Mean Time to Failure of High Temperature Thermocouples in Irradiation Capsules

摘要

The results of calculations of the mean time before failure of thermocouples as a function of temperature and neutron flux are presented. These thermocouples were used in the performance of in-reactor tests of the coated particle fuel for use in high-temperture gas-cooled nuclear reactors. The results cover 429 type K chromel-alumel thermocouples tested in an atmosphere of helium and argon gas at temperatures of 300 to 1000 exp 0 C, at fast neutron (E greater than 0.18 MeV) fluxes of 1.44 x 10 exp 13 to 6.48 x 10 exp 14 , for periods up to 6000 hours.