|Comments by Marion Hill on the Draft ICRP Document
‘The Scope of Radiological Protection Regulations’
(02/258/05 – spring 2006 version)
i) I do not think that it is within ICRP’s responsibilities or competence to specify what regulators or legislators should or should not do. ICRP’s role is to provide recommendations and advice on radiological protection, which other organisations can use if they wish to. In general this document is too didactic in tone. The inclusion of caveats about not being ‘categorical’ does not resolve this problem. It would be much better to change the tone of the whole document so that it contains mainly advice and suggestions, with few recommendations and sparing use of ‘should’.
ii) I am uneasy about the relationship between this document and IAEA standards, regulations and guides, and those from other international organisations. I do not think that support for or criticism of what has been done by the IAEA and others should have such a prominent place in an ICRP document. Attempts to justify, explain or even modify IAEA and other organisations’ documents have no place within a formal ICRP publication. They belong elsewhere, for example in an open letter from the chairman of ICRP to the IAEA director general or a division head.
iii) The style of the draft document is, in places, too wordy and academic. It would benefit from thorough editing and shortening.
iv) It is a good idea for ICRP to issue a publication on exclusion and exemption but this draft requires substantial work to make it acceptable.
i) Concepts of Exclusion and Exemption
The basic concepts of excluding situations that are not amenable to control and exempting situations that do not warrant control are very useful. In explaining the concept of exemption, less attention needs to be paid to exempting entire practices or sources from all controls, because in most cases this is not appropriate or desirable. The more usual case is when it is optimum to exempt a part of a practice or source from some controls or from all controls. For example, it is important to control the manufacture and supply of smoke detectors but sensible to exempt their use in and disposal from homes. Similarly, there should be controls on exposures in many workplaces that produce radioactive wastes, but the disposal of some of the wastes produced can be exempted from some controls. It would be much better to focus the document on the majority of practical exemption cases, rather than the theory of exemption. (I would also suggest that Figure 2 is omitted or substantially amended.)
ii) Concept of Clearance
With the clarification above it becomes obvious that ‘clearance’ is a special case of exemption, not an entirely different concept. While I do not disagree with much of what the document says about clearance (in Section 5.4), the discussion is somewhat theoretical and I doubt whether it will help most readers.
iii) Concept of Exemption in Intervention Situations
Ideally the concept of exemption from intervention would not have been introduced. Since it exists, ICRP has no option but to deal with it and Section 5.5 seems basically acceptable.
iv) Exclusion Criteria
Section 4 states, correctly, that it is for national authorities to decide what is or is not amenable to control, but it does not offer much assistance to help them make such decisions. The section is very unhelpful indeed on the subject of NORM because it does not deal adequately with the concepts of technological enhancement of exposures or imposed risk. It is not that countries have fundamentally different regulatory approaches or perceptions of NORM exposures, it is that they wish to treat exposure situations according to these characteristics, as well as considering amenability to control.
For example, monazite sands in situ are entirely natural and people are free to choose whether or not to go to beaches with such sands. Extraction of monazite sands and their transport elsewhere for processing and use are human actions that impose risks on people who would not otherwise be exposed to the sands and have no choice about being exposed. It is reasonable to exclude the sands in situ from regulation but to control the extraction, transport, processing and use of the sands. Alternatively, extraction and subsequent actions could be exempted; they should not be excluded. More generally, it is inconsistent and unacceptable to allow the exclusion of raw materials with ‘unmodified’ concentrations of naturally occurring radionuclides from all forms of control (para f in the Executive Summary, para 35 in Section 4). Many human activities involving such materials are eminently controllable and can also impose unwanted risks. What is required is some form of exemption. (Incidentally, deliberate dilution of NORM materials to make them ‘natural’ is completely unacceptable too (see para 143).)
It would be helpful if ICRP developed a self-consistent radiological protection framework for exclusion and exemption of NORM. The advice on exclusion should also cover the ubiquitous artificial background (eg from weapons test fallout, Chernobyl, global circulation of carbon-14 effluent releases). At present this is only mentioned in the context of commodities; it is a wider issue than this.
v) Exemption Criteria
I think that many of the difficulties over exemption criteria and the derivation of exemption levels stem from a lack of clarity about what sort of practice, part of a practice or source is being exempted from what sort of controls. A further problem is that numerical criteria (especially 10 microsieverts and 1 man Sievert) have been used almost mechanically to derive exemption levels, with no check on whether the levels derived are really needed and no consideration of social and economic factors. (In particular, there are many examples in the IAEA BSS, IAEA RS-G-1.17 and EU publications of exemption levels for radionuclides that are much higher than could conceivably be needed.) These are other ways in which exemption criteria should be ‘situation specific’ and have ‘multiple attributes’ (eg para 76).
Rather than discussing existing exemption levels, the document should give firmer advice on deriving new levels and revising existing ones. In doing so, it may be best to make a distinction between international exemption levels (for use in promoting consistency in protection standards and facilitating trade) and national exemption levels (that are more situation specific, for example for areas of high natural background). (I would avoid the term ‘generic exemption’ because it can become confused with the existing term ‘generic authorisation’ as a way to carry out exemption.) I would also like to see much clearer advice about dose criteria for exemption. As I understand it, ICRP suggests that 10 microsieverts is the lowest dose criterion and is for use when large populations will be exposed by practices or parts of practices. 1 millisievert is the highest dose criterion, for use in exemptions from intervention to reduce prolonged exposures. Dose criteria between these two levels will be appropriate in other situations.
vi) Activity Levels
I think that it is inappropriate for ICRP to specify or endorse any numerical activity levels (radionuclide quantities or concentrations) to be used internationally or nationally for exclusion or exemption. Establishing such levels requires societal value judgements that it is not ICRP’s role to make. ICRP should provide a radiological protection framework in which national and international organisations can work to establish levels. Furthermore, some of the levels given in the draft document are of no practical value.