Advanced nuclear reactor designs

This section provides descriptions of the technology options currently avail­able for newcomer countries, in particular evolutionary reactor designs, as these are the most likely candidate technologies for most countries’ first nuclear power plant, particularly in the near to middle term. For complete­ness, however, a brief discussion examining future trends for the develop­ment of nuclear reactors in the long term has also been included.

9.1.1 Evolutionary reactor designs

As described above, evolutionary designs achieve improvements over exist­ing designs through small to moderate modifications, with a strong emphasis on maintaining design proveness to minimize technological risks. Not sur­prisingly, most of these are water-cooled reactors, as this type of design is the one where the nuclear community has more lessons learned and expertise.

The following designs, which have been ordered alphabetically herein, are those in a more advanced stage of development and would presumably be available for near-term deployment. In some cases, they have even been built or are in the process of being built somewhere in the world, and this will be indicated. The detailed technical data for all these designs can be found in IAEA (2010).

ABWR

The Advanced Boiling Water Reactor (ABWR), which is available from two competing vendors (GE-Hitachi and Toshiba, Fig. 9.3), combines the

image022

9.3 The ABWR design (Toshiba).

best BWR design features from Europe, Japan and USA. The ABWR was developed in direct response to the EPRI Utility Requirements Document (URd) (EPRI, 1995, 1999), it is licensed in the USA, Japan and Taiwan (China) and it is the first evolutionary reactor design to operate commer­cially. There are currently four ABWRs in operation in Japan (Kashiwazaki — Kariwa 6 and 7, Hamaoka-5 and Shika-2), two in construction in Taiwan, China, and several more planned in Japan and the USA. In this sense, there is a proven capital and operation and maintenance cost structure associated with this design. The ABWR was designed with a shorter construction schedule in mind, by taking advantage of existing prefabricated construc­tion experience and applying it into a modularized design. Although exist­ing ABWRs are 1370 MWe, future ones are expected to be 1500 MWe as the reactor core has enough margins for these uprates. The ABWR has fully digital I&C and has adopted reactor internal pumps that eliminate the need for the large external recirculation coolant loops that involved penetrations below the top of the core elevation, thus making it possible to maintain core coverage during a postulated loss-of-coolant accident. This design also includes the capability to mitigate severe accidents and to reduce off-site consequences of accidents. The ABWR containment vessel is made of rein­forced concrete with an internal steel liner.