December 10, 1996

On December 6, Science Magazine published an article reporting the results of calculations at the University of Texas predicting that the International Thermonuclear Experimental Reactor (ITER) would not reach its performance objectives if built as currently designed (See FPN-25). At the time this article appeared late last week, the ITER Technical Advisory Committee (TAC) was meeting in Tokyo. The TAC consists of senior fusion scientists from around the world, and is chaired by Dr. Paul Rutherford, a highly respected fusion theoretical physicist from the U.S. The TAC issued the following statement, dated December 7:

The members of the ITER Technical Advisory Committee (TAC), meeting in Japan for the purpose of reviewing the ITER Detailed Design Report, take note of the concerns expressed in the latest issue of Science Magazine in regard to projected performance in ITER. The following relevant statements are extracted from the report of the TAC meeting:

"In regard to the physics basis for ITER, the TAC notes that there is an international worldwide physics effort in support of ITER, encompassing seven Physics Expert Groups and involving many ITER-specific studies in the experimental and theoretical programs of the Parties. This effort was reflected in a large number of ITER-relevant papers presented at the recent IAEA Fusion Energy Conference. The new experimental results presented at the IAEA conference have, in general terms, confirmed and strengthened the physics basis for the ITER design. Remaining open issues are being resolved by focussed experimental effort in the tokamak programs of the Parties. The TAC also takes note of the encouraging worldwide progress in the development of physics-based transport models for tokamaks and endorses the ongoing effort by the JCT and the Physics Expert Groups to include such models in projections of plasma performance in ITER. The TAC's overall assessment of the physics basis for ITER is that the present design parameters have been well-chosen for meeting ITER's technical objectives.

"The development of new databases and dimensionally correct characterizations, implemented with care, provides at the present time the most validated way of projecting ITER performance. The Home Teams, Physics Expert Groups and the fusion community are to be congratulated for their combined efforts on ITER performance predictions. Significant progress has also been made in the development of turbulent transport models, taking into account flow shear and flux surface geometry. However, further evaluation and validation of these models against experiment is needed before they can be relied upon for quantitative ITER projections."

A statement has also been prepared by several members of the U.S. fusion community. Contact Dale Meade at PPPL to request a copy: dmeade@pppl.gov

For more information, contact: Stephen O. Dean