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Meeting Slides (Applicant) - Terrapower Natrium November 7, 2024 Plume Exposure Applicant Presentation - Fc - November 6-8, 2024
	ML24310A105
Person / Time
Site:	Kemmerer File:TerraPower icon.png
Issue date:	11/05/2024
From:	; TerraPower
To:	; Advisory Committee on Reactor Safeguards
References
	TP-LIC-PRSNT-0031
	Download: ML24310A105 (1)
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SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2024 TerraPower, LLC. All Rights Reserved SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2024 TerraPower, LLC. All Rights Reserved Natrium reactor is a TerraPower & GE Hitachi technology ACRS Full Committee Meeting November 2024 Plume Exposure Pathway Emergency Planning Zone Sizing Methodology TP-LIC-PRSNT-0031

Overview of NAT-3056, TerraPower, LLC (TerraPower) Natrium Topical Report:

Plume Exposure Pathway Emergency Planning Zone Sizing Methodology

Guidance Used

Methodology

Conclusion Table of Contents

Regulatory Guide 1.242, Performance-Based Emergency Preparedness for Small Modular Reactors, Non Light-Water Reactors, and Non-Power Production or Utilization Facilities was utilized in developing the overall methodology.

Supporting information from NUREG-0396, Planning Basis for the Development of State and Local Government Radiological Emergency Response Plans in Support of Light Water Nuclear Power Plants was used to assist in the development of the evaluation criteria.

NAT-3056 Guidance Used

Assesses all modes and all hazards

Incorporates site specific meteorological data

Assesses radiological consequences

Identifies prompt protective measures

Establishes final PEP EPZ Size NAT-3056 Overall EPZ methodology

Includes DBAs

Includes events with a 95th percentile release frequency greater than 1E-7

Includes events for cliff-edge consideration if they have a release frequency greater than 1E-8 NAT-3056 Non-seismic Event Selection

Mean: 2E-7, 95th percentile: 6E-7 screened into EPZ evaluation

Mean: 8E-8, 95th percentile: 2E-7 screened into EPZ evaluation

Mean: 2E-8, 95th percentile: 6E-8 considered for cliff-edge effects

Mean: 8E-9, 95th percentile: 2E-8 screened out of EPZ evaluation NAT-3056 Non-Seismic Event Selection Example

Developed a bounding seismic event for the CPA

Will generate a list of seismic EPZ events using a limiting PGA as threshold NAT-3056 Seismic Event Selection

Limiting PGA is LOWER of the two:

2x(GMRS) OR 1.0g

Ensures that range of seismic hazard within credible range of ground motions

Acknowledges limitations of the SPRA

Acknowledges uncertainties in the emergency response infrastructure NAT-3056 Development of Limiting PGA

Criterion A: Projected doses from the DBAs would not exceed 1 rem mean 4-day TEDE and 5 rem 95th percentile 4-day TEDE.

Criterion B: Projected doses from most radiological release sequences would not exceed 1 rem mean 4-day TEDE and 5 rem 95th percentile 4-day TEDE.

Criterion C: Immediate life-threatening doses from the worst-case radiological release sequences would not exceed 24-hour, 200 rem red marrow acute effective dose.

NAT-3056 Criteria for PEP EPZ Sizing

NUREG-0396 - Planning Basis for the Development of State and Local Government Radiological Emergency Response Plans in Support of Light Water Nuclear Power Plants

NUREG-7009 and NUREG-7161 - MACCS best practices and technical basis in the SOARCA

NUREG-4214 - Health Effects Models for Nuclear Power Plant Accident Consequence Analysis Identified as most limiting and confirmed by sensitivity analysis Available for quantification within MACCS NAT-3056 Red Bone Marrow Use

EPZ size is set based on smallest distance criteria are met.

If the criteria are NOT met at the desired EPZ size, determination is made if design changes or refinements can be made to reduce EPZ size. Otherwise EPZ is expanded to meet the criteria.

NAT-3056 Conclusion

SUBJECT TO DOE COOPERATIVE AGREEMENT NO. DE-NE0009054 Copyright © 2024 TerraPower, LLC. All Rights Reserved 13 CPA - Construction Permit Application DBA - Design Basis Accident EPZ - Emergency Planning Zone GMRS - Ground Motion Response Spectra MACCS - MELCOR Accident Consequence Code System PEP - Plume Exposure Pathway PGA - Peak Ground Acceleration PRA - Probabilistic Risk Assessment SOARCA - State-of-the-Art Reactor Consequence Analysis SPRA - Seismic Probabilistic Risk Assessment TEDE - Total Effective Dose Equivalent Acronym List

ML24310A105

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