|By: Eliana Amaral, Institute of Radiation Protection and Dosimetry, Brazil (former Director, 1994-2003) with the
collaboration of Dunstana Melo and Elaine Rochedo Institute of Radiation Protection and Dosimetry, Brazil
1- GENERAL COMMENTS
The fundamental objective of a radiation protection system is to provide an easy operational procedure to assure radiation safety clearly understandable by all stakeholders worldwide. More and more it is necessary to demonstrate a clear and credible system; consistency and coherence are fundamental to improve credibility and public acceptance.
Many countries are in the process of implementing the BSS 115. This represents the idea of a consistent system. A lot of effort is being made by IAEA in the elaboration of documents based on BSS115 in order to have the same system being applied worldwide. It is not time for another major change, unless of course there has been a scientific finding that requires it.
In addition, the framework involved for the elaboration and approval of the international system of normalization on radiation safety has to be maintained. The two scientific committees, UNSCEAR and ICRP, as bases for IAEA standards and finally for Governments regulations, contribute to improving consistency and credibility, mainly because the ICRP is seen as an independent committee. However the ICRP 2005 new recommendations without any consistent justification will probably affect this framework. Some Governments will follow but others not; the IAEA can adopt some recommendations but others not. Therefore the importance of ICRP within the system will turn into a weakness and the worldwide uniformity will disappear despite all the efforts which have been made by the IAEA over the last 10 years.
Therefore ICRP should consider that the basic recommendations should only be changed due to any scientific finding that will affect safety. Even though considerations shall be made about the regulatory implications of any change, since ICRP recommendations are not only based on scientific knowledge. Other factors have also to be considered.
2- Specific comments
Concepts can not be changed or principles be removed because they were not adequately used:
Justification is a fundamental principle and has to be maintained. However it is important to explain the meaning of this principle. In my point of view society has to justify any additional radiation exposure. Society participation is different from country to country and depends on the circumstances.
Dose constraint is also an important quantity for source related dose limits. However it has been used sometimes as an optimized limit and the concept of dose limit was forgotten. This has to be clarified instead of changing the dose constraint concept.
Practices/intervention/controllable dose/dose constraint - We have spent years explaining what is a practice and an intervention, a planned and the facto situation, in order to justify different acceptable risk levels applied to each situation. The new proposal no longer mentions the averted dose, apply dose constraints to intervention situations, and makes a big mixture of both situations. What would the new proposal add to the system in terms of operationally, credibility, worldwide harmonization? I do not see any positive contribution but it will increase the confusion and differences between countries in applying different dose constraints values.
Change in terminology for health effects – It does not make any sense to substitute terms that will introduce more confusion. Epidemiological studies are showing cardiovascular diseases as being connected to radiation stochastic effects; therefore it is not only “cancer development”. In addition, tissue reaction may also mean cancer development as well a simple allergy.
Tissue weighting factors - If there are new numbers that will affect safety then it is important to use them. But we have to be careful do not change everything as new models appear as it happened with the introduction of the effective dose. One way to minimize this problem would be that Basic Documents only encompass concepts, principles and dose limits. All derived numbers could be described in reports documents easier to adopt modifications.
Optimization of protection - Here we have the same situation, since this principle was not well applied it was decided to forget it. This principle has to be maintained as it was but a clear explanation on how to apply is needed. Optimization is much more than safety culture. It has to be used in the everyday work decisions by radiation protection supervisors. Stakeholder involvement is important in some circumstances, such as decision for an investment to adopt a remediation action. Society has to be seen as a Stakeholder, and, as for the justification principle, has to decide what level of risk it will accept. Depending on the country and circumstances, society can be seen as sectors representatives or even the government.
Occupational exposure - It is important to remind the ICRP that there is an ILO recommendation for not changing concepts and terminologies. In addition the ILO is absolutely against classification of radiation workers.
Dose constraints/dose limit/critical group - Both concepts, dose constraint and dose limit for public and numbers have to be maintained since they are already accepted worldwide , otherwise it is not possible to assess the situation of multiple sources at the same site and the impact of global radionuclides. The concept of critical group proposed by ICRP is an average critical group and will neglect children. It cannot be accepted.
Emergency exposure - The avertable dose concept was neglected . The avertable dose is fundamental for the justification of the action. In addition limits based on dose rate has to be used for this situation. It does not make any sense to adopt a protection action based on annual dose!!! Can we imagine giving iodine tablets over a year?