Relativistic mass of secondary neutrons in nuclear fission

The relativistic variation of mass with speed is experimentally confirmed and widely used in physics. In fission reactions, neutrons have energy 0.025 eV or velocity 2185 m/s, whereas secondary neutrons have energy 2 MeV or 1.954 × 10⁷ m/s: ∼7% speed of light. The mass of neutrons having classical velocity is 1.0086649 u and that of a neutron moving with relativistic velocity is 1.01080879 u (thus the increase in mass of a neutron is 0.212547% as the difference in mass is 0.00213 u). In calculations of the Q-value for fission reactions, the masses of relativistic or nonrelativistic neutrons are considered to be the same, i.e., 1.0086649 u, which contradicts the relativistic variation of mass. Consequently, the Q-value turns out to be 173.271 MeV. If a body moves with relativistic speed then its relativistic energy (hence relativistic mass) is taken into account. If the mass of primary neutrons is considered to be 1.0086649 u and that of secondary neutrons 1.01080879 u (actual values), then the Q-value turns out to be 167.29 MeV. So there is a variation of energy: 5.99 MeV or 3.45%. This implies that the efficiency of reaction is less in this case as Q-values decrease. Therefore, in calculation of energy in reaction, the relativistic mass of a neutron must be taken into account, whence the lower efficiency of reaction/reactor is explained. It is an established experimental observation reported in the literature over the past four decades that energy emitted in fission of U²³⁵ and Pu²³⁶ is 20‐60 MeV less than the energy predicted by Δ E =  Δ mc ². This can be explained if speeds of other products are precisely measured and relativistic masses are calculated. These aspects of basic nuclear physics are not yet acknowledged, as the Q-value turns out to be lower.