Summary of Draft NEI Guidance
- November 6, 2013GUIDELINES FOR PRIORITIZATION AND
SCHEDULING IMPLEMENTATION
Pre-Draft 1 – September 30, 2013
1
Cumulative Impact Management
Potential Issue
Identified
Update/
New Issue/
Drop
Periodic Update &
Emerging Issue
Assessment
Against Original Definition
Assessment
Issue
Definition
& Closure
Criteria*
Regulatory Analysis
· Adequate Protection
Determination
· Cost benefit
Determination#
Generic
Characterization
& Prioritization
Initiate
Regulatory
Action
Process
Enhancements
LEGEND
Drop/
Reassess
Site Specific Prioritization
& Integrated Schedule
NRC &
Industry Process/Action
Industry Process/Action
w/NRC Oversight
NRC Process
NOTES
*Includes development & publication of draft
implementing guidance
# Includes development of implementation
cost estimate based on earlier publication of
draft implementing guidance
DRAFT
Implementation
Purpose
•
•
•
•
•
Summarize guidance contents
Summarize work remaining
Provide overview of process
Provide basis of safety ranking
Discuss basis for confidence in
approach
• Next Steps
3
Guidance Table of Contents
1 Introduction
1.1 Purpose
1.2 Content of this Guidance Document
2 Definitions and Applicability of Terms
3 Process Considerations
3.1 Key Characteristics of the Process
3.2 Basic Approach to Prioritization
3.3 Philosophy
3.4 Guidelines from SDP
4 Implementation Guidance
4.1 Safety
4.2 Security (In draft)
4.3 Plant Personnel Safety (Partially developed; ALARA)
4.4 External Impacts (Not developed)
4.5 Aggregating Rankings (Not developed; comparable to SAMA)
4.6 Benefit-Cost Assessment (Generic characterization and plant-specific benefit-cost)
4.7 Generic Assessment Evaluation Team (Separate guidance in draft)
4.8 Integrated Decision Making Panel (Separate guidance in draft)
5 Integrated Implementation Scheduling (Build on typical processes used today)
6 Reassessment, Review and Reconciliation (Not developed; use typical processes)
7 Documentation (Not developed; use typical processes)
8 References
4
Appendices
Appendix A
Background - History and Relevant Reference Documents
Appendix B
Guidance for Step 1 (Screening for Beneficial or Adverse Effects)
Appendix C
Guidance for Step 2 (More Than Minimal)
Appendix D
Basis for Matrix
Appendix E
Guidance for Step 3A (Qualitative Assessment of VL, L, M, H)
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Overview of Prioritization Approach
• Safety impact is the primary focus
• SDP thresholds are used (reverse perspective)
• Regulatory issues and plant-initiated activities are prioritized into
broad categories spanning a decade
• Questions to focus assessment are based on risk informed
adaptation of NEI’s 96-07 (10CFR50.59) guidance and SDP
• Definition of “more than minimal” is consistent with RG 1.174
guidelines for small increase in risk and 10% change in initiator
frequency per 50.59 guidance
• Cost/benefit is a consideration consistent with Severe Accident
Mitigation Alternatives (SAMA) approach
6
Key Elements and Features of Prioritization
• Generic characterization of regulatory issues by expert
team
– Problem statement and potential solutions
– Considerations for plant-specific prioritization
– Assignment of generic priority to be determined
• Plant-specific evaluation
• Formal plant review by Integrated Decision-making
Panel like 50.65, 50.69, RITS 5b
• Inputs to integrated scheduling
7
Safety Ranking
• Current Relative Risk Level minus Projected
Relative Risk Level
• Relative Improvement Approach used for
Matrix
• Matrix includes Lower Bound, Midpoint and
Upper Bound to display Impact of Factor of 10
range (to address uncertainty considerations)
• Tabletops to Refine
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P-S Prioritization
Process
Guidance
9
Matrix by Current Risk and Potential Impact
UB is upper bound of the risk range; Mid is “mid-range” (0.3 times UB); LB is factor of 10 lower than UB
Current Risk associated
with Issue
Note: Address the specific
issue first; then assess
impacts on other risk
contributors potentially
impacted
Potential Impact of Action (Reduction in Risk)
None
Very Small/Minimal
Small
Medium
High
Comments
0%
0-25%
25-50%
50% to 90%
>90%
Can adjust these initial ranges
as appropriate
Outcome
Note: Quantitative values are delta CDF/LERF
Green (VL) LB
<VL/Green
<VL/Green
<VL/Green
<VL/Green
<VL/Green
No change
Green (VL) Mid
VL/Green
VL/Green
VL/Green
VL/Green
VL/Green
No change
Green (VL) UB
VL/Green
VL/Green
VL/Green
VL/Green
VL/Green
Maximum reduction is 1E-6/1E-7
White (L) LB
VL/Green
VL/Green
VL/Green
VL/Green
VL/Green
White (L) Mid
VL/Green
VL/Green
L/White
L/White
L/White
White above 25% Category
White (L) UB
VL/Green
L/White
L/White
L/White
L/White
Maximum reduction is 1E-5/1E-6
Yellow (M) LB
VL/Green
L/White
L/White
L/White
L/White
Yellow (M) Mid
VL/Green
L/White
M/Yellow
M/Yellow
M/Yellow
Only change is 25% Category
Yellow (M) UB
VL/Green
M/Yellow
M/Yellow
M/Yellow
M/Yellow
Maximum reduction is 1E-4/1E-5
Addressed by upper bound Yellow
Red (H) LB
?
M/Yellow
M/Yellow
M/Yellow
M/Yellow
Red (H) Mid
?
H/Red
H/Red
H/Red
H/Red
Red (H) UB
?
H/Red
H/Red
H/Red
H/Red
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Progressive Screening
• Step 1: No Impact or Adverse Impact?
• Step 2: Minimal Impact?
• Step 3A: Relative Impact versus Current
Relative Risk
-
Very Low
Low
Medium
High
• Step 3B: Quantitative
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Safety Evaluation Questions
(No, Adverse, Less than Minimal, Relative Impact)
1. Frequency of occurrence of an accident initiator?
2. Availability, reliability, or capability of SSCs and personnel relied upon to
mitigate a transient, accident, or natural hazard?
3. Consequences of an accident sequence?
4. Capability of a fission product barrier?
5. Improvement in defense-in-depth capability?
Examples include:
a. Strengthen balance of accident prevention and mitigation
b. Reduce reliance on programmatic activities
c. Reduce probabilities of common-cause failures
Note: Risk significance is also addressed in Steps 2 (minimal) and 3 (relative
change)
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Minimal Impact
• To be more than minimal the effect of a proposed
activity must be discernible and attributable to the
proposed activity
• An impact of delta CDF and LERF of less than 1E6/1E-7 per year respectively (SDP)
• Accident initiators contributing less than 1% of total
CDF/LERF (consistent with RG 1.174)
• Less than 10% change in frequency (as this is
insignificant and consistent with 50.59 guidance)
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Initiator Considerations
Initiator Categories
(Representative)
Risk
Significant?
No, Adverse, Less
than Minimal, L, M
H Impact?
Transients initiated by frontline
systems
Transients initiated by support
systems
Primary system integrity loss (e.g.
SGTR, RCP seal LOCA, LOCA)
Secondary system integrity loss
Internal flooding
Internal fires
Earthquakes
External flooding
Tornados and High Winds
Other External Hazards
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Considerations for each Initiator Potentially Affected
Considerations
Potential Action
Effect?
No, Adverse, Less
than Minimal, L, M,
H Impact?
Changes in maintenance, training
Changes in specific SSCs (e.g., installing a
more reliable component)
Changes in materials
Equipment replacements to address age
related degradation
Changes in redundancy and diversity
Addition of equipment
Changes in operating practices
15
SSCs Considerations
Considerations
Potential Action
Effect?
None, Adverse, Less
than Minimal, L, M, H
Impact?
Changes in maintenance, testing, training
Changes in specific SSCs (e.g., installing a more
reliable component)
Changes in materials
Equipment replacements to address age related
degradation
Changes in redundancy and diversity
Addition of equipment
Strengthening of equipment
Moving equipment (to reduce the impacts of spatial
events)
Eliminating the need for recovery action (RA)
Improving performance shaping factor related to
human performance
Changes in operating practices
16
Types of Models and Evaluation Tools - Large Tool Box
The appropriate model/tool will depend on the issue
• Qualitative checklist
• Comparison to a previously ranked issue (s) –which is
addressed by using a pairwise comparison
• Review of Previous Studies (e.g. SAMA and Issuespecific cost-benefit evaluations)
• Direct use of an existing PRA model
• Adaptation of an existing PRA model
• Development of a new PRA model (e.g. a focused
scope assessment)
• Direct, adaptive or new deterministic model, such as
to characterize margin in system capability
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Generic Assessment Expert Team (GAET)
• An expert team to assess issues and develop the generic
characterization of potential actions
• Comprised of Industry leaders supported by subject
matter experts (SMEs), as needed
• GAET uses available NRC and Industry information
• GAET uses the process in the framework of a Generic
Integrated Decision Making Panel (GIDP)
• Draft Guidance has been developed
•
•
•
•
Based on Integrated decision-making Panel approaches used for
Maintenance Rule
50.69
RI ISI
18
Generic Assessment Expert Team (GAET)
• Output of the GAET deliberations is
- A document of issue and significance
characterization, cost-benefit, and associated
bases
- Includes identification of plant-specific (P-S)
considerations which could influence the
significance on a P-S basis
• Actual structure, format, team makeup, etc. is to
be determined
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Plant-Specific Integrated Decision Making Panel
(P-S IDP)
• P-S IDP is used to support final rankings on a
plant-specific basis
• IDP would not establish prioritization
- Instead they should conduct a “peer” check
• For example, in addition to reviewing the
rankings developed by plant subject matter
experts (SMEs) and the outcome of the GAET
- The P-S IDP could conduct a pairwise comparison
• If the P-S IDP conducts the actual rankings, the
benefits of a peer check would not be achieved
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Summary
• Approach is based on proven risk-informed
approaches
- SDP
- In-service Inspection
- Use of an IDP
• SDPs and SAMAs are routinely completed
successfully
- Do not require significant effort
- We can repeat these successes on Cumulative Effects
• Comments, questions and piloting
• Refine Guidance
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Next Steps
• Perform Tabletops (weeks of Dec. 9 and 16)
• Potential Issues for Tabletops
-
NFPA-805
Security (physical and cyber)
A Fukushima issue (e.g., SFP Instrumentation)
GSI-191
RCP Seal
Station Blackout
Emergency Preparedness
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