The Nuclear Regulatory Commission (NRC) concluded a comment period last Friday on Emergency Preparedness for Small Modular Reactors (SMRs), and Other New Technologies (ONTs). This rule, if enacted, would create an alternative emergency preparedness (EP) framework for SMRs and ONTs, a major departure from current NRC EP regulation which was written for large light water reactors (LWRs) and research and test reactors (RTRs). Previously NRC only granted individual waiver exemptions to some facilities with unique situations who requested them under some circumstances, a process which was slow and difficult both for the agency and for the licensee.

The current set of EP regulations were written mainly for large LWRs—along with RTRs—which average about one gigawatt of output each in the U.S. Additionally, 32 U.S. nuclear power plants have two reactors, and three of them have three. This means that their EP plans account for thousands of megawatts of generation. Many of the new reactor designs currently being developed, or that are already in the NRC approval process have a small fraction of their output. This, in addition to a variety of design features that can be found among proposed SMR and ONT designs means that these technologies require a new approach.

With many new technologies making their way through the development pipeline, NRC determined that it was time to revisit the decades old EP rules and create a new framework that emergent technologies could utilize. If enacted, this rule would allow SMRs and ONTs to replace the 10 mile plume exposure pathway (PEP), and 50 mile ingestion exposure pathway (IEP) with a “performance-based, technology-inclusive, risk-informed, and consequence oriented approach” which would allow facilities that pose less dosage risk to the public in the unlikely event of an accident to have smaller PEP and IEP emergency planning zones (EPZs)  commensurate to the risk that they pose.

According to the text of the proposed rule:

“The NRC’s objective for this rulemaking is to create alternative EP requirements that would:

1) continue to provide reasonable assurance that adequate protective measures can and will be implemented by an SMR or ONT licensee;

2) promote regulatory stability, predictability, and clarity;

3) reduce requests for exemptions from EP requirements;

4) recognize advances in design and technology advancements embedded in design features;

5) credit safety enhancements in evolutionary and passive systems; and

6) credit smaller sized reactors’ and non-LWRs’ potential benefits associated with postulated accidents, including slower transient response times, and relatively small and slow release of fission products.”

The rule has Department of Energy (DOE) support. In her public comment to the NRC on the proposed rule, Dr. Rita Baranwal, Assistant Secretary for Nuclear Energy at DOE said that the proposed rule, “is a critical step in determining the appropriate Emergency Planning Zone (EPZ) size for SMRs using a risk-informed methodology as it will properly credit the advanced safety and performance characteristics of these new advanced reactor designs.”

The “advanced safety and performance characteristics” that she refers to make many SMRs and new technologies much different from the larger LWRs that currently make up the U.S. nuclear retinue. One of these is passive safety. Many new designs are passively safe, meaning that in the unlikely event of a reactor meltdown, the reactor is able to cool itself without operator intervention, increasing its safety.

Dr. Baranwal’s comment went on to say that, “The proposed rule allows determination of a plume exposure pathway (PEP) EPZ size that is commensurate with the potential radiological risk for a specific facility and the Department agrees that a risk-informed EPZ sizing approach, as applied to SMR designs and other new technologies, accurately reflects the technological advances in reactor design, gained nuclear industry experiences, and regulatory guidance updates while ensuring that there is no undue risk to public health and safety.”

Although the rule has DOE support, it also has its detractors. These include Dr. Ed Lyman of the Union of Concerned Scientists, a mainstay of opposition to nuclear projects, who argued that, “[t]he evidence demonstrates the 10-mile EPZ for existing reactors is not adequate and it certainly doesn’t support reducing the zone.”

NRC Commissioner Jeff Baran was the only vote against the rule. In his comment on the vote he said that, “These new designs could potentially be safer than current large light-water-reactor designs. But that does not eliminate the need for EPZs and dedicated offsite emergency planning to provide defense-in-depth in case something goes wrong.” The rest of Baran’s comment against the rule focuses on the importance of coordination with FEMA and of maintaining extensive EPZs.

The proposed rule was published on May 12th, and its comment period which was supposed to end on July 27th was extended by the NRC following requests, and concluded on September 25th. Now that the commission has received comments, it will respond to them and provide an analysis, after which point the rule with whatever modifications arise from comments will be finalized.

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