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Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
J. P. Stora
Nuclear Technology | Volume 17 | Number 3 | March 1973 | Pages 225-233
Technical Paper | Material | doi.org/10.13182/NT73-A31266
Articles are hosted by Taylor and Francis Online.
A survey has been made of equations for calculating the thermal conductivity of two-phase solid bodies based on Ohm’s law and the flux laws. Most of these equations can be reduced to the Fricke relationship for a two-phase medium containing the second phase as randomly distributed ellipsoids. Fricke’s relationship is applied to porous uranium dioxide and to cermets UO2-metal with a structural orientation. First of all, in the case of UO2, Loeb’s formula based on Ohm’s law is considered. Although physically inadequate, this formula is easily handled and used by almost all of the investigators: the thermal conductivity of UO2 is corrected by introducing an empirical factor a multiplying the whole porosity of the oxide; a is generally determined by experimental measurements. The most probable value for α is 2.3 ± 0.5. By using the Fricke equation the a factor is justified and calculated. Second, the thermal conductivity of UO2-Fe, and UO2-Ni, containing 10, 20, and 30% metal by weight, is calculated, according to the parallel and perpendicular directions of “metallic veins,” using the Fricke mixture equation. Finally. the calculated values are compared with the experimental thermal dif-fusivity data measured along the two previous directions. The Fricke two-phase equation is found not to agree experimentally, especially at low temperatures. This discrepancy is probably due to the insufficiently precise mathematical formulation.
