Used fuel

There are 22 CANDU[31] (CANada Deuterium-Uranium) power reactors in Canada owned by three provincial electric utilities. Ontario Power Genera­tion Inc. (OPG) owns 20 reactors (eight of which are leased to Bruce Power Inc. for commercial electricity production), while Hydro-Quebec (HQ) and New Brunswick Power (NBP) each own one reactor. All CANDU® fuel bundles are fabricated from natural uranium oxide pellets, contained in a zirconium-alloy (Zircaloy-4) sheath. The weight of a nominal bundle is 23.6 kg, of which 21.3 kg is due to the uranium oxide, approximately 19.2 kg can be attributed to the uranium (without the oxygen component). Each year, 4,500-5,400 used fuel bundles are generated per reactor, based on 80-95% full power reactor operation (CNSC, 2008). A 600MW CANDU® nuclear reactor produces approximately 20 m3 of used nuclear fuel per year.

Nuclear fuel wastes from nuclear power generating stations are stored in wet and dry states at the locations where they are generated. The used fuel

is first placed in water-filled fuel storage bays, and after several years (i. e., six to ten years) the used fuel can be transferred to an on-site dry storage facility. These dry storage facilities are large, reinforced concrete cylinders or containers. Each nuclear power generating station in Canada has enough storage space to store all the used fuel produced during the operating life of the station.

Following a decade-long environmental assessment of a deep geological disposal concept for nuclear fuel waste that ended in 1998, the Government of Canada passed the NFWA in 2002, which made owners of nuclear fuel waste responsible for the development of long-term waste management approaches. Shortly after the NFWA came into force, the nuclear energy corporations, OPG, HQ and NBP, established the NWMO and each waste owner established trust funds to finance the implementation of long-term waste management activities. The NWMO’s mandate is to explore options for the long-term management of Canada ’s nuclear fuel waste, provide proposals to the Government of Canada and to implement the selected approach.

Following extensive studies and public consultation, the NWMO pre­sented four options, including those listed in the NFWA, namely long-term storage at the reactor sites, central shallow or below ground storage, deep geological disposal, and lastly an option called the adaptive phased manage­ment (APM) approach (NWMO, 2005). The APM approach essentially combines the three above listed options within a flexible adaptive manage­ment decision-making process. In 2007, the Government of Canada announced that it had selected the APM approach for the long-term man­agement of used fuel in Canada. With this government decision, NWMO assumed responsibility for implementing the APM approach (NWMO, www. nwmo. ca).