RE: clearance thresholds

[MOSHEK <MosheK@ENVIRONMENT.GOV.IL>]

Dear Marco,



The International Atomic Energy Agency (IAEA) published in 1996 the Basic

Safety Series No.115: International Basic Safety Standard for Protection

Against Ionizing Radiation and for the Safety of Radioactive Materials

(BSS-115). Based on recommendations of the ICRP 60, scedule I of the BSS-115

define exemption levels from the requirements of the standard. The general

principles for the exemption are (I-2):

a. the radiation risks to individuals caused by the exempted practice or

source be sufficiently low as to be of no regulatory concern.

b. the collective radiological impact of the exempted practice or source be

sufficiently low as not to warrant regulatory control under the prevailing

circumstances; and

c. the exempted practices and sources be inherently safe, with no

appreciable likelihood of scenarios that could lead to a failure to meet the

criteria in (a) and (b).

In I-3  is written: A practice or a source within a practice may be exempted

without further consideration provided that the following criteria are met

in all feasible situations:

(a) the effective dose expected to be incurred by any member of the public

due to the exempted practice or source is of the order of 10 microsievert or

less in a year, and 

(b) either the collective effective dose committed by one year of

performance of the practice is no more than about 1 man.Sv or an assessment

for the optimization of protection shows that the exemption is the optimum

option.



Please, I would like to emphasize in (a): " ......of the order of 10

microsievert or less in a year....." and not just in the order. I believe 

'





Table I-I in this schedule give exempt activity concentrations and exempt

activities of the different radionuclides, so the general figure of 70 Bq/g

for all radionuclides in not valid any more, according to the BSS.



The Bss define also  clearance values:" values, established by the

Regulatory Authority and expressed in terms of activity concentrations

and/or total activity, at or below which sources of radiation  may be

released from regulatory control". That mean that the regulatory authority

can define different values.



Regarding the connecting between waste regulations and clearance values, the

IAEA published two tecdocs:Tecdoc 855: Clearance levels for radionuclides in

solid materials - Application of exemption principles - INTERIM REPORT FOR

COMMENT!!!!!!

and tecdoc 1000 for clearance of waste generated in medicine, industry and

research. This was a final tecdoc, not an interim. 



I guess the  different values set some bewilderedness and so I in last May

got a massage from the IAEA that the agency ".... is going to try and have 1

number for thee exemption, clearance and commodities." This will be done in

an addendum to the BSS.



In that case, I will recommend to adopt the BSS now, so every change in the

BSS should be adopted automatically with no special changes in legislation.





Yours



Moshe Keren  





  



 



-----Original Message-----

From: Marco Caceci [mailto:mcaceci@radal.com]

Sent: Monday, July 30, 2001 10:23 AM

To: Radsafe (E-mail)

Subject: clearance thresholds





Hi:



I am writing a paper for a (Spanish) waste management trade magazine on the

issue of radiation protection.

This is a non-peer-reviewed article, so if anybody could volunteer to review

it (it is in Spanish) please let me know, I would

really appreciate...



Presently I find it difficult to locate primary sources and references for

clearance limits and criteria for acceptance of incoming

materials and products.

Any expert out there could check these statements and tell me if they are

true? do you have any reference to relevant laws and

regulations?



to be considered 'non radioactive'...



- underlying criteria is that no member of the public should be subject (by

a product such as recycled aluminum or steel) to a dose

higher than 10 uSv in a year



- product (such as Al or steel) or raw material (scrap) should emit less

then 1 uSv/h at contact



- product should contain less then 70 Bq/g activity



Thank you in advance...



Marco Caceci

LQC s.l.

www.radal.com

www.chemitech.com



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