Lesson.7: Nuclear Fission, Radioactivity and Energy Objectives Describe the process of generating electricity using nuclear power. Describe the process of generating electricity using nuclear power. Describe the fission process and the meaning of the term chain reaction. Describe the fission process and the meaning of the term chain reaction. Describe how the chain reaction is controlled in a conventional power station. Describe how the chain reaction is controlled in a conventional power station.

Nuclear power stations use uranium as fuel.

Electricity is generated as follows; nuclear reaction; nuclear reaction; producing heat; producing heat; producing steam; producing steam; turning a turbine; turning a turbine; turning a generator. turning a generator.

What is the nuclear reaction that produces energy (heat)?

uranium nucleus hit by neutron; uranium nucleus hit by neutron; causes nucleus to split; causes nucleus to split; energy released energy released this is called nuclear fission this is called nuclear fission

This is called nuclear fission

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Uranium decay can be a chain reaction. Chain reaction: when each uranium nucleus splits more than one neutron is given out; when each uranium nucleus splits more than one neutron is given out; these neutrons can cause further uranium nuclei to split. these neutrons can cause further uranium nuclei to split. A nuclear bomb is a chain reaction that has ‘gone’ out of control.

Scientists stop nuclear reactions going out of control by: placing rods in the reactor; placing rods in the reactor; to absorb some of the neutrons; to absorb some of the neutrons; but allowing enough neutrons to remain to keep the process operating. but allowing enough neutrons to remain to keep the process operating. Materials can be made radioactive by putting them into a nuclear reactor. These materials become radioactive when they absorb extra neutrons and so become unstable. Therefore nuclear fission produces radioactive waste.

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STATIONEN NUCLEUSO CNUCLEARI UHORCHT RADIOACTIVEC AISTRAA NNSCITE IIACR UFFEENIBRUT MURT REWOPY LGENERATOR

Background Radiation Is naturally occurring radiation which is all around us all of the time. It has a variety of sources; Air, food, building materials, soil, rocks. Cosmic rays (mainly from the Sun) All living things are a little bit radioactive Human activity, radioactive fallout from explosions, medical procedures.

Background Radiation Radon gas Food Cosmic rays Gamma rays Medical Nuclear power 13% is man-made

Homework Foundation only Complete ‘Background Radiation and Nuclear Power’ pages 136 and 137.

Learning Objectives Recognise that nuclear power stations use uranium as a fuel. Recognise that nuclear power stations use uranium as a fuel. Describe the main stages in the production of electricity: Describe the main stages in the production of electricity: source of energy; used to produce steam; used to produce electricity. Describe how domestic electricity is generated at a nuclear power station: Describe how domestic electricity is generated at a nuclear power station: nuclear reaction; producing heat; producing steam; turning a turbine; turning a generator. Describe what happens to allow Uranium to release energy: Describe what happens to allow Uranium to release energy: uranium nucleus hit by neutron; causes nucleus to split; energy released.

Describe the process that gives out energy in a nuclear reactor as nuclear fission. Describe the process that gives out energy in a nuclear reactor as nuclear fission. Recall that materials can be made radioactive by putting them into a nuclear reactor. Recall that materials can be made radioactive by putting them into a nuclear reactor. Describe how materials become radioactive when they absorb extra neutrons. Describe how materials become radioactive when they absorb extra neutrons. State that nuclear fission produces radioactive waste. State that nuclear fission produces radioactive waste. Describe that the decay of uranium can be a chain reaction. Describe that the decay of uranium can be a chain reaction. Explain what is meant by a chain reaction: Explain what is meant by a chain reaction: when each uranium nucleus splits more than one neutron is given out; these neutrons can cause further uranium nuclei to split. Describe that a nuclear bomb is a chain reaction that has gone out of control. Describe that a nuclear bomb is a chain reaction that has gone out of control. Explain how scientists stop nuclear reactions going out of control: Explain how scientists stop nuclear reactions going out of control: rods placed in the reactor; to absorb some of the neutrons; allowing enough neutrons to remain to keep the process operating.