A "dirty bomb" question

[Jose Julio Rozental <joseroze@netvision.net.il>]

Dear colleagues



 



After reading some topics on this subject I would like to make my contribution:



 



1) About smoke detector:  Two cases to consider: 





a) Country has adopted the IAEA Basic Safety Standard

b) Country not has yet adopted and uses 74 Bq/g





In the first case, Am-241 sources should be of order of 10 KBq (10 KBq Exempt Activity for Am-241); sources with higher activity, and the common smoke detector has around 35 KBq, a little higher than the IAEA value, in this case cannot be only considered trivial doses, but optimization should be taking into account, to IAEA recommendation of  a maximum collective dose commitment of 1 manSv

However many countries have accepted the exemption on the argument of minimum trivial doses, but require to return old sources to supplier, and as general rule, to be clearly identified:



Warning: radioactive material

Trefoil radioactivity symbol

Identity and amount of radioactive material

Return  to Competent Authority for Disposal, if country accept or Return to supplier



 



2) For me it is out of imagination a "dirty bomb" using source of Am-241 from smoke detectors. It is difficulty and non sense to consider the small activity of each device, today less than 10 microCurie, and the  60 keV dose rate is less than 1 micro Sv/h (100 microrem/h) at 10 cm from the surface of the device.



 



b) It seems to me out of logic even for a fanatic terrorist to remove de small sources the way that was designed to be used to avoid being detached or suffering loss of integrity in each smoke detector.



 



2) After ICRP 27 it was required justification to use such devices - The Committee on Radiation Protection and Public Health of the OECD Nuclear Energy Agency made a study to examine radiation protection problems relative to the use of Smoke Detectors and, in particular, the justification of the practice. Appendix III describes the Fire and incineration tests. The scope also mention besides fire, explosion, misuse, mutilation and theft or loss.



I would recommend to those that which in principle to understand about these devises, containing radioactive sources, before to give information on radiation safety on this topic to read the OECD/NEA document - Recommendations for ionizing chamber smoke detectors in implementation of radiation protection standards, 1977 - The document includes the reasons of justification and dose to most exposed individuals assumed to be those involved in the clear-up operation, like fire brigade in case o fire.



 



3) About panic - In the case of dirty bomb, today there are many information and scenarios made to minimize this situation - A Dirty Bomb, using high activity source, nevertheless has similar situation like the Accident in Goiania, for this reason Goiania is always mentioned as association,  presents also many different aspects, one of them is - The radiological Accident in Goiania took both, public and competent authorities by surprise and the communication during a radiological emergency where population was involved no was so well developed. Only after Chernobyl and Goiania, Radiation Safety Communication have changed in terms of population communication and now improved taking into account  the possibility of a terrorist attack.





Jose Julio Rozental

joseroze@netvision.net.il

Israel