Fission reactor — UPSC Physics Optional IFoS 2025 Paper II

If plutonium ({}^{239}_{94}\text{Pu}) is used as fuel in a fission reactor and is producing fragments barium ({}^{146}_{56}\text{Ba}) and strontium ({}^{91}_{38}\text{Sr}) by initiating the reaction by one neutron and producing three neutrons in the process, then calculate the number of fissions per second required in a 100\text{ MW} reactor. [Given : BE per nucleon (MeV) : 7\cdot 6 for {}^{239}\text{Pu}, 8\cdot 2 for {}^{146}\text{Ba} and 8\cdot 6 for {}^{91}\text{Sr}]