ML20245E147
| ML20245E147 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 08/31/2020 |
| From: | Nuclear Energy Institute |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML20245E147 (14) | |
Text
20-XX NEI Guidelines for the Implementation of the Risk-Informed Process for Evaluations Integrated Decision-Making Panel Prepared by the Nuclear Energy Institute August 2020
© NEI 2020. All rights reserved. nei.org
1.0 OVERVIEW Implementation of the NRCs Risk Informed Process for Evaluations (RIPE) allows for characterization of the safety impact of issues (e.g., non-compliances) at licensee facilities as having minimal safety impact such that streamlined regulatory review process can be requested from the NRC by the licensee [1]. The streamlined regulatory review process consists of an expedited review of licensing action requests, exemption requests, responses to orders, or responses to generic issues. For licensees to use this approach for Low Safety Significance Issue Resolution (LSSIR), there is a requirement to explore the issue in detail at a plant level using an Integrated Decision-making Panel (IDP). This report provides guidance for the development and implementation of a plant specific IDP for LSSIR purposes.
The review may be at an industry level through a generic assessment expert team (GAET) or a plant IDP. A GAET assesses the issue at a broader level and a plant wishing to use a GAET evaluation must determine the applicability to the plant as part of the review.
The GAET evaluation characterizes the importance of the regulatory issue at a generic level and provides an overall assessment and important attributes for consideration in the plant-specific evaluation.
The plant-specific process is carried out with the use of a plant IDP, which reviews the generic characterization provided by the GAET and the plant-specific evaluation provided by a plant Subject Matter Expert (SME), to arrive at plant-specific safety impact characterization. This safety impact is characterized as having either no impact or minimal impact.
2.0 IDP (INTEGRATED DECISION-MAKING PANEL) REQUIREMENT The RIPE methodology requires review by an IDP. If the IDP determines low safety impact, the issue is submitted under the LSSIR process to the NRC. If the IDP does not determine the issue is of low safety impact, it is processed per normal methods.
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The potential impact of the issue is explored in depth by a multi-disciplinary team of experts, the IDP. This team of experts is responsible for ensuring the issue is fully defined and all the potential safety impacts have been identified. If the team identifies that it needs additional information in order to make a final recommendation regarding the safety impact, additional experts should be consulted. The goal of this review is to identify and review all the available information regarding the issue and characterize its safety impact appropriately.
An example IDP charter is provided in Appendix A.
3.0 IDP OR GAET COMPOSITION 3.1 GAET composition The generic evaluation may be carried out by an industry expert team in combination with an NRC expert team or individually by the NRC or industry.
The GAET is comprised of industry or NRC experts with relevant expertise about the issue being evaluated. The GAET composition will vary depending upon the issue.
Generally, the GAET is composed of knowledgeable personnel whose expertise represents the important process and functional elements of the industry and regulatory processes, such as operations, engineering, nuclear risk management, industry operating experience, and licensing. The GAET members are expected to have the essential understanding of the issues safety impact, and familiarity with the safety impact characterization process guidance and approach. The team can call upon additional personnel, SMEs, or external consultants, as necessary, to assist in the characterization of issues. Experience, plant knowledge, familiarity with current regulatory issues, and availability to attend the most meetings, are important elements in the selection of GAET members.
In general, there should be at least five experts designated as members of the GAET with joint expertise in the following fields:
- Plant operations
- Design and systems engineering Page 3 of 14
- Safety analysis
- PRA and Risk-Informed decision-making
- Licensing
- Other SMEs as needed 3.2 IDP composition The composition of the plant IDP is the same as for the GAET, except that the members of the plant IDP and the SME for the plant IDP should have plant-specific knowledge and experience. In general, consistent with other licensee expert panels, there should be experts designated as members of the plant IDP:
- Engineering Manager
- Maintenance Manager
- Operations Manager (ideally SRO qualified)
- Risk Management (PRA) Engineer
- Systems Engineering Representative
- Safety Analysis Representative
- Licensing Representative Additionally, an SME knowledgeable in the technical disciplines relevant to the issue being evaluated should function as the lead presenter of the regulatory issue to the plant IDP.
There should be a primary member and qualified alternate for each IDP position to ensure availability of a panel when needed; only qualified alternates may serve on the IDP. A minimum quorum should be defined, including any specific members presence based on the issue to be evaluated. The presenter or other designated person such as the chair should ensure that the results of the plant IDP deliberation are documented and records are maintained. A member should be designated to chair the meeting. This may vary depending on the issue to be evaluated or one member may be designated as permanent chair.
Members may be experts in more than one field; however, excessive reliance on any one members judgment should be avoided.
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The panel can call upon additional plant personnel or external consultants, as necessary, to assist in the resolution of issues.
3.3 Member Background / Qualifications The IDP is composed of knowledgeable plant personnel whose expertise represents the important process and functional elements of the plant organization, such as operations, engineering, nuclear risk management, industry operating experience, licensing and maintenance.
The plant IDP members should be familiar with and preferably have experience with a plant SFCP IDP or maintenance rule expert panel so that they understand the consensus decision-making process.
The plant IDP should be aware of the benefits and limitations of the plant-specific PRA and other analyses, and, where necessary, should receive training on the plant-specific PRA, its assumptions, and appropriate implementation. This training facilitates making well-supported technical assumptions whether quantitative or qualitative information is used.
4.0 DOCUMENTATION 4.1 IDP and GAET Package If a generic assessment is available, this assessment is used by the SME as a key input into the plant-specific assessment, along with relevant plant-specific information. The SME should provide its evaluation and present the results of the preliminary screening questions and preliminary risk evaluation to the plant IDP. The SME should take responsibility to ensure that all relevant generic and plant-specific documents are available to the plant IDP.
The IDP package should include:
- Complete description of the issue,
- The portion of the issue to be addressed,
- The preliminary screening and basis,
- The PRA analysis, if applicable, Page 5 of 14
- Input for the final screening,
- Any additional analyses or information relevant to the issue.
The preliminary and final screening determinations are made based on the technical information supporting the issue. Technical or engineering information should demonstrate that the issue has no adverse effect on functions, or there are methods of performing or controlling functions may be used as a basis for screening the issue.
4.2 IDP and GAET Evaluation Results GAET: The GAET evaluation results, including a description of any important considerations that should be addressed in the plant-specific assessment, will be documented and provided to the industry and the NRC. Documentation will be maintained to facilitate any subsequent generic update or re-evaluation of the issue, as appropriate.
The GAET should document any considerations and characteristics that may affect the plant-specific assessment, particularly for safety. For example, the GAET may determine that based on reactor fleet considerations, the existing level of risk of an external hazard initiator is 10-5 to 10-4/yr CDF on average. If information is available, the GAET would convey what attributes could make the plant-specific assessment higher or lower.
IDP: The IDP evaluation results, including a summary of the basis for each decision will be documented and provided to the NRC. In particular, the assessment of any GAET-identified important considerations and how they apply to the plant and a basis for any plant-specific departures from the GAET assessment should be noted if a there is a GAET evaluation associated with the issue. The level of documentation should be such that a sufficient basis is provided for a knowledgeable individual to independently review the information and reach the same conclusion. The basis for any engineering judgment and the logic used in the assessment should be documented to the extent practicable and to a degree commensurate with the safety impact and complexity of the issue. The items considered by the GAET, SME, and IDP must be clearly stated.
For each issue, licensees should maintain:
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- A copy of the generic package, if applicable
- Summary of the plant IDP discussion on the issue
- Revised copy of the package, if applicable
- Final safety impact characterization assigned to the issue 5.0 DECISIONMAKING PROCESS In order to have a full understanding of the issue being characterized, all questions in each applicable step of the guidance should be answered, even if an initial yes response has already determined the outcome of that step. All aspects of the issues should be discussed and challenged to ensure that the all aspects of potential safety impact are included.
A consensus process should be used for decision-making for both GAET and plant IDP.
Differing opinions should be documented and resolved. However, a simple majority of the panel is enough for final decisions regarding the safety impact of the issues. The plant IDP should apply objective criteria and minimize subjectivity.
5.1 GAET Evaluation A GAET evaluation should consider the full scope of licensees that fall within the evaluation. For example, if this issue affects PWRs, does the PRA evaluation cover all PWR types (CE, Westinghouse, B&W)? If not, the applicability should be stated as limited to those included in the analysis.
The responses and the basis for the initial screening questions should be reviewed:
- Are there qualitative aspects that are not addressed by the quantitative PRA analysis and would affect the safety impact determination?
- Are there differences in the results for different reactor types?
- Are there assumptions or limitations in the PRA analysis that may change the result to not insignificant? If so, were they addressed by sensitivity Page 7 of 14
analyses?
- Are there any risk management actions that are being credited to mitigate the risk?
5.2 IDP Roles & Responsibilities
- 1. Review the guideline Figure 4-1 [Ref. 1] to ensure that the flow chart pathway selected by the presenter(s) is correct for the specific issue.
- 2. Review the quantitative PRA results (if applicable) and relevant qualitative considerations.
- 3. Review the response to the screening questions. Qualitative considerations include, but are not limited to:
a) Test and performance history of the components and system associated with the issue.
b) Past industry and plant-specific experience with the functions affected by the issue (GAET).
c) Impact on defense-in-depth protection.
d) Applicable industry codes and standards requirements and their basis.
e) Impact of an SSC in an adverse or harsh environment.
f) Capability of detection at of potential mechanisms and degradations that can lead to common cause failures.
g) Assumptions in the plant licensing basis would not be invalidated.
include assumptions beyond those directly associated with the issue.
5.3 IDP Evaluation The plant IDP reviews the initial characterization of the issue provided by the SME and is responsible for providing the final safety impact characterization. The final safety impact characterization consists of assessing:
- Final screening questions
- Final risk impact using a PRA Both of these activities are essential to characterizing the safety impact of the issue.
The final screening questions are similar to the preliminary screening questions; the supporting information is therefore similar. The final screening questions have two basic steps: 1) a series of screening questions to address whether there is any adverse impact to safety, and 2) a series of similar screening questions to address whether the impact to safety is minimal.
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Screening determinations are made based on the technical information supporting the issue. Technical or engineering information that demonstrates that the issue has no adverse effect on functions, or methods of performing or controlling functions may be used as a basis for screening the issue.
Figure 4-1 in Reference 1 provides a detailed overview of the safety impact characterization process. The IDP should discuss the relationship between the GAET review and conclusions and the how it is applicable to the specific plant, any identify any differences that will affect the deliberation. The preliminary safety impact screening information generated including consideration of the role of the impacted function in the plant-specific risk analyses and defense-in-depth, is provided to the IDP for review.
If a GAET evaluation is part of the basis, the IDP should confirm that the GAET evaluation applicability to that plant has been appropriately considered. (For example, a GAET evaluation for an AFW related issue should consider if the plant AFW design is the same as that assumed in the GEAT analysis, or if the differences, such as motive force for the pumps, affect the analysis.)
In order to fully understand the safety impact of an issue and account for relevant insights in an integrated manner, the IDP should consider the following important common elements:
- Ensuring the issue is well-defined Although the goal of the overall process is to have clearly defined issues prior to evaluation by the GAET or IDP, the actual assessment may indicate that additional definition is appropriate. As the assessment progresses to subsequent steps, the actual conduct of the assessment may identify additional considerations not identified in the initial definition(s). Thus, it is critical that the specific issue is appropriately defined and communicated in order to illustrate the safety impact due to the issue.
- Being realistic as to not bias the assessment The level of realism and analyses will vary depending on the issue, but in order to avoid bias, realistic analysis is the objective. The process should include sensitivity analyses to address the key assumptions and sources of uncertainty that are driving the results. If the risk impact is exceedingly small, or clearly large, then a bounding evaluation may suffice.
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- Considering uncertainty Both the GAET and IDP need to be aware of any specific issues, including external events, for which there is uncertainty. Sensitivity analysis should be performed, commensurate with the impact of the issue, to address any key assumptions and sources of uncertainty that may influence the results.
- Evaluating the overall nature of the risk impact of a potential action Both beneficial and adverse effects should be considered (e.g., replacing a small pump with a large pump could reduce the available margin of an emergency diesel generator, or closing and depowering pressurizer power operated relief valve block valves to prevent spurious operation could reduce effectiveness of feed and bleed operations).
- Identifying the extent of the impact The specific intended impact of the issue, as well as other related or indirect effects, should be considered (e.g., FLEX provides mitigation for more than external hazards even though that is its fundamental intended purpose). In other words, one specific issue could impact the specific function under consideration as well as multiple other separate plant functions. As discussed above, this could include both positive and negative impacts that may not be immediately evident if the impacts of issue are considered independently.
- Evaluation of relevant RMAs Are RMAs being included (or do they need to be included)? Are they effective at managing the issue? Are mechanisms described that the actions cannot be removed without reference to the issue?
For each of the final screening questions determine the response (Y/N) and the basis for it. The basis should be detailed enough that the conclusion can be reached by a reviewer whether or the NRC is involved in the initial evaluation.
At the end of the review of the material provided and responding to the final screening questions the IDP should reach a consensus on whether the issue can be considered as low safety impact. Any differing opinions should be included in the documentation of the meeting.
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6.0 PROCESS DOCUMENTATION The plant IDP should be described in a plant administrative procedure that includes the designated chairman, panel members, and panel alternates; required training and expectations for the chairman, members, and alternates; requirements for a quorum; attendance records; agendas; and meeting minutes.
The licensee should establish and document specific requirements for ensuring adequate expertise levels of IDP members and ensure that expertise levels are maintained. Two key areas of expertise to be emphasized are experience at the specific plant being evaluated and experience with the plant-specific risk information.
The IDP should be aware of the limitations of the plant specific PRA and, where necessary, should receive training on the plant specific PRA, its assumptions, and limitations. This training is for IDP familiarity (i.e., it is not intended to make the IDP PRA experts).
The IDP should be trained in the specific technical aspects and requirements related to the RIPE process. Training should address:
- The purpose of the safety impact determination, the RIPE process, the Risk-Informed defense-in-depth philosophy and criteria to maintain this philosophy,
- PRA fundamentals including o Details of the plant-specific PRA analyses that are relied upon for the preliminary categorization, including
- the modeling scope and assumptions,
- interpretation of risk importance measures, and
- the role of sensitivity studies and change in risk evaluations
- The IDP process, including roles and responsibilities.
Each of these topics should be covered to the extent necessary to provide the IDP with a level of knowledge sufficient to evaluate and approve safety impact using both probabilistic and deterministic information.
IDP decision criteria for categorizing issues as low safety impact should be documented.
A consensus process should be used for decision-making. Differing opinions should be documented and resolved, if possible.
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7.0 REFERENCES
- 1. U.S. Nuclear Regulatory Commission, Guidelines for Characterizing the Safety Impact of Issues, Draft, ADAMS Accession Number ML20118C231.
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APPENDIX A: SAMPLE PLANT IDP CHARTER FOR RISK INFORMED PROCESS FOR EVALUATIONS (RIPE)
Overview The RIPE pursues expedited review by the NRC of low safety impact issues. NEI has developed a Risk-Informed methodology for determining the safety impact of an issue.
The RIPE methodology requires review by an Integrated Decision-making Panel (IDP).
This charter provides an overview of IDP composition, roles and responsibilities per the guideline.
IDP is comprised of the following individuals, or their designated alternates :
- Engineering Manager
- Maintenance Manager
- Operations Manager (ideally SRO qualified)
- Risk Management (PRA) Engineer
- Systems Engineering Representative
- Safety Analysis Representative
- Licensing Representative Additionally, an SME knowledgeable in the technical disciplines relevant to the issue being evaluated should function as the lead presenter of the regulatory issue to the plant IDP.
IDP Roles & Responsibilities
- 1. Ensure the issue is fully defined and all the potential safety impacts have been identified.
- 2. If the team identifies that it needs additional information in order to make a final recommendation regarding the safety impact, additional experts should be consulted.
- 3. Review preliminary screening information
- 4. Review PRA analysis, if applicable
- 5. Review the generic characterization provided by the GAET if applicable
- 6. Review all the available information regarding the issue and characterize its safety impact. This safety impact is characterized as having either no Page 13 of 14
impact or minimal impact.
- 7. Document the decision and its basis.
Approval/Disapproval
- 1. If the IDP determines the issue is low safety impact, the issue may be submitted to the NRC for expedited review.
- 2. If the IDP determines that the issue is NOT low safety impact, the issue must be submitted via normal processes to the NRC (no expedited review).
- 3. if the IDP determines that additional information is required to make its determination, no decision is made until the information is provided to the IDP.
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