Radioactive waste (RAW) categories, characterization and processing route selection

R. B U R C L, Freelance consultant (formerly of IAEA and EC-JRC Institute for Energy and Transport), Slovak Republic

DOI: 10.1533/9780857097446.1.50

Abstract: The principal approach to radioactive waste management is to transform ‘as generated’ waste to a waste package suitable for safe long-term storage or ultimate disposal. A waste characterization system allows an assessment of the potential risks connected with waste handling and disposal and also allows the waste to be classified into groups (streams) according to their properties and projected processing routes. A properly selected waste classification system also enables the selection of the proper processing technology for each class of waste, tailored to waste volume, properties and available technologies in each country or waste processing organization. Long-term safe disposal of processed waste is a basic requirement of all waste classification and waste processing schemes discussed in this chapter.

Key words: radioactive waste, properties, characterization, record keeping, waste processing routes.

2.1 Introduction

The use of nuclear energy for power generation and application of radionuclides in medicine, research, education and in several industrial fields is still increasing. Generation of radioactive waste (RAW) is an unavoidable by-product of generating nuclear energy and safe and sound waste management to ultimate disposal in environmentally safe conditions is not only a technical and technological problem, but also a serious socio­political problem, with potential direct impact on the future of nuclear energy.

Radioactive waste is generated in a wide variety of compositions, radio­nuclide content, physicochemical parameters, and volume. Each category of RAW requires individual management and an individual technological approach. However, there is a basic tenet for all waste processing which is to transform each waste into a waste package suitable for safe isolation either in storage or in a final disposal facility to ensure that any impact on the population and environment is as low as possible.

Many classification systems have been developed and implemented in the more than 60 years of the nuclear era. Most of them are based on the radiological characteristics of the waste. However, the classification systems are usually tailored to adhere to technological requirements, country-spe­cific legislation, as well as national waste management policy requirements and limitations. The International Atomic Energy Agency (IAEA), as world co-ordinator of nuclear issues, facilitates dissemination and exchange of information, ‘know-how’ and good operational practice in waste classifica­tion. This makes a big difference in the harmonization of approaches at an international level; in particular, in the proposed general RAW classifica­tion scheme, depending primarily on the final disposal options being con­sidered in relation to the radiological parameters of the waste. This scheme can be tailored according to the individual requirements of the various countries or even the various waste management organizations. However, even though the classification scheme is in a generalized form, it allows the intercomparison of various classification systems and is often used to facili­tate the transfer of RAW management ‘know-how’ among the international community.

Based on a generated waste volume and the characteristics of a waste, a proper and safe waste processing technology can be selected. At present, there are safe and proven technologies available for processing of all kinds of RAW. The main issue is, therefore, to select an optimum tech­nology or a sequence of technological procedures to produce a waste package that corresponds to the safety requirements for long-term storage and ultimate disposal, while at the same time considering the operational staff radiation protection, economic issues, public perception and other aspects.

All these issues are discussed in this chapter as a general introduction to the more technologically oriented chapters in this book.

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