Nuclear Reactors
To use the nuclear energy--> to control the chain reaction
the reaction should not die-out, neither become subcritical!
We should work under critical condition--> energy released at steady state
controlling and driving the reaction in reactors:
- fuel: mixture of U-235 and U-238
(can be enhanced in U-235)
bigger amount than the critical mass!
- U-238 captures the fast neutrons,
and produces no useful reaction
- U-235 fission mainly due to slow
- moderator: materials that slow
down the neutrons (heavy water,
- neutron absorbent rod (boron,…):
control mechanism for fne-tuning the criticality
- heat-exchanger: remove the heat from the core to
drive electric generators (water, steam, etc…)