Fusion energy offers the potential for cheap, clean, and abundant energy. It also offers a number of significant advantages when compared with fission technology. In particular, fusion facilities do not suffer from many of the issues associated with fission reactors, including reactor safety, nuclear waste generation, disposition of spent reactor fuel, vulnerability to terrorist attacks, and nuclear proliferation. These factors offer considerable motivation for replacing fission reactors with fusion reactors. Unfortunately, fusion reactors are not yet a viable alternative to fission facilities.
Fusion energy is a potential source for power production in the mid-to late twentyfirst century. The fusion reaction or process occurs within the plasma composed of light nuclei. A commercial fusion power facility would likely use either magnetic or inertial means to confine the plasma and facilitate the fusion process. The fusion confinement method influences the radiation types and fuel materials that must be controlled by the health physicist.
Fusion processes substantially differ from those encountered in fission reactors because they do not produce actinides or radioactive isotopes of iodine, cesium, or strontium. A fusion reactor does produce a wide variety of reaction and activation products and these products depend on the selected fusion process, the reaction energies, and the materials of construction selected for the facility. Fusion products and activation products present a challenge for the health physicist responsible for worker radiation protection at a fusion power facility. Both internal and external radiation challenges are present. In addition, tritium fuel material presents an internal hazard in its initial state prior to introduction into the fusion reactor.
In this chapter, we review the radiological hazards associated with a fusion power facility, identify the anticipated sources of radiation exposure from this facility, and identify possible as low as reasonably achievable (ALARA) measures to reduce the occupational doses. This chapter also reviews the basic physics principles and relationships that govern the fusion process. These relationships will be shown to define the basic plasma properties, govern the nuclides interacting to form the plasma, and determine their energy. The underlying physics also determines the types of radiation that are produced within the plasma.