Plasma based 14 MeV neutron sources

The utmost urgency to develop powerful 14 MeV neutron sources is now well understood among fusion community of engineers and material scientists. The time of influence of 14 MeV neutrons upon the fusion reactor components is estimated at 10 endash 20 years and corresponds to a fluence of 1.5 endash 4.5 1022 n/cm2. As yet, no reliable data are available on the behavior of reactor component materials exposed to such a flux. This creates a great deal of uncertainty in the performance and endurance predictions of future fusion reactor main components. The first wall flux from ITER will be approximately 1 MW year/m2 by the time that the choice of materials for DEMO will have to be made. A comparison of the desired flux from DEMO of 10 endash 20 MW year/m2 shows quite clearly that ITER will provide too small a flux and too late in time to contribute usefully to the materials selection process. On the other hand, before DEMO is built, suitable materials for the first wall and other critical reactor elements must be selected. Thus, DEMO cannot be constructed without a wide program of material study (end-of-life, resistivity increase from neutron damage, H, He, dpa production rates, activation of nuclei, etc.) as well as the welds and brazes to be used in the reactor. To realize this program a high-flux neutron source of DT-neutrons, covering a sufficiently large test zone, should be rapidly constructed. At present, a number of proposals for 14 MeV neutron sources are known. Among these are: sources based on the acceleration of ions, interaction of ions with targets, volumetric plasma neutron sources based on tokamaks and mirrors, open-quote open-quote exotic close-quote close-quote schemes using μ-catalysis and lasers. In this paper the advantages and shortcomings of various approaches are discussed, from both the technical feasibility and economic points of view. copyright 1995 American Institute of Physics