Worldwide, LWRs (PWRs, BWRs and WWERs) are the major types of nuclear power plants. They represent approximately 88% of today’s global nuclear power capacity, and evolutionary designs, based on this experience base, are being developed in several countries. The major evolutionary LWR designs are shown in Table V.

The evolutionary LWR activities in different countries are briefly described in the following10:

In the USA, designs for a large sized advanced PWR (the Combustion Engineering System 80+) and a large sized BWR (General Electric’s ABWR) were certified by the U. S. NRC in May 1997. Westinghouse’s mid-size AP-600 design with passive safety systems was certified in December 1999. Efforts are currently underway by Westinghouse on a 1090 MWe plant called the “AP-1000,” applying the passive safety technology developed for the AP-600 with the goal to reduce the capital costs through economies-of-scale. A certification application for the AP-1000 design has been made to the US NRC this year. General Electric is also designing a 1380 MWe ESBWR applying economies-of-scale together with modular passive safety systems. The design draws on technology features from General Electric’s ABWR and from their earlier 670 MWe simplified BWR with passive systems.

In France and Germany, Framatome ANP completed the basic design for a 1545 MW(e) European Pressurized Water Reactor (EPR) in 1998, which meets European utility requirements. The EPR design includes the mitigation of core melt and vessel penetration accident scenarios ensuring the avoidance of evacuation of people in the vicinity of the plant. Accidents with molten core material outside the reactor pressure vessel are handled via a spreading concept in the basement of the containment. The EPR’s higher power level relative to the latest series of PWRs operating in France (the N4 series) and Germany (the Konvoi series) has been selected to capture economies of scale. Framatome ANP’s SWR 1000 is based on German BWR experience with added features to increase safety. It is an advanced BWR with active and passive safety features which allows for extended grace period for accident control and consequences of a core melt accident is limited to the immediate vicinity of the plant. This has been achieved by providing cooling of the reactor pressure vessel exterior. The essential elements of the SWR safety concepts are shown in figure 4.

SWR 1000 Safety Concept

In Sweden, Westinghouse Atom is also developing the 1500 MWe BWR 90+, an advanced boiling water reactor with improved safety and operability. This is an upgraded version of the BWR operating in Sweden and Finland.

The first two ABWRs in Japan, the 1360 MWe Kashiwazaki-Kariwa 6 and 7 units, have been in commercial operation since 1996 and 1997, respectively. ABWR plants are under construction at Hamaoka Unit no. 5 and Shika Unit no. 2, and under licensing at Ohma Unit no. 1. Another eight ABWR plants are in the planning stage in Japan. The benefits of standardization and construction in series are being realized with the ABWR units. Expectations are that future ABWRs will achieve a significant reduction in generation cost due to standardization, design improvements and better project management. In addition, a development programme was started in 1991 for 1700 MWe ABWR-II, aiming to further improve and evolve the ABWR, with the goal of significant reduction in power generation cost. Commissioning of the first ABWR-II is foreseen in the late 2010s. Also in Japan, the basic design of a 1530 MWe advanced PWR has been completed by Mitsubishi Heavy Industries and Westinghouse for the Japan Atomic Power Company’s Tsuruga-3 and -4 units.

In the Republic of Korea, the benefits of standardization and construction in series are also being realized with the 1000 MWe Korean Standard Nuclear Plant (KSNP). The first two KSNPs, Ulchin 3 and 4, have been in commercial operation
since 1998 and 1999, respectively, and four more units (Yonggwang 5 and 6 and Ulchin 5 and 6) were under construction in 2001, with Yonggwang 5 and 6 scheduled to begin commercial operation in 2002. In addition, ROK is developing the Korean Next Generation Reactor, now named the Advanced Power Reactor 1400 (APR- 1400), which is focusing on improving availability and reducing costs. It has received design certification and is expected to be constructed by 2010.

In the Russian Federation, efforts continue on evolutionary versions of the currently operating WWER-1000 (V-320) plants. This includes the WWER-1000 (V — 392) design, of which two units are planned at the Novovoronezh site, and WWER — 1000 units are also planned in China, India and the Islamic Republic of Iran. Development of a WWER-1500 design has been initiated. Development is also ongoing on a mid-size WWER-640 with passive safety systems, and on an integral design with the steam generator system inside the reactor pressure vessel.

In China, the China National Nuclear Corporation (CNNC) is developing the CNP-1000 plant. China is pursuing self-reliance both in designing the plant to meet Chinese safety requirements, and in fostering local equipment manufacture with the objective of reducing construction and operation costs. Lessons learned from the design, construction and operation of the Qinshan and Daya Bay NPPs are being incorporated. Two ABWRs are under construction in Taiwan.