Nuclear Power

Nuclear Power Stations and Nuclear Fission

1. Nuclear power station = powered by Nuclear Reactor

2. In NR, controlled chain reaction - uranium/plutonium atoms split up - releases heat energy

3. Heat energy - heats water - drives steam turbine

4. Nuclear energy - heat energy - kinetic energy - electrical energy

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Uranium 235 = used in some nuclear reactors/bombs - (uncontrolled fission reaction)

1. U-235 = quite stable - unstable to split

2. Done by firing S-M neutrons @ U-235 atom

3. Neutrons + nucleus - U-236 = unstable

4. U-236 splits - 2 smaller atoms + 2/3 F-M neutrons

5. Dif. pairs of atoms U-236 splits into e.g. Krypton-90 + Barium-144 = Radioactive

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1. Get useful amount of energy - loads of U-235 has to be split. Neutrons released from previous fissions = used to hit other U-235 atoms.

2. This causes more U-235 atoms to split, releasing even more neutrons and this continues - CHAIN REACTION

3. The fission of an atom releases loads of energy in the form of the kinetic energy of the two new atoms. (heat)

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1. Free neutrons in the reactor start the process

2. Two fission fragments collide with surrounding atoms - temperature rises

3. Control rods, boron, limit rate of fission by absorbing excess neutrons

4. Carbon dioxide = pumped through reactor - carries away heat generated

5. gas = passed through heat exchanger - gives energy to H2O. Water = heated - into steam - turns turbines

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