1. Lesson 8: Waste from Power Stations

2.  MUST understand that nuclear and other power stations produce radioactive waste  SHOULD understand the difference between irradiation and contamination, and their different risks  COULD understand how people may perceive different risks

3.  You need to be able to define the following:  Radioactive  Ionising radiation  Irradiated  Contaminated

4. 1)Radioactive waste emits harmful radiation. 2)Some waste has a higher level of radioactivity than other waste; so needs to be stored away from people. 3)Contamination is when the radioactive substance mixes with a material; irradiation is when the material is in the path of ionising radiation coming from the radioactive substance. 4)Contamination is reduced by storing radioactive waste as solid substances; contamination and irradiation are reduced by using shielding. 5)For example, flying off on holiday. 6) It is important to estimate risks correctly so we take suitable precautions.

5. Activity 1 (Low demand)  Most radioactive waste is thrown out with household rubbish − false  Over time, radioactive waste becomes less radioactive − true  It is safe to store radioactive waste in warehouses – false  Some radioactive waste is recycled and reused – true  Radioactive was emits ionising radiation – true  All radioactive waste is highly dangerous – false

6. Activity 2 (Standard demand) 1)a) Putting diesel into a car that runs on petrol − contamination. Ideas to reduce: warning signs to reduce human error; different size/shaped nozzles to prevent contamination; on realising error don’t run the engine, to reduce chance of fuels mixing. b) Exposure to sunlight – irradiation. Ideas to reduce: stay out of the sun as much as possible to reduce exposure time; cover up with clothes and wear a hat and sunglasses to shield. c) Standing near a bonfire – contamination (with smoke). Ideas to reduce: stand upwind not downwind of the fire to reduce contamination; stay indoors to shield; wash hair, clothing etc. afterwards to decontaminate. Also irradiation from the bonfire. Ideas to reduce: move further away to reduce intensity; stand behind something to shield; stay indoors to shield or move indoors to reduce exposure time. 2)It is harder to control or remove contamination; it is mixed in with other substances; irradiation can be controlled by distance or shielding.

7. Activity 3 (High demand)  In decreasing order of risk (figures in brackets give the lifetime chance of dying from these causes): smoking 10 cigarettes per day (1 in 200); influenza (1 in 500); road accident (1 in 8000); playing football (1 in 25 000); accident at home (1 in 26 000); accident at work (1 in 43 000); hit by lightning / radiation from nuclear power station (1 in 10 000 000).