Number 158 (Story #4), December 30, 1993 by Phillip F. Schewe and Ben Stein A NEW FISSION REACTOR CONCEPT has been proposed by CERN director Carlo Rubbia and, independently, by scientists at Los Alamos. In this scheme protons from an accelerator would bombard a sample of normally nonfissile thorium-232, causing reactions that would create both fissile uranium-233 and enough neutrons to sustain fission. Rubbia claims that this approach to providing energy would reduce or eliminate some of the grave problems facing the nuclear power industry, namely the chance of dangerous accidents, the accumulation of long- lived radioactive waste, and the production of weapons-grade materials. Disputes have arisen between Rubbia and the Los Alamos scientists over patents and over the feasibility of the experimental details. Rubbia plans to pursue the issue full time after he steps down from his post at CERN next week. (Science 26 Nov. and Nature, 2 Dec.)