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Slides (External) - ACRS Presentation for DG-1425 - Draft RG 1.183 - Sc - December 19, 2024
	ML24352A260
Person / Time
Site:	Nuclear Energy Institute
Issue date:	12/17/2024
From:	Csontos A; Nuclear Energy Institute
To:	; Advisory Committee on Reactor Safeguards
References
	Download: ML24352A260 (7)
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Draft RG 1.183 R2

©2024 Nuclear Energy Institute 2 IE Rulemaking Interface with RG 1.183 How does the proposed addition of a new non-bounding radiological accident (FFRD LOCA) and addition of new proposed tech specs supporting LOCA align with the intent of the ADVANCE Act?

Since MHA LOCA bounds the LOCA consequences inclusive of FFRD, what is the safety benefit of the new analysis requirement?

How is the NRC evaluating the holistic implementation of the rule package?

Is this a modern and cohesive rule package?

Proposed changes are based on out-of-date risk information as compared to what plants are currently approved for in recent TSTF-505 and 425 It is unclear if the dose consequence evaluation requires a separate dispersal calculation from the coolability assessment Alignment of Rule Package to Commission direction and intent of ADVANCE Act for a more risk-informed, modern, efficient regulatory process

Appreciates the open and transparent dialogue with NRC staff during the public workshops (3) and information meetings (2)

Critical in addressing key technical issues supporting future industry initiatives and operation Increased fuel enrichment and fuel cycle burnup Discussions highlighted industry interest in NRC addressing technical and regulatory improvements BWR suppression pool scrubbing credit Best-Estimate Plus Uncertainty Approaches Incorporation of Probabilistic Risk Assessment (PRA) basis providing relief in Control Room Design Criteria

Encourages NRC to continue this practice in future Regulatory Guide developments Industry is supportive of NRC efforts in DG-1425 development

Acknowledges significant technical items remain to be addressed Equipment Qualification (EQ) applicability for continued use of TID-14844 source term

NRC communicated clarification is planned for a subsequent Regulatory Issue Summary (RIS) or another regulatory vehicle

Industry provided a White Paper position to the NRC (ML24165A085)

Development of updated deposition coefficients using the new phase durations for both BWR and PWR containments

NRC communicated updated are planned for a subsequent regulatory vehicle (possible Technical Report update)

Challenges remain to implementation of Revision 2

Adding a new analysis for LOCA + FFRD does not appear to be risk-informed MHA LOCA bounds the LOCA consequences inclusive of FFRD, regardless of fuel form Has the proposed approach been exercised to assess its usability and impacts?

Efficiency improvement could be a generic approach showing MHA LOCA bounds the FFRD LOCA for all sites Proposed Revision 2 adds another dose DBA for "LOCA with FFRD"

Industry supports the Staffs position to keep all versions

Application of the revised MHA-LOCA source term and new DBA-LOCA requirements should not be backfit on the existing fleet without proper justification in accordance with 10 CFR 50.109

Application of the new or modified staff positions should not be forward fit on future licensing actions except for those supporting HBU and increased enrichment above 5 wt%

Multiple Revisions of RG 1.183 remain in effect

Additional technical and methodological updates may be considered taking advantage of reactor design and operational improvements justifying relaxation of conservative, hypothetical models Maximum Hypothetical Accident (MHA) release fractions and timing scenarios reflect unrealistically long timelines to release termination for DBA dose consequences

When is "release of appreciable quantities of fission products" achieved?

Plant configurations, safety-related features, and operator actions and training make these outcomes extremely unlikely Enhancements to be considered in future revisions

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