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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.
Mojtaba Taherzadeh, Peter J. Gingo
Nuclear Technology | Volume 15 | Number 3 | September 1972 | Pages 396-410
Technical Paper | Fuel | doi.org/10.13182/NT72-A16037
Articles are hosted by Taylor and Francis Online.
The major sources of neutrons from plutonium dioxide nuclear fuel are considered in detail. These sources include spontaneous fission of several of the plutonium isotopes, (α,n) reactions with low Z impurities in the fuel, and (α,n) reactions with 180. For spontaneous fission neutrons a value of (1.95 ± 0.07) × 103 n/sec/g PuO2 is used. The neutron yield from (α,n) reactions with oxygen is calculated by integrating the reaction rate equation over all alpha-particle energies and all centerofmass angles. The results indicate a neutron emission rate of (1.14 ± 0.26) × 104 n/sec/g PuO2. The neutron yield from (α,n) reactions with low Z impurities in the fuel is presented in tabular form for 1 ppm of each impurity. The total neutron yield due to the combined effects of all the impurities depends on the fractional weight concentration of each impurity. The total neutron flux emitted from a particular fuel geometry is estimated by adding the neutron yield due to the induced fission to the other neutron sources.