|Draft 2005 Recommendations of the International Commission on Radiological Protection
Comments from Radiation Protection Professionals of Danish Decommissioning, DK-4000 Roskilde
The draft 2005 recommendations from ICRP has been published on the ICRP website for comments. This procedure is much appreciated as a fruitful way of communicating comments from radiation protection professionals back to the ICRP. The draft 2005 recommendations suggests some fundamental changes to the 1990-recommendations. Some overall comments to these major changes are given below.
Principle of justification
It is stated that the method of justification is largely outside the scope of the 2005 Recommendations. Downgrading the principle of justification would weaken the coherent basic principles in the System of Radiological Protection. Furthermore, as the justification principle is suggested to be maintained for medical exposures, but not for occupational and public exposures, neither normal nor emergency and existing
situations, the proposed System appears to be distorted compared to the existing System and with reduced clarity and logic.
The concept of justification has been one of the basic principles of radiation protection for many decades. The principle is simple in essence - that any practice involving radiation exposure should overall do more good than harm, and that any intervention with the purpose to reduce existing doses also should do more good than
harm. Another important issue is that the principles of justification and optimisation should be applied together, e.g. to arrive at generic reference levels of protection or to be used in a real-time decision-aiding process.
Although the justification requirement is a key principle within the System of Radiological Protection, any clear and detailed procedure as to how the justification principle should be implemented in practice has hardly been elaborated. Even if it is recognised that in some major practices involving radiation, e.g. the generation of
nuclear power, the decisions on whether to carry out the practice have been taken on strategic grounds rather than being primarily based on radiation protection considerations, it is suggested:
• that the principle of justification is retained in the 2005 recommendations for normal, emergency and existing exposure situations,
• that guidance is given on how to apply the principle of justification,
• that guidance is given on how to apply the principles of justification and optimisation together, and
• that guidance is given on the radiological protection attributes to be used in the process of justification
It is further suggested that ICRP might consider a two-level process of justification (generic - specific) for normal, emergency and existing exposure situations in the same way as for the justification of radiological procedures in medical exposure situations.
Constraints and dose quantities
The proposed set of source-related individual dose constraints to be used in all situations of controllable exposures, except for medical exposures, appears conceptually difficult. The concept of dose constraints in the existing System means that individual doses received in normal situations should be restricted below the constraint. It might therefore be confusing to apply the concept of a dose constraint in emergency
and existing exposure situations as maximum values of individual doses received when the quantity of individual doses averted still is necessary.
The draft recommendations apply to situations in which doses received can be controlled (para 15) but also to situations where actions to avert exposures and reduce doses are almost certain to be justified (para S5). The supplementary requirement for optimisation of protection in all situations does not remove the distinction between
the quantities ‘doses received’ and ‘doses averted’. The numerical values of dose constraints and the explanation to which situations they apply as given in Table 7 appears very condensed and difficult to grasp. Although it might destroy the alleged simplicity of ‘only four numerical values’, the message in the table should be disaggregated.
Given the statement in para (166) that “it is useful to introduce further constraints to deal with all situations in more detail” and “these include the normal situation, preparation for emergencies, dealing with contaminated land or existing controllable sources” together with the considerations above, it is suggested:
• that the constraints relating to protective actions in non-normal situations with the goal of averting doses should be given another name, e.g. action level as already used for protection against radon at home and at work,
• that Table 7 is split into two, three or four tables covering public, medical and occupational exposures in normal, emergency and existing exposure situations,
• that a subset of generically optimised constraints should be developed for a number of generic exposure situations and included in the 2005 recommendations, and
• that the procedure for applying the dose constraints/action levels in ‘dose received’ and ‘dose averted’ situations should be elaborated.
Although a firm decision apparently has been taken on the concept of dose limits for the public, it is after all suggested that these public dose limits are abolished for clarity and for logical reasons.
Practices and interventions
The ‘fusion’ of the existing sub-systems for practices and interventions would somehow break the logic in the existing System. This rather fundamental change has been suggested on the grounds that it has been difficult to explain to the public and others. There is, however, still a need to distinguish between normal and non-normal
exposure situations and therefore also a need for a different approach in the application of the constraints in such situations as mentioned above. It is therefore suggested:
• that constraints are defined for normal and non-normal situations, respectively, and
• that the procedures for applying the two sets of main constraints are described (see comments to ‘Constraints and dose quantities’ above)
Even if the constraints are defined for different exposure situations and applied conceptually different, the proposed 2005 System of Protection would still appear as a single line system in contrast to the existing binary system.
Optimisation of protection
The 2005 recommendations includes a requirement to optimize the radiological protection for a given source to achieve the best level of protection that is reasonable involving stakeholders with the purpose of incorporating societal values into the decisions.
A long-standing question is if societal aspects should be integrated into radiation protection decisions or if radiation protection should be integrated into societal decisions. ICRP has up until now considered that the optimization of radiological protection should be assessed by means of a decision-aiding process requiring a positive balance of all relevant attributes related to radiological protection. The result of such a process can be used as input into a wider decision-making process.
It seems rather important that this distinction be maintained and that societal aspects enter the decision-making process in parallel with radiological protection aspects. Otherwise, radiation protection would drive the decision-making process and radiation protection professionals act as decision-makers.
The description of the optimisation process in Chapter 7 appears rather short and general. It is therefore suggested that the 2005 recommendations should elaborate much more detailed on the methodology of optimising radiological protection, both for normal, emergency and existing exposure situations, and with emphasis on:
• a thorough description of the radiological protection attributes to be used as input to the process of optimising radiological protection,
• the role of radiological protection in the final decision-making process,
• the role of stakeholders in the process of optimising radiological protection,
• the role of stakeholders in the final decision-making process, and
• the methodology to be used to arrive at an optimised radiological protection.
It is further suggested that ICRP should consider if generically optimised reference levels for protective actions in emergency and existing exposure situations as mentioned in para 192 should be included in the 2005 recommendations.
The name of the dose quantity ‘equivalent dose’ is suggested to be ‘radiation weighted dose’ with a unit no longer to be the sievert. The change of unit name might create confusion, also because the unit of the operational quantity ‘dose equivalent’ still is the sievert. It is therefore suggested that the unit for radiation weighted dose is
retained as sievert.
In the draft recommendations it is stated in several places that constraints could be recommended by the ICRP or chosen by national authorities or operating managements. Such an approach will not necessarily support international harmonization on reference levels. It is therefore suggested that ICRP should consider, as in the
past, to recommend generically optimised reference levels.
In general, the draft 2005 recommendations needs to be elaborated so they would appear more clear and logic in their final form. Another round of commenting within the radiation protection community is therefore suggested.