A. J. GONZALEZ, Autoridad Regulatoria Nuclear de Argentina (Argentine Nuclear Regulatory Authority), Argentina

Abstract: The international radiation protection system for nuclear power plants (NPPs) is described. It includes the estimates of the United Nations Scientific Committee on the Effects of Atomic Radiation, the recommendations from the International Commission on Radiological Protection, and the safety standards established by the International Atomic Energy Agency. The aim is to summarize the sytem’s fundamental principles. Their application to potential exposures (and therefore to nuclear safety) is portrayed including a compliance criterion for prospective probabilistic safety assessments. Practical considerations on occupational and public protection are discussed, including a description of the latest assessments of the radiological consequences of the Chernobyl accident.

Key words: radiation safety, radiation protection, nuclear safety, safety assessment, nuclear regulation.

11.1 Introduction

Ionizing radiation (named, in short, radiation) is perceived to be the nemesis of nuclear energy. This is unsurprising: radiation exposure is detrimental to human health and omnipresent in activities and installations of the nuclear fuel cycle, including regulated nuclear power plants (hereinafter termed NPPs) for electricity production. These installations routinely discharge into the atmosphere and watercourses, gases, aerosols and liquids contain­ing small amounts of radioactive substances, which may cause radiation exposure to members of the public; their operators are occupationally exposed to radiation delivered by ubiquitous radioactive materials in work­places. NPP safety assessments demonstrate that the likelihood of a cata­strophic accident is exceedingly small; however, should a nuclear accident occur its consequences can be severe: emergency workers may be exposed to high radiation levels and large amounts of radioactive materials can be uncontrollably released into the environment, contaminating vast territo­ries and exposing large populations. NPPs also generate large amounts of radioactive waste that have to be transported over public places and which are viewed as a radiation exposure legacy for our descendants.

Decommissioning activities, necessary for the termination of nuclear opera­tions, may leave radioactive residues that will likely remain in the habitat. Ultimately, concerns have been growing on the security of the radioactive materials in the nuclear fuel cycle since their malevolent use might cause serious radiological harm.

Predictably, the protection against radiation exposure, namely radiation protection (sometimes termed radiological protection), has become a sine — qua-non condition for the justification of nuclear power.

The protection against radiation exposure has been fully internatio­nalized and the current radiation protection rests on four international foundations:

1. The estimates of radiation levels and effects are assessed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). UNSCEAR is an intergovernmental scientific body founded in 1955 and since reporting radiation levels and effects to the United Nations General Assembly (UNGA) (UNSCEAR, 1958, 1962, 1964, 1966, 1969, 1972, 1977, 1982, 1986, 1988, 1993, 1994, 1996, 2000, 2001, 2009, 2011).

2. A radiation protection paradigm is recommended by the International Commission on Radiological Protection (ICRP). ICRP is a scientific non-governmental independent charity, i. e., a non-profit-making orga­nization, providing advice on radiation protection (ICRP, 1951, 1955, 1957, 1959, 1964, 1966, 1977, 1978, 1985a, 1985b, 1991, 2007a). It was established in 1928 by the International Congress of Radiology, with the name of the International X-Ray and Radium Protection Committee (IXRPC) (IXRPC, 1928, 1934), following a decision by the Second International Congress of Radiology, and in 1950 it was restructured and renamed as now.

3. International standards on radiation safety are established under the aegis of the International Atomic Energy Agency (IAEA) (IAEA, 1960, 1962, 1967, 1976, 1982, 1996a, 2011), lately in co-sponsorship with other relevant intergovernmental organizations within the United Nations (UN) system, therefore becoming the de facto international radiation protection authority. Since its creation in 1957, the IAEA has been responsible for safety-related functions that are precisely described in its Statute, namely (1) establishing standards of safety for the protection of health against the detrimental effects attributable to radiation expo­sure; and (2) providing for the application of those standards at the request of any State.

4. Global provisions for the implementation of radiation safety standards, through mechanisms put in place by national agencies and by the IAEA and other international organizations.

On the basis described heretofore, this chapter will explore the interna­tional approach for radiation protection at nuclear activities in general and the nuclear fuel cycle and its NPPs in particular. Its aim is to provide guid­ance on the fundamental principles on which appropriate radiation protec­tion can be based rather than a regulatory text. International radiation protection trends and achievements have been reviewed at the recent 12th Congress of the International Radiation Protection Association (IRPA): Strengthening Radiation Protection Worldwide: Highlights, Global Perspective and Future Trends (IAEA, 2010; Gonzalez, 2009a).

The chapter will not review a number of issues closely related to radiation protection and NPPs, inter alia the following:

• The radiological security of radiation sources at NPPs and of the NPP itself, a subject for which there are detailed recommendations from ICRP (ICRP, 2005a) and which has been amply reviewed by the IAEA (IAEA, 1999b, 2000a, 2001, 2003a, 2006c) and by the author (Gonzalez, 1999a, 1999b, 2001b, 2003a, 2006)

• The radiation protection aspects of waste and spent fuel management, an issue that is discussed separately in Chapter 14, for which there are several recommendations from ICRP (ICRP, 1985b, 1997a, 1998) and which has been thoroughly discussed globally, mainly at the IAEA (IAEA, 2003d; Gonzalez, 2000, 2003c), and is regulated by an interna­tional convention (IAEA, 1997)

• The radiation safety of the transport of nuclear and other radioactive materials associated with nuclear fuel cycle operations, an activity that is heavily regulated globally by standards (IAEA, 2008b, 2009) consti­tuting a real international regime (Gonzalez, 2004a) and for which there is a global consensus (IAEA, 2004a)

• The radiation legacy from the termination of NPP operation and the consequent decommissioning, and also from accidents, a subject to be discussed in Chapter 24, which has been the subject of intense IAEA activity (IAEA, 2003c, 2007) and ICRP recommendations (ICRP, 2009a) but which still lacks an international regime (Gonzalez, 2003d)

• Last but not least, the radiological consequences of NPP accidents (except the Chernobyl accident, which will be briefly covered hereinaf­ter), and the protection of people in emergencies, a subject covered by ICRP (ICRP, 2009b), as well as emergency planning and preparedness, a subject that will be treated in Chapter 12.