Construction of US radioisotope facility complete

Mo-99 is used in more than 40,000 medical diagnostic procedures in the USA every day but for decades the USA relied entirely on imported material. Most of the world's supply of the isotope is produced by irradiation of uranium-235 targets in a nuclear research reactor. However the high-enriched uranium (HEU) targets used for much of that production is a proliferation-sensitive material that, if diverted or stolen, could be used as a component of a nuclear weapon.

In 2018, NorthStar began production of non-HEU Mo-99 by irradiating and processing molybdenum-98 targets at the University of Missouri Research Reactor. It is currently the USA's only domestic producer of the isotope, capable of producing enough Mo-99 to meet about 20% of US demand.

The new facility will produce Mo-99 using a different method, based on the irradiation of molybdenum-100 targets using electron accelerators. It will be the first facility in the world to produce commercial-scale Mo-99 in this way, which the company says is more efficient than converting Mo-98 to Mo-99 via neutron capture, producing about 30% more Mo-99 per gram of target material.

One of the electron accelerators that will be used for Mo-99 production at the new facility (Image: NNSA)

The company expects to complete start-up and regulatory submissions for the new facility before the end of 2023. NorthStar's combined production capability will then be enough to meet nearly 40% of US demand for Mo-99.

In 2012, the US Congress directed NNSA to establish a programme to support the development of commercial domestic production of Mo-99 without the use of HEU, and since then the agency has awarded some USD245 million in cost-shared cooperative agreements to US companies, including USD109 million to NorthStar. It also works with international Mo-99 producers to reduce proliferation risks by helping them to convert their production processes to use low-enriched uranium instead of HEU.