N. BUTTERY, EDF Energy, UK

Abstract: This chapter discusses the various designs of light water reactors currently in operation and future developments of these, some of which are already under construction. Light water reactors currently account for almost 90% of the world’s installed nuclear capacity. The principal design features of both pressurised water reactors and boiling water reactor are discussed including their safety systems. Operational requirements are outlined and fuel design and performance are discussed. The chapter then outlines future developments in terms of both the development of advanced light water reactors and small and medium reactors.

Key words: light water reactors, boiling water reactors, pressurised water reactors, advanced light water reactors.

10.1 Introduction

According to figures from the International Atomic Energy Agency (IAEA) PRIS database (IAEA, 2011) in January 2012 more than 80% of the world’s nuclear power plants are Light Water Reactors (LWRs). These account for almost 90% of the installed nuclear generation capacity (see Table 10.1). A number of different designs of both Pressurised Water Reactors (PWRs) and Boiling Water Reactors (BWRs) are in operation throughout the world and are manufactured by a number of different companies. The earliest commercial reactors were produced in the USA and many of the modern plants were developed from these as the technology

was transferred to customers outside the US. In other cases indigenous designs developed based on similar principles but with detailed design differences.

In this chapter the main plant features of LWRs will be discussed together with their operational requirements, before outlining the different designs of PWRs and BWRs currently in operation. In Section 10.11 future developments, including plants, which are currently under construction will be discussed.