Candu technology is to be developed in Ukraine, following a memorandum of understanding (MoU) between Ukraine's Ministry of Fuels and Energy and Atomic Energy of Canada Ltd (AECL). Victor Yushchenko, President of Ukraine, witnessed the signing in Toronto.
Uranium oxide powder, fuel pellets and
a Candu fuel bundle (Image: Cameco)
The MoU serves as a framework for collaboration on the technical and economic feasibility of a Candu nuclear power program in Ukraine, and sets out the process for commercial implementation. The feasibility study will be conducted jointly by AECL and the Ukrainian government and is to be completed within four months.
The introduction of Candu reactors could provide synergies with the existing Ukrainian VVER pressurized water reactors (PWRs) by burning uranium recovered from nuclear fuel already used in the VVERs. Such recycled uranium has fissile content similar to natural uranium and can be directly used in Candu reactors.
A Dupic explanation?
The technology development possibly being picked up in Ukraine is known as Dupic (Direct Use of spent PWR fuel In Candu reactors). The Dupic fuel cycle involves taking used nuclear fuel from light water reactors such as PWRs, crushing it, heating it in oxygen to remove some 40% of the fission products, and re-forming it into fuel pressurized heavy water reactors (PHWRs) such as Candu models. The fissile content of the fuel is about 1.5% - more than double that of natural uranium usually used for today's PHWR units.
Candu technology therefore offers the unique option of uranium recycling without re-enrichment. Twice the energy can also be extracted from burning LWR-recycled plutonium in a Candu reactor, compared to using an LWR.
About half of Ukraine's electricity is generated by its 15 VVER (PWR) reactors and these would provide a substantial flow of used fuel - some 400 tonnes per year - sufficient for perhaps two Candu units. The Ukrainian government said it sees the prospect of improving its energy and ecological security through the development of Candu nuclear technology.
Canada, which developed the Candu reactor, and South Korea, which hosts four Candu units as well as many PWRs, have initiated a bilateral joint research program to develop Dupic and the Korean Atomic Energy Research Institute (Kaeri) has been implementing a development program since 1992 to demonstrate the Dupic fuel cycle concept. Kaeri believes that although it is too early to commercialise the Dupic fuel cycle, the key technologies are in place for a practical demonstration of the technique.