Research Reactors Scientists employ research reactors to study the atomic properties of matter. When non-radioactive materials are bombarded by neutrons inside a reactor, they become radioactive, making high precision chemical analyses possible. Isotope Production Radioactive isotopes can be produced in abundance in research reactors; these are sold for use in medicine, industry and science. Canada is the world's largest supplier of molybdenum-99 and cobalt-60. In addition to the large research and isotope production reactors at Chalk River, several universities in Canada have their own research reactors. Food Irradiation In an effort to find new markets for isotopes, the Canadian nuclear industry intends to use gamma radiation from cobalt-60 to kill insects and microbes in spices, fruit, poultry, grain and other foodstuffs. The purpose is to prolong shelf-life. A similar technology is used to sterilize medical equipment. The irradiation process can create new chemical substances (radiolytic products) in the food, some of which are carcinogenic. As well, irradiation can eliminate or reduce vitamins and minerals, including vitamin A, thiamine, B2, B3, B6, B12, folic acid, C, E and amino acids. The loss can vary between 20 and 80 percent. The industry proposes that irradiated food be labeled inconspicuously to minimize consumer anxiety. District Heating Reactors Small reactors can provide hot water or steam to heat a group of buildings. At Whiteshell, a prototype district heating reactor was built but never licensed for full power operation. Two universities in Quebec and Saskatchewan refused offers of free district heating reactors. Canadian research on such reactors has since been suspended. Geologic Disposal At the Underground Research Laboratory in Manitoba, a shaft has been sunk 500 meters down into the hard rock of the Canadian Shield and underground chambers have been excavated. The aim is to explore the possibility of permanent burial of high level radioactive waste. The Government of Manitoba has outlawed the import of high level waste into Manitoba for the purpose of burial. High Level Liquid Radwastes Scientists at Whiteshell have studied the solidification of high level radioactive liquid waste left over from reprocessing spent nuclear fuel. Nuclear proponents expect that plutonium will be extracted from spent fuel before the waste is placed in geologic disposal. In that case, the liquid waste will have to be solidified. At Chalk River, there are six underground tanks of high level radioactive liquid waste left over from reprocessing in the 1950s. Some of this liquid waste was cast into glass blocks and buried in sandy soil near the Ottawa River. It was the world's first radwaste solidification pilot project. Plutonium Fuel Chalk River ran a pilot plutonium fuel fabrication line for years, planning for the day when plutonium fuel would be standard. These plans were given reduced priority when President Carter opposed reprocessing on global security grounds. Recently, President Clinton has adopted a similar point of view on reprocessing. But Canada still keeps the plutonium option open. In 1997, plutonium from dismantled nuclear bombs was approved for testing as reactor fuel at Chalk River.
Photo copyright Robert Del Tredici
|
