1 INTRODUCTION

1.1 Definition

Radioactive waste is any waste material—gas, liquid, or solid—whose radioactivity exceeds certain limits. These limits have been established by governments or by local authorities, guided by the recommendations of the International Commission on Radiation Protection (ICRP). The ICRP recommendations define the maximum permissible concentration (MPC) for each individual radionuclide and for mixtures of radionuclides in water or air. The U. S. regulation defines such limiting concentration as the radioactivity concentration limit (C), which is the terminology used in this text. Values of C for selected actinides and long-lived fission products in water or air are given in App. D.

The intention of regulations limiting the release of radioactive material from nuclear installations is to keep the radioactivity concentration in ground and surface water or in air well below the levels recommended by the ICRP. The regulations may follow either one of two principles or may combine them:

Limitation of the total amount of radioactivity associated with a certain material that may be released over a given period of time

Limitation of the radioactivity concentration in the material to be released

As a consequence of these limitations, most of the radioactivity arising as waste from nuclear technology has to be isolated from the environment by some storage or final disposal technique. The first step toward this goal is usually a volume reduction, preparing the waste for interim storage as a liquid or solid. This is considered part of the waste-generating technology rather than of the waste management. Waste management is defined to include interim storage, final conditioning, and long-term storage or disposal.