By Matthew Bandyk

NuScale Power LLC is aiming to have the first federally certified design for a small modular nuclear reactor, and approving that design brings in some unprecedented technical issues that could complicate and lengthen the Nuclear Regulatory Commission's review period, the staff of the federal agency recently said.

"The NRC is concerned that the schedule for submitting the information is inconsistent with the time necessary for the staff to act on the information so that NuScale's desired review duration can be achieved," according to a letter to NuScale released by the NRC June 10.

The Oregon-based developer NuScale is on track to be the first small modular reactor developer to apply for NRC certification of its reactor design, with a target of submitting the 12,000-page application around the end of 2016. The company, owned by Fluor Corp., is being awarded $452 million in aid from the U.S. Department of Energy to help get through the certification process. Energy Secretary Ernest Moniz has said small modular reactors, or SMRs, could revolutionize the future of nuclear power through their potentially simpler, cheaper and more portable modules.

But the distinguishing features of SMRs — passive safety systems, more reactors at a single site, fewer plant operators — also make them in some ways uncharted territory for federal nuclear regulators.

NuScale needs to prioritize submitting more information on SMR design features that "are not consistent with existing regulation and have little precedent for exemptions," the letter said.

For example, NRC requires current operating reactors to use Class 1E electrical equipment, which is equipment related to keeping power flowing for critical safety systems at the plant, such as emergency diesel generators. But NuScale believes that much of the Class 1E equipment required at conventional reactors should not be required at its SMRs because of automatic, passive systems that can keep the reactor cool and avoid a meltdown in case of loss of power.

The NRC staff believes that the Class 1E issue is an example of where NuScale needs to show a bit more evidence. "Additional discussion is needed on this subject so that the NRC staff can decide if this will rise to a policy matter for a Commission decision," the staff said in a summary of an April meeting with NuScale.

"They've never considered the possibility of a nuclear plant without Class 1E systems," NuScale Chief Commercial Officer Michael McGough said.

Showing that SMRs do not require expensive equipment like emergency diesel generators is important for the economic case for the new technology. Energy providers like the Public Service Enterprise Group Inc. have said they are interested in adding SMRs to their portfolio as a less daunting way of getting new nuclear generation compared to building multibillion-dollar conventional reactors, but only if the SMRs can prove to be significantly cheaper to build and operate.

The NRC is requiring the developer to submit topical reports on individual areas of concern like the Class 1E issue and additional risks that come with having many reactor modules at one plant. NuScale is looking at submitting 17 of these reports before applying for the certification, McGough said. The agency hopes to review these topical reports in parallel with the design certification application review, but "if there are significant issues identified in the topical reports that could require policy changes or lengthy reviews, the schedule could be impacted," according to the meeting summary. It will take about 40 months for the NRC to review the design once the application is submitted. About six months after the design certification is approved, NuScale hopes to get a license to build its first SMR. The construction period will in turn take about another three years. This project is likely to be at a site near the Idaho National Laboratory, supplying power to the Utah Associated Municipal Power Systems and operated by Energy Northwest. The utilities hope the plant can be finished in the mid-2020s.

NuScale has said one of the most important milestones for keeping its application on schedule is the receipt of a design-specific review standard from the NRC, a document that will guide the certification process. The NRC still plans to release that standard to NuScale in July, as stated at the April meeting, according to an NRC spokesman.