A method for monitoring radiation damage irradiations using the change of the electrical conductivity of graphite is described. Results of monitoring operations in a number of locations are given. An attempt is made to explain the damage rate found in the converter at CP-3. An estimate of the flux spectrum in VT-4 and the converter of CP-3 is made and the damage rate is computed according to theories of Seitz and James. It is found that the experimental results are more in accord with the predictions of Seitz. A number of corrections to James' report, ORNL-307, are noted in an appendix. It is shown that some information about the fast flux spectrum can be inferred from the radiation damage rate.

Experiments are described in which the pile-induced changes in electrical resistivity and elastic modulus of graphite were investigated as functions of the sample temperature during bombardment and the amount of bombardment. The data are for relatively low bombardment times (up to ca. 20 L-units) and temperatures (up to 340*C) and are not sufficiently extensive to permit unequivocal conclusions.