United States: experience of radioactive waste (RAW) management and contaminated site cleanup

M. REGALBUTO, Argonne N ational Laboratory, USA and J. JONES and S. P. SCHNEIDER, US Department of Energy, USA

DOI: 10.1533/9780857097446.2.567

Abstract: The federal government of the United States is responsible for the safe disposal of spent nuclear fuel and high-level radioactive waste. The development of policies and practices has evolved over the years to ensure that the waste is managed appropriately. The major agency involved in the implementation of these activities is the Department of Energy (DOE), and the regulatory authority is assigned to the Nuclear Regulatory Commission (NRC) and Environmental Protection Agency (EPA). The US waste classification system is divided into two areas — commercial and government owned. Current storage and disposal techniques are described, addressing the different types of waste. The cleanup history and current strategies for these waste types are discussed in detail to provide the reader with an overall understanding of the US national waste management system.

Key words: radioactive waste, regulations, Department of Energy (DOE), Nuclear Regulatory Commission (NRC), low-level waste (LLW), high-level waste (HLW), mixed waste, spent fuel, storage, disposal, transuranic (TRU) waste, uranium mines and mills, Waste Isolation Pilot Plant (WIPP) , cleanup program

18.1 Introduction

The United States operates waste storage facilities for low-level waste (LLW) and transuranic (TRU) waste. It is the only country in the world that has successfully licensed, constructed, and now operates a deep geo­logical repository for defense-generated radioactive waste (RAW), the Waste Isolation Pilot Plant (WIPP). There are three main sources of nuclear

Note: The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (‘Argonne’). Argonne, a US Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC0206CHH357. The US Govern­ment retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.

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waste in the United States that resulted from either defense or civilian applications:

1. Legacy waste from military operations — defense waste was the first type of radioactive waste generated. It is the byproduct of nuclear weapons production. Legacy waste from defense applications includes materials of multiple compositions and forms, presenting challenges for stabiliza­tion before disposal. In general, the management of legacy waste con­sists of a highly integrated operation that involves storing liquid waste in underground tanks; removing, treating, and dispositioning the low — activity fraction in concrete vaults; and vitrifying and storing the higher — activity waste until permanent disposal at a federal repository. There are 88 million gallons of liquid waste stored in tanks, 1.5 million m3 of solids, and a variety of contaminated equipment. In addition, there are surplus weapons materials and spent nuclear fuel (SNF) from reactors on naval vessels.

2. Fuel cycle operations for energy production — civilian waste that results from fuel cycle stages for electricity production. This waste is the byprod­uct of facilities used for:

• uranium mining and milling — waste consists mainly of sandy tailings whose composition is the same as uranium ore (absent uranium)

• conversion, enrichment, and fuel manufacturing — the main byprod­uct is depleted uranium (DU) stored as either UF6 or U3O8

• electricity generation — the main waste in terms of activity is spent fuel, which consists of highly radioactive fission products and transu­ranic elements, and is classified as high-level waste (HLW). Nuclear wastes resulting from these operations are stable, unlike defense legacy waste, and may be readily stored and disposed. In addition to spent fuel, other low- and intermediate-level waste is generated from support and decommissioning operations.

3. Others types of waste — research and development, accelerators, medical, industrial, and naturally occurring. This waste composition is mainly short-lived radionuclides, usually classified as LLW, and is mainly stored onsite until it decays.

Both defense and civilian applications produced radioactive waste ranging from LLW to HLW. Defense and civilian generated waste have similar characteristics in terms of radiotoxicity and need to be isolated from the public; however, their forms are significantly different and the waste con­ditioning necessary before disposal differs significantly: [30]

• Defense waste needs to be concentrated and converted to a stable form before disposal, whereas civilian waste in the absence of reprocessing may be directly packaged, stored, and disposed.

Nuclear waste from both civilian and defense applications varies in its composition and form. In general, the nuclear waste attributes that affect humans and the environment and that determine the disposal path are chemical composition, physical form, and type of radiation. To facilitate a safe and cost effective waste disposal strategy, waste is categorized to provide guidance for its handling, transportation, storage, and ultimately final disposal. It is important to understand that how the waste is catego­rized ultimately affects how its final disposition is determined. The classifi­cation system ranges from very low-level waste (VLLW) to HLW. It varies from country to country but falls into two main types: those that are based on ‘where’ the waste was generated (i. e., point of origin) and those that are based on the ‘intrinsic qualities’ (i. e., risk-based parameters) of the material. The United States adopted a point of origin system, whereas the interna­tional community uses a risk-based system.

This chapter describes the current radioactive waste (RAW) manage­ment programs in the United States. The distinct policies, practices, and regulatory standards are explained, as well as the unique US waste classi­fication system used. Strategies for implementing the RAW management programs are explained for different currently existing US facilities. Multi­ple US storage and disposal facilities contain various defense and commer­cial RAW (Fig. 18.1) , which are discussed later in the chapter. The last

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18.1 Dry cask storage of spent nuclear fuel (Nuclear Energy Institute).

sections address the cleanup and closure process for specific US radioactive waste facilities, and the lessons learned from past experiences.

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