Radioactive Sources & Their Dangers

1. Radioactive Sources & Their Dangers Noadswood Science, 2012

2. Radioactive Sources & Their Dangers • To know the dangers associated with different radioactive sources

3. Detecting Radiation • Radiation cannot be detected by human senses, so requires machines to do so… • Photographic film goes darker when it absorbs radiation, just like it does when it absorbs visible light – the more radiation the film absorbs, the darker it is when it is developed • People who work with radiation wear film badges, which are checked regularly to monitor the levels of radiation absorbed

4. Detecting Radiation • There is a light-proof packet of photographic film inside the badge – the more radiation this absorbs, the darker it becomes when it is developed • To get an accurate measure of the dose received, the badge contains different materials that the radiation must penetrate to reach the film • These materials may include aluminium, copper, lead-tin alloy and plastic • There is also an open area at the centre of the badge

5. Detecting Radiation • The Geiger-Muller tube detects radiation – each time it absorbs radiation, it transmits an electrical pulse to a counting machine which makes a clicking sound or displays the count rate • The greater the frequency of clicks, or the higher the count rate, the more radiation the Geiger-Muller tube is absorbing

6. Radiation Dangers • When radiation collides with molecules in living cells it can damage them • If the DNA in the nucleus of a cell is damaged, the cell may become cancerous – the cell then goes out of control, divides rapidly and causes serious health problems • The greater the dose of radiation a cell gets, the greater the chance that the cell will become cancerous • However, very high doses of radiation can kill the cell completely – used to kill cancer cells, and also harmful bacteria and other micro-organisms

7. Radiation Dangers • If radiation enters your body it will collide with molecules in your cells • These collisions cause ionisation, which damages or destroys the molecules (lower doses tend to cause minor damage without killing the cell, whilst higher doses can kill the cell completely) β and γ β and γ α β and γ β and γ

8. Radiation Dangers – Inside The Body α • If the radioactive source is inside the body, perhaps after being swallowed or breathed in: - • Alpha radiation is the most dangerous because it is easily absorbed by cells • Beta and gamma radiation are not as dangerous because they are less likely to be absorbed by a cell and will usually just pass right through it

9. Radiation Dangers – Outside The Body • If the radioactive source is outside the body: - • Alpha radiation is not as dangerous because it is unlikely to reach living cells inside the body • Beta and gamma radiation are the most dangerous sources because they can penetrate the skin and damage the cells inside βγ

10. Radiation Poisoning • There have been a few high-profile cases of radiation poisoning, including the Chernobyl disaster and the death of the ex-KGB spy Alexander Litvinenko… Japanese woman suffering burns from thermal radiation of the WWII atomic bomb, dropped by the USA

11. Radiation Poisoning – Chernobyl • The Chernobyl disaster (26/04/1986) was a nuclear reactor accident in the former Soviet Union – it was the worst nuclear power plant disaster ever, resulting in a severe release of radioactivity into the environment following a massive power excursion which destroyed the reactor • Two people died in the initial steam explosion, but most deaths from the accident were attributed to radiation poisoning

12. Chernobyl

13. Radiation Poisoning – KGB Poisoning • Alexander Litvinenko was an officer within the KGB • In 1998 he made various accusations against numerous KGB officials, and was dismissed followed by a subsequent arrested (acquitted) • He fled from his re-trial to London, and as a writer accused Putin and other figures in the Russian government of a range crimes, including ordering the murder of Russian journalist Anna Politkovskaya • On 01/11/2006 Litvinenko suddenly fell ill, in what was established as a case of poisoning by radioactive polonium-210 resulting in his death on 26/11/2006

14. KGB Poisoning

15. Radiation – Exposure

16. Radiation – Prognosis