Part 1 of 2 Parts
Most of the articles I write about nuclear power generation are about nuclear fission reactors. This technology has been producing electricity for sixty year and there are about four hundred commercial power reactors in operation today producing about ten percent of world’s electricity. However, the high cost, long construction time, long lived nuclear waste and possibility of nuclear proliferation are all serious problems that are slowing the wide-spread adoption of nuclear power based on fission.
Scientists are exploring a variety of technologies and fuels to produce a solution to the world’s energy needs that can be scaled rapidly enough to replace the world’s current dependence on fossil fuels before climate change reaches a point of no return. Solar concentrators and solar photovoltaic systems are evolving rapidly as are a variety of winds turbines. Geothermal and wave power are far behind wind and solar but are also evolving rapidly. Rapidly dropping costs for renewable alternatives are making it difficult to proceed with the construction of new fossil and nuclear power plants. The most promising yet most difficult new source of energy would be the creation of a competitive commercial nuclear fusion power reactor.
The DIII-D National Fusion Facility (DNFF) is operated by General Atomic on behalf of the United States Department of Energy (DoE). The DNFF experiments with fusion initiated in a donut shaped vessel surrounded by magnets called a tokamak. Hydrogen gas is injected into the circular chamber. It is then heated and compressed by magnetic fields until it reaches conditions which allow the hydrogen atoms fuse into helium and produce huge amounts of energy. New research has aroused their interest in the use of pellets of hydrogen gas as another approach to creating fusion.
A recent article in phys.org said, “The studies by physicists based at DOE's Princeton Plasma Physics Laboratory (PPPL) and Oak Ridge National Laboratory (ORNL) compared the two methods, looking ahead to the fueling that will be used in [International Thermonuclear Experimental Reactor] ITER, the international fusion experiment under construction in France.”
Fusion reactors that are fueled by hydrogen require a steady supply of hydrogen to supply the fusion reaction. The question of how best to supply this constant stream of hydrogen to a commercial fusion reactor is a major concern for those researching nuclear fusion. As test reactors are scaled up on the way to developing a commercial fusion reactor, the question of how to fuel them will be more and more important. The phys.org article goes on to say, “As fusion reactors get bigger and hotter it will become harder for the gas to penetrate into the core of the reactor where fusion reactions take place. New methods thus need to be developed to feed the fusion core without degrading the plasma performance.”
The report on experiments that compared the traditional injection of room-temperature hydrogen gas with the insertion of hydrogen ice pellets indicates that despite what might be expected, it turns out the hydrogen ice pellets may actually be better for achieving the enormous temperatures that will be required to produce hydrogen fusion in a tokamak reactor.
Please read Part 2 next