MOX requirements advance fast reactor plans

18 October 2007

Requirements for mixed-oxide (MOX) nuclear fuel in Russia have been approved by the regulator, Rostechnadzor. It is Russia's goal to use the MOX fuel in fast breeder reactors able to destroy plutonium from dismantled weapons and re-use materials from used nuclear fuel.

Rostechnadzor's documentation sets out the standards MOX fuel assemblies must meet in terms of thermal and mechanical stresses and resistance to effects of radiation. The fuel rods must withstand these potentially damaging forces lest they degrade to the point where heat from the highly-radioactive fuel inside could not be safely removed.

One driving force for the use of MOX is the strategic approach Russia has taken to close its nuclear fuel cycle in the long term, which assumes the recycling of plutonium. The other is an agreement Russia made with the USA in 2000 which said both sides must convert 34 tonnes of plutonium from nuclear weapons into fuel for power reactors by 2014.

The USA is doing this at the Savannah River site, where a MOX fuel manufacturing plant is under construction. Four test MOX assemblies made in France are already in use at the Catawba 1 PWR.

However, Russia does not intends to use MOX widely in its PWR fleet and would prefer to load it instead in the prototype of the fast breeder reactor (FBR) family it hopes to use widely in coming decades.

One FBR already operates at Beloyarsk (unit 3), supplying 560 MWe to the grid, while Beloyarsk 4 is under contruction now. This 800 MWe FBR should operate from 2012 and is planned to use all 34 tonnes of weapons plutonium during its life, even if not by 2014. Other stocks of plutonium have already been separated from previously used nuclear fuel.

Future plans envisage an 1600 MWe unit which should be economically competitive with conventional water-cooled reactors from operation in 2020.

Fifteen test MOX fuel assemblies are currently in use within the core of Beloyarsk 3, where they will stay until 2009. These were produced using a vibro-packing method developed by Research Institute of Atomic Reactors (NIIAR). Uranium/plutonium feed for the test assemblies was prepared by the Mining and Chemical Combine (MCC).

If post-use tests verify the vibro-packing technique it is expected that NIIAR and MCC would create a production line capable of producing 50 MOX assemblies per year exclusively for use in Beloyarsk 4.

Further information

WNA's Nuclear Power in Russia information paper
WNA's Mixed Oxide (MOX) information paper