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Re: Domestic smoke detector disposal

Dear colleagues,

Let me consider the  ICRP/IAEA  documents:

The ICRP 60 describes the condition of exemption at 7.8 (pages 64/66)

(articles 285/293)

Article  287 - page 65, consider two reasons for exempting a source or an

environmental situation from regulatory control.

1. The source gives rise to small individual doses and small collective

doses in both normal and accident conditions.

2. No  reasonable control procedures can achieve significant reductions in

individual and collective doses

After this article the others are very important to complement the basis for

exemption and how to apply it in general activities.

The IAEA BSS Safety Series 115 edition, 1996, was revised to reflect the

consensus surrounding these ICRP recommendations to exempt from regulatory

control and also to apply to waste and transport. The IAEA recommendation

refers to an individual dose of "some tens of microsieverts per year

 (ÁSv/y)" as being trivial and therefore a basis for exemption from

regulatory control. Furthermore, the IAEA suggests that in order to account

for exposures from more than one exempt practice, the exposure to the

critical group from one such practice should be in the order of 10 ÁSv/y. In

addition the IAEA recommends a maximum collective dose commitment of 1 manSv

per year for each such practice. (GO TO ICRP 288 page 65 IAEA I-3, page 81).

It was recognized that the single exemption level of 70 Bq/g has no dose

basis and that it was unlikely that this level satisfied the primary dose

criterion of 10 microsievert in a year for exemption for all radionuclides.

Values were derived comparable to the exemption values and resulted in

recommended activity concentrations ranging from 1 to 10^6 Bq/g. and

Activities from 10^3  to 10^9 Bq.

Now lets go to the specific part of Smoke detector: - Two cases to consider:

a) Country has  adopted the IAEA Basic Safety Standard

b) Country not has yet adopted and use 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

For political reasons and also technical circumstances,  many countries have

accepted the exemption on the argument of minimum trivial doses, however

require to return old sources to supplier, and as general rule, to be

clearly identifyed:

Warning: radioactive material

Trefoil radioactivity symbol

Identity and amount of radioactive material

Return  to Competent Auhtority for Disposal, if country accept or

Return to supplier

Jose Julio Rozental




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