spectra (GMRS). - Application of the Senior Seismic Hazard Analysis Committee (SSHAC)

guidelines for determination of source characterization and GMPEs (NUREG/CR-6372)

- Integrated site response (NUREG/CR-6728) - RG 1.208 states: “The guidelines detailed in NUREG/CR-6372 should be

incorporated into the PSHA process to the extent possible.”

ANS/ANSI Standards 2.27 (Criteria for Investigations of Nuclear Facility Sites for Seismic Hazard Assessments) and 2.29 (Probabilistic Seismic Hazards Analysis) have been issued subsequent to the publication of RG 1.208 Detailed implementation guidance for Study Level 3 and 4 projects (NRC 2011, NUREG, in draft)

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William Lettis November 29, 2011


Workshop 1 – Project plan and

Schedule


Diablo Canyon SSHAC Level 3 Scope Review of Draft Project Plan and Schedule

Outline of project plan • Objectives • Description of SSHAC Methodology • Selection of SSHAC Level • Project Organization • Work Plan • Schedule • Quality Assurance

Conforms to Kammerer and Ake (2011) Draft NUREG Subject to PPRP Review and Revision

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Diablo Canyon SSHAC Level 3 Objectives

(1) Develop fully hazard-informed SSC and GMC models for use in

the Blue Castle PSHA for development of site GMRS (2) Provide regulatory assurance that the site PSHA adequately

captures uncertainties in data and scientific knowledge (3) Identify important data needs for reducing uncertainties in

significant SSC and GMC parameters that can be fulfilled by the ongoing Diablo Canyon field and research program

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Selection of SSHAC Level 3 (1) SSHAC Methodology defines four different levels of study distinguished

by increasing level of sophistication, resources, and participation by technical experts

(2) NRC expectations are that a SSHAC Level 3 or 4 study will be performed for sites in the WUS in areas where a similar level study has not previously been performed and accepted by the NRC

(3) A SSHAC Level 3 or 4 study should be performed in regions of - active, complex tectonic settings

- Potential for significant public impact/scrutiny - Significant Regulatory scrutiny

(4) Based on this guidance a SSHAC Level 3 study has been selected for the DCPP LTSP Update

(5) A SSHAC Level 4 study is not being used because of (1) significantly increased schedule requirement, (2) Iterative process of Evaluation and Integration, and (3) relatively minor increase in regulatory assurance associated with a Level 4 study

(6) - “From the regulatory perspective of the NRC, there is no essential difference between Level 3 and 4 studies” (NRC, 2011, Draft NUREG)

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SSHAC Level 3 Workshops (cont’d)

Workshops 2a, b and c – Preliminary Model and Hazard Feedback Workshops - Present preliminary logic tree of alternative models including discussion of epistemic uncertainty - Iterative process of data acquisition, evaluation and integration for each workshop - Present sensitivity analyses by Hazard Analyst - Identify additional sensitivity analyses to be performed by Hazard Analyst (if any) Attendees: Same as Workshop 1 (selected Resource and Proponent Experts only) Length: 1 to 2 days - Working meetings to develop V2, V3 and Final models and for Hazard Analyst to perform sensitivity analyses

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SSHAC Level 3 Workshops (cont’d)

Workshop 3 – Final Model and Hazard Feedback Workshop - Present Final SSC V4 and GMC V2 Models - Present final hazard sensitivity results - Finalize fault data sheets and SSC and GMC documentation Attendees: TI Staff, Evaluator team, PPRP, Hazard Analyst and selected resource and/or proponent expert observers Length: 1 to 2 days - Working meetings to develop Final Model (incorporating final PPRP comments)

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SSHAC Level 3 Workshops (cont’d) Final Briefing Meeting – Presentation of Final Model - Present Final logic tree of alternative models for SSC and GMC for use in the LTSP PSHA Update Attendees: TI Staff, Evaluator team, PPRP Length: 1 day

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Data Summary Tables


Data Evaluation Tables


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Thank You

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