Effects of Neutron Irradiation on Physical and Mechanical Properties of SM1-24 and IG-11 Graphites. Report on JAERI/KFA Juelich Graphite Irradiation Experiment HFR GG14

摘要

Results of the neutron irradiation tests of near-isotropic graphites (SM1-24 and IG-11) for HTGR with HFR in Petten through KFA Juelich are described, together with those of the preirradiation tests which were performed in JAERI and KFA. Irradiations were made to a maximum of about 2.5 x 10 exp 21 n/cm exp 2 (EDN) at temperatures from 1050 exp 0 C to 1150 exp 0 C. Measured were dimensional change, Young's modulus, thermal expansion coefficient up to 1000 exp 0 C, apparent density, electrical resistivity at room temperature, open porosity, thermal conductivity, and electrical resistivity between 100 to about 1000 exp 0 C, and ring compressive strength (for IG-11). 1) Dimensional change of IG-11 by high temperature irradiation was similar to that of 7477PT graphite irradiated in JMTR under same condition as HFR. Dimensional change of SM1-24 was the same as those obtained in JAERI and other institutes. 2) Increase in the Young's modulus was about 30% - 40% for both graphites. 3) Thermal expansivity of IG-11 graphite was not much changed by irradiation. 4) The increase in apparent density was about 2% in IG-11 and about 3% in SM1-24. 5) The decrease in thermal conductivity by irradiation at 1100 exp 0 C was not as large as expected, especially in SM1-24. 6) The increases in strength were about 15% for the large and about 30% for the small ring specimens. (Atomindex citation 11:524933)