|Additional contributions to the drafting of the new ICRP Recommendations
At the meeting of the Group of Experts under Article 31 EURATOM on 18 October three further documents were discussed which the Group felt could benefit to the drafting of the new recommendations. These documents elaborate on our earlier corrections and comments to the draft in public consultation, on three specific issues:
– The concept of "constraint";
– The scope of regulatory control;
– Definitions (endeavour, practices and intervention, workers and members of the public).
These documents emerge as building blocks to our ongoing work with revising the EURATOM Basic Safety Standards. They will also be shared with the other co-sponsors for the revision of the IAEA Basic Safety Standards. It should be emphasized that while the Experts thought these documents would help clarifying important concepts, this does not preclude that these views would evolve further in the course of our work. While I am pleased to forward the documents as they are on behalf of the Group of Experts, this does not mean that there is full consensus nor that there is agreement on each sentence.
The document on "constraints" attempts to clarify the concept, which currently is defined in different parts of the ICRP draft, and to put emphasis on the importance of the "bands of constraints". We feel the introduction of constraints in all situations and the introduction of societal criteria for that purpose is the real novelty of the recommendation, and therefore deserves careful drafting.
The document on "scope" elaborates further on our earlier comments on the draft foundation document. We believe it to offer a brief yet comprehensive discussion of the issue, which is as far as ICRP should go. The implementation of the concepts should be left to national authorities.
Both the considerations on "constraints" and on "scope" call for careful definitions, in particular for regulatory transposition. While this may not be so much a matter for ICRP, we believe the discussion of definitions to be helpful in clarifying the recommendations.
I would like to take this opportunity for correcting slightly the list of comments sent earlier (before 15 september):
– We proposed the deletion of the last sentence in (342), this was however a mistake;
– The comment on the use of "effective dose" in medical applications was not rendered with sufficient precision: attention was drawn to misuse of the concept in medical applications in particular for individual risk assessment.
I trust these late contributions will nevertheless help ICRP in getting around some of the most difficult issues.
THE CONCEPT OF "CONSTRAINT" IN THE NEW ICRP RECOMMENDATIONS
The latest draft of ICRP confirms the important role of the constraints in radiation protection. Comments transmitted so far, however, underline that constraints do not establish "the most fundamental level of protection" in their own right (184). Optimisation of protection is the fundamental tool to achieve acceptable exposures. Optimisation is, however, "constrained by a level of dose where action is almost always warranted" (33).
The above is not very new. The important novelty is that constraints would apply regardless of the type of source or the exposure situation. ICRP distinguishes between planned, existing and emergency situations, and between public, occupational and medical exposures.
The second novelty is that ICRP has introduced "bands of constraints":
– below 1 mSv per year;
– in the range 1-20 mSv per year;
– in the range 20-100 mSv (per year, but with the understanding that such exposures would arise exceptionally, in particular in an emergency situation).
The bands are defined on the basis of societal criteria (very much in terms of "equity") to be fulfilled in order that it may be appropriate for a constraint for a given type of exposure or exposure situation to be set in this range. The criteria encompass considerations such as:
– individual benefit (societal benefit is required on grounds of the justification principle), either directly (e.g., consumer products, medical exposures, workers in the nuclear industry) from a planned exposure or indirectly (in an existing or emergency situation, to avoid the detriment or cost of remedial action);
– information on radiation risks provided to the affected individuals and training, where appropriate;
– the degree of individual exposure monitoring (individual dosimetry, individual assessment on the basis of ambient or workplace monitoring, assessment for reference groups of the population rather than individuals, no identified reference groups);
– the degree of involvement of the individual in managing his own exposure (e.g., for classified workers, for people living in contaminated areas, exposure to radon in dwellings).
It is important to distinguish between the two different, complementary, approaches to setting constraints, either on the basis of any of the above societal criteria, or on the basis of an assessment of a reasonable starting point of optimisation. The latter "level where action is almost always warranted", can be the result of:
– generic optimisation;
– experience ("best practice");
– intervention levels set in the past for existing situations (e.g., radon in dwellings) or for emergency planning;
– the number of sources to be taken into account for compliance with dose limits.
There is some ambiguity in the ICRP draft with regard to equating constraints to existing numerical values labelled as "action levels". Where "intervention levels" are defined on the basis of generic optimisation, "action levels" originally related to levels below which in general no action needs to be taken, and are thus more related to the scope of regulatory control (exclusion, exemption, etc). It is now clear that optimisation below constraints may lead up to exposures far below the constraint. It must also be borne in mind that intervention levels are in principle derived on the basis of "averted dose", while the constraints should be expressed in total dose or residual (after intervention) dose. They also most often take only societal benefits into account, rather than individual benefit.
ICRP is not clear on which priority to give to the two different bases of constraints. This will probably depend on the situation. One can start from a generic constraint and optimise below, and check whether the societal criteria are satisfied. To the greatest extent possible, appropriate societal measures (e.g., information, involvement, compensation) need to be taken. One can also start from a point in the bands of constraint on the basis of the societal aspects of the exposure situation and optimise below. This point should be close to the upper boundary of the band of constraints.
In a number of paragraphs (e.g., 279) constraints are described as "levels of aspiration". This rightly emphasises that constraints should apply prospectively, rather than retrospectively, as in the case of limits. While retrospective assessment will have an impact on setting future constraints, it may happen that in the actual situation the outcome of optimisation is that the constraints would be exceeded; it is not appropriate to cause undue costs or detriments merely for the sake of complying with the pre established constraint. However, it seems better to reserve the term "level of aspiration" in relation to time horizons. For instance, in the event of an emergency, while it may be appropriate to set constraints in the range 20-100 mSv initially, in the long term there could be societal acceptance only in the range of 1-20 mSv, whereas the "level of aspiration" is obviously below 1 mSv.
THE SCOPE OF REGULATORY CONTROL
1. REGULATORY CONTROL
Before defining the scope of application of regulatory control, it is important to define regulatory control as such. There is often confusion between the general object of regulatory control, or the general scope of legislation, and the actual range of control measures. Legislation may impose requirements on legal persons without any further implication of the controlling authorities. The authorities may also exempt legal persons from certain requirements, in particular such requirements (e.g. reporting) on which the authorities would need to respond.
In broad terms and in normal circumstances the task of the regulatory authority includes the following:
• Permission of types of practices on grounds of justification
• Licensing the operation of facilities and authorising discharge (this may include stakeholder involvement and environmental impact assessment)
• Inspection of compliance with legislation or licensing conditions
• Review the operation of facilities, e.g. through an assessment of the operational implementation of optimisation
• Check monitoring data (workers' exposure, discharge data, environmental radioactivity) as appropriate through a complementary monitoring programme.
• Regulate the import, export and shipment of sources.
In case of an emergency a specific authority, not necessarily the same as in case of normal operation will decide on the implementation of the intervention plan and on long-term measures to be taken in the aftermath of the accident (e.g. food controls). There is no point in using the concept of exemption in this context since the authority makes autonomous decisions.
2. CONTROLLABLE SOURCES
The legislation should not cover sources that are not amenable to control. This includes such sources which are "essentially" unamenable (e.g. K-40 in the human body) and those for which there is a certain extent of judgement to be made. There are obvious cases for which a reduction of exposure is possible only by affecting people's lifestyle and any intervention would be regarded as highly unjustified and even in breach of individual rights. There are less obvious cases where it is concluded that regulatory control is not warranted and that no responsibilities can be assigned to, nor meaningful requirements be imposed on, any responsible legal person.
The system of radiation protection in principle only applies to controllable sources. The new dose limitation system, based on source related constraints on individual doses, confirms this concept. There is still ambiguity with regard to the application of individual dose limits for the sum of all exposures, which remain part of the system, even though their role is now less prominent.
The exposure resulting from sources which are not amenable to control should not be included in the total individual dose. The external exposure at ground level (cosmic + natural terrestrial sources) has always been excluded as "background" exposure. The external exposure from deposited artificial radionuclides can also be excluded to the extent that controls are (no longer) justified and doses are sufficiently low so that they no longer represent a notable risk to health. To a certain extent this applies also to internal exposure resulting from environmental contamination or from commodities placed freely on the market.
The legal person responsible for a practice or for an existing situation may be exempted from certain administrative requirements. This exemption should not derogate from compliance with basic principles of radiation protection or specific rules laid down in the law (e.g. maximum dose constraints) to the extent the legal person can reasonably be assumed to have control of the situation.
Exemption can be granted by the regulatory authority to an identified legal person. In many cases, however, the exemption will be defined on a general basis, so that it is up to the legal person itself to decide whether the exemption criteria apply to the practice or situation under his responsibility. The exemption from reporting or notification as laid down in the Basic Safety Standards implies that the regulatory authority has no means of control. Hence the exemption criteria should be defined unambiguously so that the legal person can be confident that he complies with the law.
Exemption from notification implies that the regulatory authority has no intention of controlling the exempted practices individually. There is, nevertheless, a slight difference with the concept of exclusion. The regulatory authority may decide to implement monitoring programmes, to carry out inspections, to control the import of commodities or the placing on the market of commodities produced within its territory, etc. The regulatory authority is legally accountable for the consequences of its decision not to regulate certain practices.
Clearance relates to materials which are part of regulated practice. The practice as a whole is in general under strict regulatory control, e.g. the dismantling of a nuclear installation. Materials which are contaminated or activated in the course of the operational history of installation need to be categorised, sorted and managed as radioactive waste. The corresponding requirements are laid down in a dismantling licence. Premises within the licensed facility may have no contamination history or buildings or materials may have such low levels of contamination that the building may be used for any purpose or the materials can be reused, recycled or disposed of in installations which are not under regulatory control.
Compliance with clearance criteria needs to be demonstrated by the legal person responsible for the dismantling operations. This demonstration can be on the basis of records or, most often, measurements. The regulatory authority has a responsibility for checking that such measurements and records are reliable and that materials are managed as specified in the licence. In general the licensing requirements will preclude the mixing of contaminated and clean materials.
Clearance is a form of exemption, for a specific practice, of the requirement either to keep all materials under control of the licensee or to ship the materials to a licensed facility, e.g. for disposal as radioactive waste.
Cleared materials can be released from the premises to any possible destination. At the same time, the regulatory authority expresses its intention that the released materials should not be under regulatory control. The authorities may judge that no person holding such materials can be held legally responsible for the resulting exposures and hence they should not be within the scope of the regulations or legal requirements. Again, as with exemption from notification, this is close to the concept of exclusion, except that the regulatory authority may decide to monitor, for example, the accumulation of radioactivity in recycled metals or on conventional disposal sites.
5. CRITERIA FOR EXEMPTION OR CLEARANCE
In principle practices can be exempted, or materials cleared, from regulatory control, irrespective of the level of exposure that could result as a consequence of this decision. Responsible authorities will, however, need to demonstrate that there is no benefit in regulatory control either on grounds of an assessment of optimisation, or because there is too little room for reducing exposures substantially. This is the case when activity concentrations are close to zero or close to the prevailing background. In the case of artificial radionuclides this has been translated into resulting exposures of the order of 10 ìSv or less; for naturally occurring radionuclides, into concentrations of the order of the high range of those prevailing in soil or rock in the world.
The latter criteria for naturally occurring radionuclides should be formulated carefully. Reference to prevailing activity concentrations is justified only if the resulting exposures are deemed acceptable from a health point of view. It may also be argued that in regions with relatively low back ground it is not reasonable to refer to much higher concentrations elsewhere in the world. Within the range of controllable concentrations there is merit in defining a common level of ambition for different radionuclide chains and radionuclides within a chain (in case there is no secular equilibrium) in terms of dose: this allows a fair balance to be made allowing for the most important exposure pathways. In Europe this approach has led to exemption of naturally occurring radionuclides on the basic of an additional exposure of 0.3 up to 1 mSv/a.
The criteria are meant to apply to any type of practice involving exempted materials (below exempt concentration values) for reasons of legal accountability. However, it is possible to apply the criteria only to specific practices or to exclude others from general exemption. For instance, the use of construction materials may be subject to restrictions while other uses are generally exempted.
6. EXPOSURE PATHWAYS
It will often be necessary to allow for the fact that radiation protection legislation does not apply in isolation. For instance, for drinking water there are guidelines of WHO, for foodstuffs by Codex Alimentarius (FAO/WHO). In many countries, e.g. the EU, controls of drinking water and food have been incorporated in specific legislation. Hence, when considering the impact of radioactive effluent, it may be argued that corresponding exposure pathways should not be considered as long as the maximum permitted levels are not exceeded. It should be noted however that the Codex Alimentarius levels do not apply to normal situations but only to post-accidental contamination of foodstuffs. For drinking water or the other hand, in particular for naturally occurring radionuclides, it may be appropriate to exclude the ingestion pathway from the assessment of the doses for exemption.
Similarly, where there are legal requirements on levels of radioactivity in construction products, the recycling of residues from NORM industries may not be regarded as an exposure pathway, as long as the legal constraints are respected. One should also bear in mind that the justification principle prevails, and that therefore all industries producing such residues for recycling may therefore be subject to prior authorisation.
Radon gas can be considered as part of the exposure pathway resulting from NORM materials or constructions materials ubiquitous. Radon is, however, controllable in its own right and in situations where no controls are necessary for the ingress of radon from the soil below buildings, it would not be coherent to allow for the inhalation of radon on thoron daughter products as an exposure pathway in work places as long as the reference level for control of radon concentrations is not exceeded. In Europe this level has been set at 500 Bqm-3. Similarly, the exhalation of radon from construction materials can be ignored as long as the expected total concentration, in future constructions, does not exceed 200 Bqm-3. This approach is valid only if, in situations where these reference concentrations are exceeded, remedial action is expected to reduce the concentrations down to below the reference levels.
7. COHERENCE OF THE REGULATORY CONTROL SYSTEM
It is important that the exemption criteria are applied in a coherent way. The system should avoid a "merry-go-round", whereby materials are cleared from regulatory control on the one hand and would be liable to re-enter the system through a requirement of reporting. Traceability of materials to a decision for clearance is difficult and contrary to the absence of controls. Inversely, it would seem incoherent to put severe restrictions on clearance, while materials at higher activity concentrations could freely be processed elsewhere.
Coherence can either be assured by carefully matching the criteria or by properly defining the accountability of a legal person for a practice. "Practices" may inversely be defined in such a way as to exclude situations for which there is no accountable legal person. In this way, levels of radioactivity as a result of past (terminated) emergencies, authorised discharges of radioactive effluent, cleared material, etc, may be excluded from the definition of legal accountability for practices.
Finally, it is very important to pursue coherence or even uniformity of exemption and clearance levels at international level, in particular where this would affect trade in commodities such as scrap metal, foodstuffs, etc.
DEFINITIONS FOR THE NEW RECOMMENDATIONS
The current definition of "practices" ("a human activity that can increase the exposure of individuals to radiation…") is too broad so that it causes problems with legal transposition, in particular with regard to the scope of regulatory control. The new Recommendations of ICRP do not fully resolve the issue either. In the current Draft for consultation (5 June 2006) a "practice" is defined as: "an endeavour that causes an increase in exposure to radiation." The concept of "endeavour" is better than that of "a human activity". While in the Oxford dictionary it is a synonym for "attempt at doing", ICRP enumerates as endeavours: "business, trade, industry or any other productive enterprise, ...". The underlying idea is that of a planned activity. In the current EURATOM BSS the word "deliberate" has already been used on a number of occasions in the same sense (Article 4.1 (c) and (d), Article 6.5) to exclude inadvertent or adventitious additions of radioactive substances.
What is still missing in the definition of practices is the concept of a responsible natural or legal person. In the EURATOM BSS this concept has been included in the definition of "undertaking". It should be noted that the latter definition allows only for a legal person who "carries out the practices or work activities", and does not take account of an employer who has legal responsibility for the health protection of workers, but who may not be "carrying out" the practice (cf. Outside Workers).
The introduction of the concept of "endeavour" appears to be useful also for the definition of "intervention" situations. While the new Recommendations rightly pursue a common framework for practices and interventions, it is still very useful to keep the old terms for the sake of clarity. The last sentence in paragraph 38 limits the use of "endeavours" to situations where the source is under control.
This has led us to consider the following set of definitions:
Endeavour: Any planned activities to the extent that these activities involve the introduction or handling of radiation sources or radioactive substances, or affect exposure pathways from existing sources or radioactive substances. An endeavour may be undertaken either in view of a resulting benefit or in order to intervene in existing exposure situations with a view to reducing the exposures.
Undertaking: Any natural or legal person who derives a benefit from carrying out an endeavour or who has legal responsibility for the resulting exposures, to the extent that either the radiation sources or radioactive substances are introduced or handled consciously and can be controlled directly by actions on the source or the exposures or exposure pathways are reasonably controllable. Such legal responsibility is deemed to exist neither for levels of radioactivity in the environment which result from authorised practices or from past uncontrolled events, nor for endeavours involving naturally occurring radionuclides except those identified as being of concern.
Practice: An endeavour that causes an increase in exposure to radiation or in the risk of exposure to radiation, and which is the legal responsibility of an undertaking.
Intervention: An endeavour planned with a view to reducing the exposure in existing situations or in an emergency. The legal responsibility for intervention may be with a government agency or by an undertaking under command of the legal authority to carry out remediation works; this responsibility includes the exposure of intervening staff.
Employer: Any natural or legal person who has legal responsibility for the exposure of workers under his command; this responsibility may rest with the undertaking carrying out the endeavour or with an outside undertaking in command of workers exercising professional activities in endeavours by several other undertakings. A self-employed person has the same responsibility as an employer for his own radiation safety.
2. MEMBERS OF THE PUBLIC
The distinction between exposed workers and members of the public is important from a regulatory perspective. Different dose limits and constraints are applied and also different criteria for exemption are considered, in particular with regard to natural radiation sources. The old definition of "members of the public" in the EURATOM BSS is: "individuals in the population, excluding exposed workers…", hence "… excluding persons, either self-employed or working for an employer, subject to an exposure incurred at work from practices […] and liable to result in doses exceeding one or other of the dose levels equal to the dose limits for members of the public."
This definition implied that workers who are not liable to exceed the dose limits for members of the public would not be regarded as "exposed workers" but as members of the public. Despite the circular reasoning in this definition there was rarely a problem in practice, even though many who are classified as "exposed workers" actually do not exceed 1 mSv/year. In general only some administrative staff in nuclear industry and in hospitals would be regarded as "members of the public".
With the new definition of "practice" the concept of "members of the public" would include exposures at work only to the extent that these are not the "legal responsibility of the undertaking"; this enables the avoidance of further reference to doses exceeding limits for members of the public.
In the old definition, "exposed workers" are "persons… subject to an exposure incurred at work … and liable to exceeding one or other of the dose levels …" In the Euratom BSS exposed workers are subsequently classified as category A or B, depending on their exposure situation; hence one could change the term to "classified workers". This would allow the use of the term "exposed workers" for the category of individuals who are exposed at work and where such exposure is the legal responsibility of the undertaking, but who are not necessarily classified.
This would then allow a new definition of "exposed workers" as simply, "persons, either self-employed or working under an employer, subject to exposure at work from practices covered by this Directive."
Thus the old definition of "members of the public" as "individuals in the population, excluding exposed workers" would be retained. The new definition of "exposed workers", however, broadens this category to all those who receive an exposure, however small, as a result of their work in an undertaking conducting a practice. While in operational terms there should be no implication, it might have a negative perceptual impact for such workers now to be regarded as "exposed workers". Hence, there may be a benefit in using a different term, for instance, simply "workers" (in the sense of radiation protection legislation). If such a specific definition of "worker" is acceptable, one could also keep the old term "exposed worker". However, "classified worker" seems to better express what it means in operational terms. It should be noted that in the current IAEA BSS no distinction is made between different categories of workers.
It would be helpful if ICRP provided guidance on these matters, and on related issues such as the status of people exposed as a result of caring for patients in nuclear medicine. The current draft of RP06 seems to be incoherent in this respect. Also the foetus borne by a pregnant worker is defined as a "member of the public", which looks odd (even though it is right that he receives an equivalent level of protection).
The system of bands of constraints for different social qualifications of the affected individuals (benefit, information, involvement, etc.) should allow to define members of the public, workers and patients exactly in those terms.