In a former farm field just outside the historic town of Janesville in south-central Wisconsin, a large concrete-and-steel building is taking shape. Dubbed the Chrysalis, the building will eventually house eight accelerator-based neutron generators, which start-up company SHINE Technologies will use to produce molybdenum-99. As the precursor to the medical radioisotope technetium-99m, Mo-99 is used in tens of millions of diagnostic procedures every year, primarily as a radioactive tracer.

At the heart of the Chrysalis will be the high-flux neutron generators, being supplied by SHINE’s sister company, Phoenix. The compact accelerators use a deuterium-tritium fusion process to produce neutrons, which in turn induce a subcritical fission reaction in an aqueous low-enriched uranium target (19.75 percent uranium-235) to produce Mo-99.

The Nuclear Regulatory Commission is requesting public input on preliminary language for a proposed rule that would set out a risk-informed, technology-inclusive framework for the licensing and regulation of advanced nuclear reactors, according to a notice published in the November 6 Federal Register.

The Nuclear Energy Innovation and Modernization Act, or NEIMA, signed into law in January 2019, tasked the agency with developing a regulatory infrastructure for the development and commercialization of advanced reactors.

Artist’s rendering of a Holtec SMR-160 plant. Image: Holtec International.

Holtec International announced yesterday a drive to secure Nuclear Regulatory Commission design certification of the company’s SMR-160 small modular reactor on an accelerated schedule.

According to the announcement, Holtec met with NRC officials and staff on September 30 to present a licensing roadmap that charts what the company referred to as a “seamless progression from [10 CFR Part 50] to [10 CFR Part 52] and a licensing topical report submittal schedule to support an accelerated availability plan for our global customers.”

The first planned submittal, scheduled to occur within the next few weeks, is a topical report covering the SMR-160’s essential safety features: the Passive Core Cooling System (PCCS) and Passive Containment Heat Removal System (PCHR). These systems, Holtec said, “undergird the SMR’s guaranteed safety under the various operational occurrences and hypothetical accidents that may afflict the plant.”

The submittal also aims to demonstrate that the PCCS and PCHR comply with the NRC’s General Design Criteria (Part 50, Appendix A), “an important enabler to expedite licensing efforts,” according to Holtec.