ML22104A191
| ML22104A191 | |
| Person / Time | |
|---|---|
| Issue date: | 04/14/2022 |
| From: | Tanya Smith NRC/NSIR/DPR |
| To: | |
| Smith T | |
| References | |
| Download: ML22104A191 (32) | |
Text
Pillars of Emergency Preparedness
Todd Smith, PhD Senior Level Advisor for Emergency Preparedness and Incident Response Office of Nuclear Security and Incident Response Objective of Radiological Emergency Preparedness
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)
NRC EP regulations provide 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 Whats changed over 40 years?
Technology is Advancing Advanced light water reactors, non-light water reactors, and small modular reactors (SMR) with passive safety features, microreactors, accident tolerant fuels, and other new technologies (ONT)
Technology important to Emergency Preparedness (e.g., IPAWS, artificial intelligence)
Knowledge is Increasing Better understanding of actual effects of radiation Research to inform protective action decision-making Lessons learned from real world events Regulations and Guidance are Evolving NRC has a vision to become a modern risk-informed regulator Nuclear Energy Innovation and Modernization Act (NEIMA)
EP rulemaking for SMR & ONT and decommissioning power reactors What about?
A robust defense-in -depth strategy includes EP
Defense-in-depth is an approach to designing and operating nuclear facilities that prevents and mitigates accidents that release radiation or hazardous materials.
Provides multiple independent and redundant layers of defense to compensate for potential human and mechanical failures so that no single layer, no matter how robust, is exclusively relied upon.
EP is required as a final, independent layer of defense-in-depth The NRC employs a graded approach to EP
A graded approach is a risk-informed process in which the safety requirements and criteria are set commensurate to the risk of the facility EP regulations employ a graded approach to provide the same level of protection Power reactors (low-power testing, power operations, decommissioning)
Research and test reactors Fuel Fabrication Facilities Independent Spent Fuel Storage Installations Monitored Retrievable Storage Distance Time Materials NUREG-0396 Planning Basis for EP
Pillars of EP:
The consequences from a spectrum of accidents, tempered by probability considerations, should be considered to scope the planning efforts for:
The d i sta n ce to which planning for predetermined protective actions is warranted The time dependent characteristics of a potential release 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 Planning Distance The distance to which planning for predetermined protective actions is warranted EPZ size is 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 s ite-boundary or no EPZ Considerable number of studies since the 1980s on sizing EPZs for passive and advanced reactor designs all Distance based on NUREG-0396 methodology EP EPZ The EPZ is a planning tool
Pillars of EP:
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
The EPZ guidance does not change the requirements for emergency planning, it only sets bounds on the planning problem.
beyond the generic distance it was concluded that Distance actions could be taken on an ad hoc 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 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 Whats the likelihood of events considered?
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 EPZ size methodology can be applied to any facility
EPRI TR-113509, Technical Aspects of ALWR Emergency Planning, Final Report, September 1999 Uncertainty can be quantified and bounded
NUREG/CR-7245, State -of-the-Art Reactor Consequence Analyses (SOARCA) Project: Sequoyah Integrated Deterministic and Uncertainty Analyses, October 2019 Planning Time The time dependent characteristics of a potential release
Time
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 Conservatively bounds timing of severe accidents
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 Applying the Time basis to regulation
Proposed rule for power reactors based on the reduction in risk at four levels of decommissioning,
including the time when spent fuel has sufficiently decayed such that it would not reach self -ignition temperature in 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> under adiabatic heatup conditions
Initiating Event 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> Mitigate or (Severe Earthquake) Initiate Response
Time
Federal Register Notice Proposed Rule, Regulatory Improvements for Production and Utilization Facilities Transitioning to Decommissioning: Proposed Rule, 87 FR 12254 March 3, 2022 Conservatively assumes spent fuel pool damaged and drains instantaneously
NUREG-2161, Consequence Study of a Beyond -Design-Basis Earthquake Affecting the Spent Fuel Pool for a U.S.
Mark I Boiling Water Reactor, September 2014 Conservatively assumes unfavorable heat transfer
Transmittal of Reports to Inform Decommissioning Plant Rulemaking for User Need Request NSIR-2015- 001, dated May 31, 2016 (ADAMS Accession No. ML16110A416)
Conservatively assumes instantaneous release
Transmittal of Reports to Inform Decommissioning Plant Rulemaking for User Need Request NSIR-2015- 001, dated May 31, 2016 (ADAMS Accession No. ML16110A416)
Conservative regulations cover uncertainty
Proposed regulatory criteria
Minimum time margin: + 8.5 hr
Median time margin: + 24 hr
Realistic time margin: + days
10 hr Margin in 10 hr criteria Time Release Characteristics The type of radioactive materials
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 Our understanding of accidents has evolved
NUREG/BR-0359, Revision 3, Modeling Potential Reactor Accident Consequences State-of-the-Art Reactor Consequence Analyses: Using decades of research and experience to model accident progression, mitigation, emergency response, and health effects, October 2020 and will continue to evolve The planning basis informs EP planning functions
Prescriptive and/or Performance -Based Ensure capabilities exist to detect, classify, notify, assess, mitigate, and effectively respond to an emergency Probabilistic vs. Deterministic Approach
Pillars of EP:
If it were possible to identify a single accident on which to base emergency response planning, one could use the release characteristics of that single accident in connection with site specific characteristics and other generic information to specify the planning effort.
Deterministic approach can be used
Fuel Cycle and Other Radioactive Material Licensees Research and Test Reactors
Spent Fuel Storage FacilitiesPillars of EP:
Pillars of EP (NUREG-1140):
NUREG-1140, A Regulatory Analysis on Emergency Preparedness for Fuel Cycle and Other Radioactive Material Licensees, August 1991 ANSI/ANS-15.16-2008, American National Standard: Emergency Planning for Research Reactors, September 23, 2008 EP has always been a whole community approach
Pillars of EP:
The planning basisincludes 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 NRC regulations are built upon the foundational pillars for preparedness and response