Senate committee seeks to create a US source for widely used medical isotope

A bill to create a domestic supply base for molybdenum-99, a short-lived radioactive isotope widely used for medical imaging, was reintroduced in the Senate in late January. Virtually identical to a measure that passed the House by a 400–17 vote last year, the bill (S-99) would codify and authorize funds for an interagency effort already under way to help establish a US supply of ⁹⁹Mo that would be produced without the use of highly enriched uranium (HEU).

The introduction of S-99 restarts a legislative push that stalled last year due to opposition from a single lawmaker, Senator Christopher Bond (R-MO). Bond, who retired in December, used a Senate procedure known as a hold to prevent the measure from coming to a vote. The measure aims to establish a reliable source of ⁹⁹Mo in the US and to prevent a recurrence of a shortage like the one that occurred last year, when two of the five research reactors that account for nearly all the world’s supply of the radioisotope were shut down for the better part of 2010.

The US, which consumes about half the world’s ⁹⁹Mo output, imports material from a Canadian company and from two European suppliers. A fourth producer, located in South Africa, serves mostly customers located outside North America. Because of its 66-hour half-life, ⁹⁹Mo can’t be stockpiled. It is the parent of the even shorter-lived technetium-99m, which is used as a tracer in about 18 million US medical diagnostic procedures each year.

At a 1 February hearing before the Senate Committee on Energy and Natural Resources—Parrish Staples, director of the office of European and African threat reduction, at the Department of Energy’s National Nuclear Security Administration—welcomed the bill’s provisions to phase out use of HEU in ⁹⁹Mo production. The American Medical Isotopes Production Act would prohibit US exports of HEU in seven years, a deadline that could be extended by as much as six years if the administration determines that there is insufficient ⁹⁹Mo produced without HEU.

To reduce the threat the material poses to nuclear proliferation, the Obama administration is pressuring other nations to end all civilian uses of HEU, including for medical isotopes. The US, however, continues to export HEU to Canada for ⁹⁹Mo production there. Since 2005, the Nuclear Regulatory Commission has licensed seven shipments of HEU to Canada and Belgium for use in medical isotope production, according to Margaret Doane, director of NRC’s international programs. Two more license applications, from Canada and France, are pending before the commission.

NNSA is offering financial and technical assistance for ⁹⁹Mo producers to convert their HEU-based production processes to low-enriched uranium. Last year, with NNSA’s help, the South African Nuclear Energy Corp (Necsa ) became the first of the major producers to ship a commercial quantity of the isotope that was made without HEU.

The Senate bill would authorize $143 million over three years for the development of HEU-free domestic production sources. NNSA has cooperative agreements in place with four US industry teams, each of which is developing a different novel approach to manufacturing ⁹⁹Mo. The cost-shared grants allow for up to $25 million in federal funds for each of the teams: GE Hitachi Nuclear Energy, Babcock & Wilcox, NorthStar Nuclear Medicine and Morgridge Institute for Research.

Three of the processes would not require uranium of any type. But Staples warned that long-term subsidies provided to the current HEU-based ⁹⁹Mo producers undercut US efforts to establish a domestic supply. “We must achieve full cost recovery across the entire global commercial industry,” he testified. “Any foreign government subsidy of HEU-based production puts the objectives of this legislation at risk.”

David Kramer