ML22189A100

Resolution of Public Comments - Final Interim Staff Guidance DNRL-ISG-2022-01 - Safety Review of Light-Water-Reactor Construction Permit Applications

ML22189A100
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Issue date:	11/04/2022
From:	NRC/NRR/DNRL/NRLB
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Lauron C
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ML22189A097	List: ML22189A098 ML22189A099 ML22189A100 ML22189A101
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ML120310169, ML20098D702
Download: ML22189A100 (18)

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APPENDIX C Analysis of Public Comments on Draft Interim Staff Guidance DNRL-ISG-2022-XX, Safety Review of Light-Water Power-Reactor Construction Permit Applications Comments on the subject draft interim staff guidance (ISG) are available electronically at http://www.nrc.gov/reading-rm/adams.html. From this page, the public can access the Agencywide Documents Access and Management System (ADAMS), which provides text and image files of the U.S. Nuclear Regulatory Commission (NRC) public documents. The following table lists the comments the NRC received on the draft ISG.

ADAMS Comment Number Commenter Affiliation Commenter Name Accession No.

NRC-2021-0162-ML22005A064 NewClear Day M.J. Burzynski DRAFT-0002 NRC-2021-0162-ML22039A110 Nuclear Energy Institute B. Holtzman DRAFT-0003 NRC-2021-0162-ML22152A063 Nuclear Energy Institute K. Austgen DRAFT-0004 NRC-2021-0162-ML22152A064 Breakthrough Institute R. Franovich DRAFT-0005 The following table lists each public comment by letter number, as given in the table above. It provides the original comment as written by the commenter. The comments are arranged to group similar comments together.

Comment Topic Specific Comment NRC Staff Response Identifier NRC- General The successful use of DSRS The NRC staff acknowledges the 2021- Chapter 7 on the NuScale DCA positive feedback on the 0162- review illustrates NRC willingness to development and use of the DRAFT- adapt better review methods to review guidance in NuScale 0002-7 improve efficiency and effectiveness DSRS Chapter 7.

and accommodate technology changes. It was effective for the The NRC staff made no changes review of a passive plant design using to the final ISG as a result of this integrated digital I&C systems in a comment.

risk-based classification system. It enabled the NRC staff to maintain focus on significant aspects of the I&C design in a unified manner throughout the review. It avoided inefficiencies experienced with the large LWR design certification reviews by tailoring the review guidance to the specific SMR technology. It reinforced the flexibility to consider and accept alternative approaches, when justified, to provide adequate safety. IEEE Standards for digital system and software development were within a graded quality assurance framework for

DNRL-ISG-2022-01, Appendix C Page 2 of 18 Comment Topic Specific Comment NRC Staff Response Identifier safety systems, based on the system classification.

NRC- General The ISG is applicable for reactors that The NRC staff agrees that the 2021- are using NUREG-0800 and not using purpose and use of the ISG could 0162- Licensing Modernization Project be clarified.

DRAFT- (LMP).

0003-2 The NRC staff has updated the Applicants using LMP will use the purpose section of the final ISG to advanced reactor content of read, The U.S. Nuclear application project (ARCAP) Regulatory Commission (NRC or Appendix E guidance. Commission) staff is providing this However, this distinction is not very interim staff guidance (ISG) to clear in the ISG. facilitate the safety review of light-water power reactor construction Proposed change: Please clarify in permit (CP) applications and to the text under what circumstances supplement the guidance in applicants would use this ISG and NUREG-0800.

under what circumstances applicants would use the ARCAP guidance. The NRC staff has updated the applicability section of the final ISG to read, This guidance applies to all applicants for a CP for a light-water power reactor under 10 CFR Part 50 but not to non-LWR applicants or those following the Advanced Reactor Content of Application Project (ARCAP) guidance to the extent the guidance is issued as final and is relevant to the application from a technical and regulatory perspective.

NRC- General (ISG Appendix, p. 16 [sic]) The ISG The NRC staff understands that 2021- text denotes the commenter requests a list of 0162- SRP sections that retained DRAFT- Many SRP sections retained separate CP guidance in the SRP; 0003-5 separate guidance for the review however, the staff believes that of a CP application, while other listing those sections with SRP sections consolidated that separate CP guidance may guidance in the review mislead applicants that those are procedures for applications the only applicable sections to a submitted under 10 CFR Part 52. CP application. An applicant should go through the information It would be helpful to state explicitly in each SRP chapter to what sections of the SRP retain understand the staffs review of a separate guidance for the review of a CP application and the information CP application. needed to support its review.

Proposed change: The SRP provides guidance to the Please state which sections of the NRC staff in performing safety SRP retain separate guidance for the reviews of CP or OL applications review of a CP application. (including requests for amendments) under 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, and early site permit, design certification, combined license (COL), standard design approval, or manufacturing license applications under

DNRL-ISG-2022-01, Appendix C Page 3 of 18 Comment Topic Specific Comment NRC Staff Response Identifier 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants, including requests for amendments. The principal purpose of the SRP is to ensure the quality and uniformity of staff safety reviews.

The ISG supplements the guidance in the SRP, which is the starting point for the review of a CP application. Therefore, those interested in applying for a CP should consider the review procedures in the SRP. Also, prospective applicants are encouraged to engage in preapplication activities to gain insights on the regulatory requirements for their design and enhance the stability and predictability of the review and schedule of their future application, including engagement on alternative ways to meet the regulations.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- General (ISG Appendix, p. 16 [sic]) Industry The NRC staff understands that 2021- agrees that CP application reviews the commenter seeks additional 0162- should be risk-significant and information on how risk details DRAFT- safety-significant commensurate with would be used in the NRC staffs 0003-6 their significance, however, its not evaluation. The SRP Introduction, clear from the ISG how this would be Rev. 2, provides a discussion on implemented when the overall design the use of the SRP in guiding the may still be in finalization. review of initial applications and use of risk-insights to determine Proposed change: the depth of review. It should be Please provide any additional detail noted that the regulations in 10 available on how the risk details CFR Part 50 do not require the would be evaluated to help ensure submission of probabilistic risk regulatory stability and predictability assessment information; however, for CP applications and reviews. the submission of such information would be reviewed consistent with the guidance in SRP Chapter 19.

Applicants with questions related to their specific designs are encouraged to engage in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule of their future application, including engagement on alternative ways to meet the regulations.

DNRL-ISG-2022-01, Appendix C Page 4 of 18 Comment Topic Specific Comment NRC Staff Response Identifier The NRC staff made no changes to the final ISG as a result of this comment.

NRC- General The NRC is preparing guidance for At the February 25, 2021, periodic 2021- applicants of a non-light-water reactor advanced reactor stakeholders 0162- CP separate from the instant CP public meeting, the NRC DRAFT- guidance for light-water reactors. Like presented a draft white paper that 0005-1 the regulations themselves, guidance covered the CP guidance for LWR should be technology inclusive. One and advanced reactor designs guidance document would be most (ML21055A541). Based on the appropriate for addressing discussion during the meeting and commonality where it will largely exist feedback on the draft, the NRC and divergence only where staff decided to separate the CP appropriate and necessary. To guidance for LWR and advanced ensure better consistency in reactor designs to minimize regulatory outcomes, products and confusion on its applicability services for the widest variety of (ML21068A141).

applicants, the Agency should carefully consider an organizational While there are two NRR divisions restructure that better integrates staff involved in the development of activities for light-water and guidance for new LWRs and non-non-light-water reactors in a truly LWRs, their activities are closely technology-inclusive manner coordinated. No organizational consistent with the Nuclear Energy restructure was deemed Innovation and Modernization Act of necessary and the suggested 2019. Bifurcated efforts to modernize NRC restructuring is outside the different and largely duplicative scope of the ISG.

regulatory frameworks within two separate NRC organizations (the The NRC staff made no changes Division of New and Renewed to the final ISG as a result of this Licenses and the Division of comment.

Advanced Reactors) is inefficient; it also introduces uncertainty and could result in inconsistent, difficult to navigate pathways to licensing and deployment of all new nuclear reactor technologies.

NRC- General We believe one ISG for light-water The NRC staff addresses this 2021- and non-light-water reactors is more comment in the response to NRC-0162- open, clear, and efficient. More 2021-0162-DRAFT-0005-1.

DRAFT- importantly, [the] NRCs fundamental 0005-2 approach to preparing frameworks, rules, and guidance to enable the licensing and deployment of all new technologies (light-water and non-light-water) in this iterative fashion is ineffective and unnecessarily time consuming.

NRC- General The NRCs engagements with The NRC staff understands that 2021- external stakeholders appear to have the commenter is providing 0162- been limited to requests for feedback on the process used to DRAFT- comments on iterations of NRC work develop the ISG. During a 0005-3 products after they have been June 12, 2020, periodic advanced developed solely by NRC. Early reactor stakeholders public engagement and involvement of meeting, industry representatives those stakeholders in the initial identified the need for near-term

DNRL-ISG-2022-01, Appendix C Page 5 of 18 Comment Topic Specific Comment NRC Staff Response Identifier development of these products would light-water small modular reactor have been more consistent with the (SMR) construction permit Principles of Good Regulation. guidance (ML20195B104). In a subsequent meeting on July 31, 2020, the NRC staff presented three options to address the need: development of an ISG, issuance of a draft strategy paper for SMR CP reviews, or issuance of an office instruction. Industry feedback indicated that development of an ISG appeared to be an efficient way of providing CP guidance to support the submission of a CP application as early as the end of 2021 (ML20233A990).

The NRC staff continued to engage industry representatives on the development of guidance during the August 27, 2020 (ML20253A307), and February 25, 2021 (ML21068A141) public meetings, during which the NRC staff discussed and received feedback on its draft white paper (ML21043A339).

Based on these engagements, the NRC staff believes it has engaged industry early in the process and afforded opportunities to actively engage in the development of the guidance consistent with the Principles of Good Regulation.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- General BTI urges the NRC to invite The NRC staff addresses this 2021- external stakeholders to participate in comment in the response to NRC-0162- the development process rather than 2021-0162-DRAFT-0005-3.

DRAFT- simply afford them an opportunity to 0005-4 comment on NRCs products, and then comment again on narrowly defined aspects of original comments NRC- CP Level of Detail [S]ome comments provided in [the The NRC staff does not agree with 2021- Nuclear Energy Institutes] letter this comment. NUREG-0800, 0162- regarding the draft NRC white paper Standard Review Plan for the DRAFT- remain applicable (ML21092A115). Review of Safety Analysis Reports 0003-1 for Nuclear Power Plants: [Light-Most notably is that the level of detail Water Reactor] (LWR) Edition requested for the construction permit (SRP), and the ISG provide application in several areas appears guidance to the NRC staff on the inconsistent with previous review of LWR applications, construction permit applications and including construction permit (CP) instead is aligned with the level of applications. The ISG references

DNRL-ISG-2022-01, Appendix C Page 6 of 18 Comment Topic Specific Comment NRC Staff Response Identifier detail needed for a Part 52 combined Revision 3 of Regulatory Guide operating license application or a (RG) 1.70, Standard Format and Part 50 operating license application. Content of Safety Analysis Reports for Nuclear Power Plants, Clarification in the guidance on this LWR Edition, issued point would be very helpful to ensure November 1978 (ML011340122),

that prospective applicants which was developed from the appropriately determine whether to lessons learned in licensing the use the Part 50 or Part 52 licensing current fleet of operating reactors.

process. Although RG 1.70 dates from the late 1970s and does not account for subsequent requirements, NRC technical positions, or advances in technical knowledge, it describes the level of detail needed to support CPs and operating licenses (OLs) and generally follows the structure of the SRP.

Prospective LWR CP applicants should consider the level of detail described in RG 1.70 and the review guidance in the SRP and the ISG to develop their CP applications.

The NRC encourages prospective applicants with regulatory questions concerning their specific design to engage in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule of their future application, including engagement on alternative ways to meet the regulations.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- CP Level of Detail Its not clear the distinction being The NRC staff understands that 2021- made between the level of detail the commenter seeks an 0162- requested for the CP application acceptance review template to DRAFT- compared to an operating license reduce the uncertainty and 0003-3 application. If there is no distinction subjectively of application between the information considered development and reviews; necessary and sufficient for a Part 50 however, the acceptance criteria CP and operating license application, for a construction permit is including information that may not be provided in the SRP, as available for a preliminary design, supplemented by the final ISG. A then there would be no purpose in prospective applicant should using a Part 50 licensing pathway. review each SRP chapter to The Part 52 combined operating understand the NRC staffs review license application would avoid the of a CP application, including the need for a subsequent operating acceptance criteria to meet the licensing application associated with applicable regulatory the Part 50 process. The text should

DNRL-ISG-2022-01, Appendix C Page 7 of 18 Comment Topic Specific Comment NRC Staff Response Identifier avoid the impression that the only requirements, as supplemented by acceptable CP application is one with the final ISG.

a finalized design.

Similar to the response to Proposed change: comment NRC-2021-0162-Please review the ISG to ensure the DRAFT-0003-1, the ISG CP requires a level of information references RG 1.70, which was consistent with past CP applications developed from the lessons that NRC has approved. learned in licensing the current fleet of operating reactors.

Please consider developing a CP Although RG 1.70 dates from the acceptance review template to reduce late 1970s and does not account

[the] uncertainty and subjectivity of for subsequent requirements, application development and reviews. NRC technical positions, or advances in technical knowledge, it describes the level of detail needed to support CPs and OLs and generally follows the structure of the SRP.

Prospective LWR CP applicants should consider the format, structure, and level of detail described in RG 1.70 and the review guidance in the SRP and the ISG to develop a CP application.

The ISG notes that CP applications must address all regulatory requirements applicable to a CP. If a design has not sufficiently progressed such that certain information is not available at the time the CP application is submitted, the PSAR should provide the criteria and bases that will be used to develop the required information, the concepts and alternatives to be considered, and the schedule for completing the design and submitting the missing information. In general, a PSAR should describe the preliminary design of the facility in sufficient detail to enable the NRC staff to evaluate whether the facility can be constructed and operated without undue risk to public health and safety.

Applicants with questions related to their specific design are encouraged to engage in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule of their future application, including engagement

DNRL-ISG-2022-01, Appendix C Page 8 of 18 Comment Topic Specific Comment NRC Staff Response Identifier on alternative ways to meet the regulations.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- CP Level of Detail The draft ISG (DNRL-ISG-2022-XX) The NRC staff understands that 2021- currently provides high-level the commenter seeks a checklist 0162- statements but doesnt provide of information needed in a DRAFT- sufficient details for an applicant to construction permit along with a 0004-1 have assurance of what information listing of applicable regulations would be required in the construction and associated regulatory guides; permit (CP) application. Additional however, that information is detail associated with what specific included in the SRP. An applicant information a staff reviewer would be should go through each SRP looking for would be a great help. A chapter to understand the table or checklist that denotes information needed in a CP minimum information required for a application to support the NRC CP application that does not request staffs review of a CP. Each SRP finality should be provided as a section provides the areas of baseline, i.e., include a complete review, the acceptance criteria, composite listing of the applicable the review procedures and regulations and associated regulatory applicable regulations.

guides. Additional information pertaining to CP applications The ISG is not a standalone requesting finality in one or more document but supplements the targeted areas could be included to SRP and points to other guidance reflect the option (not requirement) to as appropriate. The ISG, in provide additional information in some conjunction with the SRP, CP applications. identifies the information that would be reviewed and evaluated by the NRC staff to reach its findings. The ISG notes that prospective LWR CP applicants should consider the information described in RG 1.70 and review the guidance in the SRP and the ISG to develop their CP and OL applications. Also, the ISG points to RG 1.206 as including insights on the level of detail needed for final design information if the CP applicant chooses to provide such information. Further, the ISG encourages applicants with questions related to their specific design to engage in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule of their future application, including engagement on alternative ways to meet the regulations.

The NRC staff made no changes to the final ISG as a result of this comment.

DNRL-ISG-2022-01, Appendix C Page 9 of 18 Comment Topic Specific Comment NRC Staff Response Identifier NRC- CP Level of Detail The text of the draft ISG should avoid The NRC staff does not agree with 2021- the impression that the only this comment. The ISG discusses 0162- acceptable CP application is one with the information in a PSAR that the DRAFT- a finalized design. The draft ISG NRC staff would review using the 0004-2 appears to indicate that a design guidance in the SRP as would need to be sufficiently far along supplemented by the ISG.

in design finalization to enable the use of a Part 52 process, in which The ISG identifies the case there is no benefit in using the requirements in 10 CFR 50.34(a)

Part 50 CP process. regarding the minimum technical information in the PSAR accompanying a CP application, including the principal design criteria; the design bases and how they relate to the principal design criteria; and sufficient information on the materials of construction, general arrangement, and approximate dimensions for the NRC staff to conclude that the final design will conform to the design bases with adequate margin for safety.

The ISG further notes that if a novel design has not sufficiently progressed and certain information is not available at the time a CP application is submitted, the PSAR should provide the criteria and bases that will be used to develop the required information, the concepts and alternatives to be considered, and the schedule for completing the design and submitting the missing information. In general, the PSAR should describe the preliminary design of the facility in sufficient detail to enable the NRC staff to evaluate whether the facility can be constructed and operated without undue risk to public health and safety. The NRC expects CP applications to address all regulatory requirements applicable to a CP.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- CP Content (ISG Appendix, p. 17 [sic]) The text The NRC staff understands that 2021- Finally, the NRC staff should note the commenter seeks clarification 0162- that the information in [Appendix A] is on why the ISG does not include DRAFT- not intended to include all topics all the topics expected and 0003-7 expected and reviewed in a CP reviewed in a CP application. The application. If this is the case, how ISG is not intended to be a stand-can an applicant have a reasonable alone document. The ISG supplements the NRC staffs

DNRL-ISG-2022-01, Appendix C Page 10 of 18 Comment Topic Specific Comment NRC Staff Response Identifier expectation of what material would be primary review guidance in expected for a CP application? NUREG-0800 (SRP). Prospective applicants for a CP should first Proposed change: review each SRP chapter to Please clarify the intent of this line understand the information and consider developing a CP needed in the application to acceptance review template to reduce support the NRC staffs review uncertainty and subjectivity of along with the additional application development and reviews. (clarifying) information in the ISG.

The ISG references RG 1.70, which was developed from the lessons learned in licensing the current fleet of operating reactors.

Although RG 1.70 dates from the late 1970s and does not account for subsequent requirements, NRC technical positions, or advances in technical knowledge, it describes the level of detail needed to support CPs and OLs and generally follows the structure of the SRP.

Prospective LWR CP applicants should consider the format, structure, and level of detail described in RG 1.70, as well as the review guidance in the SRP and the ISG on developing a CP application. Applicants with questions related to their specific design are encouraged to engage in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule of their future application, including engagement on alternative ways to meet the regulations.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- Instrumentation and [Regarding the instrumentation and The NRC staff agrees that the 2021- Control (I&C) control guidance in Appendix A], the purpose of discussing the unifying 0162- Reference to NuScale discussion seems to suggest that the I&C framework in NuScale DSRS DRAFT- Design-Specific Review NuScale DSRS is the preferred chapter 7 could be clarified.

0002-1 Standard (DSRS) review format; however, no discussion is provided on how to The NRC staff updated the I&C adapt or adopt the DSRS for a section in Appendix A to the final particular new plant design. It would ISG to read:

be better to more fully the develop how an alternative to the SRP The guidance in NuScale DSRS Chapter 7 could be adopted. Chapter 7 reflects an approach that a prospective applicant may use to develop a unifying I&C framework that addresses all the significant aspects of the

DNRL-ISG-2022-01, Appendix C Page 11 of 18 Comment Topic Specific Comment NRC Staff Response Identifier I&C design in a unified manner to minimize the repetition of the requirements.

To more fully develop how an alternative to SRP Chapter 7 could be adopted, as suggested by the comment, would require additional resources and time that would be inconsistent with the timeliness goals for issuing the ISG to support the review of applications submitted within the next few years. The guidance in the SRP as supplemented by the ISG is one acceptable way of meeting the regulatory requirements. Prospective LWR CP applicants are encouraged to engage in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule of their future application, including the development of an alternative to meet the regulations instead of following the guidance in SRP Chapter 7.

NRC- I&CReference to [Regarding the I&C guidance in NuScale DSRS Chapter 7 2021- NuScale DSRS Appendix A]: The discussion on the provides guidance to the NRC 0162- review criteria for the I&C review is staff on the review of the I&C DRAFT- appropriately defined; however, the information for the NuScale 0002-2 chosen PSAR format for the I&C design. The guidance in the systems should clearly address the appendices to NuScale DSRS first three bullets. The NuScale DSRS Chapter 7 is intended to focus on structure does not reflect these specific topics applicable to the review objectives since key NuScale design and is used with information on these topics is the other sections of NuScale relegated to appendices. DSRS Chapter 7.

((T]he first three bullets refers to the The NRC does not require a following bullets (and explanatory specific format for the PSAR. The material) that precede the comment: NuScale final safety analysis report (FSAR) presented the I&C In evaluating a CP application, the information consistent with the NRC staff should focus on the NuScale DSRS. An applicant may following elements of the I&C design: use the NuScale FSAR format to

• an overall I&C architecture that guide its CP application demonstrates adherence to the development or may use a fundamental I&C design principles different format, if justified.

• plant safety functions allocated to each of the safety-related I&C An applicant can gain further systems insights on how best to present

• proposed communications between information related to its design safety-related and non-safety-related through preapplication activities.

I&C systems]

DNRL-ISG-2022-01, Appendix C Page 12 of 18 Comment Topic Specific Comment NRC Staff Response Identifier The NRC staff made no changes to the final ISG as a result of this comment.

NRC- I&CSRP Organization The SRP Chapter 7 organization for The NRC staff understands that 2021- presentation of I&C systems the commenter finds the SRP 0162- informationis not an effective format Chapter 7 format ineffective and DRAFT- to describe modern integrated I&C not reflective of ongoing activities 0002-3 systemsdoes not reflect all relevant or the evolution of related the regulatory topics of interest[and is] topics. The SRP provides not up to date with ongoing evolution guidance to the NRC staff in of graded approaches to system performing safety reviews of classification or treatment of various license applications, beyond-design-basis-event mitigation including for amendments to topics. previously issued licenses.

Because the SRP is used for more The Advisory Committee on Reactor than initial licensing and is the Safeguards (ACRS) commented structure against which the current during reviews of large LWR design operating fleet was licensed, a certifications that the SRP Chapter 7 change to the SRP structure format had a compliance mentality would cause confusion and not that did not effectively address what effectively support the NRC staffs I&C systems do, why they do what review of various licensing they do, and why they are safe. The actions. Therefore, the review ACRS feedback led to improvements guidance used to license the for small modular reactor (SMR) existing fleet of nuclear power Design Certification Application plants is retained.

(DCA) reviews.

The NRC disseminates Adoption of the SRP Chapter 7 model information regarding current requires small initial investment of safety issues and proposed project time or resources; however, solutions through various means, experience has shown that managing such as generic communications the safety I&C reviews for modern and the process for treating highly integrated digital I&C systems, generic safety issues. When using the SRP Chapter 7 model, current issues are resolved, the results in longer reviews with higher NRC staff determines the need, review costs. extent, and nature of revisions that should be made to the SRP to reflect new NRC guidance. The NRC has developed a schedule for the periodic review and updating of the SRP and has initiated efforts to modernize the guidance.

The SRPs Introduction, Rev. 2, and the ISG note that the NRC staff should use the SRP as superseded or supplemented by new or revised regulations, regulatory guidance, NRC staff analyses of previous applications, and other published staff positions to perform its review.

The NRC staff made no changes to the final ISG as a result of this comment.

DNRL-ISG-2022-01, Appendix C Page 13 of 18 Comment Topic Specific Comment NRC Staff Response Identifier NRC- I&CNuScale DSRS DSRS Chapter 7 did not address The commenter notes that the 2021- ongoing evolution of DSRS guidance did not address 0162- beyond-design-basis event mitigation ongoing activities related to a DRAFT- topics due to the timing of the rulemaking that was later finalized 0002-4 associated [10 CFR] 50.155 in August 2019. There are no rulemaking for mitigation of requirements for CP applications beyond-design-basis events. in 10 CFR 50.155.

In April 2019, the NRC staff issued RG 1.97, Criteria for Accident Monitoring Instrumentation for Nuclear Power Plants, Revision 5, to endorse IEEE 497-2016, IEEE Standard Criteria for Accident Monitoring Instrumentation for Nuclear Power Generating Stations, which added Type F variables to provide primary information to accident management personnel to indicate fuel damage and the effects of fuel damage for beyond-design-basis conditions.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- I&CRecently Issued [The] NRC issued a new I&C review The NRC developed the DRG to 2021- Guidance guidance in March 2021 titled Design address the needs associated with 0162- Review Guide (DRG): Instrumentation the non-LWR community using a DRAFT- and Controls for Non-Light-Water risk-informed, performance-based 0002-5 Reactor (Non-LWR) Reviews. approach. The DRG notes that it is technology inclusive. The NRC The DRG review priorities are staff agrees that the DRG may be established in a comparable manner used for the review of LWR plant as in DSRS Chapter 7 for I&C designs using the same architectures and safety-significant risk-informed, performance-based systems. The DRG adds an approach.

improvement by clarifying that the review of other I&C systems should The DRG assumes the use of a focus on hazards that could impair licensing framework where the the performance of safety-significant foundations of the safety case are systems. provided in terms of quantitative frequencies and consequences of The DRG proposal was well received events modeled in the PRA. The by the ACRS and noted it had a more DRG is intended for evaluating universal applicability for I&C system I&C designs that follow the reviews than the limitation to non- NEI 18-04 framework. This LWR reviews, since it was applicable framework is different from the to the I&C systems review for any traditional framework for the type of reactor. review of CP applications following the SRP. The ISG is The DRG proposal provides an intended to supplement the SRP opportunity to achieve a measure of guidance on the traditional international harmonization with framework for CP application respect to International Atomic reviews.

Energy Agency (IAEA) safety guidance and International Electrotechnical Commission (IEC)

DNRL-ISG-2022-01, Appendix C Page 14 of 18 Comment Topic Specific Comment NRC Staff Response Identifier standards for nuclear power plant The NRC staff made no changes safety systems. The DRG framework to the final ISG as a result of this aligns with new plant design comment.

philosophy for plant safety based on lines of defense and use of international standards for I&C systems.

NRC- I&CRegulatory The fundamental regulatory challenge The NRC staff understands that 2021- Framework posed by modern I&C designs is not the commenter provided an 0162- one related to technology or design, alternative I&C regulatory DRAFT- but the challenge is the effective framework to address a 0002-6 communication and explanation of the communication challenge. To fully integration such that it can be clearly consider the commenters and easily understood. An alternative proposed alternative I&C I&C regulatory framework is proposed regulatory framework would that organizes the key regulatory require additional resources and topics for I&C system reviews that is time that would be inconsistent more accessible and understandable. with the timeliness goals for The alternative I&C regulatory issuing the ISG to support the framework is illustrated in Figure 1. review of applications submitted within the next few years.

The alternative I&C regulatory framework separates the [defense-in- The SRP and the ISG generally depth] framework from the DRG describe an acceptable means of placement as an element of meeting the regulations but not robustness to provide a more necessarily the only means.

prominent focus on a key part of the Prospective applicants may new plant design concepts. It also deviate from the SRP and the ISG adds in a secure I&C element to and propose alternatives in their reflect the overall importance to this applications.

topic to any digital I&C system design. Prospective applicants with regulatory questions on their new The overall I&C architecture provides plant design are encouraged to a framework to systematically engage the NRC in preapplication develop, present, and understand the activities to gain insights and I&C design bases in the necessary enhance the stability and context (i.e., the plant-level). predictability of the review and schedule of their future A suggested outline for the I&C application, including engagement systems PSAR content is provided to on alternative ways to meet the best explain the features of the I&C regulations.

system of system architecture and the individual I&C system: [the proposed The NRC staff made no changes outline follows.] to the final ISG as a result of this comment.

NRC- I&CReference to (ISG Appendix, p. 21 [sic]) The ISG The NRC staff understands that 2021- NuScale DSRS highlights the value in NuScales the commenter is seeking 0162- design-specific review standard clarification on the purpose and DRAFT- guidance, which was developed as intent of discussing the NuScale 0003-10 part of NuScales design certification, DSRS which is applicable to a combined operating license, and early combined license application.

site permit reviewsnot a construction permit. However, the The NRC staff agrees that the ISG does not clarify the NRC purpose of discussing the unifying expectation for future non-NuScale I&C framework in NuScale DSRS construction permit applications chapter 7 could be clarified.

regarding scope or format. A document developed for a different,

DNRL-ISG-2022-01, Appendix C Page 15 of 18 Comment Topic Specific Comment NRC Staff Response Identifier more in-depth, regulatory process The NRC staff updated the I&C (Part 52 COL) should not be section in Appendix A to the final comparable in a blanket manner for ISG to read:

Part 50 construction permit applications. The guidance in NuScale DSRS chapter 7 reflects an Proposed change: approach that a prospective Please be clearer regarding the intent applicant may use develop a of mentioning the NuScale unifying I&C framework that design-specific review standard addresses all the significant guidance in the construction permit aspects of the I&C design in a ISG. unified manner to minimize the repetition of the requirements.

NRC- I&CLevel of Detail in the draft ISG is not clear on what The NRC staff understands that 2021- a CP information is necessary for the the commenter seeks clarity on 0162- instrumentation and control aspects what information is needed for the DRAFT- of a design specifically for a CP. The I&C section in a CP application 0004-4 draft ISG discusses several areas of and that the reference to guidance focus but also highlights the value of applicable to a Part 52 application design-specific review standard review creates uncertainty.

guidance that was developed as part of design certification reviews under This comment is similar to Part 52. This creates uncertainty comments NRC-2021-0162-regarding the information for a Part DRAFT-0002-1 and NRC-2021-50 CP compared to Part 52 0162-DRAFT-0003-10. The NRC applications. staff responses to these comments are addressed above.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- Transient and Accident (ISG Appendix, p. 18 [sic], Transient The NRC staff expects the same 2021- Analyses and Accident Analyses) The detail level of detail as previous CP 0162- and specified completion of safety applications, consistent with DRAFT- analysis in this section goes beyond guidance in RG 1.70, Revision 3, 0003-8 what the industry believes should be and the SRP.

required for a construction permit (CP) application. The ISG states that a quantitative analysis should be performed for Specifically, the draft guidance notes each potentially limiting event that the review of transients and within each category. Each accident analyses requires an category may have multiple evaluation of analytical methods, limiting events to the various inputs, and results of analyses. acceptance criteria based on There should be an option for different initiating events. PSARs qualitative arguments that provide should include the rationale for justification of why certain transients determining that the limiting event or accidents are bounding. The draft is in fact limiting. Qualitative guidance notes that all credible arguments that provide the accidents are considered and technical basis for the evaluated during the CP application determination that an event within stage, but there should be an a category is nonlimiting are explanation with that paragraph that acceptable and should be provides a description of the documented in PSARs.

acceptability of the use of a bounding events approach. In 10 CFR 50.34(a)(4), the NRC requires a preliminary analysis

DNRL-ISG-2022-01, Appendix C Page 16 of 18 Comment Topic Specific Comment NRC Staff Response Identifier The guidance states that for the and evaluation of the design. The selected events that are limiting, the NRC staff does not expect the reviewer verifies that the applicant design of the facility to be final at systematically analyzed and the CP stage and understands evaluated the limiting events in each that the design is subject to category using a detailed quantitative change in the future. Analyses analysis. This seems to imply that all performed at the CP stage should events are required to be fully be based on the preliminary analyzed for the CP application. A design.

construction permit should not need design finalization. This seems to go The NRC staff modified the ISG to beyond the specified level of clarify that the analysis of limiting completion of analysis that should be events is based on the preliminary required at the CP application stage design and that the use of and conflicts with the ISG text qualitative justification is referencing 10 CFR 50.35, some acceptable for nonlimiting events technical and design information may within a category.

reasonably be left for a later stage of licensing.

Proposed change:

Please clarify the level of detail expected for a construction permit that is not requested final design approval.

NRC- Transient and Accident A specific example can be found in The NRC staff addresses this 2021- Analyses the transient and accident analyses comment in the response to NRC-0162- section where the text states 2021-0162-DRAFT-0003-8.

DRAFT- reviewing transient and accident 0004-3 analyses requires an evaluation of analytical methods, inputs, and results of analyses. Detailed transient and accident analyses require the design to be sufficiently complete to support the finalization of the safety analysis report, which occurs at the operating license stage.

It is assumed that this does not reference final analyses, which would require the incorporation of as-built conditions and be reflective of the FSAR or operating license.

Additionally, the text in that section states the NRC staff verifies that the applicant systematically analyzed and evaluated the limiting events in each categoryusing a detailed quantitative analysis. This seems to imply that all events are required to be fully analyzed for the CP application. A CP should not need design finalization.

Furthermore, the statement that all credible accidents are considered and evaluated during the CP application stage is very open-ended. Additional details are needed to constrain the

DNRL-ISG-2022-01, Appendix C Page 17 of 18 Comment Topic Specific Comment NRC Staff Response Identifier extent to which credible accidents need to be evaluated in a preliminary fashion, so that evaluations that are provided/requested for a CP application are not more than would be necessary for a Part 52 combined license application, which is how previous CP applications were undertaken.

All three of these transient and accident analyses section examples indicate that the level of design completion required would be beyond that traditionally required for a CP application. However, other parts of the draft guidance appear to reflect a different interpretation. One part references 10 CFR 50.35 and denotes technical and design information may reasonably be left for a later stage of licensing. We believe that the latter is the correct interpretation and suggest that other parts of the draft ISG should be aligned to reflect this interpretation throughout (e.g., minimum requirements for transient and accident analyses in a CP application would reflect bounding, not detailed analyses).

NRC- Coatings (ISG Appendix, p. 21 [sic], Protective The guidance for protective 2021- Coatings Systems) The information in coatings systems in ISG 0162- this section of [Appendix A] does not Appendix A notes that in a CP DRAFT- specify what aspects of information application, the NRC staff reviews 0003-9 needed for an operating license the applicants commitment to would be required for the construction using protective coating systems permit application. to meet the acceptance criterion in SRP section 6.1.2, Protective Proposed change: Coating Systems (Paints)

Please differentiate what information Organic Materialsthis is also is needed for a CP and what can be how SRP Section 6.1.2 describes deferred to the operating license the NRC staffs review of a CP application. application. The ISG guidance clarifies one acceptable way to meet the acceptance criterion and how the NRC staff would review an applicants proposed alternative to meeting the acceptance criterion.

Prospective LWR CP applicants should consider the information described in RG 1.70 and the review guidance in the SRP and the ISG to develop their CP and OL applications. Applicants with questions related to their specific design are encouraged to engage

DNRL-ISG-2022-01, Appendix C Page 18 of 18 Comment Topic Specific Comment NRC Staff Response Identifier in preapplication activities to gain further insights and enhance the stability and predictability of the review and schedule for its future application, including engagement on alternative ways to meet the regulations.

The NRC staff made no changes to the final ISG as a result of this comment.

NRC- Microreactors Guidance (ISG, p. 5) The NRC staff understands that 2021- The draft guidance doesnt the commenter is requesting that 0162- incorporate the NRCs approach for microreactor guidance be included DRAFT- addressing aircraft impact for micro in the ISG.

0003-4 reactors as described in an NRC paper on the subject. The ISG is intended to support the review of light-water power reactor Proposed change: CP applications submitted within Please revise the ISG to incorporate the next few years. The NRC staff a reference to NRCs guidance for does not anticipate the submission micro reactors for applicable designs. of light-water power microreactor applications in the near future.

Prospective light-water microreactor applicants with regulatory questions are encouraged to engage the NRC in preapplication activities to gain insights and enhance the stability and predictability of the review and schedule of their future application, including engagement on alternative ways to meet the regulations.

The NRC is currently developing guidance for non-LWR designs in the ARCAP, which is expected to address the review of microreactor designs.

The NRC staff made no changes to the final ISG as a result of this comment.