The decommissioning of nuclear power stations and their related facilities, as well as the clean-up of sites contaminated by radionuclides from acci­dents and nuclear weapons programs, are international issues. The remedia­tion of sites at Chernobyl and Fukushima have required and will continue to require decades of effort and billions of dollars. At the center of all of these issues, however, is the storage, transportation and disposal of radioac­tive waste generated at the back-end of the nuclear fuel cycle. Inaction is not an option because we should not leave a legacy of used fuel, high-level waste and contaminated sites to future generations. Indeed, a failure to solve the nuclear waste problem limits the potential of nuclear power to play a role as a major energy producing system, one that does not produce any significant quantity of greenhouse gases.

Many countries with large volumes of nuclear waste from civilian power production and waste from military programs have started cleaning up contaminated sites and have made significant progress in the design and construction of repositories for permanent disposal of these high-activity wastes. However, progress in other countries has been slow, notably Japan where local opposition has largely halted their waste programs and in the United States, where the demise of Yucca Mountain as a geologic repository for high-level waste and spent nuclear fuel has left the United States without a clear path to the solution of this vexing technical and political problem. The recommendations of the Blue Ribbon Commission on America’s Nuclear Future have essentially taken the U. S. program back to the first steps of the site selection process.

This volume, edited by three eminent international authorities, is a timely contribution that emphasizes the global nature of the problem. It features contributed chapters by experts from most countries with nuclear programs.

Most importantly, this book highlights the opportunities for good science and engineering that can be applied to some very difficult and complex problems, opportunities that we must address if we are to solve the nuclear waste problems created at the back-end of the nuclear fuel cycle.

Professor Rodney C. Ewing Edward H. Kraus Distinguished University Professor

University of Michigan

RAW containing radionuclides with very short half-lives can be stored while it decays over a limited period of up to a few years and is subsequently cleared from regulatory control according to arrangements approved by the regulatory body. This category typically includes ‘monoisotopic’ RAW coming from institutional applications of radionuclides, in particular, in medicine and research. Proper storage conditions should be arranged to ensure safety during the decay period.

The disposal of radioactive waste is the final step in its management and one aimed at providing a permanent and final safety option. The radiation safety principles and ideas remain the same as for any other aspect of waste management, nevertheless the long timeframes involved give rise to par­ticular challenges which are given particular consideration. The interna­tional standards for the disposal of RAW were updated and agreed in 2011 [40] and provide a comprehensive set of safety requirements for all types of waste and disposal options. The standards set down clear safety objec­tives and criteria (see Box 3.3) and a number of discrete requirements to be fulfilled in order to provide for safety. As with pre-disposal management of RAW, these requirements apply to governments, regulators and opera­tors developing and operating RAW disposal facilities.

Governments are required to establish and maintain an appropriate legal and regulatory framework for safety within which responsibilities are to be clearly allocated for the siting, design, construction, operation and closure of disposal facilities. This must include: confirmation at a national level of the need for disposal facilities of different types; specification of the steps in the development and licensing of facilities of different types; a clear allocation of responsibilities, securing of financial and other resources, and provision of independent regulatory functions relating to planned disposal facilities.

The regulatory body must establish regulatory requirements for the development of different types of disposal facility for radioactive waste and set out the procedures for meeting the requirements for the various stages of the licensing process. It must also set conditions for the development, operation and closure of each individual disposal facility and carry out activities to ensure that the conditions are met.

process of development and operation of a disposal facility, an understand­ing of the relevance and the implications for safety of the available options for the facility must be developed by the operator for the purpose of pro­viding an optimised level of safety in the operational stage and after closure. Operators must evaluate the site and design, construct, operate and close the disposal facility in such a way that safety is ensured by passive means to the fullest extent possible and the need for actions to be taken after closure of the facility is minimised.

The host environment must be selected, the engineered barriers of the disposal facility designed and the facility operated in a manner such as to ensure that safety is provided by means of multiple safety functions, the overall performance of the disposal system not being unduly dependent on a single safety function. Containment and isolation of the waste needs to be provided by means of a number of physical barriers of the disposal system. The performance of these physical barriers must be achieved by means of diverse physical and chemical processes together with various operational controls. In addition, the capability of the individual barriers and controls together with that of the overall disposal system to perform as assumed in the safety case has to be demonstrated.

The engineered barriers, including the waste form and packaging, must be designed, and the host environment selected so as to provide contain­ment of the radionuclides associated with the waste. Containment functions must remain available until radioactive decay has significantly reduced the hazard posed by the waste, and in the case of heat generating waste, con­tainment must be available during the timeframe over which the waste is still producing heat energy in amounts that could adversely affect the per­formance of the disposal system. Disposal facilities must be sited, designed and operated in such a manner that provides features that are aimed at isolation of the RAW from people and from the accessible biosphere. The features must aim to provide isolation for several hundreds of years for short-lived waste and at least several thousand years for intermediate and high level waste. In providing isolation, consideration needs to be given to both the natural evolution of the disposal system and events causing dis­turbance to the facility. An appropriate level of surveillance and control has to be applied to protect and preserve the passive safety features, to the extent that this is necessary for them to fulfil the functions that they are assigned in the safety case for safety after closure.

In developing disposal facilities, it is important that a systematic step-by­step process is adopted. Each step must be supported, as necessary, by itera­tive evaluations of the site, of the options for design, construction, operation and management, and of the performance and safety of the disposal system.

As with pre-disposal facilities and activities, a safety case and supporting safety assessment needs to be prepared and updated by the operator, as necessary, at each step in the development of a disposal facility, during its operation and after closure. The safety case and supporting safety assess­ment must be submitted to the regulatory body for approval and must be sufficiently detailed and comprehensive to provide the necessary technical input for the regulatory process and for informing the decisions necessary at each step. The scope of the safety case for a disposal facility must include a description of all safety relevant aspects of the site, the design of the facil­ity and the managerial control measures and regulatory controls that will be applied. It must demonstrate the level of protection that will be provided for people and the environment and provide assurance to the regulatory body and other interested parties that all safety requirements will be met. The safety case and supporting safety assessment have to be documented to a level of detail and quality sufficient to inform and support decisions to be made at each step and to allow for independent review.

The site for a disposal facility must be characterised at a level of detail sufficient to support a general understanding of both the characteristics of the site and how the site will evolve over time. This needs to include its present condition, its probable natural evolution and possible natural events, and also human activities in the vicinity that may affect the safety of the facility over the period of interest. It must also show a specific under­standing of the impact on safety of features, events and processes associated with the site and the facility.

The disposal facility and its engineered barriers have to be designed to contain the waste with its associated hazard, to be physically and chemically compatible with the host geological formation and/or surface environment, and to provide safety features after closure that complement those features afforded by the host environment. The facility and its engineered barriers must be designed to provide safety during the operational period. The facil­ity must be constructed in accordance with the design as described in the approved safety case and supporting safety assessment and in such a way as to preserve the safety functions of the host environment that have been shown by the safety case to be important for safety after closure. Construc­tion activities must be carried out in such a way as to ensure safety during the operational period.

Facilities have to be operated in accordance with the conditions of the licence and the relevant regulatory requirements so as to maintain safety during the operational period and in such a manner as to preserve the safety functions assumed in the safety case that are important to safety after closure. At the end of operations, disposal facilities must be closed in a way that provides for those safety functions that have been shown by the safety case to be important after closure. Plans for closure, including the transition from active management of the facility, need to be well defined and prac­ticable, so that closure can be carried out safely at an appropriate time.

Waste packages and unpackaged waste accepted for emplacement in a disposal facility must conform to criteria that are fully consistent with, and are derived from, the safety case for the disposal facility both during opera­tion and after closure. A programme of monitoring needs to be carried out prior to, and during, the construction and operation of a disposal facility and after its closure, if this is part of the safety case. This programme must be designed to collect and update information necessary for the purposes of protection and safety. Information must be obtained to confirm the condi­tions necessary for the safety of workers and members of the public and protection of the environment during the period of operation of the facility. Monitoring also needs to be carried out to confirm the absence of any condi­tions that could affect the safety of the facility in the period after closure.

Elements of isolation can be provided by institutional control following the closure of disposal facilities, specifically those on or near to the surface (i. e., a few tens of metres). Plans need to be prepared for the period after closure to address institutional control and the arrangements for maintain­ing the availability of information on the disposal facility. These plans have to be consistent with passive safety features and must form part of the safety case on which authorisation to close the facility is granted.

In the design and operation of disposal facilities subject to nuclear safe­guards, consideration has to be given to ensuring that safety is not compro­mised by the measures required under the safeguards system. Similarly, measures must be implemented to ensure an integrated approach to safety measures and nuclear security measures.

Management systems to provide for the assurance of quality must be applied to all safety related activities, systems and components throughout all the steps of the development and operation of a disposal facility, the level of assurance for each element being commensurate with its impor­tance to safety.

The safety of existing disposal facilities developed prior to current safety standards needs to be assessed periodically until termination of the licence. During this period, the safety also needs to be assessed when a safety sig­nificant modification is planned or in the event of changes with regard to the conditions of the authorisation. In the event that any of the current safety requirements are not met, measures need to be put in place to upgrade the safety of the facility, appropriate economic and social factors being taken into account.

In the ‘once-through’ fuel cycle concept, the 3-5% 235U enriched fuel is burned once in the power reactor. It is then removed from the reactor, stored temporarily, and ultimately packaged for disposal in a deep geologi­cal repository. Because the once-through fuel cycle has been the official policy for managing irradiated commercial nuclear fuel in the US, the geo­logical repository program in the US was highly developed. It had advanced to the point that the US Department of Energy (DOE) submitted the license application for the Yucca Mountain repository to the US Nuclear Regulatory Commission in 2008 (OCRWM, 2008). Although the DOE recently withdrew the license application for the Yucca Mountain reposi­tory, the development of this repository represents a good example appropriate for the once-through fuel cycle. For this reason, the discussion in this section will focus on the Yucca Mountain repository concept.

The site of the proposed Yucca Mountain repository is located in an arid region, about 145 km northwest of Las Vegas, Nevada. The geology and hydrology of this site have been extensively studied, as have the volcanic and seismic characteristics of the area (OCRWM, 2002). The Yucca Mountain repository is designed to accommodate three primary waste types: (1) commercial irradiated nuclear fuel from power generating plants, (2) DOE-owned irradiated fuel, including naval reactor fuel, and (3) vitri­fied high level waste (HLW). The latter category consists mostly of HLW borosilicate glass canisters generated from vitrifying radioactive tank wastes at the Hanford and Savannah River sites in the US (see Chapter 18). Under current US law, a maximum of 70,000 metric tonnes heavy metal (MTHM) can be disposed of at the Yucca Mountain repository. Of this, 63,000 MTHM is allocated to the disposition of commercial irradiated fuel, representing approximately 221,000 fuel assemblies (OCRWM, 2008). The DOE-owned irradiated fuel would constitute 2,333 MTHM, and the remaining 4,667 MTHM would be allocated for disposal of vitrified HLW. It is interesting to note that under the current statute, the Yucca Mountain repository (if built) would already be oversubscribed because the 4,667 MTHM allocated to vitrified HLW represents only approximately 9,334 of the 22,000 canisters expected to be produced and also 292,000 commercial irradiated fuel assemblies are expected to be produced by 2040, far in excess of the space allotted for 221,000 assemblies (OCRWM, 2008).

There is a single design for the Yucca Mountain waste package, but it has six configurations providing flexibility to accommodate the different types of waste to be received. Figure 5.3 illustrates the six waste package configu­rations (OCRWM, 2008). All six configurations consist of two concentric cylindrical containers. The primary (inner) waste container is made of 316 stainless steel and has walls 50.8 mm thick (Skinner et al., 2005). The outer secondary containment has 20.3 mm thick walls and is made of alloy C-22. The secondary container is designed to provide corrosion resistance, so it is referred to as the outer corrosion barrier. Each waste package has three welded lids, one on the primary container and two on the corrosion barrier. After welding of the inner lid, the primary waste vessel is evacuated and back-filled with helium. The helium serves three primary purposes:

1. It inhibits internal corrosion.

2. It improves heat transfer between the waste and the waste package.

3. It provides a tag for leak testing of the inner vessel closure welds.

Because of the intense radiation involved, all the waste package closure operations must be conducted robotically (Skinner et al., 2005 ).

5-DHLW/DOE SNF 2-MCO/2-DHLW Short

5.3 Approved waste package configurations for the Yucca Mountain repository.

In the design concept for Yucca Mountain, the loaded waste packages were to be transported to emplacement drifts carved within the repository. The emplacement drifts are nominally 5.5 m in excavated diameter with an average length of approximately 600 m. The length of the emplacement drifts is constrained to no more than 800 m to allow for efficient ventilation. The drifts have been excavated in parallel, spaced 81 m apart. This spacing is designed to prevent thermal interaction between adjacent drifts and allows infiltrating water from the surface to percolate past the drifts.

Encroachment of water onto the waste packages was to be further miti­gated by installation of a titanium drip shield. Water percolating into the emplacement drift from above the waste package is directed to a point below the waste package by the drip shield. Figure 5.4 provides a cross­sectional illustration of an emplacement drift, as designed for the Yucca Mountain Repository (OCRWM, 2008).

Sweden also practices a once-through nuclear fuel cycle and substantial progress has been made in that country on the establishment of a geological repository (see Chapter 13). These efforts are led by the Swedish Nuclear Fuel and Waste Management Company (SKB). Three decades of research and development and a 20-year site development process has resulted in the selection of Forsmark in the municipality of Osthammar as the site for the Swedish geological nuclear repository. In contrast to the arid environ­ment of Yucca Mountain, the Forsmark site is located along a coastal area. However, there are relatively few water-conducting fractures in the bed­rock at the depth of the fuel emplacement (500 m) at the Forsmark site (SKB, 2009). For emplacement into the Swedish repository, it is planned that the irradiated assemblies will be packed into cast iron baskets, which

in turn will be placed within thick copper canisters. Once placed within the repository, the loaded copper canisters will be packed in bentonite clay.

Finland is taking a similar approach to Sweden, having chosen the Olkiluoto site for the Finnish HLW repository (Okko and Rautjarvi, 2004). In this case, the waste packages will be placed in excavated tunnels hun­dreds of meters below the surface. The tunnels will be separated by a dis­tance of 25 m. As for the Swedish repository, the irradiated fuel will be packaged into nodular cast iron containers, which will then be enclosed in a 5 cm thick copper shell. The waste packages will be surrounded with ben­tonite clay to absorb water and to protect the waste from minor movements in the surrounding bedrock.

The long-term behavior of a waste disposal facility is a function of the entire disposal system, including the waste form, engineered barriers, and
surrounding environment. In order to assess the ability of a given disposal concept to meet regulatory requirements, it is necessary to consider the influence of each of these system components on short — and long-term performance. This is accomplished through the performance assessment (PA) process. For HLW, many countries are proposing long storage life for the canistered glass waste forms during geological repository siting and preparation. During that time, a great many of the radionuclides will decay leaving the long-lived radionuclides as the primary sources that need be considered in a PA.

Figure 6.5 is a schematic of a generic high level waste repository. It shows the relative role of the waste form, the role of the multiple barriers (canis­ters, containers, overpacks, and casks) in the waste disposal system. It is the multi-barrier concept — a barrier within a barrier within a barrier as dis­cussed in Chapter 1. Ultimately the role of the repository or disposal envi­ronment is to isolate the waste from the biosphere until all the barriers have failed at which time almost all of the radionuclides will have decayed.

While the waste form is the source term and should be as durable as reasonably possible, multiple barriers must corrode before the waste form will be exposed to groundwater. As a result of the research programs over the past several decades, there is now an extensive database and substantial understanding of the behavior of nuclear waste glasses in a variety of dis­posal environments [159]. The present challenge is to model glass behavior

in the near-field of specific geologic repository environments and to develop a fundamental understanding of the long-term corrosion rate [160].

It is recognized that the presence of radionuclides causes fear, as radiation is not visible and its effects may only be noticeable after long periods of time. A remediation programme, therefore, has to address not only the scientific aspects of the problem, but also its societal dimension. One impor­tant aspect of the societal dimension is the communication between the different parties having an interest in the problem, i. e. the stakeholders. Communication is often hampered by differing levels of knowledge of the subject and the specific language associated with it. In addition, there may be human values and expectations that are not shared by the different groups of stakeholders.

One cannot forget that ER of radioactively contaminated sites is also linked in people ’s mind to the prevailing views of different societies on nuclear power. The perception is that this technology had been historically associated with technological ‘hubris’, over-optimistic claims of its initial promoters, and military uses and secrecy; major accidents (e. g. Chernobyl and Fukushima), intense environmental concerns associated with RAW disposal and the stigma on communities associated with contaminated areas. There is also a widespread distrust in regulators, governments and practitioners to provide truthful information and manage risk responsibility. However, a key element that needs to be considered is that communities located very near existing nuclear power stations may hold more favourable attitudes to any new development than those who live much further away. This may be an indication than familiarity with the issue may be a positive element as people will tend to reject what they do not know. One potential avenue to explore in terms of public acceptance to remediation projects may be to share the opinions of communities living in remediated areas with those communities that will undergo a process of ER.

Involving the various stakeholders in the remediation programme will be beneficial to all parties concerned and it is advisable to involve them from an early point in the process.

Public participation in decision-making processes regarding the living environment is backed up by international agreements; one example is the Aarhus Declaration (UNECE, 1998). See the following excerpt from the Aarhus Declaration:

We recognize and support the crucial role played in society by environmental NGOs (non-governmental organizations) as an important channel for articulating the opinions of the environmentally concerned public. An engaged, critically aware public is essential to a healthy democracy. By helping to empower individual citizens and environmental NGOs to play an active role in environ­mental policy-making and awareness raising, the Aarhus Convention will promote responsible environmental citizenship and better enable all members of society to fulfill their duty, both individually and in association with others, to protect and improve the environment for the benefit of present and future generations.

Remediation projects tend, to a large extent, to be driven by stakeholder (generally laypeople) opinions. Contrary to what is proposed by interna­tional recommendations, interested parties may wish to drive remediation projects well below clean-up levels that would be recommended if only risk criteria were taken into account. It is not uncommon that in some occasions it is suggested/demanded by laypeople the return of the contaminated land to the conditions prior to the occurrence of contamination even if no com­mensurable benefit for the population/community potentially affected by the contaminated land were achieved. This tendency may cause ‘over­remediation’ of the site or expenditure of resources (e. g., due to excessive production of wastes) which are greater than necessary in terms of cost — benefit. In other words, resources that could be invested in other priorities, with clearer and measurable social benefit, will be spent in favour of the remediation of the site with the objective of meeting the demands of the target community. These demands may be sustained mainly by the percep­tion and fear of radiological impacts rather than by the real effects that would be incurred by the population. A comprehensive overview of non­technical factors in an ER project (with a focus on stakeholders’ views and factors) is given in IAEA (2002). In particular, this report expands on the role that planned (or preferred) land use may play in the ER decision making. It is evident that residual (post-ER) radioactive concentrations greater than ‘greenfield’ criteria may prevent certain uses of the site (e. g., residential); conversely, a ‘brownfield’ end-state may still allow reuse of the site (e. g., for industrial purposes), be acceptable to the public and cost much less. The reader could usefully consult two more IAEA reports focusing on the parallel field of decommissioning (IAEA, 2006c; 2011). The reader should note that several technical aspects are common to decommissioning and ER: Fig. 8.3 exemplifies a typical case in question, i. e. the removal of underground pipes that may have leaked and contaminated the environment.

314 Radioactive waste management and contaminated site clean-up

On 29 June 2011, the State Representative Assembly of the Russian Federa­tion passed a law called ‘On the Management of Radioactive Waste’. This federal law deals with crossover issues such as interim storage, the final isolation of RAW, and the financing of the measures required in RAW management. Crucially, it also lays out the responsibilities of the different authorities, including the Russian government, Rosatom, federal bodies, state and local government authorities, the national RAW management operator, and RAW suppliers. The law establishes the legal organizational basis for all forms of RAW management, as well as government control of RAW rates and costs and financial schemes. The requirements for RAW disposal, and the state’s role in accounting, storage, control and registration are all determined by this law, along with the establishment of radiological controls and radiation monitoring. It further states that RAW containing nuclear materials is exclusively federal property. The system of state accounting and control of RAW and RAM is responsible for all RAW found on Russian territory, including registering RAW and its storage loca­tions. Responsibility for newly generated RAW lies with the organization in which the RAW is produced: the same operations also take responsibility for the safe handling of RAW treatment up to the point of transfer to the national operator.

378 Radioactive waste management and contaminated site clean-up

1.1.2 Government-led programmes

Mechanisms for managing controlled radioactive wastes are invariably under national government control with legislative and regulatory systems in place to ensure safety and security. In the UK, for example, in 2004 the government commissioned an independent Committee on Radioactive Waste Management (CoRWM) and in 2005 it established the NDA to ensure its 20 civil public sector nuclear sites were decommissioned and cleaned up, safely, securely, cost effectively in ways that would protect the environment for this and future generations. CoRWM recommended to government (CoRWM, 2006) that geological disposal be the end-point for long-term management of RAW but with robust storage in the interim period with provision against delay or failure in reaching the end-point. It also recommended a staged process with flexibility in decision making and partnership with communities willing to participate in the siting process and an expanded national R&D programme to support the process. In response the government published a White Paper outlining the process and stages (Fig. 1.7) that would lead to permanent geological disposal of the UK ’ s wastes (DEFRA, 2008). Figure 1.7 shows steps in the UK’s Managing Radioactive Waste Safely (MRWS) process.

An invitation was sent out to communities in stage 1, inviting expressions of interest in hosting a repository or geological disposal facility (GDF). In stage 2, simple criteria were used to determine if the location was likely to be suitable. At this stage, areas were ruled out, for example, if they had mineral resources which might prove useful in future or aquifers. Communi­ties in potentially suitable areas could decide to participate further in stage 3, while in stage 4 desk-based studies would be carried out which would lead to borehole investigations in stage 5 prior to actual construction of the GDF underground in stage 6. Extensive work is needed during the early stages to underpin the safety case to the regulators to allow construction and safe operation and eventual closure of the GDF, including decades of R&D. This volunteer approach also needs intensive public and stakeholder

engagement to convince communities that this is the right approach to dealing with the waste problem. UK government extended the NDA’s responsibility to include geological disposal of the waste and in 2007 it established the Radioactive Waste Management Directorate (RWMD) as the implementing body responsible for constructing the GDF.

In other countries the process of developing a strategy for managing radioactive waste has been difficult. In the USA and Japan national pro­grammes have been hindered by a lack of public support, and without a clear end-point (repository site) the programmes flounder. The Yucca Mountain project in Nevada, USA, was hindered by lack of public accept­ability, legal challenge and technical shortcomings. In 2009, the Obama Administration announced that it had determined that developing a reposi­tory at Yucca Mountain was not a workable option and that the US needs a different solution for nuclear waste disposal. The Secretary of Energy established the Blue Ribbon Commission (BRC) on America ’s Nuclear Future in January 2010 to evaluate alternative approaches for managing SF and HLW from commercial and defence activities. The BRC conducted a comprehensive review of policies for managing the back end of the nuclear fuel cycle. It has provided recommendations for ‘developing a safe long­term solution to managing the Nation’s used nuclear fuel and nuclear waste.’ Their final report was submitted to the Secretary of Energy in January 2012 (BRC, 2012) and it contained eight recommendations for legislative and administrative action to develop a ‘new’ strategy to manage nuclear waste:

1. A new, consent-based approach to siting future nuclear waste manage­ment facilities.

2. A new organization dedicated solely to implementing the waste man­agement programme and empowered with the authority and resources to succeed.

3. Access to the funds nuclear utility ratepayers are providing for the purpose of nuclear waste management.

4. Prompt efforts to develop one or more geological disposal facilities.

5. Prompt efforts to develop one or more consolidated storage facilities.

6. Prompt efforts to prepare for the eventual large-scale transport of SF and HLW to consolidated storage and disposal facilities when such facilities become available.

7. Support for continued US innovation in nuclear energy technology and for workforce development.

8. Active US leadership in international efforts to address safety, waste management, non — proliferation, and security concerns.

The near-term direction advocated by the BRC aligns with ongoing DOE programming and planning. Current programmes will identify alternatives and conduct scientific research and technology development to enable long­term storage, transportation, and geological disposal of SF and all radioac­tive wastes generated by existing and future NFCs. The BRC report has informed the Administration’s work with Congress to define a responsible and achievable path forward to manage SF and nuclear waste in the US. The US DOE endorsed the key principles of the BRC recommendations and published a strategy (DOE, 2013) to move forward with their implementation.

During its processing, radioactive waste is converted from an ‘as generated’ state to a processed waste form and placed in a container to form a final waste package for storage and disposal. A principal condition for accept­ance of waste packages for disposal is full compliance with the disposal site WAC, in other words, to demonstrate that chemical, radiochemical, biologi­cal, mechanical and other parameters of the waste form are in accordance with the required values. The waste parameters can change during handling and processing, and to ensure compliance of a waste package with a WAC, a system for generating and maintaining records should be established in order to save and track all relevant information. It is worth registering not only the waste parameters but also the technological parameters of the processing facilities. A record-keeping system should define the data, which should be collected and stored at each step of the waste life cycle and for each waste stream. A reliable selection system should be imple­mented not only to avoid collecting too much information, but, also to assure the long-term availability of all significant and potentially needed data. Record-keeping systems for the pre-disposal period of the waste life cycle should ideally be coordinated and interconnected with the record­keeping system for the disposal facility. However, a reasonable data reduc­tion approach should be applied for transfer of the information. More detailed information for the identification of requirements and establish­ment of record-keeping systems can be found in Ref. [9].

The main nuclear material routes are (Fig. 4.1):

• clearance from regulatory control, which assumes unrestricted disposal of waste and unrestricted reuse of useful materials;

• authorized release, which assumes authorized discharge of waste to the environment and authorized reuse of useful materials;

• regulated disposal of waste and regulated transfer of useful materials to other practices.

There is great diversity in the types and amounts of radioactive waste in different countries. Technologies for management of the waste are also diverse, although the main technological approaches are likely to be similar everywhere. Adequate processes and technologies can be identified based on detailed information about the current or forecast waste, e. g. waste clas­sification, categorization, properties and inventory.

The IAEA provided an internationally accepted waste classification system [7] which define the following classes according to the activity and half-lives of radionuclides in waste:

• exempt waste (EW);

• very short lived waste (VSLW);

• very low level waste (VLLW);

• low level waste (LLW);

• intermediate level waste (ILW);

• high level waste (HLW).

The IAEA classification is based primarily on long-term safety and there­fore is oriented on the selection of the most appropriate disposal routes (end-points) for solid or solidified waste.

Management of waste in different steps prior to disposal (e. g., pre­treatment, processing, storage) requires complementary information on the waste properties relevant to particular activities. Categorization of waste is used to provide a consistent approach to waste processing and storage. Categorization of waste has to include information such as origin, physical state, types, properties and process options [8, 9] .

118 Radioactive waste management and contaminated site clean-up