ML23317A043
| ML23317A043 | |
| Person / Time | |
|---|---|
| Issue date: | 11/21/2023 |
| From: | Tanya Smith Office of Nuclear Security and Incident Response |
| To: | |
| References | |
| Download: ML23317A043 (1) | |
Text
NRC Emergency Preparedness for Small Modular Reactors and Other New Technologies Todd Smith, PhD Senior Level Advisor for Emergency Preparedness and Incident Response Office of Nuclear Security and Incident Response U.S. Nuclear Regulatory Commission 48th Meeting of the Nuclear Energy Agency (NEA) Working Party on Nuclear Emergency Matters (WPNEM)
November 21, 2023
Preparedness begins with a proven planning basis The consequences from a spectrum of accidents, tempered by probability considerations, should be considered to scope the planning efforts for the distance to which planning for predetermined protective actions is warranted [the emergency planning zone (EPZ)]
the time-dependent characteristics of a potential release the type of radioactive materials
The NRC applies a graded approach to EP A graded approach is a risk-informed process in which the safety requirements and criteria are set commensurate to facility hazards Existing NRC regulations use a graded approach to EP Power reactors (low-power testing, power operations, decommissioning)
Research and test reactors Fuel Fabrication Facilities Independent Spent Fuel Storage Installations Monitored Retrievable Storage
Major provisions of alternative EP regulations Draft final 10 CFR 50.160 provides an alternative framework for small modular reactors and other new technologies:
regulatory framework proportional to facility risk required EP functions set commensurate to radiological risk technology inclusive, performance based performance demonstration in drills and exercises hazard analysis for contiguous facilities ingestion planning capabilities scalable EPZ according to planning needs
Ingestion Pathway Planning Emphasizes capabilities and readiness to respond Identification of major exposure pathways for ingestion Identify resources available at all levels of government to sample, assess, and implement a quarantine or embargo of food and water to prevent ingestion
Scalable EPZ to support planning needs The EPZ is a planning tool, not a design feature The EPZ determination considers form and function:
The area within which public dose is projected to exceed 10 mSv TEDE over 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> considering:
accident likelihood source term timing of the accident sequence meteorology The area within which predetermined, prompt protective measures are warranted
The EPZ size is risk-informed The EPZ guidance does not change the requirements for emergency planning, it only sets bounds on the planning problem.
This figure is for illustration only.
SMR/ONT rule is based on established regulatory approaches for determining an EPZ
it was the consensus of the Task Force that emergency plans could be based upon a generic distance out to which predetermined actions would provide dose savings beyond the generic distance it was concluded that actions could be taken on an ad hoc basis The EPZ guidance does not change the requirements for emergency planning, it only sets bounds on the planning problem.
NUREG-0396, Planning Basis for the Development of State and Local Government Radiological Emergency Response Plans in Support of Light Water Nuclear Power Plants, November 1978 The EPZ is a planning tool not a design feature
PAR EPZ simplifies decisions for a prompt response PAD PAG Protective Action Guide (PAG) projected dose to an individual member of the public that warrants protective action Protective Action Recommendation (PAR) recommended protective measure from the nuclear power plant to offsite response organizations (OROs)
Protective Action Decision (PAD) measures taken in response to an actual or anticipated radiological release PAG PAR PAD
~ 32 km (20 miles)
The EPZ is scalable EPZ size based on the consequences from a spectrum of accidents, tempered by probability considerations NRC regulations provide for scalable EPZs Reactors have been approved for a 5 mile EPZ in the past Depending on facility type, the EPZ may be at the site-boundary or have no EPZ Considerable number of studies since the 1980s on sizing EPZs for passive and advanced reactor designs, many based on the NUREG-0396 methodology
The EPZ size is based on many factors The size of the EPZ for large light water reactors is based on the following considerations:
a.
Projected doses from traditional design basis accidents would not exceed Federal PAG levels outside the EPZ b.
Projected doses from most core melt sequences would not exceed Federal PAG levels outside the EPZ c.
For the worst-case core melt sequences, immediate life-threatening doses would generally not occur outside the EPZ d.
Detailed planning within [the EPZ] would provide a substantial base for expansion of response efforts in the event that this proved necessary
The EPZ size is risk-informed Design Basis Accidents Beyond Design Basis NUREG-0396, Planning Basis for the Development of State and Local Government Radiological Emergency Response Plans in Support of Light Water Nuclear Power Plants, November 1978
Deterministic approach can be applied ANSI/ANS-15.16-2008, American National Standard: Emergency Planning for Research Reactors, September 23, 2008 For Research and Test Reactors:
and you may not always need an EPZ For Spent Fuel Storage Facilities, Fuel Cycle Facilities, and Radioactive Material Licensees:
We have intentionally not defined an emergency planning zone for either the plume exposure pathway or the ingestion pathway as is done for nuclear power plant emergency planning plant emergency planning.
NUREG-1140, A Regulatory Analysis on Emergency Preparedness for Fuel Cycle and Other Radioactive Material Licensees, August 1991
Emergency planning is not based on the worst-case Regulation does not require dedication of resources to handle every possible accident that can be imagined. The concept of the regulation is that there should be core planning with sufficient planning flexibility to develop reasonable response to those very serious low probability accidents which could affect the public.
[SONGS CLI-83-10, 17 NRC 528, (1983)]
Capabilities are augmented as needed The Task Force believes that it is not appropriate to develop specific plans for the most severe and most improbable Class 9 events.
The Task Force, however, does believe that consideration should be given to the characteristics of Class 9 events in judging whether emergency plans based primarily on smaller accidents can be expanded to cope with larger events.
The planning basis recommended by the Task Force therefore includes some of the key characteristics of very large releases to assure that site specific capabilities could be effectively augmented with general emergency preparedness (response) resources of the Federal government should the need arise.
NUREG-0396, Planning Basis for the Development of State and Local Government Radiological Emergency Response Plans in Support of Light Water Nuclear Power Plants, November 1978
Consequence analyses are conservative NUREG-075/014 (WASH-1400), Reactor Safety Study: An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, October 1975
NUREG/BR-0359, Revision 3, Modeling Potential Reactor Accident ConsequencesState-of-the-Art Reactor Consequence Analyses: Using decades of research and experience to model accident progression, mitigation, emergency response, and health effects, October 2020 Our understanding of accidents has evolved
and will continue to evolve
Flexibility for how to meet an EP function Flexible frequency of inspection and oversight Scaled response capabilities commensurate with the facility hazards Recognizes diversity in design and enhanced safety potential for evolutionary technologies Risk-informed, performance-based EP is adaptable
EP is the answer to uncertainty
Todd Smith, PhD todd.smith@nrc.gov 301-287-3744