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Swiss nuclear power and the case for long-term operation
Designed for 40 years but built to last far longer, Switzerland’s nuclear power plants have all entered long-term operation. Yet age alone says little about safety or performance. Through continuous upgrades, strict regulatory oversight, and extensive aging management, the country’s reactors are being prepared for decades of continued operation, in line with international practice.
D. L. Smith
Nuclear Technology | Volume 20 | Number 3 | December 1973 | Pages 190-199
Technical Paper | Fuel | doi.org/10.13182/NT73-A31357
Articles are hosted by Taylor and Francis Online.
The oxygen concentration of sodium in equilibrium with uranium-25% plutonium oxide fuel has been measured at temperatures of 650 to 900°C for fuels with oxygen-to-metal ratios of 1.90, 1.94, and 1.97. The oxygen concentration in sodium at the three-phase Na-MO2-x-Na3MO4 (M = uranium plus plutonium) equilibrium has also been measured for the same temperature range. This three-phase equilibrium was established by reacting mixed-oxide fuel with sodium to which Na2O had been added. The oxygen concentrations in sodium were determined by the vanadium-wire equilibration method. The oxygen concentration in sodium at the three-phase equilibrium varied from ∼0.1 to 0.4 ppm in the temperature range investigated. Oxygen concentrations in EBR-II primary sodium, which have been measured by the same method, vary from 0.4 to 0.9 ppm oxygen depending on the cold-trap operation. These values indicate that the sodium -fuel reaction product, i.e., Na3MO4, is stable in sodium at the temperatures (<1000°C) and oxygen levels present in EBR -II.
