ML22014A167

Combined Slides for January 18, 2022, Technology Inclusive Content of Application Project (Ticap) Public Meeting

ML22014A167
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Issue date:	01/18/2022
From:	Joseph Sebrosky NRC/NRR/DANU/UARP
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Sebrosky J
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Download: ML22014A167 (47)

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Technology Inclusive Content of Application Project (TICAP)

TICAP Response to NRC Position on Principal Design Criteria (PDC) approach in NEI 21- 07 Technology Inclusive Guidance for Non -Light Water Reactors

Brandon Chisholm, Southern Company Steve Nesbit, LMNT Consulting

NRC Public Meeting January 18, 2022

1 Outline

• TICAP response to NRC position on PDC scope and changes to NEI 21-07 guidance

• Proposed TICAP PDC approach

• Response to NRC recommendations #1-3, 5 from Dec 14 meeting (ML21344A006)

• Potential Alternate TICAP PDC guidance - justification of exemption(s)

• Response to NRC recommendation #4 from Dec 14 meeting (ML21344A006)

22 Overview and Perspective

• Both the Technology Inclusive Content of Application Project (TICAP) team and the Nuclear Regulatory Commission (NRC) staff have been working to formulate acceptable approaches to specifying principal design criteria (PDC) for a risk-inform ed, performance-based (RIPB) license application based on NEI 18-04

• There is agreement that the regulations require the applicant to specify its PDC for the facility (e.g., 10 CFR 50.34(a)(3)(i) for a construction permit application)

• There is agreement that a non-LWR applicants PDC are not required to meet the light water reactor general design criteria (GDC) in 10 CFR 50 Appendix A or the Advanced Reactor Design Criteria in RG 1.232

33 NRC Position on PDC scope (ML21344A006)

44 TICAP Response: PDC scope

• The TICAP team agrees with the NRC position that:

- The scope of PDC under 10 CFR Part 50/52 (without an exemption) includes the necessary design, fabrication, construction, testing, and performance requirements for structures, systems, and components important to safety

- Although the NEI 21-07, Rev. 0 proposed SAR content:

>> would require the information to satisfy the above scope, it is not consistent with the current scope definition of PDC and regulatory history that requires that the information be labeled explicitly as PDC

>> would, if the safety case is based on it, include additional SSCs or programmatic elements beyond the minimum required to meet the performance objectives of regulations (i.e., Complementary Design Criteria), it does not label such additional elements as PDC

• The TICAP team will revise the approach for identifying PDC to satisfy the above description of scope

55 Description of Revised TICAP PDC Approach Proposed Changes to NEI 21-07

• According to the guidance in NEI 21- 07 Rev 0, the set of PDC consisted of the Required Functional Design Criteria (RFDC). This definition of scope was missing the following elements to satisfy the scope required by the regulatory history:

- Applicable special treatments (i.e., fabrication, construction, testing)

- Safety-significant functions and supporting SSCs beyond the RFDC (i.e., the Complementary Design Criteria, CDC)

• As such, NEI 21-07 wi ll be revised to reflect an approach for developing a set of PDC that includes:

- A graded Quality Assurance (QA) criterion that identifies the special treatments for the SSCs performing the functions comprising the PDC

- All safety-significant functions (i.e., RFDC and CDC)

77 PDC include Safety-Significant Functions/SSCs

PDC-RFDC

Required Required Safety Functional SR SSC Design Functions (RSFs) Design Cr iteria Criteria (SRDC)

(RFDC)

Fundamental Frequency-Safety Functions Consequence S af e ty SR SSC SR SSC Special

( FSF s) and Cumulative Related Performa nce Treatment Risk Targets (SR) SSCs Ta rgets Requirements

PRA Safety LBEs from LMP Design Basis Design Basis Functions (PSFs) (AOOs, DBEs, Accidents Externa l H aza rd and BDBEs) PDC-CDC (DBAs) Levels (DBEHLs)

Other Risk Significant Functions Safety Functions Provided in the Non-SR N SRS T SS C N SRS T SS C D es ig n with ST Performa nce Special (NSRST) Ta rgets Treatment Other Safety S SC s Requirements Functions for Adequ ate DID

Other Safety Non-SR Functions W ith N o ST S SC s ( N ST )

88 Example of Functional PDC (MHTGR)

Required Safety PDC-RFDC Function/Subfunctions Shutdown Reactor VI: The equipment needed to sense, command, and execute a trip of the control rods, along with any necessary electrical power, shall be designed and operated in such a manner that reactor core shutdown is assured during off-normal conditions.

Transfer Heat to X: A highly reliable, passive means of removing the heat Ultimate Heat Sink generated in the reactor core and radiated from the reactor vessel wall shall be provided. The system shall remove heat at a rate which limits core and vessel temperatures to acceptable levels during a loss of forced circulation.

Limit Fuel Oxidation XII: The primary system/boundary shall be designed to ensure high reliability of the primary system/boundary integrity needed to prevent air ingress during normal and off-normal conditions. The plant shall be designed and operated in a manner that ensures that the primary system boundary design limits are not exceeded.

From Appendix A of LMP SSC report: https://doi.org/10.2172/1700535 99 Handling of Special Treatments in PDC

• In addition to the functional criteria and the supporting SSCs, the PDC will include one Quality Assurance criterion (i.e., similar to GDC/ARDC 1) that addresses design, fabrication, construction, and testing quality standards for safety-significant (i.e., SR and NSRST) functions/SSCs

- NEI 18-04 Section 4.4.5: the applicability of any category of special treatment to any SSC must be evaluated on a case-by -case basis and in the context of the SSC functions in the prevention and mitigation of applicable LBEs

- i.e., the application will not necessarily state special treatments in every area for each and every safety-significant function/SSC, but the necessary special treatments (identified via the LMP approach) will be explicitly stated in the appropriate section of the SAR

- Note: fabrication, construction, testing, and performance requirements are not provided for every criterion uniformly in the GDC

>> Criterion 64 - Monitoring radioactivity releases. Means shall be provided for monitoring the reactor containment atmosphere, spaces containing components for recirculation of loss-of-coolant accident fluids, effluent discharge paths, and the plant environs for radioactivity that may be released from normal operations, including anticipated operational occurrences, and from postulated accidents. 1010 Considerations for QA PDC in TICAP

From 10 CFR Part 50, Appendix A (emphasis added):

Criterion 1 - Quality standards and records. Structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. Where generally recognized codes and standards are used, they shall be identified and evaluated to determine their applicability, adequacy, and sufficiency and shall be supplemented or modified as necessary to assure a quality product in keeping with the required safety function. A quality assurance program shall be established and implemented in order to provide adequate assurance that these structures, systems, and components will satisfactorily perform their safety functions. Appropriate records of the design, fabrication, erection, and testing of structures, systems, and components important to safety shall be maintained by or under the control of the nuclear power unit licensee throughout the life of the unit.

1111 Considerations for QA PDC in TICAP

• 10 CFR 50, Appendix A: S tructures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed.

• important/importance to safety would be replaced with safety -

significant and/or safety significance

1212 Considerations for QA PDC in TICAP

• 10 CFR 50, Appendix A: S tructures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed.

• NEI 18-04 provides guidance on SSC treatment commensurate with the safety-significance of the function to be performed

- Section 4.4.5: This is determined by design and confirmed via an Integrated Decision Process that is part of the LMP methodology for evaluating DID adequacy.

1313 Considerations for QA PDC in TICAP

• 10 CFR 50, Appendix A: W here generally recognized codes and standards are used, they shall be identified and evaluated to determine their applicability, adequacy, and sufficiency and shall be supplemented or modified as necessary to assure a quality product in keeping with the required safety function. A quality assurance program shall be established and implemented in order to provide adequate assurance that these structures, systems, and components will satisfactorily perform their safety functions.

• Under LMP, required safety function only pertains to SR-SSC

• safety function is not inclusive, since NSRST SSCs are non-safety

• Could replace with safety-significance/significant for inclusi on of SR and NSRST functions/SSCs

1414 Response to NRC Recommendations #1-3, 5

(See ML21344A006)

NRC Recommendation #1

• NRC: Include discussion on the affirmative safety case that recognizes that use of the LMP process by a non-LWR applicant under 10 CFR Parts 50 and 52 will inform the development of a safety case for the facility but may not address the entirety of the safety case necessary for an application for a license (e.g., normal operations, stable long-term subcriticality and cooling, etc.).

Elements of the safety case not informed by the LMP process and addressed in the TICAP guidance will be addressed in the ARCAP guidance.

1616 TICAP Response (Recommendation #1)

• TICAP: NEI 21-07 Rev0b specifically notes that the affirmativ e safety case does not address

- normal operations, and

- potential licensing basis events (such as subcriticality events) that applicant and regulator may decide are prudent to be added beyond the reasonable assurance of adequate protection standard.

• Additionally, TICAP will revise the guidance for SAR Chapter 5 to note that the PDC developed using the LMP and TICAP methodologies will not address the entirety of the safety case necessary for a license

1717 NRC Recommendation #2

• NRC: Include a discussion on the development of proposed PDC that recognizes that use of the LMP process by a non-LW R applicant under 10 CFR Parts 50 and 52 will inform the development of proposed PDC for the facility but may not include the entirety of PDC necessary to demonstrate, and for the NRC to find, that the facility will operate so as to provide adequate protection of the health and safety of the public (e.g., normal operations, stable long-term subcriticality and cooling, etc.).

Development of proposed PDC not informed by the LMP process and not addressed in the TICAP guidance will be addressed in the ARCAP guidance.

1818 TICAP Responses (Recommendation #2)

• TICAP: Rather than a few examples and etc., can the NRC pleas e provide a complete list of areas that it considers to require PDC that are not covered by LMP/TICAP?

• TICAP recognizes that an affirmative safety case developed using NEI 21-07 will not cover normal operations (see response to Recommendation #1)

- TICAP will note in the guidance for SAR Chapter 5 that the PDC developed using the LMP and TICAP methodologies will not address the entirety of the safety case necessary for a license

1919 NRC Recommendation #3 and TICAP Response

• NRC: Include a discussion on the development of proposed PDC that recognizes that the GDC in 10 CFR Part 50, Appendix A, and the ARDC in RG 1.232 provide guidance on the scope of proposed PDC to be developed by a non-LWR applicant under 10 CFR Parts 50 and 52 and contain the criteria that are sufficient to support an NRC finding that there is reasonable assurance of adequate protection of the health and safety of the public (i.e., design, fabrication, construction, testing, and performance requirements for structures, systems, and components).

• TICAP: NEI 21-07 will be revised to reflect the NRCs position on the scope of PDC with respect to the elements that must be addressed (without an exemption)

- Additional guidance will be added to NEI 21-0 7 guidance for SAR Chapter 5 regarding the development of an advanced reactor QA principal design criterion 2020 NRC Recommendation #5

• NRC: Include a discussion on the development of proposed P DC and CDC by a non-LWR applicant under 10 CFR Parts 50 and 52 that certain CDC may be considered by the NRC to be equivalent to PDC if necessary to support its finding if the CDC contain the criteria that are necessary to demonstrate there is reasonable assurance of adequate protection of the health and safety of the public (i.e., design, fabrication, construction, testing, and performance requirements for structures, systems, and components). In such cases, those CDC should be recategorized as PDC and may be categorized, for example, as PDC-B in a two-group PDC construct where PDC-A address SR SSCs and PDC-B address NSRST SSCs.

2121 TICAP Response (Recommendation #5)

• TICAP: The TICAP team will revise the guidance in NEI 21- 07 to reflect that the set of PDC should include both the RFDC and the CDC (if the applicant does not request an exemption)

• However, the TICAP team proposes defining the two categories of PDC as PDC-RFDC (corresponding to the RFDC and supporti ng SR SSCs) and PDC-CDC (corresponding to the CDC and supporting NSRST SSCs)

- This categorization has inherent consistency with the LMP approach (e.g., the meaning of RFDC is maintained)

2222 Potential Additional TICAP PDC Guidance: Justification for Exemption(s) on PDC Scope and Response to NRC Recommendation #4

Background:

Exemption for Reduced PDC Scope

• In the Dec 14 public meeting (ML21344A006), the staff opened to door to a combination of a risk-informed approach and an exemption request for applicants proposing PDC that do not fully address design, fabrication, construction, testing, and performance requirements

- Applicants would need to provide supporting information that justifies to the NRC how their design meets their proposed PDC and how their proposed PDC demonstrate reasonable assurance of safety.

- Applicants would need to ensure that the elements of the P DC scope not specifically included in their proposed PDC are included in their application.

2424 Proposed Additional TICAP PDC Guidance

• Some applicants may want to retain current TICAP PDC approach (PDC=RFDC) and obtain a partial exemption for the scope of PDC

1. Exemption from the implicit scope requirement of PDC from 10 CFR 50 Appendix A, i.e., that PDC include the necessary design, fabrication, construction, testing, and performance requirements for structures, systems, and components important to safety.

2. Exemption from implicit scope requirement of PDC from 10 CFR 50 Appendix A, i.e., that PDC include the necessary design, fabrication, construction, testing, and performance requirements for structures, systems, and components important to safety.

2525 Proposed Additional TICAP PDC Guidance

1. Functions and SSCs addressed by PDC

- NEI 18-04 method systematically identifies as safety -related selected SSCs available to perform Required Safety Functions

- NEI 18-0 4 method systematically identifies as NSRST selected SSCs that perform risk-significant functions or functions requiring special treatment for defense-in-depth adequacy

- NEI 21-0 7 approach (PDC RFDC) provides PDC applicable to safety-related SSCs but not to NSRST SSCs

• Justification for exemption:

>> The LMP process identifies NSRST SSCs through a systematic, risk-inf ormed process

>> Those NSRST SSCs are documented in the Safety Analysis Report (SAR) Chapter 7, along with special treatments and reliability and capability targets

>> Therefore elements of the PDC scope not specifically included in their proposed PDC are included in their application

2626 Proposed Additional TICAP PDC Guidance

2. design, fabrication, construction, testing, and performance requirements

- The RFDC and their supporting SSCs address How (=Adequate Protection; design requirements), but How Well (=Reasonable Assurance; fabrication, construction, testing, and, in some cases, performance requirements) is addressed elsewhere in the SAR

• Justification for exemption:

>> The LMP process systematically identifies special treatments for safety-rel ated and NSRST SSCs

>> Those special treatments provide reasonable assurance the SSCs will accomplish their safety functions

• The special treatments are documented in SAR Chapter 6 (safety-related SSCs) and Chapter 7 (NSRST SSCs)

• Reliability and capability targets for both classes of safety-s ignificant SSCs are also provided in SAR Chapter 6 and Chapter 7

>> Therefore elements of the PDC scope not specifically included in their proposed

32 of 47PDC are included in their application 2727 NRC Recommendation #4

• NRC: Include a discussion on the development of proposed PDC that informs non-LWR applicants that proposed PDC that do not address the comprehensive scope of criteria that are sufficient to support an NRC finding should request an exemption from the applicable regulations (i.e., 10 CFR 50.34(a)(3), 10 CFR 52.79(a)(4), 10 CFR 52.47(a)(3), 10 CFR 52.137(a)(3), and 10 CFR 52.157(a) and provide appropriate justification for the request.

2828 TICAP Response (Recommendation #4)

• TICAP: The TICAP team is amenable to this suggestion and sees it as part of the discussion to be added to NEI 21-07 to address an exemption-based approach for PDC.

- Clarification from the NRC regarding the relationship between the use of guidance in NEI 18-04 and/or NEI 21 -07 and justification for the exemption would be helpful to frame discussion of this exemption request

- Is NRC amenable to including a generic exemption in this endorsing RG for those applicants that include the How Well (the reasonable assurance element) in specific chapters of TICAP (e.g., Chapter X and Y)?

2929