Sir

Your Editorial “Time for Japan to shine?” (Nature 427, 763; 2004) clearly presents the necessity of building ITER, formerly the International Thermonuclear Experimental Reactor. But I must say — as a European negotiator in the ITER talks — that, in trying not to be Euro-parochial, you do injustice to the role played by Europe in controlled fusion and in ITER.

Indeed, there is no mention of Europe's uncontested leading role in fusion, nor of the fact that data from the largest and best-performing machine, the Joint European Torus (JET) — which is above par — proved essential in designing ITER and in creating our confidence that ITER will meet its aims. The European Union (EU), more than any other partner, has provided constant, substantial support to the ITER project since its inception. The remarkable support given by Japan should also be mentioned at this point, although in terms of financial and human resources it has taken place at a significantly lower level.

Since July 2001, the EU has kept the project alive by spending €160 million (US$197 million), at a time when the United States had left the project. Your assertion that political and public support for ITER is less than whole-hearted in Europe does not rest on facts. The European Council of Ministers decided unanimously to present Cadarache, France, as the site, with reference to the financial estimate of costs made by the European Commission. The people living around Cadarache support ITER, and the region of Provence–Alpes–Côte d'Azur unanimously agreed to pay €447 million towards its costs. Although you say that Japan has a greater commitment to future energy sources, the legal framework for licensing ITER does not yet exist in Japan — whereas the licensing procedure has already started in Cadarache.

Nature correctly states that, if Europe's case is technically strongest, then Japan's compensation should include international contribution to an upgrade of the JT-60 tokamak to achieve critical science on the way to Demo, the engineering prototype reactor. But the EU negotiators deplore the fact that the United States and Japan refuse a direct and objective comparison of the technical assets of the European and Japanese sites. Is this because Cadarache meets most of the nine criteria better?

For the above reasons, we feel that the ITER partners should now quickly decide to locate ITER in Cadarache, and that this decision should be accompanied by a commitment at the highest political level to implement a broader approach to fusion energy, well balanced between the needs of the programme and the capabilities of the partners. The world programme could include, in addition to ITER, the technology programme required for a commercial reactor (for example, a material-testing facility) and joint exploitation of ‘satellite’ tokamak facilities. This coherent approach would be the best way of getting on as quickly as possible with one of the most important world challenges of this century.