ML23184A115
| ML23184A115 | |
| Person / Time | |
|---|---|
| Issue date: | 06/08/2023 |
| From: | Tanya Smith Office of Nuclear Security and Incident Response |
| To: | |
| References | |
| Download: ML23184A115 (1) | |
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Planning Basis for Radiological Emergency Preparedness National SLO Conference June 8, 2023 Todd Smith, PhD Senior Level Advisor for Emergency Preparedness and Incident Response Office of Nuclear Security and Incident Response U.S. Nuclear Regulatory Commission
Objective of Radiological EP
- The objective of emergency preparedness (EP) is to provide dose savings for a spectrum of accidents that could produce doses in excess of the Environment Protection Agency (EPA) protective action guides (PAG)
- Meeting NRC EP regulations provides reasonable assurance that adequate protective measures can and will be taken in the event of a radiological emergency Reasonable assurance finding is made before a nuclear facility is licensed Inspected over the lifetime of that facility
EP EPZ The NRC employs a graded approach to EP
- A graded approach is a process by which the safety requirements and criteria are set commensurate with several factors including magnitude of hazards involved, characteristics of a facility, the balance between radiological and nonradiological hazards.
- EP regulations employ a graded approach, which is a risk-informed process Power reactors (low-power testing, power operations, decommissioning)
Research and test reactors Fuel Fabrication Facilities Independent Spent Fuel Storage Installations Monitored Retrievable Storage
EP has a firmly established risk-informed 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 time dependent characteristics of a potential release
- The type of radioactive materials The planning basis document included a recommended 10 mile plume exposure path emergency planning zone (EPZ) and a 50 mile ingestion pathway zone for large light water reactors (PWR and BWR)
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
Planning Distance The distance to which planning for predetermined protective actions is warranted
- The EPZ is a planning tool 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 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
- Considerable number of studies since the 1980s on sizing EPZs for passive and advanced reactor designs, many based on the NUREG-0396 methodology
EPZ simplifies decisions PAG for a prompt response PAR PAD Protective Action Guide (PAG) projected dose to an individual member of the public that warrants protective action Protective Action Recommendation (PAR) PAG recommended protective measure from the nuclear power plant to offsite response PAD PAR organizations (OROs)
Protective Action Decision (PAD) measures taken in response to an actual or anticipated radiological release
Planning Time The time dependent characteristics of a potential release 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
Effectiveness of protective actions related to timing The guidance cannot be very specific because of the wide range of time frames associated with the spectrum of accidents considered.
Therefore, it will be necessary for planners to consider the possible different time periods between the initiating event and arrival of the plume and possible time periods of release in relationship to time needed to implement protective actions.
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
Timing considerations are conservatively bounded NUREG-075/014 (WASH-1400), Reactor Safety Study: An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, October 1975
Time basis informs functional requirements
- nuclear power reactor licensees shall establish and maintain the capability to assess, classify, and declare an emergency condition within 15 minutes after the availability of indications to plant operators that an emergency action level has been exceeded
- A licensee shall have the capability to notify responsible State and local governmental agencies within 15 minutes after declaring an emergency
- The design objective of the prompt public alert and notification system shall be to have the capability to essentially complete the initial alerting and initiate notification of the public within the plume exposure pathway EPZ within about 15 minutes Appendix E to 10 CFR Part 50
Our understanding of accidents has evolved More time is available to act than previously understood 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
Release Characteristics The type of radioactive materials 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
WASH-1400 informed early understanding NUREG-075/014 (WASH-1400), Reactor Safety Study: An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, October 1975
Our understanding of accidents has evolved Release fractions are much smaller than previously undertood 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
Planning basis balances protection and resources 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 time dependent characteristics of a potential release
- The type of radioactive materials The planning basis document included a recommended 10 mile plume exposure path emergency planning zone (EPZ) and a 50 mile ingestion pathway zone for large light water reactors (PWR and BWR)
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 likelihood of events considered is very low NUREG-075/014 (WASH-1400), Reactor Safety Study: An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, October 1975
down to 1 chance in 10 lifetimes of the universe NUREG-075/014 (WASH-1400), Reactor Safety Study: An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, October 1975
Worst case is addressed in the planning 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 available at Federal level 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
Response capabilities are coordinated across levels Licensee State Federal
Different facilities require different capabilities The planning basis informs EP planning functions Ensure capabilities exist to detect, classify, notify, assess, mitigate, and effectively respond to an emergency Planning Basis Emergency Planning Needs and Functions EPZ size, exposure pathways, protective Distance action strategies Spectrum Timeliness of classification and notification, of Time protective action strategies, mitigation Accidents Detection and assessment capabilities, Materials radiological protection, mitigation
EP > EPZ Key Takeaways Emergency Preparedness
- EP ensures protective actions can and will be taken
- The EP planning basis is valid and useful
- EP regulations are risk-informed and commensurate to the potential hazards presented by the class of facility Informed by characteristics of a spectrum of accidents Evidence-based Contain built-in conservatisms Emphasize capabilities