NUCLEAR POWER SANS RADIOACTIVITY

Widespread superstitions to the contrary, nuclear energy is at present the cleanest form of energy available on a large scale (except for hydroelectric power, which is limited by available sites). The sum of the parts of an atomic nucleus differs from its total mass. The difference an excess for the light elements like hydrogen, and a defect for the heavy elements like uranium is liberated as nuclear energy when the corresponding nucleus is fused or split. That is a natural law. The fission or fusion products are radioactive for the low and high ends of the periodic table of elements, but that is not a natural law valid for all elements.

Dr. T.A. Weaver and a group of scientists at the Lawrence Livermore Laboratory have therefore been searching for a process in which nuclear fiSa on and/ or fusion does not yield radioactive by produ:ts. As announced by Dr. Weaver at a recent meeting of the Physical Society's Plasma Physics Division. such a process has now been identified, though not yet realized on a large scale.

The proposal is to fuse hydrogen and boron 11, both in plentiful supply, resulting in boron 12 nuclei, and these would then be split evenly into three helium 4 nuclei. This even split is totally void of all radioactivity. and occurs in 99.950 of all fissions of boron 12 nuclei.

Apart from liberating nuclear energy with minimal radioactivity (only O.Ol Co of all fissions, compared to the present 100%), the process also has another advantage. In uranium or plutonium fission, the liberated energy appears in the form of fast neutrons, which produce heat in the substance trapping them, and the resulting heat is used to produce steam for a conventional electric generator. The conversion from nuclear energy via heat to electricity results in a net 60% loss of energy (into heat). On the other hand, the new "thermonuclear fission" process produces highenergy charged particles, which can be converted to electricity directly by using the MHD process (Sept. AtE).

The feasibility of the process has been demonstrated using boron 11 samples and protons from an accelerator, that is, so to speak, atom by atom. Large scale conversion hinges, above all, on the problem of fusion, which has not yet been achieved (slowly, and on a large scale) for any element. It is proposed to do this by irradiating small pellets of a hydrogenboron ll mixture by sqirts of powerful laser light (Sept. AtE). The trouble is that the temperatures needed to achieve fusion in this case are much higher than those needed in the "conventional" fusion process using only hydrogen, which has itself not yet been achieved.

On the other hand, the time from basic research to large scale application, which used to be measured in centuries, is now down to decades or even years. And so the discovery made in the Lawrence Livermore Laboratory is another blow to those who claim we have reached the bottom of the energy barrel.