Explain the physical mechanism by which a deuterium nucleus (${}_1^{2}H$) in a heavy-water moderator reduces the kinetic energy of a fast-moving neutron.

Hafnium is commonly used in control assemblies due to its high neutron absorption cross-section. Describe the physical interaction that occurs when a thermal neutron encounters a control rod containing hafnium.

Describe the step-by-step sequence of events that occurs when a thermal neutron induces fission in a nucleus of Uranium-233 (${}_{92}^{233}U$).

A major challenge in nuclear power generation is the management of high-level waste (HLW).

Identify the primary source of HLW in a reactor and discuss the subsequent stages of its treatment and the physical and technical challenges associated with its long-term disposal.

Your answer should include:

• identification of the primary source of high-level waste
• a description of the treatment and storage stages once removed from the reactor core
• specific physical or safety problems involved in long-term disposal and how they are addressed.