12.1. INTRODUCTION/OBJECTIVES

This chapter considers the innovative reactor designs that are being put forward as likely candidates for future generations of reactors. Higher efficiencies can be achieved for electricity generation by increasing the temperature of the reactor systems. Higher temperatures are a feature of many of the most promising future reactor designs.

There is also the potential of exploiting nuclear energy for more general energy applications than have been considered previously. These applications could be many and varied. They include the utilisation of fuel cycle systems to burn weapons grade plutonium or minor actinides from spent fuel. The possibility of utilising nuclear energy to generate hydrogen is an attractive option for transport. Efficient future reactors for electricity generation and for these additional applications are considered in this chapter.

Similar design requirements to those described for evolutionary plants in Chapter 7, relating to reliability, economics, safety and acceptability apply also to these type of systems, together with some additional requirements. General design requirements for these future reactors are described in this chapter.

It is worth noting at this stage that sub-critical reactors based on accelerator driven systems (ADS) are also attractive candidates for plutonium destruction and minor actinide conversion. These are considered separately in Chapter 13.

Some of the innovative reactor designs reviewed in this chapter are also being considered for heat applications. Heat and other novel applications for nuclear energy are considered in more detail in Chapter 14. In Chapter 12, the focus is on the innovative reactor designs, in Chapter 14 the focus is on novelties in the applications. Already in some countries, e. g. Russia, waste heat from electricity generators is being used for district heating. Most of the experience to date has been with low-temperature applications. Other low-temperature applications include desalination plants. In many cases, the proposed reactor designs and certainly already operating systems are based on established reactor designs; the novel aspects relate to the balance of plant configurations to achieve the desired goals.

Many of the most promising future reactor designs have been examined by the US instigated Generation IV Forum (GIF) programme that started a little over 2 years ago. There are a number of signatories from among the major nuclear plant operating countries, 10 countries have joined, Argentina, Brazil, Canada, France, Japan, South Africa, South Korea, Switzerland, UK and the US. Other European countries are participating through the EU, which is also a member.

The objective of Generation IV is to identify the most promising types of reactor design that will contribute to future generations of reactors and to put in place R&D to promote further understanding of the designs and their performance.

Initially over 100 different designs were considered under the simple title of future energy systems (not just nuclear). These were reduced to 19 designs and finally to the following 6 most promising designs, see Table 12.1.

There has also been a ‘Three Agency Study’ carried out by the International Energy Agency (IEA), the OECD Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA) (IEA/OECD (NEA)/IAEA, 2002). There were 34 innovative designs considered. Of these, a total of 12 designs have been considered in some detail. Most of these are also included in the Table 12.1 categorisations.