Deep blue: light is emitted from the core of the ILL reactor as a result of Cerenkov radiation. Credit: ILL

The Institut Laue Langevin (ILL) in Grenoble, France, has bowed to US pressure and agreed to convert its high-flux 57 MW research reactor to use low enriched uranium (LEU) rather than ‘bomb-grade’ highly enriched uranium (HEU). The move follows the institute's failure to secure sources of HEU from Russia.

According to a memorandum of understanding signed on 12 November, the conversion will take place “when it becomes technically and economically possible”. In return, the United States will supply HEU to the reactor until it converts, and also take back spent fuel.

The Reduced Enrichment for Research and Test Reactors (RERTR) programme, which started in 1978, requires the United States to promote the development of LEU fuel for reactors wishing to convert. The programme is intended to reduce international commerce in bomb-grade uranium.

It was strengthened in 1992 by the so-called Schumer Amendment, banning the delivery of US HEU to reactors that refuse to cooperate with the RERTR programme. The amendment was named after Democrat Congressman Charles Schumer, who earlier this month defeated incumbent Alfonse D'Amato to win a seat in the US Senate, representing New York.

As a result of US pressure, most research reactors have converted to existing LEU fuel or have agreed to work with US scientists to develop LEU fuel which they can use without loss of performance or extra cost. The ILL reactor, which provides neutron beams for structural analysis for scientists from ILL's seven member states, was one of the few to hold out, partly because France objected to US interference in European affairs.

When the ILL restarted operation in 1995 after a four-year shutdown for repair, it found its normal fuel supply blocked by the Schumer agreement. ILL officials turned to Russia for HEU supplies rather than accept US terms, and Russia became an associate member of ILL in November 1996 in exchange for supplying HEU from Minatom, the Russian Atomic Agency.

But the Russian fuel failed to materialize and ILL suspended Russian membership at the beginning of this year. Dirk Dubbers, the director of the ILL, cites “problems between the Russian science ministry, which benefited from the scientific opportunities, and Minatom, which saw no exchange of cash”.

The agreement between ILL and the United States took observers by surprise. A spokesman for Greenpeace International described it as “welcome, even if not motivated by non-proliferation concerns”.

The European Union's Petten research reactor in Belgium and Belgium's national research reactor BR2 have long expressed interest in conversion, but have not yet agreed to do so. If they do convert, the only remaining European reactor to hold out will be the controversial German research reactor FRM II, being built by the Technical University of Munich.

The operators of FRM II have cited the reluctance of ILL to comply with US terms for HEU supply as support for their reluctance to do so. But the ILL's change of heart comes on top of a statement from the new red-green federal government in Germany saying that use of bomb-grade uranium in research reactors is “problematic and dubious in terms of foreign policy”. The statement says the government will check again whether FRM II could be converted to LEU.