Photovoltaic reactor?

Random thought of the day. If you stuck photovoltaic cells all over the inside of a nuclear reactor, how much additional energy would you capture? That would be converting the output energy directly into electrical power, whereas the current design has to capture the output energy as heat going into water, then transfer that energy through conduction to another pipe of water, then transfer that energy through mechanical means (turning a turbine) into electrical energy. It seems like photovoltaics might capture a worthwhile amount of energy.