UnderstandingRadiationNatural and Man-made
We are all exposed to ionisingradiation from natural sourcesall the time- called naturalbackground radiation.This radiatio...
outer space- Cosmic Raysbombard the earthEarth- which itself issignificantly radioactive dueto Radioactive substances inth...
These are extremely energeticparticles, primarily protonsoriginating from Sun, stars,galaxiesThese react with air and fina...
When earth was formed itcontained many radioactiveisotopes.Long lived isotopes and theirdecay products are stillpresent an...
Radon comes from the decay(change) of Uranium. Uraniumdecays through a long chain ofradionuclides that includes radon.   R...
The radon itself has a small chance ofdecay as you breath it in and out. Most of our actual dose comes fromthe decay produ...
There are several othernaturally occurring radioactivenuclides. Most notable areCarbon-14 (C-14) and Potassium40 (K-40). T...
Humans are exposed to radiationfrom natural sources. The sources include the ground wewalk on, the air we breath, the food...
Average Annual Radiation Exposure ( micro Sv)   Type    Source        World     Range                         Average   Na...
Place    Average Maximum MinimumBhuj     692    876     561Nagpur   736    858     674
In India the background natural radiationis available from fields measured byINDIAN ENVIRONMENTALRADIATION MONITORING NETW...
We also receive radiation dose due toman-made sourcesMedical radioactivity exposures duringdiagnostic radiology such as X-...
A CT scan gives a dose of 5000-10000 micro Sv.  PET scans give a similar dose from an internalinjected radioactive source....
Average Annual Radiation Exposure ( micro Sv)Type    Source     World      Range                   AverageNatural Air     ...
Karunagappally taluk in costalKerala has radiation backgroundup to 70,000 micro Sv/y due tothe deposits of Thorium in thes...
In some parts of Ramsar, a city inNorthern Iran people have beenreceiving up to 260,000 micro Sv/ydose due to natural radi...
High natural radiation   Thorium sands   Study conducted byRegional Cancer Centre, Trivandrum
Jayalekshmi P et al. High natural radiation and cancer in Karunagapally, Kerala
Compared to the average natural radiationbackground dose of 2400 micro Sv/y theradiation dose from Indian Nuclear PowerPla...
National regulations are based on  “reduce radiation toAs Low As Reasonably Achievable  (ALARA),”close to natural levels, ...
Ref: United Nations Scientific Committee on theEffects of Atomic Radiation   UNSCEAR - Appendix B              Thanks for ...
Low or modest levels of nuclearradiation and radioactivity are notharmful. Fear of radiation causes personal stressand soc...
Workers at Chernobyl- No worker with less than 2000 mSv died from ARS.Workers at Fukushima- After six weeks 30 workers had...
Understanding radiation
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Understanding radiation

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This presentation by Mr Bharadwaj, Technical Director of Nuclear Power Corporation of India explains the various types of radiation.

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Understanding radiation

  1. 1. UnderstandingRadiationNatural and Man-made
  2. 2. We are all exposed to ionisingradiation from natural sourcesall the time- called naturalbackground radiation.This radiation is always aroundus whether we are indoors oroutdoors.
  3. 3. outer space- Cosmic Raysbombard the earthEarth- which itself issignificantly radioactive dueto Radioactive substances inthe earth’s crust
  4. 4. These are extremely energeticparticles, primarily protonsoriginating from Sun, stars,galaxiesThese react with air and finallyreach us as muons, gamma rays,neutrons and electrons
  5. 5. When earth was formed itcontained many radioactiveisotopes.Long lived isotopes and theirdecay products are stillpresent and are irradiatingus constantly
  6. 6. Radon comes from the decay(change) of Uranium. Uraniumdecays through a long chain ofradionuclides that includes radon. Radon is a noble gas, notchemically active, so it migratesthrough porous materials like theground and your housesfoundation.
  7. 7. The radon itself has a small chance ofdecay as you breath it in and out. Most of our actual dose comes fromthe decay products of radon.These radon progeny are particles notgases, and can be deposited in yourlungs as you breath. There they havesome chance of decaying before yourbody can get rid of them, resulting ina radioactive dose.
  8. 8. There are several othernaturally occurring radioactivenuclides. Most notable areCarbon-14 (C-14) and Potassium40 (K-40). They eventually maketheir way into our food chain.Once ingested, they decay andgive us an internal dose.
  9. 9. Humans are exposed to radiationfrom natural sources. The sources include the ground wewalk on, the air we breath, the foodwe eat – the entire solar system onthe whole.Everything in our world contains smallamounts of radioactive atoms likePotassium 40, Radium 226 and Radon222.
  10. 10. Average Annual Radiation Exposure ( micro Sv) Type Source World Range Average Natural Air 1260 200 – 10000 Internal 290 200 - 1000 Terrestrial 480 300 - 1000 Cosmic 390 300 - 1000 Total ~2400 1000 -13000
  11. 11. Place Average Maximum MinimumBhuj 692 876 561Nagpur 736 858 674
  12. 12. In India the background natural radiationis available from fields measured byINDIAN ENVIRONMENTALRADIATION MONITORING NETWORK(IERMON) by BARC, DAEThe IERMON network has severalstations across the country and thereadings of the radiation fields areavailable on-line in DAE. The data showthat there is at least 10 % variation inthe radiation fields on both the sides ofaverage readings.
  13. 13. We also receive radiation dose due toman-made sourcesMedical radioactivity exposures duringdiagnostic radiology such as X-rays andCAT scans , nuclear medicine andradiotherapy gives radiation dose to usDose is also received from nuclear fall-out, occupational exposures and fromradioactive discharges during operationof Nuclear Power Plants
  14. 14. A CT scan gives a dose of 5000-10000 micro Sv. PET scans give a similar dose from an internalinjected radioactive source. A screening CT+PET scan gives a whole-body doseof 15000 micro Sv. Today many people benefit from radiationdiagnostic scans and some have radiation therapy forcancer.This radiation and radioactivity, internal andexternal, are essentially the same types as thatemitted at Fukushima.
  15. 15. Average Annual Radiation Exposure ( micro Sv)Type Source World Range AverageNatural Air 1260 200 – 10000 Internal 290 200 - 1000 Terrestrial 480 300 - 1000 Cosmic 390 300 - 1000 Sub-total ~2400 1000 -13000Man Medical 600 30 - 2000Made Fall-out 7 0- 1000 Others 5.2 0- 20000 Sub-total ~600 0- 20000Total ~3000 0- 20000
  16. 16. Karunagappally taluk in costalKerala has radiation backgroundup to 70,000 micro Sv/y due tothe deposits of Thorium in thesand.
  17. 17. In some parts of Ramsar, a city inNorthern Iran people have beenreceiving up to 260,000 micro Sv/ydose due to natural radiationbackground. Cytogenetic studiesshow no significant differencesbetween people in the highbackground compared to people innormal background areas.
  18. 18. High natural radiation Thorium sands Study conducted byRegional Cancer Centre, Trivandrum
  19. 19. Jayalekshmi P et al. High natural radiation and cancer in Karunagapally, Kerala
  20. 20. Compared to the average natural radiationbackground dose of 2400 micro Sv/y theradiation dose from Indian Nuclear PowerPlants during 2010 was 0.42 to 39.6 microSv to the persons near plant boundarieswhich is insignificant compared to thenatural background and the seasonalvariations in natural background at a place.
  21. 21. National regulations are based on “reduce radiation toAs Low As Reasonably Achievable (ALARA),”close to natural levels, not for safety but for social reasons.
  22. 22. Ref: United Nations Scientific Committee on theEffects of Atomic Radiation UNSCEAR - Appendix B Thanks for your kind attention
  23. 23. Low or modest levels of nuclearradiation and radioactivity are notharmful. Fear of radiation causes personal stressand social damage that is very harmful. Current evacuation regulations arescientifically unreasonable and causehardship. International “safety” levels based on thelowest achievable can be relaxed upwardsby a large factor.
  24. 24. Workers at Chernobyl- No worker with less than 2000 mSv died from ARS.Workers at Fukushima- After six weeks 30 workers had received between 100-250 mSv.- So there will be no deaths from ARS at Fukushima.Radiation therapy to cure cancer- Patients receiving radiotherapy spread over about 6 weeks to curecancer get a daily dose of 2000 mSv to the tumour that kills thecancer cells.- They also receive daily 1000 mSv to many healthy organs andtissue that survive -- more than 20,000 mSv per month.- That is more than 5 X an acute fatal dose (4,000mSv).- Credible data?Most people personally know someone who has benefited from suchtreatment.- How? Recovery from radiation damage.After each daily treatment healthy organs just have time to repair theradiation damage - and the tumour cells just do not.
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