1. INTRODUCTION

Many developing countries are experiencing a rapid growth of their economies and an increasing need for the supply of both heat and electrical energy. The present primary energy production is based predominantly on fossil fuels, adding to the C02 burden on the environment. Nuclear power has the potential to bring about a substantial reduction in C02 releases arising from both heat and electricity generation. Although there was a rapid growth in the seventies and early eighties, in the nuclear share of total electricity generation, several factors including the impact of the Three Mile Island and Chernobyl accidents have resulted in dampening further growth. For harnessing the potential benefits of nuclear energy in meeting the future needs of both heat and electricity, it is necessary to develop cogeneration nuclear plants having the following characteristics:

• Low capital investment to reduce the financial risk.

• Construction period of 5 years or less to improve the economics of nuclear heat and power generation.

• High operational reliability through simplification of the plant systems.

• Enhanced safety features enabling siting near densely populated areas.

In response to these needs nuclear power plant designers in many countries have been developing new designs including integral reactors. Integral reactors are heat and/or power generation reactors, in which the primary coolant system components including steam generators(SGs), pressurizers and pumps are contained within the reactor pressure vessel (RPV). The current loop type power reactors have these components located outside the RPV.

The purpose of this report is to provide up-to-date technical information on the current status of the design and development of integral reactors in the Member States, based on information presented in two technical committee meetings organized by the Agency on the subject. Important aspects regarding integral reactor design and development are highlighted in the summary and the presented papers are included under the following headings:

• Development programmes and conceptual design descriptions.

• Specific systems and analyses.

• Operational, manufacturing and decommissioning aspects.