| Table # | Technical Issue | Affected Supporting Requirements | General Position | Supporting Requirement | Position | Discussion |
|---|---|---|---|---|---|---|
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Site-Specific Features and Characteristics | Clarification: SFR-C2, SFR-C4, SFR-C5, SFR-C6, EXT-C2, XHA-A1 Qualification: SHA-A1, SHA-A2, SHA-A3, SHA-A4, SHA-A5, SHA-B1, SHA-B2, SHA-B3, SHA-C1, SHA-C2, SHA-C3, SHA-C4, SHA-D1, SHA-D2, SHA-D3, SHA-D4, SHA-E1, SHA-E2, SHA-F1, SHA-F2, SHA-F3, SHA-G1, SHA-H, SHA-I, SFR-C1, EXT-A2, WHA-A1, WHA-A2, WHA-A3, WHA-A4, WHA-A5, SPR-B1, WPR-B2, XFHA-A1, XFHA-A2, XFHA-A3, XFHA-A4, XFHA-A5, XFHA-A6, XFPR-B1, XFPR-B2 | The staff recognizes that DC applications will not have regional or site-specific information on which to base their external hazard PRA/analysis or to ensure the information characterizes all credible hazards/sources at the site. DC applicants will typically establish site characteristics and site interface requirements upon which the specific hazards analysis will be performed. For COL applications, site-specific information will be available to address the supporting requirement directly and/or confirm that the DC analysis bounds the actual site and regional characteristics. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Screening Events/Hazards for Analysis | Clarification: EXT-B4 Qualification: IE-C6, QU-D8, LE-F2, IFSN-A12, IFSN-A13, IFSN-A14, IFSN-A15, IFSN-A16, IFQU-A12, QNS-A1, QNS-C1, EXT-B1, EXT-B2, EXT-B3, EXT-C1, WPR-A6, XFPR-A6, XPR-A6 | The staff recognizes that DC applications will not have regional or site-specific information on which to base the screening of external hazards or to ensure the information characterizes all credible hazards/sources at the site. DC applicants will establish site characteristics and site interface requirements on which specific hazards will be screened from further analysis. For COL applications, the site-specific conditions can be assessed to determine if there are additional hazards to consider. However, when performing this screening analysis, the qualitative and quantitative criteria (provided directly or as implied) in the PRA Standard should not be used for internal and external events/hazards. This is because of the potentially low plant CDF and LRF. Screening based on the PRA Standard’s cited CDF criteria is not appropriate for ALWRs because it infers a CDF of up to about 1×10-6/year and some qualitative criteria for screening external hazards can be even higher, which might be orders of magnitude greater than the base CDF at the site. The current version of the PRA standard does not identify unique screening criteria for new reactor designs that can have substantially lower risk profiles (e.g., plants with internal events CDF well below 1×10-6/year). As stated in RG 1.200, the quantitative screening value should be adjusted according to the relative baseline risk value. Therefore, screening values lower than those in the PRA Standard need to be used commensurate with the lower CDF and LRF estimates expected for ALWRs. A number of supporting requirements are identified as not applicable and should not be used for screening purposes or are identified as needing to be replaced or enhanced with the criteria provided in the clarification. In addition, to ensure that internal and external hazard screening does not result in the screened out contribution being significant relative to the risk of the hazard group, a number of supporting requirements were enhanced (or new supporting requirements created) to check for this condition. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Plant-Specific Layouts and Capabilities | Clarification: FSS-F1, FSS-F3 Qualification: CS-A2, CS-A3, CS-A4, CS-A5, CS-A6, CS-A7, CS-A8, CS-A9, CS-B1, FSS-F2 | If the DC or COL applicant has specific information regarding equipment locations and layouts and cable routing, then these supporting requirements can be achieved. However, the staff recognizes that DC and COL applications might not have some plant-specific information; particularly associated with equipment layout and locations and cable routing. Under these conditions, the applicant will likely use design and operational guidance documents, general good engineering practices, and “exclusion” approaches in their analyses, which are acceptable to the staff. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Plant-Specific Operating Experience and Data | Clarification: IE-A3, IE-C2, IE-C4, DA-C4, DA-C10, DA-C11, DA-C12, DA-C13, DA-C16, DA-D8, IGN-A6 IGN-B4 Qualification: DA-C2, DA-C3, DA-C5, DA-C6 | The staff recognizes that DC and COL applications will not have plant-specific operating experience and associated data on which to base component failure rates and maintenance, surveillance, testing, and train realignment frequencies. That being the case, applicants either cannot meet the supporting requirement or, for cases in which the supporting requirement is conditioned on another supporting requirement, it is not applicable. The applicants should address these supporting requirements using generic data and general industry operating practices and documenting the assumptions used in developing their PRA. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Plant-Specific Guidance (Procedures, Operating Practices, etc.) | Clarification: IE-C3, IE-C11, IE-C14, AS-A5, SC-A6, SY-A2, SY-A3, SY-A19, SY-A20, SY-B12, SY-B15, HR-A1, HR-A2, HR-A3, HR-D4, HR-D5, HR-E1, HR-E2, HR-F2, HR-G4, HR-G6, HR-H2, QU-D2, LE-D6, IFSN-A3, ES-A1, HRA-A2, HRA-B3 Qualification: WPR-A11, XFPR-A11, XPR-A11 | The staff recognizes that for the DC and COL application stages, plant-specific procedures and operating practices will not exist. The staff recognizes that the PRA at these stages will be based on design and operational guidance documents and typical industry practices, appropriate for that stage. That being the case, the staff believes applicants can meet these supporting requirements using general industry practices and design and operational guidance. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Interviews | Clarification: SY-A2, SY-A4, HR-E3, HRA-A4 Qualification: HR-E4, SF-A5 | There appear to be only a few supporting requirements that specifically require interviews or reviews to achieve CC I in the PRA Standard (and one other, SY-A2, identifies interviews as part of a list of sources of information). Most of the supporting requirements that require the review of procedure interpretations or confirmation that the system model reflects the design of the system can be achieved through interviews of knowledgeable design and/or plant personnel, appropriate for that stage. The staff also recognizes that, for DC and COL applications, the model will be based on design and guidance documents. Only SF-A5, which involves the review of plant fire brigade training procedure to establish the extent to which these procedures have prepared the personnel to respond to a fire, is not feasible at these application stages. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Walkdowns | Clarification: PP-B7, FSS-D10, FSS-D11, FSS-H10, SFR-E1, SFR-E2, SFR-E3, EXT-D1, EXT-D2, Qualification: IFPP-A5, IFSO-A6, IFSN-A17, IFQU-A11, SFR-D1, SFR-E4, SFR-E5, SPR-B11, WFR-A1, XFFR-A1, XFR-A2 | The staff recognizes that, for DC and COL applications, walkdowns will not be able to be performed in most cases to collect or verify the information regarding specific site and design characteristics and features. The information considered in the PRA should be based on the available design and operational information for that stage. | |||
| Table 1 - Challenges to Meeting Capability Category I of the PRA Standard for an ALWR DC Application and COL Application | Treatment of Uncertainties | Qualification: IE-D1, IE-D3, AS-C1, AS-C3, SC-C1, SC-C3, SY-C1, SY-C3, HR-I1, HR-I3, DA-E1, DA-E3, QU-F1, QU-F4, LE-G1, LE-G4, IFPP-B1, IFPP-B3, IFSO-B1, IFSO-B3, IFSN-B1, IFSN-B3, IFEV-B1, IFEV-B3, IFQU-B1, IFQU-B3, PP-C1, PP-C3, ES-D1, ES-D2, CS-C1, CS-C2, CS-C3, CS-C4, CS-C5, QLS-B2, QLS-B4, PRM-C1, PRM-C2, FSS-H9, FSS-H11, IGN-B1, IGN-B3, IGN-B5, QNS-D1, QNS-D2, QNS-D3, CF-B1, CF-B2, HRA-E1, HRA-E2, SF-B1, SF-B2, FQ-F1, FQ-F3, UNC-B1, UNC-B2, SHA-J1, SHA-J3, SFR-G1, SFR-G3, SPR-F1, SPR-F3, EXT-E1, EXT-E3, WHA-B1, WHA-B3, WFR-B1, WFR-B3, WPR-C1, WPR-C3, XFHA-B1, XFHA-B3, XFFR-B1, XFFR-B3, XFPR-C1, XFPR-C3, XHA-B1, XHA-B3, XFR-B1, XFR-B3, XPR-C1, XPR-C3 | The staff recognizes that both increased uncertainty and reliance on more assumptions are associated with these application stages because of the status of the site, design, operational, and maintenance information and data. This additional uncertainty needs to be addressed in two aspects of how the supporting requirements are documented. First, by enhancing the existing supporting requirement related to documenting aspects that facilitate PRA applications, upgrades, and peer reviews, with the requirement to document limitations, and their bases, which would impact risk-informed applications because of the status of the site, design, operational, and maintenance information and data. (This might also include a discussion of sensitivity studies performed to provide a perspective on these impacts.) Second, by enhancing the existing supporting requirement related to characterizing the sources of model uncertainty and related assumptions with the requirement to document the additional sources of uncertainty and assumptions specifically related to the status of the design, site, operational, and maintenance information or data. For a few technical elements, it was necessary to develop a new supporting requirement to capture one or both of these enhancements. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-IE-A | The initiating event analysis shall provide a reasonably complete identification of initiating events. | The initiating event analysis shall provide a reasonably complete identification of initiating events. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A2 | Clarification | DC applicants may make assumptions regarding the design of some of the support systems (e.g., service water ultimate heat sink) to address the special initiators, while the COL applicant can more directly address the site-specific support system initiators if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A3 | Clarification | No plant-specific experience is available during these application stages. Because the objective of this supporting requirement is to ensure that the list of initiators is as complete as possible, and IE-A4 addresses the review of generic analysis of similar plants, this supporting requirement is Not Applicable. Therefore, the applicant does not need to address this supporting requirement. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A4 | Clarification | For most DC and COL applicants, there may be generic analysis of similar plants at the application stage. The supporting requirement is using this information to ensure that the list of initiators is as complete as possible in reflecting relevant industry experience. If there is no similar plant generic analysis, then the supporting requirement is Not Applicable and these applications do not need to address this supporting requirement. If there is similar plant generic analysis available, then the supporting requirement is feasible to meet as written. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A5 | Clarification | DC applicants may make assumptions regarding the design of some of the support systems though the impact of the loss of the system (or train of the system) can still be evaluated. The COL applicant can more directly address the site-specific support system design if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A6 | Clarification | DC applicants may make assumptions regarding the design of some of the support systems though the impact of the loss of the system (or train of the system) can still be evaluated. The COL applicant can more directly address the site-specific support-system design if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A7 | Clarification | For most DC and COL applicants, there will be no plant-specific experience, but there may be generic experience, to draw from at the application stage. The supporting requirement is using this information to ensure that the list of initiators is as complete as possible in reflecting relevant experience. If there is no relevant experience (including similar plant experience), then the supporting requirement is Not Applicable and these applications do not need to address this supporting requirement. If relevant generic experience (including similar plant experience) is available, then the supporting requirement is feasible to meet as written. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A8 | Qualification | CC I contains no requirement for interviewing plant personnel, while interviews are needed to achieve CC II. The DC application and COL application PRAs should include interviews of personnel familiar with the design, analysis, and expected operations appropriate for that stage to ensure no potential initiating events have been overlooked; recognizing that the interviews will not reflect plant-specific experiences, but design and general experiences. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A9 | Clarification | CC I contains no requirement for performing a precursor review using plant-specific operating experience, while such a review is needed to achieve CC II and a review of industry precursor events is needed to achieve CC III. It is not feasible to have plant-specific operating experience at these application stages. Therefore, these applicants are not expected to perform additional precursor reviews and this supporting requirement is met at CC I with no action. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-A10 | Clarification | If the DC or COL is for a single unit or for a site in which there are no shared systems (including for example, separate switchyards and service water), then this supporting requirement is Not Applicable. For multi-unit designs, a DC may include assumptions regarding shared support system arrangements, while a COL can more directly address the designs for the alignment of site-specific shared support systems if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-IE-B | The initiating event analysis shall group the initiating events so that events in the same group have similar mitigation requirements (i.e., the requirements for most events in the group are less restrictive than the limiting mitigation requirements for the group) to facilitate an efficient but realistic estimation of CDF. | The initiating event analysis shall group the initiating events so that events in the same group have similar mitigation requirements (i.e., the requirements for most events in the group are less restrictive than the limiting mitigation requirements for the group) to facilitate an efficient but realistic estimation of CDF. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-B1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-B2 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-B3 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-B4 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-B5 | Clarification | If the DC or COL is for a single unit or for a site in which there are no shared systems (including for example, separate switchyards and service water), then this supporting requirement is Not Applicable. For multi-unit designs, a DC may make assumptions regarding shared support system arrangements, while a COL can more directly address the designs for the alignment of site-specific shared support systems if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-IE-C | The initiating event analysis shall estimate the annual frequency of each initiating event or initiating event group. | The initiating event analysis shall estimate the annual frequency of each initiating event or initiating event group. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C1 | Clarification | The supporting requirement directs the use of relevant generic and plant-specific data. Because plant-specific data will not be available for these application stages, the initiating event frequency will be calculated from relevant generic data. This approach meets the supporting requirement as written. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C2 | Clarification | Because plant-specific data will not exist during these application stages it is not necessary to provide a justification for their use. That being the case, this supporting requirement is Not Applicable. Therefore, the applicant does not need to address this supporting requirement. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C3 | Clarification | For DC and COL applications, the justification for credited recovery actions will likely be based on design and guidance documents and good engineering practices; not procedures or training. These sources provide sufficient evidence to meet the supporting requirement as written for these applications. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C4 | Clarification | Because plant-specific data will not exist during these application stages, and thus generic and plant-specific data are not combined, it is not necessary to use a Bayesian update process to include plant- specific data or justify a generic prior. That being the case, this supporting requirement is Not Applicable. Therefore, the applicant does not need to address this supporting requirement. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C5 | Clarification | The supporting requirement requires that the frequency be calculated on a reactor year basis, which can be performed. However, because no operating experience data will exist for these application stages on which to estimate plant availability, an assumed expected availability will need to be used, with an appropriate justification. If 100% availability is used, which maximizes the at-power risk estimates, this availability should not be assumed for assessing the low power/shutdown risk estimate (i.e., for the low power/shutdown risk estimate a lower plant availability should be used and justified). | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C6 | Qualification | The current version of the PRA standard does not identify unique screening criteria for new reactor designs that can have substantially lower risk profiles (e.g., internal events CDF well below 1×10-6/year). RG 1.200 states the quantitative screening value should be adjusted according to the relative baseline risk value. Lower screening values may need to be used commensurate with the lower CDF and LRF estimates expected from ALWRs. As a result, this supporting requirement should be replaced with the following: USE the following screening criteria to eliminate initiating events or groups from further evaluation: the mean frequency of the initiating event is less than 1×10-6 per reactor year (/ry) and core damage could not occur unless at least two trains of mitigating systems are failed independent of the initiating event, or the mean frequency of the initiating event is less than 1×10-7/ry and the initiating event does not involve or create an ISLOCA [interfacing systems loss-of-coolant accident], containment bypass, containment failure, or direct core damage (e.g., reactor pressure vessel rupture), or the mean frequency of the initiating event is less than 1×10-8/ry, or the event does not result in a plant trip (manual or automatic) or a controlled manual shutdown. If credit is taken for operator actions to correct the condition to avoid a plant trip or controlled shutdown, then ENSURE that the credited operator actions and associated equipment have an exceedingly low probability of failure (i.e., collectively less than or equal to 1× 10-5) following the applicable supporting requirements of this part (e.g., Human Reliability Analysis – Subsection 2-2.5). ENSURE that the value specified in the criterion meets the applicable requirements in the Data Analysis (Subsection 2-2.6) and Level 1 Quantification (Subsection 2-2.7). If additional screening criteria are applied, DEFINE the applied criteria and PROVIDE a basis that demonstrates internal initiating events that are screened out using the criteria are not significant contributors to internal events risk. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C7 | Clarification | CC I and CC II contain no requirement for performing time trend analysis; only CC III contains this requirement. At these application stages the initiating event frequencies should be based on generic information. That being the case, this supporting requirement is met at CC I with no action. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C8 | Clarification | If fault tree modeling is not used, then the supporting requirement is Not Applicable. If fault tree modeling is used, then meeting the supporting requirement is feasible. For DC and COL applicants some support systems may not be amenable to developing fault tree models because of the lack of site-specific information, so applicants instead might use generic data or bounding analyses or will assume specific aspects of the design to enable modeling. The COL applicant may be able to use fault tree modeling approaches for addressing some of these site-specific support systems if additional design and site information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C9 | Clarification | If fault tree modeling is not used, then the supporting requirement is Not Applicable. If fault tree modeling is used, then meeting the supporting requirement is feasible. For DC and COL applicants some support systems might not be amenable to developing fault tree models because of the lack of site-specific information, so applicants instead might use generic data or bounding analyses or will assume specific aspects of the design to enable modeling. The COL applicant may be able to use fault tree modeling approaches for these site-specific support systems if additional design and site information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C10 | Clarification | If fault tree modeling is not used, then the supporting requirement is Not Applicable. If fault tree modeling is used, then meeting the supporting requirement is feasible. For DC and COL applicants some support systems may not be amenable to developing fault tree models because of the lack of site-specific information, so applicants instead might use generic data or bounding analyses or will assume specific aspects of the design to enable modeling. The COL applicant may be able to use fault tree modeling approaches for these site-specific support systems if additional design and site information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C11 | Clarification | If fault tree modeling is not used, then the supporting requirement is Not Applicable. If fault tree modeling is used, then meeting the supporting requirement is feasible. For DC and COL applicants some support systems might not be amenable to developing fault tree models because of the lack of site-specific information, so applicants instead might use generic data or bounding analyses or will assume specific aspects of the design to enable modeling. The COL applicant may be able to use fault tree modeling approaches for these site-specific support systems if additional design and site information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. Further, for DC and COL applicants, plant-specific information, such as procedures and operating experience, will not be available, but the applicants should use the available design and guidance documents to inform the assessment of recovery actions. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C12 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C13 | Clarification | For DC applicants, plant-specific features related to support systems may be assumed (e.g., service water ultimate heat sink). For COL applicants, if additional design information is available these features may be considered directly in determining the most applicable generic data to use for rare events; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C14 | Clarification | For DC and COL applicants, the procedures will not be available, but design and guidance documents and good engineering practices may be used in assessing the influences on ISLOCA frequency. Similarly, plant-specific features may be assumed. For COL applicants, if additional design information is available these features may be considered directly; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-C15 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-IE-D | Documentation of the initiating event analysis shall be consistent with the applicable supporting requirements. | Documentation of the initiating event analysis shall be consistent with the applicable supporting requirements. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-D1 | Qualification | DC and COL applicants may make additional assumptions regarding the site, design, and operational practices, which need to be documented, including their impact on applications. Therefore, the following requirement is added to this supporting requirement: DOCUMENT the limitations, and their bases, resulting from the status of the design, site, operational, and maintenance information or data that would affect applications. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-D2 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | IE-D3 | Qualification | DC and COL applicants may make additional assumptions regarding the site, design, and operational practices, which need to be documented, including their consideration as a source of uncertainty. Therefore, the following requirement is added to this supporting requirement: DOCUMENT the additional sources of uncertainty and related assumptions resulting from the status of design, site, operational, and maintenance information or data. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-AS-A | The accident sequence analysis shall describe the plant-specific scenarios that can lead to core damage following each modeled initiating event. These scenarios shall address system responses and operator actions, including recovery actions that support the key safety functions necessary to prevent core damage. | The accident sequence analysis shall describe the plant-specific scenarios that can lead to core damage following each modeled initiating event. These scenarios shall address system responses and operator actions, including recovery actions that support the key safety functions necessary to prevent core damage. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A2 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A3 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A4 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A5 | Clarification | For DC and COL applications, the justification will likely be based on design and guidance documents; not on emergency or abnormal procedures. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A6 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A7 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A8 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A9 | Clarification | For DC and initial COLs, the thermal hydraulics will be primarily based on the design-related (deterministic and probabilistic) thermal hydraulics, although there might also be some similar plant analyses that could be utilized. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A10 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-A11 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-AS-B | Dependencies that can impact the ability of the mitigating systems to operate and function shall be addressed. | Dependencies that can impact the ability of the mitigating systems to operate and function shall be addressed. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B2 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B3 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B4 | Clarification | If the conditional split fraction method is not used, then this supporting requirement is Not Applicable. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B5 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B6 | Clarification | For DC and COL applications, non-normal plant configurations and maintenance practices might not be established, so dependencies between system alignments might not be completely recognized. Those aspects recognized at DC and COL stages should be defined and modeled in accordance with the supporting requirement. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-B7 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-AS-C | Documentation of the accident sequence analysis shall be consistent with the applicable supporting requirements. | Documentation of the accident sequence analysis shall be consistent with the applicable supporting requirements. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-C1 | Qualification | DC and COL applicants may make additional assumptions regarding the site, design, and operational practices, which need to be documented, including their impact on applications. Therefore, the following requirement is added to this supporting requirement: DOCUMENT the limitations and bases, resulting from the status of the design, site, operational, and maintenance information or data that would affect applications. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-C2 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | AS-C3 | Qualification | DC and COL applicants may make additional assumptions regarding the site, design, and operational practices, which need to be documented, including their consideration as a source of uncertainty. Therefore, the following requirement is added to this supporting requirement: DOCUMENT the additional sources of uncertainty and related assumptions resulting from the status of the design, site, operational, and maintenance information or data. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-SC-A | The overall success criteria for the PRA and the system, structure, component, and human action success criteria used in the PRA shall be defined and referenced, and shall be consistent with the features, procedures, and operating philosophy of the plant. | The overall success criteria for the PRA and the system, structure, component, and human action success criteria used in the PRA shall be defined and referenced, and shall be consistent with the features, procedures, and operating philosophy of the plant. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-A1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-A2 | Clarification | If core damage is defined based on the simplified definitions of NUREG/CR-4550, then a justification should be provided that establishes the appropriateness of the definition for the particular design. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-A3 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-A4 | Clarification | If the DC or COL is for a single unit site or for a site in which there are no shared systems (including e.g., separate switchyards and service water) then this supporting requirement is Not Applicable. For multi- unit designs, a DC may make assumptions regarding shared support system arrangements, while a COL can more directly address the designs for the alignment of site-specific shared support systems if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-A5 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-A6 | Clarification | For DC and COL applications, the justification will likely be based on design and guidance documents that reflect the “operating philosophy;” not on procedures. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-SC-B | The thermal/hydraulic, structural, and other supporting engineering bases shall be capable of providing success criteria and event timing sufficient for quantification of CDF and LERF [LRF], determination of the relative impact of success criteria on structures, systems, or components (SSC) and human actions, and impact of uncertainty on this determination. | The thermal/hydraulic, structural, and other supporting engineering bases shall be capable of providing success criteria and event timing sufficient for quantification of CDF and LERF [LRF], determination of the relative impact of success criteria on structures, systems, or components (SSC) and human actions, and impact of uncertainty on this determination. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-B1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-B2 | Qualification | CC I contains no restriction regarding the use of expert judgment, while restriction is placed on the use of expert judgment to achieve CC II/III. The applicant should use expert judgment only in those situations for which there is a lack of available information or methods, consistent with CC II/III. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-B3 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-B4 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-B5 | Clarification | For DC and initial COL applications there might be no similar plants against which to check results, though this is identified as an approach within the example list. The objective of the supporting requirement is to check for reasonableness and acceptability of analysis results, which could also be achieved by comparison against the traditional design engineering analysis results and other means. That being the case, meeting this supporting requirement is feasible for these application stages. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-SC-C | Documentation of the success criteria shall be consistent with the applicable supporting requirements. | Documentation of the success criteria shall be consistent with the applicable supporting requirements. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-C1 | Qualification | DC and COL applicants may make additional assumptions regarding the site, design, and operational practices, which need to be documented, including their impact on applications. Therefore, the following requirement is added to this supporting requirement: DOCUMENT the limitations, and bases, resulting from the status of the design, site, operational, and maintenance information or data that would affect applications. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-C2 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SC-C3 | Qualification | DC and COL applicants may make additional assumptions regarding the site, design, and operational practices, which need to be documented, including their consideration as a source of uncertainty. Therefore, the following requirement is added to this supporting requirement: DOCUMENT the additional sources of uncertainty and related assumptions resulting from the status of the design, site, operational, and maintenance information or data. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | HLR-SY-A | The systems analysis shall provide a reasonably complete treatment of the causes of system failure and unavailability modes represented in the initiating events analysis and sequence definition. | The systems analysis shall provide a reasonably complete treatment of the causes of system failure and unavailability modes represented in the initiating events analysis and sequence definition. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A1 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A2 | Clarification | For the DC application and COL application, the pertinent information used for the systems analysis will be that which reflects the “as-to-be- built” and “as-to-be-operated” design appropriate for that application stage. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A3 | Clarification | For DCs and COLs the procedures will not be available and some limits might not be established, but design and guidance documents may be used to enable the systems modeling. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A4 | Clarification | For the DC application and COL application, the pertinent information used for the systems analysis will be that which reflects the “as-to-be- built” and “as-to-be-operated” design appropriate for that application stage. The confirmation that the system model reflects the design of the system can be achieved through interviews of knowledgeable design and/or plant personnel, appropriate for that application stage. This confirmatory supporting requirement will be enhanced if additional system design information is available at the COL application stage. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A5 | Clarification | For these application stages, the system alignments might be known for most, but not all systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A6 | Clarification | DC applicants may make assumptions regarding the design of some of the support systems. The COL applicant can more directly address the site-specific support system design if the design information is available; recognizing that even at this stage some assumptions will be made regarding the design and operations of systems. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A7 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A8 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A9 | Clarification | If “super components” are not used, then the supporting requirement is Not Applicable. If “super components” are used, then it is feasible to meet the supporting requirement. | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A10 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A11 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A12 | No Objection | ------------------------------------ | |||
| Table 2 - Addressing Part 2, Internal Events, Supporting Requirements | SY-A13 | No Objection | ------------------------------------ |
Showing 1 to 100 of 842 entries