In a pressurized water reactor (PWR), liquid water serves a dual purpose as both the coolant and the moderator. During a hypothetical accident, a breach in the cooling system causes a rapid drop in pressure, causing the liquid water inside the reactor core to instantly flash into low-density steam.
Explain how this sudden change in the state of the water affects the rate of nuclear fission inside the reactor.
94 exam-style questions on Edexcel GCSE Physics 6.5 Uses and dangers of radioactivity, covering 6.5.1 Uses of radioactivity, 6.5.2 Dangers of ionising radiation and precautions, 6.5.3 Half-life and radiation dangers, 6.5.4 Safety precautions for radiation exposure, and 6.5.5 Contamination and irradiation. Each one has a worked solution and a mark scheme showing where the marks go.