Russian nuclear fuel fabricator Tvel, part of the Russian State-owned Rosatom nuclear energy group, is offering Eskom its TVS-K type of nuclear fuel assembly. The South African national power utility operates two nuclear power reactors at its Koeberg power plant near Cape Town and is reported to be interested in diversifying its sources of nuclear fuel from 2021 onward. Indeed, it has been reported that Eskom would like to increase the number of its nuclear fuel suppliers to three, even four, and that Tvel is one of those under consideration.
According to Tvel, the TVS-K type fuel assembly has been developed from experience with Russian VVER reactors. VVERs are equivalent to pressurised water reactors (PWRs). Koeberg’s reactors are PWRs. Tvel’s designers also took into consideration the experiences of fuel assembly manufacturers in other countries.
Nuclear fuel, in the form of small hard uranium dioxide pellets, is put into long thin tubes manufactured from zirconium alloys, forming fuel rods. Fuel rods are then grouped together to form fuel assemblies. These assemblies possess strong frameworks to which are attached grid supports/spacers, which firmly hold and precisely align the fuel rods within the assembly. Each fuel assembly is several metres long and its structures are made from steel and zirconium.
Tvel states that the TVS-K fuel assembly is geometrically stable – that is, it keeps its shape and maintains the alignment of its fuel rods – during operation and that it does not suffer wear from fretting between the fuel rods and the grid supports/spacers. It also has high fuel effectiveness and can operate in flexible fuel cycles of varying durations. Its improved engineering and better operating characteristics ensure increased operating reliability and allow an increase in core power.
As the TVS-K is a new initiative by the Russian company, it is able to meet any specific design adaptations required by customers. It will also be able to adjust production to meet current and forecast market needs.
The company argues that, because it is part of the giant Rosatom group, which embraces all aspects of nuclear energy, it can provide significantly wider support to customers for the TVS-K fuel assemblies. This could include the return of spent TVS-K assemblies to Russia (eliminating the need for the customer country to process or store them). The enrichment of uranium could be another service that could be provided, if the customer desired. And there would also be the possibility of the customer being able to set up its own TVS-K fabrication plant and manufacture the fuel assemblies locally.
Actual manufacture of the TVS-K fuel assemblies is the responsibility of Tvel subsidiary company Mashinostroitelny Zavod (MSZ). This enterprise has been manufacturing fuel assemblies for 50 years and currently its fuel assemblies are operating in 57 commercial nuclear power reactors around the world – that is one in every eight of the world’s such reactors. Outside Russia, it has customers in Armenia, the Czech Republic, Finland, Germany, Hungary, the Netherlands, Slovakia, Sweden, Switzerland and Ukraine.
Tvel is an ISO 9001:2000-certified company and was set up in 1996 to improve the management of Russia’s nuclear fuel cycle business. In its 2012 annual report, it announced revenues of almost $3.93-billion and a net profit of $632- million. The company currently holds 17% of the global market for fuel for nuclear power reactors. It also supplies the fuel for 30 research reactors around the world. Its strategic objective is to secure 30% to 32% of the global front-end nuclear fuel cycle by 2030.