New reactor in Missouri will expand medical isotope production

The University of Missouri announced last month that it will build a new research reactor with double the power and neutron flux of the university’s MURR reactor, which is currently the highest-power US research reactor outside a government facility. By providing a more intense source of neutrons, the 20 MW thermal (MWt) NextGen MURR will be able to produce a wider range and significantly larger volumes of radioisotopes for research and medical applications. And it will be fueled with low-enriched uranium, which greatly lowers the proliferation concerns associated with reactors, such as MURR, that are fueled with highly enriched uranium.

The initial planning and design work for the new reactor will be funded by a $20 million earmark from NIST’s fiscal year 2023 budget. The university is working with unnamed partners to gain additional funding, a spokesperson says. An overall cost estimate has not been developed.

A request for qualifications released on 10 April says the reactor will, like its predecessor, have a low-temperature, tank-in-pool design with multiple reconfigurable target facilities situated throughout the core. It will operate year-round.

The university’s existing reactor manufactures active ingredients that industry partners use in their radiopharmaceuticals. Those include molybdenum-99, the parent of technetium-99m, a gamma emitter used as a medical imaging tracer in 40 000 diagnostic procedures in the US each day. With a half-life of 66 hours, ⁹⁹Mo is delivered to radiopharmacies where the ^99mTc is eluted.

NorthStar Medical Radioisotopes, the sole US producer of ⁹⁹Mo, irradiates its targets at MURR. The company says it currently has the capability to produce around 20% of US demand. The rest of the ⁹⁹Mo used in the US is imported from Europe, Australia, and South Africa. Another company, SHINE Technologies, expects to begin producing the isotope next year at a Wisconsin plant.

MURR claims to be the only US producer of other medical isotopes such as yttrium-90 (half-life 64 hours), which is used for the treatment of liver cancer, and iodine-131 (half-life 8 days), used to treat thyroid cancer. It is one of two US producers of lutetium-177 (half-life 6.6 days), used in the treatment of pancreatic and prostate cancers.

Given the short half-lives of those isotopes, they can’t be stockpiled and must be produced and shipped continually. “The central location of Missouri in the US will ensure rapid deployment to patients, no matter where they live,” said Matt Sanford, interim director of MURR, in a statement.

Commissioned in 1966, MURR received a 20-year extension to its license from the Nuclear Regulatory Commission in 2017. It is one of five remaining US research reactors fueled with highly enriched uranium. (The others are at MIT, NIST, Idaho National Laboratory, and Oak Ridge National Laboratory.) MURR is to be converted to run on low-enriched uranium in about seven years, when a suitable fuel is developed by Argonne National Laboratory.