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Inadequate Emergency Planning Zones for small modular nuclear reactors

No emergency planning zones for SMRs? NRC commissioner warns against “flimsy” rule that could extend to current reactor fleet, Beyond Nuclear International By Jeff Baran,  12 Oct  20, In a 3-1 vote by NRC Commissioners on December 17, 2019, Proposed Rule: Emergency Preparedness for Small Modular Reactors and Other New Technologies (SECY-18-0103) was accepted. The Rule would eliminate the need for Emergency Planning Zones and dedicated offsite emergency planning for Small Modular Reactors. The lone dissenting vote came from NRC Commissioner Jeff Baran. These are his comments.

For the last 40 years, NRC has required emergency planning zones, or EPZs, (Emergency Planning Zones) around nuclear power plants “to assure that prompt and effective actions can be taken to protect the public in the event of an accident.” Every one of the 96* operating large light-water reactors in the country has a plume exposure pathway EPZ that extends about 10 miles around the site with dedicated offsite radiological emergency plans and protective actions in place to avoid or reduce radiation dose to the public during an accident. An ingestion exposure pathway EPZ with a radius of 50 miles around each of these sites is designed to avoid or reduce dose from consuming food and water contaminated by a radiological release.

The EPZs and dedicated radiological emergency plans are meant to provide multiple layers of protection – or defense-in-depth – against potential radiological exposure. Other NRC requirements are focused on preventing or mitigating a radioactive release. The emergency planning regulations are there to provide another layer of defense in case a release occurs despite those safety requirements.

In other words, EPZs and radiological emergency planning are designed to address low-probability, high-consequence events. The Federal Emergency Management Agency (FEMA) assesses the adequacy of the offsite emergency plans, and NRC regulations require licensees to hold offsite emergency preparedness drills at each plant at least once every 2 years to practice implementing the plan .

Under this proposed rule, emergency planning for small modular reactors (SMRs) and non-light-water reactors would be flimsy by comparison. Instead of a 10-mile plume exposure pathway EPZ, these reactors would have EPZs that encompass only areas where the projected dose from “credible” accidents could exceed 1 rem. An EPZ extending only to the site boundary is explicitly permitted under this methodology.

In the case of a site-boundary EPZ, NRC would not require dedicated offsite radiological emergency planning and FEMA would have no role in evaluating the adequacy of a site’s emergency plans. In addition, the proposed rule would eliminate the requirement for an ingestion exposure pathway EPZ and no longer require a specific drill frequency for emergency planning exercises. Overall, this proposed rule represents a radical departure from more than 40 years of radiological emergency planning…………

We need to take FEMA’s warnings seriously. FEMA has a key role in determining whether the emergency planning for a nuclear power plant site is adequate. Under NRC’s regulations, a nuclear power plant license cannot be issued unless NRC makes a finding that the major features of the emergency plan meet the regulatory requirements. And NRC is supposed to base its finding on FEMA’s determinations as to whether the offsite emergency plans are adequate and whether there is reasonable assurance that they can be implemented.

No new SMR or non-light-water reactor designs have yet been approved by NRC, and only one SMR design has been submitted for the staff’s review. 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…….

In addition to the issues identified by FEMA, there are several other significant problems with the proposed rule.

First, the logic of the proposed EPZ sizing methodology could be applied to the existing fleet of large light-water reactors to weaken the current level of protection. As the Advisory Committee on Reactor Safeguards noted:

No technical basis is stated in the rule or the guidance for restricting the use of the new rule to SMRs and [other new technologies] with a limit on thermal power. The rule could apply to any reactor technology regardless of size. During our meetings, the staff acknowledged this point.

In fact, the proposed rule explicitly seeks comment on whether to apply this kind of approach to large light-water reactors. This opens the door to smaller EPZs and reduced emergency planning for the existing fleet of power reactors. If the proposed rule’s formulaic approach is adopted, a precedent will be established for applying a purely risk-based methodology to EPZ sizing. 

Second, the proposed rule does not account for the possibility of accidents affecting more than one SMR module. Even though some SMR designs contemplate several reactors at one site, the EPZ sizing methodology addresses each reactor in isolation. This ignores a key lesson of the Fukushima accident – that severe natural disasters can simultaneously threaten multiple reactors at a site. Under the draft proposed rule, a SMR is defined as a power reactor that produces less than 1,000 megawatts-thermal. The combined heat energy produced by just two SMRs of this size could be larger than that of some existing large light-water reactors in the U.S. But, under the proposed rule, each module could individually qualify for a site boundary EPZ without consideration of the other.

Third, unlike the existing regulations for large light-water reactors, the proposed rule “would not define the required frequency of drills and exercises” for emergency preparedness. As a result, SMR and non-light-water reactor licensees would not be required to conduct a full offsite emergency preparedness drill every 2 years. The NRC staff provides no basis for this weaker standard.

Finally, the proposed rule would eliminate the ingestion pathway EPZ for SMRs and non- light-water reactors . . . No FEMA evaluation of this change is provided. Nor is there any discussion of the effectiveness of ad hoc responses to previous radiological releases. Moreover, if the staff’s unbounded rationale were adopted, it could ultimately lead to ingestion pathway EPZs being dropped for the existing fleet of large light-water reactors.

For these reasons, I do not support finalizing the proposed rule in its current form. NRC needs a rule that provides regulatory certainty for potential applicants and recognizes that SMRs and non-light-water reactors will be different than traditional, large light-water reactors. It makes sense to have a graded approach that accounts for potential safety improvements in new designs. But the rule should not be purely risk-based, relying entirely on the results of a dose formula. Instead, NRC should issue a rule to establish the following emergency planning requirements for three categories of nuclear power plants………….https://beyondnuclearinternational.org/2020/10/12/no-emergency-planning-zones-for-smrs/

 

October 13, 2020 - Posted by | safety, Small Modular Nuclear Reactors, USA

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