ABSTRACT
This chapter describes a number of proposed ways of quantifying and presenting risk. This is particularly important for nuclear risks which are of a different nature to many common risks. The chapter outlines the most important various types of risk, which are sub-divided into personal and non-personal, that is, purely social. It introduces the idea of a risk profile' of a disaster to characterise the numbers of people who would be affected in different ways by it for serious consequences to individuals. The chapter discusses two matters which relate to the risk caused by nuclear installations. These are the effects of radiation and the question of using release as a surrogate for risk. The basic expression of a societal risk is a graph which shows the frequency of a given level of harm plotted against the level of harm. The level of harm may be either a discrete variable or a continuous variable.
