The US Nuclear Regulatory Commission (NRC) has issued a final rule and associated regulatory guide providing an alternative avenue for small modular reactors (SMRs) and advanced reactors to satisfy emergency preparedness requirements. The long-anticipated rulemaking allows SMRs and advanced reactor license applicants to develop performance-based emergency preparedness programs instead of using the current prescriptive offsite radiological emergency planning requirements originally designed for large light-water reactors (LWRs).
This rule becomes effective on December 18, 2023. The NRC concurrently issued an associated regulatory guide, Regulatory Guide 1.242, Performance-Based Emergency Preparedness for Small Modular Reactors, Non-Light-Water Reactors, and Non-Power Production or Utilization Facilities.
The final rule creates alternative emergency preparedness requirements for SMRs and advanced reactors that “continue to provide reasonable assurance” of public health and safety while “promot[ing] regulatory stability, predictability, and clarity.” The shift to a performance-based model “recognize[s] advances in design and technology advancements embedded in design features” and “safety enhancements in evolutionary and passive systems” of these reactor types in planning for and responding to potential accidents.
Background
Existing emergency preparedness requirements and guidance focus primarily on large LWRs. Recent technological advancements in reactor design allow for a different approach to emergency planning that accounts for the lower-risk and advanced safety features of these new designs. As Morgan Lewis discussed in August 2023, the NRC has fulfilled its goal of finalizing this rulemaking by the end of 2023.
Final Rule Applicability and Approach
The final rule provides “a performance-based, technology-inclusive, risk-informed, and consequence-oriented alternative approach to [emergency preparedness] for SMRs and [advanced reactors].” It applies both to existing and future SMRs and advanced reactors.
Facilities covered by the final rule are limited to SMRs (defined by the rule as LWRs generating 1,000 MW thermal power or less per module), advanced reactors (i.e., non-LWRs), research and test reactors, and medical radioisotope production facilities. The rulemaking excludes LWRs licensed to produce greater than 1,000 MW thermal power, fuel cycle facilities, and existing research and test reactors, all of which will remain subject to existing emergency preparedness requirements.
The final rule creates a new alternative performance-based emergency preparedness framework at 10 CFR § 50.160. Current regulations for reactors require site-specific emergency plans designed around 16 planning standards.
While this deterministic structure works well for large LWRs whose risks are well defined and understood, because SMRs and other new nuclear technologies may use a wide range of design and safety features, the NRC finds a performance-based approach better suited while also reducing the administrative burden to evaluate expected requests for exemption from existing regulations.
A key feature of the performance-based framework is the ability of a licensee to use drills and exercises to demonstrate that it can carry out an effective emergency response. Under the new regulations in 10 CFR § 50.160(b)(1)(iii), a licensee’s emergency response team needs to perform the following tasks:
- Establish an emergency classification and action level scheme with criteria for determining when to notify and request support from other government agencies
- Demonstrate the ability to assess, classify, monitor, and repair facility malfunctions and return the facility to safe conditions
- Demonstrate the capability to implement and maintain protective actions
- Demonstrate that control room staff are capable of making effective communications to emergency responders and the NRC
- Demonstrate continuity of operations through one or more shift changes of emergency response personnel
- Demonstrate effective emergency response with the level of staffing
- Demonstrate the ability to assess radiological conditions
- Demonstrate general plans for reentry after an emergency
- Implement a corrective action program to evaluate, track, and correct weaknesses and deficiencies identified in drills and exercises
The final rule also amends 10 CFR § 50.33 to provide for a scalable approach to determining the size of an emergency planning zone (EPZ). Currently, the plume exposure pathway and ingesting pathway EPZs are set at a 10-mile and 50-mile radius, respectively, although reactors under 250 MW thermal and gas-cooled reactors can apply for smaller zones.
To account for the safety features of newer reactor designs that reduce or eliminate the offsite dose consequence, the Final Rule employs a consequence-oriented approach to determine the size of an exposure plume.
Specifically, licensees must establish an EPZ for the area within which the public dose would exceed 10 millisieverts over 96 hours after a release. That is, rather than setting a predetermined inflexible distance for the EPZ, the distance would be determined by the potential consequence of an accident based on factors such as accident likelihood and source term, timing of the accident sequence, and meteorology.
For a facility with an EPZ that does not extend beyond the site boundary, the licensee need not determine the exact configuration of a plume exposure pathway. Additionally, where the EPZ remains onsite, local first responders are not required to participate in radiological drills and exercises. In such instances, the NRC is reasonably assured that appropriate response actions can and will be taken in the event of a radiological emergency without the need for regulatory standards.
The final rule also clarifies that an emergency plan that satisfies the Section 50.160 requirements also will satisfy the emergency preparedness requirements for a co-located independent spent fuel storage installation licensed under 10 CFR Part 72.
Regulatory Guide 1.242
Regulatory Guide 1.242 identifies methods and procedures that NRC staff considers to be acceptable for SMRs and advanced reactors (i.e., non-LWRs) to demonstrate compliance with the NRC’s new performance-based emergency preparedness requirements. Regulatory Guide 1.242 provides several general recommendations in addition to specific recommendations for implementing the performance-based framework, ensuring a sufficient emergency plan, and guiding offsite planning if required.
NRC regulatory guides are not regulations and compliance is not mandatory, and as such compliance proposals that differ from those set forth in the Regulatory Guide may still be deemed acceptable by the Commission. Such guides, however, help licensees comply with regulations, and following the guides makes NRC approval more likely and timely. A licensee seeking to satisfy the NRC’s new performance-based emergency preparedness requirements should consult Regulatory Guide 1.242.
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