Nuclear Power

Nuclear fission reactor - anatomy

Questions Fuel rods – what do they contain? Nuclear reactors use ‘induced fission’. What does this mean? What is ‘enrichment’? What is ‘critical mass’ Control rods – what do they do? Control rods – what are they made of?

Further questions Why is a heat exchanger required? How is water recycled? What is a moderator, and why is it needed? What materials are used for a moderator? How are nuclear power stations similar to fossil fuel power stations?

More questions - safety What safety features does a nuclear power station have? Radioactive waste is classified as low-level, intermediate-level and high-level. What materials do they consist of? How are low, intermediate and high-level wastes disposed of?

Nuclear fusion

Nuclear fusion 3 step fusion reactions to fuse hydrogen into helium-4

In a nuclear fusion reactor

Ingredients Deuterium – from sea water Tritium from bombarding lithium – 6 with neutrons Very high temperatures need to be created 150 million degrees C Plasma contained by magnetic fields Plasma heated by large electric currents

Q1 A nuclear submarine needs 500kW, which is provided by the fission of uranium 235. The fuel is enriched uranium which may be 3% uranium-235 and the rest is uranium-238. A) Show that there are about 8x1022 atoms of uranium 235 in 1.0kg of this fuel B) The energy released at each fission is 3x10-11J i) How many fissions per second are needed to provide the required power? ii) How long will 1.0kg of fuel last?

Q2 Two almost stationary deuterium nuclei can fuse to form a tritium nucleus and a proton. This releases energy of 6.4x10-13J. A) In what form is the energy released? B) Write an equation for this reaction. C) Calculate the ratio of the speed of the proton to that of the tritium nucleus. D) Calculate the ratio of the kinetic energy of the proton to that of the tritium nucleus.