Graphite permeability measurements at pressures up to 41 bars

Graphite permeability measurements made at AERE in support of the commercial AGR moderator corrosion studies have been made at and below 1 bar pressure. Doubts have been expressed regarding the validity of permeability coefficients, particularly A0 (the turbulent flow coefficient), measured at low pressure when applied to commercial AGR pressures. This paper describes permeability measurements made in a simple apparatus operated at pressures up to 41 bars in carbon dioxide. The results obtained are compared with those derived from the conventional low pressure method. Within a factor of approximately 2, B0 (the viscous flow coefficient) remained constant for all the specimens examined over the whole pressure range of 1 to 41 bars. In all cases, A0 showed a decrease with increasing pressure from 1 to 20 bars but thereafter the coefficient remained effectively constant at pressures up to 41 bars. These figures are similar to those previously reported. (U.K.)