Fast-Neutron Damaging in Nuclear Reactors: Its Kinetics and the Carbon Atom Displacement Rate

It is shown that the radiation damage produced in graphite at near room temperature is labile. A theory describing this lability is developed. Then using this theory and an identification and determination of the portion of the neutron flux spectrum responsible for the damage as obtained in another paper, the displacement rates for the condition that no annealing had intervened are calculated from the number of displacements which had been determined in graphite samples which had been irradiated near room temperature. From several different methods there is obtained, within a factor of 2, the following result: ${10}^{-21\mathrm{}}$ displacements atom per damaging neutron/${\mathrm{cm}}^2$ for the number of displacements which remain after a scattering event involving a fast neutron near the beginning of the irradiation under conditions in which thermal annealing is not occurring.