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Title: Effects of fast-neutron irradiation on sheathed Chromel/Alumel thermocouples

Technical Report ·
DOI:https://doi.org/10.2172/7267723· OSTI ID:7267723

Stainless steel sheathed, magnesium oxide insulated, Chromel-P/Alumel thermocouples were tested by irradiation in the EBR-II reactor to determine their suitability for use in the Fast Test Reactor at the Hanford Engineering Development Laboratory. After exposure to high temperature (1200/sup 0/F) and fast-flux irradiation (2 x 10/sup 22/ nvt) in the reactor, there were small changes in the thermocouple characteristics. The measured error of these thermocouples was 2 percent at 1200/sup 0/F. Thermoelectric inhomogeneities were generated in the Chromel and Alumel wires in opposite polarities with respect to unirradiated wires. These inhomogeneities were annealed at temperatures above 900/sup 0/F. The outer diameter of the sheath increased no more than 1.2 percent. Irradiated thermocouples can be expected to perform satisfactorily in this environment and would survive many thermal cycles such as might occur in a reactor scram.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
US Energy Research and Development Administration (ERDA)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
7267723
Report Number(s):
ORNL/TM-3803
Country of Publication:
United States
Language:
English