State one specific isotope of an element that is commonly used as a fuel in a nuclear fission reactor.
Explain what is meant by a fission chain reaction.
Explain why the high-level waste containing fission products must be shielded and stored securely for a very long period.
Some nuclear reactors use graphite as a moderator. Describe the main purpose of a moderator.
The power output of the reactor is regulated using control rods. Explain how withdrawing control rods out of the reactor core affects the rate of nuclear fission.
A high-temperature nuclear reactor is cooled using helium gas.
The helium gas enters the reactor core at 127 ∘C127\ ^\circ\text{C}127 ∘C.
Determine this entry temperature in kelvin.
The helium gas enters at a pressure of 3.20 MPa3.20\text{ MPa}3.20 MPa and leaves the reactor core at a temperature of 900 K900\text{ K}900 K.
Calculate the pressure of the helium gas as it leaves the reactor core. Assume that the volume of the gas does not change.
