Neutron Irradiation Damage in Graphite and Its Effectson Properties

摘要

Neutron irradiation is known to markedly influence the structure and properties of nucleargraphite. Here we review the mechanism of neutron damage and discuss its effect on the structure andproperties of graphite. The results of recent irradiation experiments (HTN series capsules) on H-451graphite are reviewed and contrasted with existing data. The graphite was irradiated in the High FluxIsotope Reactor at Oak Ridge National Laboratory (ORNL) to high dose at irradiation temperatures of 600and 900 ℃. The peak doses attained were 3.8 x 10 22 n/cm 2 [E>50 keV] and 2.2 x 10 22 n/cm 2 [E>50 keV] atirradiation temperatures of 600 and 900 ℃, respectively. At these doses the graphite has passed throughvolume shrinkage turnaround into swelling and exceeded its original dimensions. Here, data for thedimensional, strength, and modulus changes are reported and discussed in terms of the structural changesthat occur in the graphite at high neutron doses.