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NEI Advanced Reactor Di&C Task Force Slides - Accident Monitoring Instrumentation
	ML24075A209
Person / Time
Site:	Nuclear Energy Institute
Issue date:	03/14/2024
From:	Quinn T, Steh W; Nuclear Energy Institute, Paragon Energy Solutions, X-Energy
To:	; NRC/NRR/DANU
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Accident Monitoring Instrumentation

NEI Advanced Reactor DI&C Task Force Wesley Steh l X-energy Ted Quinn l Paragon ES

March 14, 2024

©2024 Nuclear Energy Institute 2 History of IEEE 497 and RG 1.97 RG 1.97, Rev. 3 issued December 1983 and endorsed ANSI/ANS-4.5-1980 - and referenced but did not endorse IEEE 497-1977 Provides prescriptive listing of Type A - E variables and variable categories for both BWRs and PWRs RG 1.97, Rev. 4 issued June 2006 and endorsed IEEE 497-2002, subject to regulatory positions States that Rev. 3 had become outdated, did not provide criteria for advanced instrumentation system designs based on modern digital technology and did not address the need for technology-neutral guidance for new plant licensing Instead of prescribing instrument variables to be monitored, provides flexible, performance-based criteria for the selection, performance, design, qualification, display and quality assurance of variables per IEEE 497-2002

©2024 Nuclear Energy Institute 3 History of IEEE 497 and RG 1.97 RG 1.97, Rev. 5 issued April 2019 to endorse IEEE 497-2016, subject to regulatory positions IEEE 497-2016 incorporates some of the NRC staff s regulatory positions in Rev. 4 and to revise some definitions and terminology Based on insights from the Fukushima Dai-ichi accident in March 2011, the US nuclear industry recognized the need for instrumentation to monitor plant conditions associated with fuel damage events IEEE 497-2016 expanded the scope of the standard to include consideration of instrumentation potentially required for coping with severe accidents as Type F variables

~2012, and in 2014, the first full draft of IEEE 497 was shared with IEC for consideration and expert review In 2016, IEC received the proposal of IEEE to endorse IEEE 497-2016 as a dual-logo standard In 2017, IEEE 497-2016 adoption as IEC 63147 was approved, and IEC TR 63123, Guidance for the application of IEC 63147:2017/IEEE Std 497 -2016 in the IAEA / IEC framework, was issued IEEE standard life cycle requirements mandate that a new revision of IEEE 497 be published before the end of 2026; a draft is being developed to produce a true joint-logo standard incorporating:

Points raised in IEC TR 63123 Main points of IAEA NP-T -3.16, Accident Monitoring Systems for Nuclear Power Plants

A revision of IEC 63147 scope is not envisioned Addition of IEC terms and definitions; existing terms will be reviewed to ensure conflicts are avoided The functional types A - F from IEEE 497 and functional categories A - C from IEC 61226 will be correlated to demonstrate that the two category sets represent analogous requirements Comments provided by NRC during development of the current RG 1.97, Rev. 5 will be considered for inclusion in the standard

Characterized by intrinsically safe attributes and passive design features Capable of preventing fuel damage and meeting regulatory dose limit criteria without relying on active safety systems or operator actions during or after licensing basis events (LBEs)

Do not require active monitoring of critical plant safety functions by operators in the same manner as conventional reactor designs for implementation of emergency operating procedures (EOPs)

©2024 Nuclear Energy Institute 7 Advanced Reactor Applications Implementation of RIPB methodologies such as NEI 18-04, as endorsed by RG 1.233, uses PRA to select licensing basis events (LBEs), identify PRA safety functions (PSFs), and define performance requirements within the LBEs The PSFs provided by monitoring instrumentation are based on plant design, the risk-significance of the functions, and the role of the functions in defense-in -depth (DID) adequacy Implementation of NEI 18-04 can result in Non-Safety -Related with No Special Treatment (NST) classification of monitoring systems Disconnect between requirements derived from SSC classification per NEI 18-04 and design, qualification, and quality requirements per IEEE 497 / IEC 63147

Defines six monitoring variable types (Type A - F)

Assigns monitoring instrumentation types according to functions performed but does not provide any functional categorization or system/component classification schemes Safety classification of monitoring instrumentation per the standard is subject to interpretation, prompting issuance of IEC TR 63123 Type A - C monitoring channel requirements align with requirements conventionally applied to SR equipment Type D - F monitoring channel requirements align with requirements conventionally applied to NSR equipment

Exception: Type D monitoring channels require qualification

©2024 Nuclear Energy Institute 10 Path Forward IEEE and IEC working groups are developing a true joint-logo standard, incorporating risk-informed techniques Revision is in progress per the IEEE 10-year life cycle before standard expiration, and intends to:

Incorporate operational lessons learned and address other industry concerns Reconcile differences in definitions and applications between IEEE and IEC as indicated in IEC 63147 and IEC TR 63123 related to IEEE 497-2016 Consider functional categorization and system classification as defined in IEC 61226

A r i s k-informed revision of IEEE 497 / IEC 63147 is not expected to be published prior to 2026 and will therefore not be available for near -

term license applicants Disconnect between requirements derived from SSC classification per NEI 18-04 and design, qualification, and quality requirements per IEEE 497 / IEC 63147 Advanced reactor developers anticipate deviating from the currently endorsed standard

Ted Quinn l Paragon Energy Solutions, Licensing Vice President tquinn@paragones.com

Alan Campbell l Nuclear Energy Institute, Technical Advisor adc@nei.org

ML24075A209

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