Determination of dose and temperature in graphite irradiation experiments in the dounreay fast reactor

Abstract

Listen

Translate article

Two graphite irradiation experiments have been performed in a pitch 30 position of the Dounreay Fast Reactor core. The changes in dimensions and thermal conductivity of the graphite in these experiments have been correlated with similar changes produced by irradiations in the Harwell Reactor Dido at known temperatures. This allows the determination of the relation between the damaging power of the neutron spectrum in this D.F.R. position with that of the Dido spectrum. The relation is expressed in terms of the fast-neutron flux in the two reactors, using the reaction 58Ni (n, p) 58Co. To produce the same state of damage in graphite, the fast-neutron dose required in Didois about twice that in the D.F.R. position investigated. In the D.F.R. experiments silicon carbide specimens were included with the object of estimating irradiation temperatures. It is concluded, from the results of measurements made on these specimens and from a comparison of D.F.R. and dido data, that an equivalent temperature correction is necessary for dimensional changes over the full range of temperatures covered by the D.F.R. experiments. It cannot be concluded whether a similar correction is necessary for thermal conductivity changes for D.F.R. irradiation temperatures above 600°C.