Peaceful uses of nuclear energy
Nuclear energy generates electricity without smoke, runs ships and submarines for months, and its reactors make radioisotopes for medicine, farming, industry and research.
Peaceful uses of nuclear energy
- Electricity: the heat of controlled fission makes steam to run turbines in nuclear power stations.
- Long-running fuel: a reactor's fuel lasts for months, so nuclear power can drive large ships and submarines on long voyages without refuelling.
- Cleaner air: a nuclear plant gives out no smoke or ash, and far less carbon dioxide than a coal plant.
- Radioisotopes: research reactors make radioactive isotopes used in medicine (diagnosis and cancer treatment), agriculture (better seeds, food preservation), industry (finding flaws, measuring thickness) and research.
- Research: reactors give beams of neutrons that scientists use to study materials.
Nuclear power in India
India's first nuclear power station was set up at Tarapur. Others work at Rawatbhata (near Kota), Kaiga, Narora, Kakrapar, Kalpakkam and Kudankulam. Most use pressurised heavy water reactors with natural uranium. Dr Homi Bhabha planned three stages. First, heavy water reactors burn natural uranium and also make plutonium. Next, fast breeder reactors burn the plutonium and turn thorium into uranium-233. Finally, reactors will run on India's large reserves of thorium.
Worked example: uranium against coal
Fission of 1 kg of ²³⁵U gives about 8.2 × 10¹³ J. Burning 1 kg of coal gives about 3 × 10⁷ J (an example value). How much coal gives the same energy as 1 kg of ²³⁵U?
- Mass of coal = 8.2 × 10¹³ J ÷ 3 × 10⁷ J per kg.
- = 2.7 × 10⁶ kg.
- = 2700 tonnes (1 tonne = 1000 kg).
About 2.7 × 10⁶ kg, or 2700 tonnes of coal, close to a full goods train, for one small block of uranium
Benefits and problems of nuclear power
For reading only: atom and hydrogen bombs (not set in the exam)
An atom bomb uses an uncontrolled fission chain reaction in uranium-235 or plutonium-239. The one dropped on Hiroshima in 1945 destroyed the city in seconds. A hydrogen bomb uses fusion: a fission bomb first creates the huge temperature that fusion needs. Such weapons show why nuclear energy must be used only for peaceful purposes.
Radioisotopes from Indian research reactors are used in hospitals to diagnose thyroid problems and treat cancer, and in food plants to stop onions and potatoes from sprouting in storage.
2 marks: “State any two peaceful uses of nuclear energy.” Generating electricity; powering ships and submarines; producing radioisotopes for medicine, agriculture and industry (any two).
2 marks: “Give two advantages and one problem of nuclear power stations compared with coal power stations.” Advantages: huge energy from little fuel; no smoke or ash. Problem: radioactive waste must be stored safely for a very long time.
1 marks: “Which fuel will India use in the third stage of its nuclear power plan?” Thorium, through uranium-233.
Power, Ships, Isotopes: electricity, long voyages, and radioisotopes for health, farms and factories.