 Thus, concrete and polyethylene doped with boron make inexpensive neutron shielding materials.Once freed, the neutron has a relatively short half-life of about 10 minutes before it decays into a proton and electron with the emission of energy.When the time comes to actually try to make electricity from a tokamak-based reactor, some of the neutrons produced in the fusion process would be absorbed by a liquid metal blanket and their kinetic energy would be used in heat-transfer processes to ultimately turn a generator.