Future of Nuclear Fusion Energy Kenneth Kok Editor, Nuclear Engineering Handbook, Second Edition January 5, 2020 In the late 1970’s and early 1980’s Ken Kok became involved in both magnetic and laser fusion projects. At the time Battelle had one of the most powerful lasers in the US, larger than those at the DOE Livermore Laboratory. They were not working on the physics of the various devices but were looking at applications and maintainability of an operating machine. During that time, he was invited to give the Engineers Week Lecture at the Western Electric Works in Allentown, PA. The end of the lecture describing ongoing research he predicted that it would be more than 50 years at a minimum. He has not worked with the systems in detail since that time. The World Nuclear Association has a description of current and past fusion research on its website, see here. The laser fusion project they had at Battelle was funded by DOE, Firestone Tire and Rubber, Marathon Oil, and Standard Oil of Indiana. The industrial partners were interested in looking at advanced systems for process heat. The project provided them access to DOE projects and the DOE was interested in the point of view of the industrial partners. The most interesting outcome form his point of view came out of a multiday meeting involving the senior engineering staff from the three industrial partners. They learned that availability of constant energy was the most critical parameter for an industrial plant. They expected availability to be 99% or better. This is why many small utilities, industrial plants and institutions who relied on steam for their processes had multiple boilers, Battelle itself and the university he attended both had three boilers of which only two were needed continuously and the third was on hot standby. This could be an argument used for SMRs especially when providing process heat or in remote disconnected areas. Practically a laser fusion device for these applications is not practical from an engineering standpoint. At Livermore, the NIF laser system of 192 beams delivered more than 500 TW of peak power and 1.85 megajoules (MJ) of ultraviolet laser light to its (2mm diameter) target" for a few trillionths of a second. It was reported that 17 kilojoules of power was generated by the fusion reactions in the pellet. In work related to magnetic fusion we performed maintenance and maintainability they worked with General Atomics on their proposed fusion system. They built a series of simple models which showed how difficult maintenance would be. First from a thermal standpoint imagine the plasma suspended in a perfect vacuum at the temperature of the sun, about 5,800K. The vacuum chamber is built inside of a circular arrangement of superconducting magnets held at a temperature less than 10K. The magnets must be close to the chamber to maximize the magnetic field. D-T fusion produces 17.6 MeV of 1
energy of which 14.1 MeV is carried by neutrons. That energy must be extracted from something such as water and removed as heat. Somewhere between the toroidal vacuum chamber and the magnets will have to be a pressure vessel to hold the moderating material. Sounds like an interesting engineering problem. In addition, vacuum chamber and the exterior pressure vessel all must be constructed inside the circular or D-shaped ring of magnets. All of this, to his knowledge, has not been examined. Hence, he stands by his 50-year prediction made in 1980 and feels that adding another 40-50 years sounds reasonable.
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