GERMANY is quietly seeking a new source of neutrons for advanced scientific research. But a plan to meet its needs by building a nuclear reactor fueled with weapons-grade uranium has set off a chain reaction of criticism.
The highly enriched uranium, or HEU, is one of the nuclear materials that can be diverted to make bombs. It is also a material that some observers say Germany will eventually have to buy from Moscow, despite international concerns about Russian involvement in the nuclear trade.
Germany is pushing ahead to build the reactor despite domestic and American concern. Like the German push for a permanent seat on the United Nations Security Council, this scientific debate over nuclear research shows a growing German assertiveness in the international community.
America's frustration with Germany over the reactor also points to their changing relationship, in which the United States can no longer count on prescribing German policy on international issues.
The reactor, to be built in the southern Bavarian town of Garching, is within the bounds of the Nuclear Non-Proliferation Treaty (NPT), which commits nonnuclear states like Germany both to keep from building nuclear weapons and to help control their spread.
In a league with Libya and China
But German and American critics counter that building a reactor to run on HEU would put Germany in a league with Libya and China, which have built significant HEU reactors in recent years.
The United States, sensitive to issues of German sovereignty, has kept a low profile. But last year the US decided to cancel its own HEU reactor project, to have been built at Oak Ridge, Tenn. Since then, the US has been in a better position to claim the moral high ground with other countries like Germany.
US officials say that it has so far been tough even to engage Germany in a discussion over the reactor, let alone to pressure Germany not to build it.
''At this point we're not even saying this is a bad idea. We're saying, 'Can we meet?,' '' said a US government official dealing in nonproliferation issues.
The US has offered the Germans technical assistance in exploring alternative reactor designs, the official said, but has met with no response. US and German critics of the reactor favor designs using low-enriched uranium (LEU), which cannot be used for weapons.
The official added that although there are some applications for which LEU reactors are not suitable, ''We have seen nothing that proves that they need an HEU reactor.''
The Garching reactor is heating up as an issue within Germany as well: It will be the focus of a major protest march by the national antinuclear movement this weekend.
But at the same time, a great deal of national prestige is attached to the new reactor. Garching is to be the centerpiece of a scientific modernization program for Bavaria and a demonstration of German global competitiveness.
Scientists say the facility is sorely needed, since the research reactor in Grenoble, France, out of commission since 1991, is only just now about to become available again.
At stake here:
r The possibility of a politically unstable Russia being enticed into trade in nuclear materials.
r The ability of the international community to reduce risk of nuclear theft and terrorism.
r American ability to provide international leadership as the world faces the new post-cold-war security challenges.
r The loss of German credibility as international advocate of nuclear nonproliferation, a credibility won back only over the past few years after some time during which Germany was seen as a leading supplier to would-be nuclear powers.
r Potential constraints on Germany's ability to play a policymaking role on the world stage if it is perceived to be operating under a narrow, legalistic view of its self-interest.
The dispute over Garching is over its fuel source. The Reduced Enrichment for Research and Test Reactors (RERTR) program, established in the late 1970s, is intended to reduce proliferation risks by offering the operators of HEU-fueled research reactors a deal: If they convert to LEU, the US agrees to store their spent fuels rods - which they are glad to be rid of. Under RERTR, in which Germany has participated, some 39 HEU research reactors around the world have converted or are converting to LEU, and only Libya and China have built significant new ones.
Paul Leventhal, president of the Nuclear Control Institute in Washington, says that if stable, responsible Germany goes ahead to build a new HEU reactor, this would ''embolden the operators of other [HEU] reactors to resist conversion'' to LEU. He spoke at a Nov. 1 seminar here, sponsored by the Greens.
Where Garching will get its HEU is another question. A US law passed in 1992 in effect bars export of HEU to reactors that could use other fuel. That means Germany is likely eventually to turn to Russia for its supply.
''I would think there would be a lot of concern about looking to Russia as a source of HEU, especially over objections of the US,'' Mr. Leventhal said.
Bavarian authorities say they have a supply of HEU lined up for the first 10 years at Garching, but for the remaining 20 years of the reactor's expected 30-year life cycle a new supply will be needed. At the seminar, Hermann Schunck, assistant secretary in the German federal science ministry, denied that Bonn was negotiating to buy Russian uranium but did not identify another possible source of HEU.
Dr. Anton Axmann of the Technical University, project manager for Garching, defends it as scientifically necessary: ''Why should German scientists be disadvantaged vis-a-vis those from the US, France, and so on?'' he asked at the Greens' seminar. ''The problem [of nuclear diversion] is not going to be solved by reducing HEU in Germany.''
Gambling with German credibility
Although Germany signed the NPT in 1969 and ratified it in 1974, for years German companies exported a variety of nuclear materials and technologies to India, Pakistan, and South Africa. Since 1989, such sales have been sharply restricted by law, and Germany is now regarded as a model citizen on nonproliferation issues.
Proceeding with the current reactor design would ''gamble away that hard-won credibility,'' according to Annette Schaper, a senior research associate at the Hessian Foundation for Peace and Conflict Research in Frankfurt.
As a leading nonnuclear power, Germany is trying to establish itself as an advocate for disarmament, she argues. Changing the design at Garching is ''in Germany's own foreign-policy interest.''