Star power: an energy source both East and West agree on

SOME 40 physicists and engineers from Japan, the European Community, the Soviet Union, and the United States are setting up shop near Munich to pursue the quest to harness hydrogen fusion - the kind of nuclear reaction that powers the stars. Their joint effort to design what may be the next big experiment in that quest is a fruit of improved East-West relations. It comes at a propitious time.

The recent United Nations 1988 State of the World Population Report predicts there will be 6 billion of us by century's end. It warns that this increasing people pressure is seriously damaging basic natural resources upon which earthly life depends.

Seen in this perspective, the elusive goal of fusion power is still worth pursuing. Fusion, nuclear fission with its radioactive waste, and sunshine appear to be humanity's only major options for long-term energy supply. Conservation can stretch our resources. But we will need increasing energy supplies as population grows. There's lots of coal. But the climate-changing carbon dioxide that burning coal emits will probably limit its use.

We can't neglect fusion, even though its practical application remains several decades in the future, despite 30 years of extensive research. This realization, plus the benefits of pooling resources and sharing costs, inspired several years of negotiations leading to the project agreement signed in April at the Vienna headquarters of the International Atomic Energy Agency.

The international team that arrived at West Germany's Max Planck Institute for Plasma Physics in Garching this month now has $240 million (including funds for support work in the partner nations) to do its job. It is to design the International Thermonuclear Experimental Reactor (ITER) by the end of 1990. This will be the basis for new discussions about whether and how to proceed with the experiment.

Fusion researchers in several countries have made some progress over the past three decades. ITER will build on that progress to both carry forward fusion research and begin studies of the engineering problems a working power plant will involve.

Fission power relies on energy released when atoms of certain heavy elements such as uranium split into lighter components. Fusion power uses energy released when nuclei of light elements such as hydrogen literally fuse together to form a heavier element such as helium. Present fusion work aims at using a reaction in which deuterium (doubly heavy hydrogen) fuses with tritium (triply heavy hydrogen). The reacting gas must reach temperatures on the order of 100 million degrees C.

The first major goal has been to use magnetic fields to control this hot gas, which can't touch container walls, long enough for self-sustaining fusion to take place. Machines currently operating or authorized in Europe, Japan, and the United States should reach that goal within the next five years. ITER designers are to come up with a proposal to carry the research forward from there.

Deuterium is abundant in sea water. Tritium can be made in a blanket of lithium that absorbs neutrons produced by a fusion reactor. Eventually, engineers will probably learn to use deuterium alone as fusion fuel. Thus the ITER design project is a good start on a global effort to develop star power as a source of abundant energy for all humanity.

A Tuesday column. Robert C. Cowen is the Monitor's natural science editor.