Previously the target was about 35 nuclear reactors. Seven reactors are under construction and 31 are operating.
The basic requirements [target goals] for fuel have been set as: fuel operational lifetime extended to 6 years, improved burn-up of 70 GWd/tU, and improved fuel reliability. In addition, many nuclear plants will need to be used in load-following mode, and fuel which performs well under variable load conditions will be required.
A major current emphasis is the improvement in operation of present reactors with better fuels and greater efficiency in their use, closing much of the gap between Western and Russian performance. Fuel developments include the use of burnable poisons – gadolinium and erbium, as well as structural changes to the fuel assemblies.
With uranium-gadolinium fuel and structural changes, VVER-1000 fuel has been pushed out to 4-year endurance and VVER-440 fuel even longer. For VVER-1000, five years is envisaged by 2010, with enrichment levels increasing nearly by one third (from 3.77% to 4.87%) in that time, average burn-up going up by 40% (to 57.7 GWd/t) and operating costs dropping by 5%. With a 3 x 18 month operating cycle, burn-up would be lower (51.3 GWd/t) but load factor could increase to 87%. Comparable improvements were envisaged for later-model VVER-440 units.
Russia is the current world leader with fast neutron reactors.
The Russian BN-600 fast breeder reactor has been supplying electricity to the grid since 1981 and has the best operating and production record of all Russia’s nuclear power units. It uses uranium oxide fuel and the sodium coolant delivers 550°C at little more than atmospheric pressure. The BN 350 FBR operated in Kazakhstan for 27 years and about half of its output was used for water desalination. Russia plans to reconfigure the BN-600 to burn the plutonium from its military stockpiles.
Construction has started at Beloyarsk on the first BN-800 [it was refunded and work is expected to complete in 2012], a new larger (880 MWe) FBR from OKBM with improved features including fuel flexibility – U+Pu nitride, MOX, or metal, and with breeding ratio up to 1.3. It has much enhanced safety and improved economy – operating cost is expected to be only 15% more than VVER. It is capable of burning 2 tonnes of plutonium per year from dismantled weapons and will test the recycling of minor actinides in the fuel.
Another russian design is the BREST fast neutron reactor, of 300 MWe or more with lead as the primary coolant, at 540C, and supercritical steam generators. A pilot unit is planned for Beloyarsk and 1200 MWe units are proposed.
FRANCE UPRATING ALMOST ALL OF ITS REACTORS
EdF uprated its four Chooz and Civaux N4 reactors from 1455 to 1500 MWe each in 2003. Over 2008-10 EdF plans to uprate five of its 900 MWe reactors by 3%. Then in 2007 EdF announced that the twenty 1300 MWe reactors would be uprated some 7% from 2015, within existing licence limits, and adding about 15 TWh/yr to output.
FRANCE ALSO EXTENDING NUCLEAR PLANT OPERATING LIFE
The 900 MWe reactors all had their lifetimes extended by ten years in 2002, after their second 10-yearly review. Most started up late 1970s to early 1980s, and they are reviewed together in a process that takes four months at each unit. A review of the 1300 MWe class followed and in October 2006 the regulatory authority cleared all 20 units for an extra ten years’ operation conditional upon minor modifications at their 20-year outages over 2005-14.