National Research Universal Reactor
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The National Research Universal (NRU) reactor operated by Atomic Energy of Canada Limited is a research reactor that is still considered one of the world's finest for its versatility and high neutron flux. It produces about 60% of the world's supply of molybdenum-99, a critical isotope used for medical diagnoses, as well as other radioisotopes.
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[edit] History
The NRU reactor design was started in 1949 and it first went critical in 1957. Designed as a 200MWt reactor, it is licensed to operate at power levels of up to 135MWt. The reactor's large irradiation space has been an important factor in the testing of fuel bundles and fuel-channel components for CANDU reactors. The unit is used for research into reactor fuels, materials and components, and is the centre for neutron beam research in Canada. Originally designed for operation with natural uranium, NRU was converted to high-enriched uranium (HEU) in 1964 and converted yet again in 1991 to run on low-enriched uranium (LEU) fuel.
On 24 May 1958 the NRU suffered a major accident. A damaged uranium fuel rod caught fire and was torn in two as it was being removed from the core, due to inadequate cooling. The fire was extinguished, but not before releasing a sizeable quantity of radioactive combustion products that contaminated the interior of the reactor building and, to a lesser degree, an area of the surrounding laboratory site.
In 1996, AECL informed the Canadian Nuclear Safety Commission (then known as the Atomic Energy Control Board) that operation of the NRU reactor would not continue beyond December 31, 2005. It was expected that the Canadian Neutron Facility (CNF) would replace the research capability of NRU. However, the CNF is not ready to replace the NRU. In 2003, AECL advised the CNSC that they intended to continue operation of the NRU reactor beyond December 2005. The operating licence was initially extended to July 31, 2006, and a 63-month licence renewal was obtained in July 2006, allowing full operating of NRU until October 31, 2011. [1]
[edit] References
- ^ "CNSC Approves Renewal of AECL's Chalk River Site Operating Licence" AECL, July 31, 2006. URL accessed August 8, 2006.
