A batch of fuel is loaded with an initial enrichment of uranium-235 by mass of heavy metal

PHYSICS · Multi-part · Fermi University Physics · Nuclear Physics · Fission, fusion and nuclear energy · Fission, fusion and nuclear energy

Energy from Physics, Ch Running a reactor: kinetics, heat removal, feedback, burn-up and the fuel cycle

Problem

A batch of fuel is loaded with an initial enrichment of

4.0\%

uranium-235 by mass of heavy metal, and discharged at a burn-up of

B = 42\,\mathrm{GW\,d\,t^{-1}}

. A burn-up of

1\,\mathrm{GW\,d\,t^{-1}}

fissions a fraction

1.05\times10^{-3}

of the heavy atoms originally present. ((a)) Find the fraction of heavy atoms fissioned at discharge. ((b)) Compare this fraction with the

4.0\%

of uranium-235 loaded, and say in one sentence where the extra fissions came from.