An attempt is made in this discussion to determine the energy deposited in a small sample in terms of impinging reactor radiations, both neutron and gamma ray. The intensities of various radiations from a nuclear reactor are often presented in terms which are difficult to manipulate or interpret for energy deposition considerations. For example, the epithermal neutron flux is usually given as the integral neutron flux above the 0.4 ev cadmium resonance. However, for some energy deposition mechanisms, such as proton recoil, the neutron energy distribution is of utmost importance. These difficulties are partly resolved in this paper by using some empirical evidence of the characteristics of reactor radiations to convert the usual expression of intensities into energy deposited per gram‐hour in polyethylene. This can be easily extended to other materials, particularly polymers. It is also emphasized in this paper, by specific calculations for two reactor types, that certain simplifying assumptions, which are often made with regard to the characteristics of reactor radiation, are invalid in energy deposition considerations.