A nuclear reactor for producing neutron beams is refuelled with about 10 kg

of uranium, which contains initially 90% of the �fissile isotope 235U. The reactor operates continuously at a constant thermal power of 57 MW until the quantity of 235U is reduced by
30%, at which point the fuel is too dilute in 235U for the chain reaction to continue. At 57MW, how many neutrons are released per second, and what is the longest possible period of
continuous running?
You may assume that the fi�ssion of one 235U nucleus releases on average
2.4 neutrons and 185 MeV of energy in the form of heat.

neutrons/second=57Mw/(185Mev)* XXXev/Joule*2.4

but 1 joule =
6.2E18 electron volts
neutrons/sec= 57Mjoule/sec*1/185Mev*6.2E18/joule*2.4neutrons

check my thinking