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1 Chapter 1 : Where to dispose of Britain's nuclear waste This item: Leaching of Low and Medium Level Waste Packages Under Disposal Conditions Set up a giveaway There's a problem loading this menu right now. An analysis of principal nuclear issues No. What is high-level radioactive waste? In countries where the spent nuclear fuel arising from reactor operations is chemically reprocessed, the radioactive wastes include highly concentrated liquid solutions of nuclear fission products. These are later solidified, generally in a glass matrix in a process known as vitrification, although other solidification processes are possible. Both the liquid solutions and the vitrified solids are considered HLW. If the spent nuclear fuel is not reprocessed, it, too, is considered as HLW to be disposed of by appropriate means see reference 5. Because HLW contains relatively high concentrations of both highly radioactive and extremely long-lived radionuclides, special disposal practices are needed. Furthermore, it takes about 10, years for the radioactivity of such wastes to decay to the level which would have been generated by the original ore from which the nuclear fuel was produced, should this ore never have been mined. By far the most important of these other waste types is generally referred to as alpha-bearing wastes also called transuranic TRU waste because of its relatively high concentration of long-lived radionuclides that emit alpha particles as they decay. Indeed, these wastes are produced in volumes greater by a factor of than HLW. A main difference between such wastes and HLW, however, is that TRU waste does not generate intense levels of radioactivity and heat. When will disposal of HLW be necessary? HLW, whether spent nuclear fuel or vitrified reprocessing waste, generates such intense levels of both radioactivity and heat that heavy shielding and cooling is required during its handling and temporary storage. The wastes are therefore best stored in specially engineered cooling pools or vaults for several decades prior to disposal. While stored, both the temperature and radioactivity of the wastes gradually decrease, simplifying their handling and disposal considerably. Seen from this perspective, while disposal of HLWis not an urgent technical priority, it is nevertheless an urgent public policy issue. These political aspects have led to the need for the nuclear industry in recent years to demonstrate the feasibility and safety of HLW disposal and, in some countries, laws have been implemented that require operational HLW disposal capability in the next years. All HLW produced so far is currently being stored; no permanent disposal has yet occurred. What options are available for HLW disposal? However, the full range of options also includes disposal in geological formations under the deep ocean floor, disposal on the ocean floor, disposal in glaciated areas, extraterrestrial disposal, and destruction by nuclear transmutation. In addition, extended storage, whether at production sites or in a centralised store, may, in principle, be considered an acceptable waste management strategy, provided it is not supposed to be perpetuated for longer than feasible and safe and is to be replaced by a more permanent solution at a later date. In order to increase the safety of geological disposal, most such disposal concepts rely on a system of independent and often redundant barriers to the movement of radionuclides in an effort to provide a high degree of assurance that exposures to man will remain at acceptably low levels. There are five important reasons why deep geological disposal on land has evolved into the disposal method of choice for virtually every country with a nuclear power programme. It is an entirely passive disposal system with no requirement for continuing human involvement to ensure its safety. Radioactive wastes present no hazard while they remain in a deep underground repository. Because of their depth of burial several hundreds of metres or more, the possibility of intentional human intrusion is virtually eliminated, and, with a suitable choice of location, the likelihood of inadvertent human intrusion can be made minimal. Flexibility and convenience are provided by the large variety of geological environments suitable for disposal. Geological units under consideration are rock salt, argillaceous formations clays, and a range of crystalline rock formations including granite, welded tuff, basalt, and various metamorphic rock types. The disposal option is demonstrably practical and feasible with currently existing technology used in other mining and civil engineering practices. Although waste disposal implies the lack of intention to retrieve the waste, the Page 1

2 repository can be designed so that the waste can be recovered, while the repository is in operation or even after closure. Other options for the disposal of HLW Disposal in geological formations under the stable, deep ocean floor, also called subseabed disposal, is conceptually similar to deep geological disposal on land, but there are a few notable differences. Whether the waste is emplaced in the relatively soft near-seabed unconsolidated sediments, or in the underlying consolidated sediments or even deeper basalt, the emplacement technology is not entirely defined. A major difference, however, would be the enormous dilution capacity provided by the ocean, should the containment system prematurely fail and allow substantial releases of radionuclides to the ocean floor. Another significant difference is that this disposal would be ideally suited for the establishment of international cooperative activities, although using the high sea, which is common property, represents a major political complication. Nonetheless, subseabed disposal is currently the only other disposal option under serious consideration as an alternative to deep geologic disposal on land. With regard to other disposal options that have been discussed in OECD countries, disposal of HLW on the ocean floor in some kind of highly engineered containment would not be internationally acceptable at this stage. Disposal in glaciated areas, in Antarctica for example, would require substantial changes to international legal and political agreements. Finally, nuclear transmutation, the conversion of long-lived radionuclides into shorter-lived or even stable nuclides, is not considered feasible in the near future. The remainder of this paper will address only deep geological disposal on land, as this is currently the preferred disposal option throughout the OECD countries and, indeed, worldwide. What happens to HLW during disposal? Disposal of HLW is preceded by some period of interim storage, either on site or at a centralised location, during which time the temperature and radioactivity of the HLW decrease systematically. Movement of the wastes to the disposal site will be necessary, and this may be accomplished using specially constructed collision- and fire- resistant shipping casks, transported via designated ship, train, or truck, according to national circumstances. Finally, special waste packaging is envisaged in most disposal concepts, either at the disposal site or at some interim site. It should be noted that liquid HLW must be solidified prior to its transport, packaging, or disposal. During disposal, the individual waste packages will be lowered down shafts or transported into the repository through sloping tunnels. Once at the repository, the waste packages will be emplaced into holes predrilled into the sides or floor of the repository using equipment developed for this purpose. In most concepts, these holes will then be backfilled with suitable material. Filling the repository may require anywhere from 10 to 50 years or more, depending on the individual nuclear programme. Finally, the repository itself will be backfilled and sealed, including all shafts, boreholes, and tunnels which may have been drilled during repository construction. How can the safety of HLW disposal be assessed? The long-term safety of HLW disposal can be systematically assessed through predictive modelling of the gradual failure of the engineered barriers i. Such safety assessments must be based on a good physical understanding of the processes involved in the release and transport of radionuclides, as well as those acting on, or likely to act on, the repository and the geological formation. In addition, the potential interplay between these processes must be understood see reference 4. Finally, substantial site investigation efforts will be needed, involving the collection of data at the surface as well as in situ, at the proposed repository location. As a preliminary step to in situ studies, several OECD countries have developed Underground Research Laboratories in representative geological environments to demonstrate the safety of the geological disposal option. These laboratories are being used to provide data in support of generic safety assessments, to evaluate engineering feasibility, and to develop and refine techniques for site investigation. How much does disposal of HLW cost and how can these costs be financed? There are many parameters which affect the cost of HLW disposal, most importantly the size of the nuclear programme. Other parameters of concern that may vary from one estimate to the next are the depth of burial, the length of time the HLW cools prior to emplacement, the type of waste package used, the need to design for waste retrievability, and whether the disposal involves spent fuel or vitrified reprocessing wastes. Despite variations in these parameters, most estimates conclude that the cost of deep geological disposal will represent only a few per cent of current electricity generating costs. According to the "polluter-pays" principle, the cost of Page 2

3 HLW disposal is properly financed by the nuclear utilities. In many countries, a special waste fund has been established to cover the cost of HLW disposal according to which the utility may pay either an annual fee or an amount that in some way corresponds to the relative amount of HLW produced. The establishment of such a fund is important because disposal of HLW will not occur until many years - several decades in most cases - after its production. Whatever the system of financing, a general principle is that future generations should not have to pay for disposal of the wastes generated today. The NEA has been concerned with the problem of high-level waste disposal for more than a decade and this topic has developed in recent years into a priority area of its programme. Its principal role is to assist its Member countries in the further development of methodologies to assess the long-term safety of radioactive waste disposal systems and to increase confidence in their application and results. This is done through the exchange of information and experience among national experts, joint studies of issues important for safety assessment identification of potentially disruptive events, treatment of uncertainties, the development of related computer models in particular for probabilistic events and data bases used to assess the behaviour of radioactive materials in the geosphere, and their validation at an international level. The NEA also sponsors international research and development projects the Stripa Mine Project, in Sweden, and the Alligator Rivers Project, in Australia and co- ordinates activities of its Member countries involving in situ research and site investigations see reference 6. The ultimate purpose of this international effort is to reach the level of scientific understanding required to ensure that nuclear waste disposal systems will be able to contain and isolate the radioactive materials so that they will not cause any harm to man or his environment either now or in the future. Such co-operative programmes are also aimed at enhancing confidence in the quality of the safety analyses upon which the acceptability of nuclear waste disposal is to be judqed. Page 3

4 Chapter 2 : NEA Publications: ISSUE BRIEF No. 3 - THE DISPOSAL OF HIGH-LEVEL RADIOACTIVE WA Leaching tests are conducted according to different standards, pro- cedures or recommendations, generally under conditions different from those of the disposal media. This experience results from several decades of operational activities in the nuclear industry, covering the entire fuel cycle, from electricity production to spent fuel reprocessing. Consequently, large quantities of radioactive waste are generated by this extensive nuclear program. Currently, 20, m3 of LILW are delivered to and disposed of in surface facilities each year. The first repository for LILW, known as the Centre de la Manche, started operation in and received the final waste delivery in This facility features two disposal concepts: Its design capacity will accomodate 1,, m3 of LILW over 50 years of operation. Since, the management of all radioactive wastes generated in France has been the responsibility of the National Radioactive Waste Management Agency, ANDRA, encompassing surface operations and deep disposal projects. Establishment of waste acceptance criteria for disposal; Siting and implementation of new radwaste repositories; Management of existing disposal facilities; Participation in research on long term management of long-lived and high-level radwaste, including construction and operation of underground research laboratories; Inventory of all sites containing radioactive materials on the French territory. Consequently, the Agency is simultaneously an operator, a research organization, and a public service company with a staff of employees and a yearly budget of 1, million French Francs U. The Ministries of Industry and of the Environment are the governmental authorities responsible for matters pertaining to nuclear safety. The generators are responsible for the characterization and conditioning of their radwaste. According to these Rules, the disposal system must protect the general public and the environment and allow reuse of the site after a monitoring period of years. Isolation of radioactivity contained in the waste is achieved through a multiple-barrier system consisting of: The integrity of the waste containment system must be maintained throughout the operating period a few decades and the Institutional Control Period not to exceed years. Waste acceptance criteria for surface disposal are derived from these safety requirements. Low amounts of long-lived alpha emitters may be disposed of within specific activity limit of 3. Waste acceptance criteria also require waste to be solid or solidified, contain no free-standing liquids, no organic liquids, no pyrophorics, less than 0. LILW originates from three main sources: Since, efforts made by the nuclear industry have contributed to significant volume reductions: In the near future, two new waste treatment facilities dedicated to incineration and melting of LLW will be commissionned. Further waste volume reductions are expected, down to a total quantity of 12, m3 in the year The establishment of a disposal facility for low- and intermediate-level waste was conceived as early as near the reprocessing facility of La Hague in Normandy, and to be overseen at the time by the French Atomic Energy Commission CEA. From to, a total volume of, m3 were delivered to the Centre de la Manche and disposed of in structures built at ground level. The first disposal units, built in by the Infratome Company, which ran the center, were simple trenches in the earth, similar to other facilities around the world at that time as could be found in the United States, U. Very low-level waste was then simply packaged in steel drums. More active waste was conditioned in concrete blocks or stabilized in steel drums. The trenches were drained, and covered with a plastic liner and a layer of earth. After few months of operation, because of difficult weather conditions and ground stability problems, the disposal technique evolved and new types of structures appeared: Below-ground level, for intermediate-level waste, drained engineered trenches subdivided in small 15 or 30 m3 disposal cells built with prefabricated concrete panels. Voids between waste packages are filled with a cement mortar. Above-ground level, for low-level waste, on a 2, to 3, m2 stabilized and drained area, packages, either concrete containers or steel drums, are stacked forming 4 m-high pyramids. These two disposal concepts were widely used during the s. This incident contributed to a general awareness of the need to better define waste acceptance criteria, improve waste conditioning, implement control procedures on waste packages, strengthen site environmental monitoring, improve the water drainage system to separate run-off Page 4

5 from leachate. Further evolution of the disposal concept occured in the s and improvements implemented by ANDRA resulted in new disposal structures known as monoliths and tumuli. These structures are described in the following section. During that period, a major achievement was the construction of a new water drainage system. Its purpose was to collect water seeping into the disposal units which might be contaminated and keep it separate from run off water. The waterpipe system was installed inside buried concrete galleries to facilitate control and maintenance. Presentation of La Manche Disposal Concept As presented in Figure 1, two types of disposal structures have been used at Centre Manche since the early s till the end of operation in The monoliths are dedicated either to medium-level waste packages or to low-level waste whose packaging does not provide by itself sufficient containment of radionuclides. Some peripheric walls are not made of concrete but consist of stacked up concrete containers. Spaces between waste packages are grouted with concrete or cement mortar. Unit capacity varies from 50 to 80 m3. Tumuli, generally constructed above ground level and on top of monoliths. Pyramid-shaped tumuli are constituted with concrete containers at the periphery and metallic drums containing waste in the center. Tumuli are dedicated either to very low-level waste or to waste whose conditioning and packaging provide adequate radionuclide containment. Voids between waste packages are backfilled with gravel to ensure stability of the tumuli. La Manche Disposal Concept. All disposal structures are drained. Leachate is directed via a separative water collection system SWCS towards monitoring tanks. Leachate composition and activity are monitored. After operation, the disposal structures are covered with a several meter-thick earthen cap. This temporary impervious cover minimizes infiltration of rainwater into the structures. Data on the Centre de la Manche are presented in Table I. Data on the Centre de la Manche. Page 5

6 Chapter 3 : Storage and Disposal Options for Radioactive Waste - World Nuclear Association 4. Leaching of low and medium level waste packages under disposal conditions: synthesis of an international workshop, held at CEN-Cadarche, November 4. What are the waste management requirements for small quantity and large quantity handlers of universal waste lamps? A small quantity handler of universal waste must manage lamps in a way that prevents releases of any universal waste or component of a universal waste to the environment, as follows: Such containers and packages must remain closed and must lack evidence of leakage, spillage or damage that could cause leakage under reasonably foreseeable conditions. Containers must be closed, structurally sound, compatible with the contents of the lamps and must lack evidence of leakage, spillage or damage that could cause leakage or releases of mercury or other hazardous constituents to the environment under reasonably foreseeable conditions. A large quantity handler of universal waste must manage lamps in a way that prevents releases of any universal waste or component of a universal waste to the environment, as follows: This amount includes all hazardous waste, generated in a calendar month. Under federal regulations, this type of generator is exempt from the majority of hazardous waste regulations. However, CESQGs must ensure that their waste is sent to a permitted hazardous waste management facility, a permitted municipal or industrial solid waste facility, or a recycling facility. Contact your state environmental regulatory agency to see if your local municipal solid waste facility is permitted. While federal regulations allow some mercury-containing lamps to be landfilled, certain states may prohibit this. For example, all mercury-containing wastes are banned from landfills in the state of Vermont regardless of whether they are disposed of by CESQGs or households. California enacted a similar ban in February Therefore, you are strongly encouraged to know what is required in your state. For more information specific to your state, please contact your state or local environmental regulatory agency. Whether your state regulates more stringently or not, all states and EPA encourage the recycling of used mercury-containing lamps. Anyone can, if the lamps are whole. Intact mercury-containing lamps that are managed as a universal waste can be shipped by using a common carrier and Standard Bill of Lading in all states. An exception exists in the state of New York which requires that certified haulers must be used for shipments weighing more than pounds. Generators may self-transport their own lamps. Lamp recyclers can provide boxes that are designed to reduce breakage during transport to a recycling facility. Although the Universal Waste Rule eases restrictions on the transportation requirements for universal waste lamps, self-transport of used lamps must still comply with the Department of Transportation requirements. Transportation requirements for universal waste can be found in 40 CFR If the lamps are intentionally crushed, such lamps cannot be shipped as universal waste in many states; therefore, the full hazardous waste transportation requirements may apply, including the hazardous waste manifest and use of a licensed hazardous waste transporter. For specific requirements regarding crushed lamps, you should check with your state environmental agency. Page 6

7 Chapter 4 : Waste Package Performance Criteria for Deepsea Disposal of Low-Level Radioactive Wastes One of the aims of the investigation is to study the durability of the different cement-based materials employed in the reinforced concrete containers of LLW (low level wastes) and MLW (medium level wastes) and possible reactions which would be produced, over time, between the cement-based matrices and backfilling mortar of the concrete containers. How is radioactive waste generated? All steps in the nuclear fuel cycle generate radioactive waste. In the front end of the cycle -- i. These elements are mainly uranium and its daughter products. During reactor operation, a wide spectrum of different radionuclides are generated by nuclear reactions mainly fission in the fuel, as well as through neutron activation of different elements in reactor core materials and in the water circulating in the reactor vessel. The fate of the generated radionuclides is one of the following: Decay within the nuclear plant; Release into the environment only some gaseous radionuclides and very small amounts of some other nuclides ; Recycling within the fuel cycle uranium and possibly plutonium if the spent fuel is reprocessed ; Storage and disposal as radioactive waste. The terminology of low-, intermediate- and high-level waste is used only to provide a broad categorisation of radioactive waste. In contrast to high-level waste, low- and intermediate-level waste generates only negligible amounts of heat due to radiation and does not require cooling during storage. Low-level waste normally can be handled without particular shielding, while intermediate-level waste might require shielding and may contain significant amounts of long-lived radionuclides. More than 95 per cent of the total activity will be contained in the spent fuel, or the high-level waste if the fuel is reprocessed. This is a simplified description and the details, nuclide by nuclide, are certainly more complicated. Factors like reactor type and mode of operation of the nuclear plant, the treatment of the spent fuel and the waste handling and conditioning itself will all have an influence on determining which radionuclides are generated, the amount produced and the type of radioactive waste in which they will appear. What are the types of radioactive waste? Mill tailings The radioactive mill tailings from uranium mining are by far the most voluminous radioactive waste generated within the whole fuel cycle times more by volume than all other radioactive waste. They are normally stabilised and disposed of at or close to the mine of origin. As these wastes contain natural long-lived radionuclides, they must be disposed of in a way that affords long-term protection to man and his environment. These questions are not dealt with further in this issue brief, which is limited to a discussion of the disposal of low- and medium-level waste containing artificially generated radionuclides. The liquid is contaminated water from different parts of the reactor system and from the plant. Purification or concentration of this water gives rise to slurries that are mixed with cement or asphalt to form a stable waste form. The solid waste is any potentially radioactive material, such as filters, valves, pipes, trash, etc, from the reactor systems or the plant. Most of the solid waste is generated during maintenance and repair work. It is compacted, incinerated or simply packed in drums. Reprocessing waste During reprocessing, the spent fuel is dissolved and uranium and plutonium are separated for recycling. The main waste product is the heat-generating high-level waste solutions containing the bulk amount of fission products from the spent fuel. The treatment options are the same as for reactor waste: Decommissioning waste The decommissioning and dismantling of nuclear installations will also generate radioactive waste. In addition to the same types of waste produced during plant operation, other types of waste will be generated, notably some bulky internal structures from the reactor, the reactor vessel and its surrounding concrete structure. In countries with no nuclear power programme, this constitutes the main category of radioactive waste, while for countries with a nuclear programme, it represents only per cent of the total volume of radioactive waste. OECD trends of radioactive wastes from nuclear power operations cubic metres The amount of radioactive waste remaining after treatment will increase in years ahead because of the continuing development of nuclear power for electricity production. Quantities shown here should be used for trend purposes only, since waste quantities can vary significantly depending upon the underlying assumptions used to determine the amounts generated per installed megawatts of electric power. How is the waste handled? In some cases, however, some Page 7

8 types of waste are transported to a central treatment facility. In certain countries, for instance, low-level burnable waste is incinerated at a central site. The chemical and physical properties of the waste are essential for their management. Basically two major factors must be considered in the classification of waste for its further handling, storage, transportation and disposal. The level of radiation emitted by the waste, and The content and half-life of major radionuclides, in particular the level of long-lived radionuclides in the waste. Compared to the total amount of toxic waste that has to be handled by society, the volume of radioactive waste is still small. It only gives a rough indication of the relative order of volumes. The level of radiation will govern the need for additional radiation shielding during handling, storage and transportation and there are established international guidelines to be followed. The content of long-lived radionuclides will determine the type of long-term isolation required for disposal of the waste. What waste disposal methods are used? Multi-barrier containment systems have been designed for this purpose and most countries have already defined and sometimes implemented disposal practices and policies. The length of the isolation period required is governed by the radiotoxic properties of the waste and particularly the half-lives of the radionuclides contained. A surface or near-surface facility is usually regarded as suitable for short-lived, low-level waste, provided some form of site surveillance is maintained after closure of the site, notably to prevent intrusion by man. However, it is clearly recognised that the maintenance of institutional control i. This results in a clear requirement for surface and near-surface disposal facilities: In contrast, deep geologic isolation as a totally passive system is considered necessary for long-lived waste. In this case, institutional control measures would not be needed in the far future to preserve the long-term integrity of a well-selected site because the probability of interference by natural events and human actions is very limited. This reasoning, however, does not exclude the possibility of deep geological disposal for short-lived waste, which would make institutional control superfluous from a strict safety viewpoint. Actual practice In practice, the main policies followed for the disposal of low- and intermediate-level waste are: Near-surface disposal, which is particularly valid for relatively large nuclear power programmes which produce considerable volumes of LLW. France, the United States, and the United Kingdom already have such facilities in operation for short-lived waste. Geologic disposal, which has the advantage of avoiding the need to separate short- and long-lived radioisotopes before disposal, as in the case of shallow-land burial. Disposal in various abandoned mines or specially constructed caverns is carried out or planned, notably in Finland, the Federal Republic of Germany, Sweden, Switzerland and the United Kingdom. The total capacity of this centre is about m3 of waste and up to now, it has received about m3 of waste. The centre will be filled completely at the beginning of the s. The disposal capacity will be 1 million m3 of waste. The Swedish repository for low-level waste, SFR, is located in the bedrock below the Baltic Sea close to the Forsmark nuclear power plant, north of Stockholm. The facility, excavated rock caverns and a silo, is accessible through tunnels from the coast. The bedrock cover from the top of the caverns to the sea is 60 m. Operation of SFR began during The capacity in the first phase is 60, m3 of waste and in total it is planned to dispose of about, m3 of waste, which is the projected total amount of low-level waste produced until the year by the Swedish nuclear power programme. How are the disposal costs financed? On this basis, financing of radioactive waste disposal may take different forms, such as advance contributions from waste producers according to waste production and expenditure estimates, provisional or final fees at the time of waste delivery, fees on nuclear electricity production, and contribution to waste management funds. Decommissioning funds are also sometimes used to cover the disposal of decommissioning waste. In all countries the siting, construction, operation and closure of a radioactive waste repository is subject to an extensive licensing and control procedure. These bookkeeping procedures normally ensure that all the waste generated is actually controlled and cannot be disposed of outside the agreed system. For disposal of waste at a repository, quantitative waste acceptance criteria have to be met. These criteria may concern: Limits on the concentration of radionuclides in wastes, Limits on the total activity of radionuclides to be disposed of at a given facility, Performance standards, e. Such criteria will, to a large extent, be based on international and national radiological protection standards but the actual quantitative Page 8

9 criteria will also depend upon the type of site and repository in each case. A detailed characterisation of the site is made before proceeding to final site selection and construction of the repository. It includes, for instance, measurements and modelling of the general geological characteristics of the site, the groundwater movements and the geochemical conditions. The repository design, in many cases, includes additional engineered barriers like thick concrete vaults and backfilling by dense clay. These will enhance the protection against excessive or premature groundwater intrusion to the waste and will minimise and delay radionuclide transport from the waste to the environment. A complete safety assessment will also include an analysis of the potential effects of disruption of the repository by geological and environmental changes, e. During the licensing procedure, the results of the safety analysis and their inherent uncertainties will be checked and assessed by the regulatory authorities. During construction, operation and closure of a repository, strict control will be exercised to ensure that the disposal is implemented according to the plans. The NEA has always been concerned with the problem of radioactive waste disposal and for the past 15 years, this has been a priority area. Its principal role is to assist its Member countries in the further development of methodologies to assess the long-term safety of radioactive waste disposal systems and to increase confidence in their application and results. This is done through the exchange of information and experience among national experts, and by joint studies of issues important for safety assessment identification of potentially disruptive events, treatment of uncertainties. Related computer codes in particular for probabilistic events and data bases used to assess the behaviour of radioactive materials in the geosphere are developed and validated at an international level. These activities form part of an integrated international effort to reach the level of scientific understanding needed to ensure that nuclear waste disposal systems will be able to contain and isolate the radioactive materials so that no harm will be caused to man or his environment either now or in the future. Such co-operative programmes also enhance confidence in the quality of the safety analyses upon which the acceptability of nuclear waste disposal is to be judged. Although the NEA activities in this area are primarily focussed on deep disposal of high-level, long-lived radioactive waste, many of the results are equally valid for the disposal of low-level waste. In addition, there are regular activities directly related to questions concerning low-level waste, for example, studies of how to estimate radionuclide content in the wide range of low-level waste and a recent workshop on assessment of repositories for low-level waste. From to, sea-dumping operations for radioactive waste were carried out in the North-East Atlantic under the supervision of NEA. Up to 8 NEA countries participated in these operations. However, since there has been a non-binding moratorium on the sea-dumping of radioactive waste. A co-ordinated Research and Environmental Surveillance Programme CRESP was set up in and continues to operate, mainly to collect scientific information on the Atlantic disposal sites. Shallow Land Disposal of Radioactive Waste. Update on Waste Management Policies and Programmes. Page 9