Instead of combustion, you also want to consider a small nuclear generator that uses natural uranium $0\mathrm{.}86\%U235$ as a fuel. Electricity is generated from the heat of the reaction using a small steam turbine with an efficiency of $46\mathrm{.}23\%$

The atomic masses of the components are as follows:

I

${?}^{235}U235\mathrm{.}0439$

${?}^{139}Ba138\mathrm{.}9088$

${?}^{94}Kr93\mathrm{.}9343$

neutron $1\mathrm{.}0087$

The nuclear reaction follows the scheme: ${?}^{235}U+{?}^{1}n{?}^{139}Ba+{?}^{94}Kr+3^{1}n.$

If the radioactive isotope can be degraded by half before the fuel must be replaced, how much Uranium is needed for one year of operation?

If you operate the reactor for one year, how long would you need to store the used fuel have less than $0\mathrm{.}58$ g of U$235$ remaining?