TL: DISPOSAL OF RADIOACTIVE WASTES INTO SUBSEABED REPOSITORIES ACCESSED FROM LAND SO: Greenpeace International (GP) DT: February 1991 Keywords: Greenpeace Reports Oceans Ocean Dumping Conferences Nuclear Waste Radioactive Disposal / Submitted by Greenpeace International to the Twelfth Meeting of the Helsinki Commission Helsinki, 19-22 February 1991 Agenda Item 10: Matters related to the ad hoc Group for Revision of the Convention (HELCOM GRC) Prepared by: Jesper Grolin Remi Parmentier Philip Richardson, BSc, C.Geol E.Geol FGS, MIGeol Peter Taylor 1. INTRODUCTION The area covered by the Helsinki Convention is the only one in the world where radioactive waste is disposed into seabed repositories accessed from the shore. This is taking place at Forsmark, Sweden, and other subseabed repositories are under construction at Olkiluoto and planned near the Loviisa reactor, both in Finland. Subseabed disposal has become a topic familiar to marine policy-makers in recent years. Since 1984, the London Dumping Convention (LDC) has been debating the legal status of subseabed disposal, and during its Thirteenth Consultative Meeting (October/November 1990), it adopted a resolution (Resolution LDC.41(13), in LDC 13/15, Annex 7) by which it was agreed that: (a) the LDC is the appropriate body to address the issue of Low- Level radioactive waste disposal into subseabed repositories accessed from the sea; and (b) disposal of Low-Level radioactive waste into subseabed repositories accessed from the sea constitutes a form of disposal subject to resolution LDC.21(9) and is therefore suspended at present. (*) ****** footnote ******* (*) In 1985, Resolution LDC.21(9) established the current indefinite moratorium on the dumping at sea of Low-Level radioactive wastes. ******* ******* Even though Resolution LDC.41(13) reaffirms the view that subseabed disposal into repositories accessed from the sea (via a drilling platform or a ship) constitutes a form of "dumping at sea" subject to LDC regulations, the Contracting Parties to the LDC were unable to reach consensus as to whether disposal into repositories accessed from the shore (via a tunnel) is dumping under the terms of the Convention. In the absence of international regulation, subseabed disposal may well be perceived by industries as a convenient way of avoiding existing regional and global instruments, which have either severely restricted or banned sea disposal options for industrial wastes. For this reason alone, it has become urgent that the present legal void be filled as soon as possible. During the Thirteenth Meeting of the LDC, the Swedish delegation expressed the view that the possible escape of any radionuclides from such shore-accessed repositories should be considered a land-based source of marine Špollution. Greenpeace International is of the opinion that - irrespective of whether it is classified as a land-based source or not - the Helsinki Commission should urgently and explicitly cover such shore-accessed repositories. In support of this policy, we argue that LLW disposal into shore-accessed repositories presents substantially a comparable degree of risk to the marine environment as either LLW dumping of packaged wastes at sea, or subseabed disposal into repositories accessed from the sea, both of which are subject to the LDC moratorium. Section 2 shows that the classification of radioactive wastes as "high", "intermediate", and "low" does not adequately reflect the toxic potential of the waste for the marine environment. Section 3 indicates that radioactivity will inevitably reach the marine environment from repositories such as the one in operation at Forsmark, Sweden, and those planned in Finland. Finally, we conclude that shore-accessed subseabed repositories should - as a first step - be brought under the remit of the revised Helsinki Convention, and further development subjected to a moratorium pending an assessment of the present operation by the Helsinki Commission. This paper is based on the submission prepared by Greenpeace International for the 4th Meeting of the Ad-Hoc Group of Legal Experts on Dumping of the LDC (Document LDC/LG 4/3, October 1990), in which we argued that subseabed repositories accessed from the shore constitute a form of "dumping at sea". Although the LDC could not reach a consensus on this question, we maintain the opinion that it would be highly desirable that a global instrument, such as the LDC, covers all forms of subseabed disposal, whether it be accessed from sea or from shore. In addition, and without prejudice to the debate within the LDC, the Helsinki Commission, which covers the only area in the world presently affected by subseabed disposal, should regulate disposal of wastes into such repositories as a matter of urgency. 2. CLASSIFICATION OF NUCLEAR WASTES FOR DISPOSAL It has been argued by some that the present subseabed disposal operation in Forsmark, Sweden, and other subseabed disposal plans in the area covered by the Helsinki Convention, do not present significant risks for the environment because they are limited to Low- and Intermediate-Level Wastes. In this respect, it is important to recall that the classification of nuclear wastes as "High, Intermediate (or Medium) and Low" is in all systems, arbitrary as far as Šthe risk to the environment is concerned. The term "high" applies either to the heat generating capacity of the waste, or to its origin in the nuclear fuel cycle (either spent fuel or reprocessed liquid waste from the first cycle). However, a UK Royal Commission pointed out as long ago as 1976 that this classification did not relate to environmental risk, and that large quantities of nuclear waste from the UK classified as "medium" or "low", because they were neither hot nor difficult to handle because of penetrating radiation, nevertheless contained sufficient alpha emitters to make them as hazardous as any other type of waste. capacity over a relatively short time scale (on average 300 years) as its major short-lived constituents decay and would then be re-classifiable. The classification was developed primarily for operational handling. The long- lived radiotoxic nuclides, such as plutonium, would remain and it is these which dominate the risk profile which peaks well after most of the heat generating waste has decayed. Thus, a waste may be classified as "intermediate", but contain large amounts of extremely toxic long-lived nuclides. Furthermore, wastes not in the form of spent fuel or glass blocks may have other components which increase the hazard, such as material which may encourage gas formation (organic solvents etc.), and in any case will not be as resistant to leaching. It is for these reasons that the current prohibition on HLW should also be extended to any category of nuclear waste intended for subseabed disposal. As a general rule, if it requires isolation in the first place, it represents a significant hazard! 3. THE RISK FROM SHORE-ACCESSED DISPOSAL The following sections demonstrate the reliance in all concepts of radioactive waste disposal into offshore and coastal sub- seabed strata upon the diluting capacity of the overlying water body. Heat-generating or High Level wastes (HLW) are excluded from the detail of the paper, but many of the comments regarding engineered and natural barriers are equally applicable to them. As yet, however, no definite proposals exist to begin disposal of HLW, whereas Intermediate and Low Level wastes (ILW/LLW) are actively being disposed of in the deep repository at Forsmark in Sweden, and several other repositories are either under construction, or site investigation programmes are under way. Disposal of LLW in shallow engineered facilities also occurs in several countries at the present time. In many countries, it is now policy to dispose of allŠradioactive wastes in deep repositories, where isolation from the biosphere for very long time periods is to be attempted. 3.1.1. The Multi-Barrier Concept There is now general international agreement that one of the most effective potential methods of isolating radioactive wastes in deep repositories depends on the system of containment known as the Multi-Barrier (NEA 1988). This makes use of both engineered and natural barriers. The study of repository proposals divides the environment in which the repository exists into several distinct zones: The Near-field consisting of the wasteform itself and the engineered structure of the repository, as well as the area of geology around it which was disturbed during construction of the repository. The Geosphere consisting of the undisturbed geological formations between the repository and the biosphere. The Biosphere consisting of the surface layers of soil, rivers, lakes and seas, the atmosphere and plant and animal life. 3.1.2. Potential host-rocks Studies were begun in the last decade on geosphere parameters, such as host-rock type, primarily concerned with HLW. Three principle rock types were identified (salt deposits, claystones and crystalline igneous and metamorphic rocks) as exhibiting favourable properties such as low inherent permeabilities and low flow-through rates. Only the third type has been examined in the area covered by the Helsinki Convention, reflecting the local geology there. Crystalline (hard) rocks: This term is used to describe rocks which have either crystallised from cooling magma (igneous rocks) or been formed by alteration of pre-existing rocks by the effects of temperature and/or pressure (metamorphic rocks). In such rocks, flow of water only occurs via fractures, formed either during cooling or by tectonic activity (folding and faulting), and so detailed knowledge of the geological history of a region is necessary. In many countries, crystalline rocks have been chosen as the favoured media for waste disposal. The only active deep repository, at Forsmark in Sweden, is excavated in such rocks, as is the repository currently under construction at Olkiluoto and the one proposed at Loviisa, both in Finland. Š 3.2 Potential migration pathways As described in the preceding section, the multi-barrier approach depends on the performance of the three component parts: near-field, geosphere and biosphere. The near field is predominantly man-made, and the performance of the barriers needs careful scrutiny in terms of the possible pathways to the biosphere. Several potential such pathways by which radioactivity could move away from a repository have been identified: groundwater pathways; gaseous pathways; human intrusion and natural intrusion 3.2.1 Groundwater It is openly accepted within the radioactive waste management industry that at some stage following abandonment of a repository, water is going to gain access to the waste and its environment (UK NIREX 1988). The near-field barriers are the first line of defence against the outward movement of radioactive leachate, but are essentially designed to slow down the process, not prevent it. Water is expected to penetrate the backfill, corrode the waste canisters and overpack and slowly dissolve and mobilise the waste elements. Transport to the biosphere will then take place. Indeed, in safety studies carried out for the repository at Forsmark, it has been assumed that as soon as pumping has ceased, following final sealing in about 2010, "the repository is completely filled with water." (Forsstrom et al 1989). In such a situation, breakdown of the engineered barriers will begin immediately following closure. Obviously, one of the most important characteristics of a rock chosen as a host for a waste repository is that of low permeability. That is why the three rock types described above were selected for study. Unfortunately, it is not always possible to either predict the overall permeability of a rock body or indeed to accurately measure that permeability in boreholes during site investigation. This uncertainty can be broadly quantified, as mentioned by Knill in 1989: "It would be prudent to assume that consistent permeability values below 10-10 m/s are unlikely to be encountered (in crystalline rock) at shallower depths than 500 to 600m." This observation would tend to suggest that repositories sited atŠshallower depths (e.g. Forsmark and Olkiluoto) are subject to particular uncertainties regarding even such basic characteristics as permeability and hence flow-through rates. It has been assumed that the hydraulic gradient (and hence the flow rate) will be very low below coastal and marine areas, and that any flow which does occur will be in an offshore direction and take place over a long time period. The potential for error in this assumption was also pointed out by Knill (op cit): "it is apparent that a repository site located in fresh water near the coastal margin will be in an environment within which there would be both an increased hydraulic gradient and a relatively short flow path to the biosphere." 3.2.2 Gaseous pathways Gas will be generated due to microbial action on organic material in the waste itself (producing mainly methane and some radioactive carbon dioxide) and due to the corrosive action of the water which enters the repository on concrete and steel structures (producing mainly hydrogen). The production of gas has potentially important consequences. If it is unable to move quickly through the near field and out of the repository, pressure may rise locally, possibly resulting in damage to the engineered structures or the opening of fissures the surrounding rocks, which could in turn affect the groundwater movement. A general, but still unsubstantiated assumption, is that a continuous connection exists between the repository and the surface via fractures and capillaries within the surrounding rocks (Rees and Rodwell 1988). Presumably such potential gas migration is to be expected above repositories sited below marine areas. The cover of 60m to the floor of the Baltic at Forsmark (and 70-100m at Olkiluoto) suggests that gas emanation is a distinct possibility during the early post-closure phase of the repository. Such gas emanation will probably take place during the very earliest phases of the post-closure period, suggesting that Forsmark at least should be regarded as a sea-based source of potential pollution, given the expected length of the so-called `salt water period' (see 3.4.1.). 3.2.3 Human Intrusion The potential for inadvertent intrusion into a radioactive waste repository cannot be overlooked. Most facilities are only planned to have a 50-100 year operational life, and the possibility must therefore exist, over the long timescales envisaged, thatŠknowledge of the exact whereabouts, and even function of the site, may be lost. 3.2.4 Natural Intrusion This pathway includes possible disruption of the geosphere and biosphere due to major natural phenomena such as seismicity and, due to the long timescales involved, consideration must be made particularly of the potential effects of climate change upon the repository site. Although major earthquakes are obviously potentially damaging to surface facilities and shafts, smaller tremors and even microseismicity can be significant. Not only can such changes or events cause damage to the physical structure of the repository, but, more importantly, they can produce changes in the geological environment, affecting both the near- and far-field, in terms of hydrogeology and structural integrity. The potential for climatic disruption of coastal and nearshore repositories due to changes in sea-level and hence changes in hydraulic gradient, is likely to be greater than for land-based sites, and those repositories such as Forsmark and Olkiluoto, involving relatively shallow depths of excavation, are particularly vulnerable. At one time it was generally accepted that due to the effects of post-glacial rebound in the Baltic, the site of the Forsmark repository would be dry land within about 1000 years of the present. With global warming now an expectation, a greater degree of uncertainty is brought into the analysis. Certainly, the hydrological features of the site cannot be predicted with confidence over the timescales in which the waste will remain hazardous. 3.3 Safety Assessments The principal objective of safety assessment is to quantify any potential risks to the public that may arise at any time following the abandonment of a repository. The end result and main purpose of a safety assessment is to show, albeit in fairly general terms, the potential doses to Man likely to occur following the closure of a repository, and its subsequent invasion by groundwater (expected to be rapid at Forsmark). It is also important to relate this dose to the radiological regulations in force in the particular country. 3.4 Representative safety assessments 3.4.1 Sweden The repository at Forsmark is the only active repository for ILW in the OECD (excluding Morsleben in Sachsen-Anhalt, Germany, still subject to safety analysis), and is situated 1 kilometre offshore and approximately 60 metres below the bed of the Baltic. At the present rate of post-glacial rebound (6mm/year), the area is expected to begin to emerge from the Baltic within approximately 1000 years (Forsstrom et al, 1989). However, as noted earlier, global warming makes these predictions uncertain. Safety analyses were carried out at the site prior to licencing. This is not the place to discuss the validity of that modelling, given the uncertainties highlighted by Morner (1989) regarding the structural integrity of the site. What is important in the context of this paper, however, are the assumptions made regarding movement and subsequent discharge of radioactive leachate. The siting below the Baltic means `that large volumes of brackish waters are available for dilution.' (Carlsson et al 1989). A so- called `salt water period' of up to 2500 years following closure is envisaged before the land is uplifted, due to the effects of post-glacial rebound, during which this sub-marine discharge is expected to occur. The 1000 years mentioned above is for first emergence, whilst the total "salt water period" includes the existence of a possible "local sea" with salt water intrusions into the developing fresh groundwater system. Due to the expectedly rapid saturation of the Forsmark repository, mentioned earlier, movement of radioactive isotopes is likely during the initial `salt water period'. The role of the Baltic is crucial in this respect, as was pointed out by Forsstrom et al in 1989; "dissolved isotopes are assumed to follow the groundwater as it moves through the fissures to the recipient, the Baltic Sea." In Sweden there are three operational shallow sites for Low-Level wastes, at the Forsmark and Oskarshamn power plants and at the Studsvik research centre. Since all Swedish power plants are located on the coast of the Baltic, this presumes any "leakage from a shallow land disposal into the sea, which is the most important local recipient.." (Bergman et al 1989). In addition, nuclear plants have to be decommissioned after their operational lives, and according to current plans in Sweden, "a repository for decommissioning waste can be located at the same place and be constructed in a similar way as SFR-1 [Forsmark]." (ibid). 3.4.2. Finland ŠSimilar safety assessment work has been carried out concerning the repository under construction at Olkiluoto, 70-100 metres below the cape of the island adjoining the site of the active reactor. The Olkiluoto repository is expected to be in operation by the end of 1992. A comprehensive site-specific safety analysis was completed in 1986. Here again, the important point was made that `the overall measure for safety is the radiological impact to Man.' (Peltonen et al 1989). One of the major conclusions of this work was that "the groundwater passing the silos ends up in the surrounding marine area." Doses were calculated, assuming certain `critical groups', who ate large amounts of marine-derived products, and compared with the regulatory target. No account was taken of the possible direct effects of sub-marine radioactive discharges on the marine ecosystem. A second repository is planned in the future near the site of the Loviisa reactor. 3.5 The marine ecosystem It is transparently obvious from these studies that one of the major assumptions used in the safety assessments of coastal and offshore repositories is the discharge of migrating radionuclides into the adjacent marine water body. All calculations of dose to `critical groups' are then based on assuming a diet of mainly marine-derived foodstuffs. No assessment is made in any of the analyses of the likely effects on the marine ecosystem in isolation. When the ICRP published its guidelines in 1977 on environmental monitoring of radionuclide levels, the primary source of information on the effects of radiation on aquatic organisms was a 1976 IAEA report. This stressed that although no deleterious effects would be expected at the calculated dose rates used, from current discharge data, only limited data had been collected for many groups, with no data available for any marine mammal or seabird. A report produced over 10 years later, in 1988, showed that very little radiological research on such organisms had been carried out (Thompson 1988). This report concludes: "the hypothesis that wildlife species are safeguarded by current discharge limits remains untested." As most of the safety analyses referred to above concern only the effects of submarine discharges on humans, many of these comments remain valid today, and a recent paper by Linsley (1989) in the Bulletin of the IAEA illustrates the generalised approach still being applied. ŠIn this paper, the only scenario reviewed involves the impact on the marine environment of direct dumping of LLW from ships, a practice currently subject to a moratorium. It is, however, stressed that: "available information on the effects of radiation on non-human species is limited and the effects of these assessments must be treated with caution". Despite this uncertainty, the IAEA have concluded that: "at the maximum release rates for the dumping of LLW permitted under the existing definition for the London Dumping Convention, it does seem possible that some environmental impact could result." (Linsley op cit). Given the uncertainties in radiological impact due to radioactive discharges, the IAEA is under some pressure to fulfil its mandate from the 1958 UN Conference on the Law of the Sea, quoted below in full: "The IAEA should pursue whatever studies and take whatever action is necessary to assist states in controlling the discharge or release of radioactive materials to the sea, in promulgating standards, and in drawing up internationally acceptable regulations to prevent pollution of the Sea by radioactive materials which would adversely affect Man and his marine resources." The IAEA and other regulatory bodies are studying the effects of radiation on other organisms. Woodhead and Pentreath (1989) have noted that: "it is becoming increasingly necessary to assess the complete range of consequences for a variety of different options for managing the disposal of a given radioactive waste, and such assertions should include consideration of the potential effects on populations of wild organisms." At the same time, however, they have concluded that it would be "unrealistic" to believe that information on the doses and effects of radiation to other organisms would ever be available in as much detail as for humans. (acc. to your anti-male chauvinist instructions, Remi). 4. CONCLUSIONS 1. The disposal of LLW/ILW into subseabed repositories accessed from land is carried out in Sweden and planned in Finland, in the area covered by the Helsinki Convention. 2. Discharge of migrating radionuclides is assumed to occur into the marine environment in all such scenarios, and is actively Špromoted as an additional safety feature due to the dilution effect. 3. Little or no account is taken in safety assessment studies of the impact of such discharges on the marine environment. Only the doses likely to be received by humans in so-called "critical groups" in direct contact with the marine biosphere are considered. 4. The potential impact of future discharges, which could occur over timescales of thousands of years, and which would be subject to dispersal to international waters, perhaps on a global scale, has not been assessed by HELCOM or any other international Conventions for the control of marine pollution. 5. The case for disposal into any medium, as compared with indefinite monitorable and retrievable storage, has not been proven, and even more so with respect to subseabed operations with the potential to contaminate international waters. 6. Although it is desirable that the disposal of wastes into subseabed repositories accessed from the shore be regulated on a global scale, through the London Dumping Convention, regional bodies directly affected by this disposal method should also adopt stringent regulation measures in this respect. 7. In view of the nature of the potential impacts upon marine life, fisheries, amenities and human health, and in light of the fact that the Baltic Sea remains so far the only area in the world where radioactive wastes are disposed of into subseabed repositories, it is important that such repositories accessed from the shore be brought, as a first step, under the remit of the revised Helsinki Convention. 8. In addition, Greenpeace calls for a moratorium on further development of this method of disposal pending an assessment of the present operation, in line with the Principle of Precautionary Action. 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