A Novel Fusion Power Concept Based on Molten-Salt Technology: PACER Revisited

This paper discusses modifications to an old concept for using peaceful nuclear explosions to achieve practical fusion power. With this concept, useful energy and materials are obtained by repetitively setting off nuclear explosions in an underground cavity. This proposal, which is based on molten-salt technology, involves two modifications: line the cavity with steel to make it engineerable and predictable rather than relying on an unsupported earthen cavity such as a cavity excavated in a salt dome; and use molten salt rather than steam. More than 70% of the energy released is then absorbed by liquid-salt evaporation, and the pressure to be contained for a given yield can be reduced by a factor of 3 or more. These modifications result in several improvements in the safety and feasibility of the contained fusion concept which includes: the tritium produced, being insoluble in the molten salt, can easily be pumped away and purified when all the vaporized salt condenses, rather than being mixed with steam; the tritium inventory is substantially reduced, effectively reducing the large hazard in case of accidental venting to the atmosphere; and reducing the yield used in the older studied could reduce the cost of the cavity considerably.