ENISS Comments to the ICRP draft document “Protection of the Environment under Different Exposure Situations”
General Comment
This document has been awaited for a long time after ICRP had founded Committee 5 “Environmental Protection”, issued ICRP Publications 91 and 108, and finally formed Task Force 82 with the aim to explain the new environmental radiation protection conceptually and in more detail than ICRP Publication 103 did. We highly appreciate that ICRP now presents a system of environmental radiation protection that is in line with the general interest of the society to consider protection of the environment not only as protection of environment in terms of maintenance of biological diversity, the conservation of species and health and status of natural habitats, communities and ecosystems but also as a part of the protection of man and society itself. In this document, we may find some answers about the practical implementation of what was expressed in ICRP 103 that there is a need for demonstrating environmental radiation protection rather than assuming it.
The proposed system is one possibility to do so and the parallelism to the system for human radiation protection is a good idea. What works effectively for protection of human beings should also work for the effective protection of non-human biota. Of course some adaption of the system is necessary and the ICRP has tried to do this by developing a new framework. Obviously, there are significant differences in protection of man and protection of the environment for instance regarding the detriment and the target of protection. From this it might be expected that there result also significant differences in the protection philosophy for the environment.
According to our opinion too much room in the document is dedicated to the description of the ICRP system of human protection and it would probably be easier to find the key points of the non-human biota protection if these descriptions are much reduced. In this respect we find a lot of text on the similarities of the systems but less information on the differences and how they are addressed. Whether the parallelism must go so far to define a new category of exposure situations may also be questioned as it may raise confusion (man is also part of the environment).
The environmental issue played a role in the discussions of the new Basic Safety Standards of the IAEA, now published as GSR Part 3 in 2011, and has also been introduced in the new draft for the EURATOM Directive on Radiation Protection, the EU-BSS. Both of these documents, the IAEA- and the EU-BSS, do not go into much detail regarding the definition of the objective and regarding guidance on the practical implementation of environmental radiation protection.
Accordingly there were high expectations with respect to this new ICRP Draft but the question remains whether this document fulfils these expectations.
However, it is the beginning of a new approach in environmental radiation protection. So far the assumption has been that if man is protected also the environment will be. This was stated in ICRP 26 (para 14) and ICRP 60 (para 16) and in principle also repeated in ICRP 103 (para 362), though with some reservation. Nevertheless, the document under consultation being the basis for the new environmental protection should repeat a statement of this kind at the very beginning. We find it necessary to have a first chapter explaining that this is still true, especially for a great number of nuclear installations that are usually not far away from human residences and where the limits for human doses are and will be the most restrictive ones. But it might be that this way to argue is no longer sufficient. Nevertheless, the old statement should be reconsidered so as to put all the other considerations on environmental protection in the draft document into the right context. Otherwise one could draw the wrong conclusion that the environment has been insufficiently protected in the past and this would be misleading.
Some prominent examples on environmental protection as it was already done in the past not having a new system should be provided. Environmental radiation protection can be addressed in a very simple way by forbidding activity releases which contaminate the environment, for instance, the banning of sea dumping of radioactive waste (Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter – known as the London Convention – adopted in 1972 and amended in 1993) or the Antarctic Treaty (entered into force in 1961) and related agreements, collectively called the Antarctic Treaty System or ATS treaty which prohibits nuclear explosions or disposal of radioactive wastes in Antarctica. Very effective measures to ensure environmental radiation protection were the 1996 Comprehensive Nuclear-Test-Ban Treaty (CNTBT) and the Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT which entered into force in 1970. The results of practical and extremely effective environmental radiation protection should be brought to the attention of the people again to achieve the right perspective. The fact that ICRP now recommends a new system of environmental radiation protection is a welcome development of what has been already achieved in this area.
The ICRP system for protecting man has resulted in lower and lower real doses to workers while implementing the ALARA-principle. Lower doses to members of the public have also been achieved by limiting the radioactive discharges due to a number of technical developments. Radioactive discharges have often been in the focus of public debates and a lot has been done to reduce them to a level which is now rather insignificant. Therefore, a generic study about a hypothetical “model nuclear installation emitting radioactive material” on the basis of the proposed ICRP system with the RAPs as generic reference organisms may show that the environment is appropriately protected or even more than this. This generic study could then serve as a benchmark for the whole system and give practical advice for a number of installations which are in the focus of public interest. We propose that ICRP with its experts and experts from the nuclear industry as part of the stakeholder involvement performs such a generic study and waits issuing any recommendation of a new system before the results are available and could be part of the recommendation.
In general the discharges are already very small with limits or constraints (for human exposure) in the order of some hundred µSv/a. In reality, due to the ALARA practices regarding the effluents, doses of a few µSv/a (for humans) will result. These doses present no problem for the RAPs which will become quite obvious by a simple calculation: 0,1 mGy/day for the more sensitive RAPs as the proposed DCRLs sums up to 36 500 µGy/a, a dose rate which is so high that it is hard to believe that it will ever occur even with long term accumulation over the life-time of the RAP. Of course this is a very rough assessment and it has to be reconsidered more precisely by e.g. a generic study as mentioned above. So taking into account the concrete situation with an existing nuclear installation it would make sense to verify the new ICRP system on the spot. We are convinced that it would be very beneficial to have a situation based and site specific approach in parallel to the philosophical one presented in the draft document.
In general, the Draft is somewhat imprecise on how and where to apply the system. In connection with the ERLs it is said that they would be applied only for “major nuclear installations” or “major … activities generating waste or discharges with significant concentrations of radionuclides”. This is a rather vague description and needs more precision on what is major or significant and who is deciding about it. Waste per se is not an environmental issue as long as it is properly isolated or disposed. Major nuclear installations, as mentioned above, do not discharge significant amounts of radioactivity. But they may stand in the focus of public interest and therefore it might be helpful to assess the environmental impact according to the new environmental ICRP system. On the other hand, quite small nuclear medicine departments may discharge significant amounts of radioactivity in connection with diagnostic methods or therapy using open radioactive substances. Patients treated in this way may be released and act like a “moving source” of radioactive effluents. So, the target area for the ICRP system needs a clearer description.
The main objective of environmental protection is formulated in para (2) of 1.1 “….preventing or reducing the frequency of deleterious radiation effects to a level where they would have a negligible impact on the maintenance of biological diversity, the conservation of species, or the health and status of natural habitats, communities and ecosystems”. We wonder if it is reflected in the suggested protection system at all. If not this would be really astonishing and we hope that it might be our misunderstanding of the text. The text of the draft refers to RAPs and representative organisms, which can be easily followed. But how that reflects ecosystems, the biological diversity or the conservation of species is unclear. All what we see in copying the human related system is, as for humans, individual related whereas the protection objective regarding non-human biota is, however, not individual related. It will be the population which counts and ICRP should within the draft document demonstrate how. This is not an easy task as acknowledged by ICRP, but it needs to be done. To simply say that when the individual non-human biota is protected, than anything is o.k. is still too simple. And it would define a protection standard which is even higher than that for human beings, where a certain but acceptable detriment is possible. Should this really be the case in the ICRP Draft it certainly would not fulfil the expectations on an environmental protection system.
There is great uncertainty in the new ICRP Draft regarding the weight of any natural occurring exposure. The Draft reflects existing exposures but does not consider exposure by natural sources. This is a significant deficit. Natural radiation sources are everywhere and exposures are unavoidable for animals and plants. So natural radiation has to be addressed in any case and there is a need to define which level is normal and should not be subject to any further regulation or control. To find out if we are within the DCRLs we need to know which contribution we have to count. And what is if the dose rate by natural radiation is very much higher than those for “practices”? Summing up, the relation to natural radiation has to be considered and it might not be an easy task to differentiate between doses from artificial or natural sources.
The DCRL’s are chosen in a way which is not so easy to understand. Often a “low probability of effects” or even “no information” is taken as reference point/band. In the example of deer, e.g. a “reduction of life span” would allow for three orders of magnitude higher DCRL. But this “reduction of life span” is more or less the measure for detrimental effects in man. So it could be concluded, that the protection of environment is three orders of magnitude more rigid as those for man. Is that really the intention of ICRP?
Optimization of protection as it is pointed out with regard to stochastic effects of radiation towards man has no basis with respect to non-human biota when also deterministic effects are considered. The LNT hypothesis which forms the scientific basis for the optimisation principle is not valid to non-human biota in the present approach. There is a priori no reason to reduce exposures down to even below the DCRL's. This means that ERLs are not needed. In addition it is hard to understand why the ERL should be at or near the lower boundary of the DCRL's for planned exposures while it is said to be sufficient to enter into the band of DCRL’s when talking about existing exposures which are above the DCRL’s.
To take care for multiple sources is normally not necessary as in nearly all cases there is one dominant source of exposure.
With regard to emergency exposure situations the levels of exposure to be considered in emergency planning should be one or two orders of magnitude above the DCRL's. This is certainly a more realistic approach but is it really useful to discuss emergency situations at all? Past experience showed that man is always in the focus of mitigating or preventing measures and even this is a very complex and problematic area. To include now non-human biota makes things not easier and we also have to face the fact that resources, especially in emergency situations, are limited. So it would be good for the system to get tested in planned exposure situations only. And perhaps one can extend the system to emergencies after a decent period of collecting practical experience.