Volume 3, Issue 9 (October 2006)
The Validity of the Use of Equivalent DIDO Nickel Dose for Graphite Dosimetry
Fast neutron dose recommendations for the graphite moderators of Magnox power plant are expressed in terms of Equivalent DIDO Nickel Dose (EDND). EDND is a calculated property that relates the damage rate in graphite at a given location to the fast neutron fluence experienced by graphite test samples irradiated in the DIDO reactor. This paper describes a study undertaken to determine the sensitivity of EDND recommendations to assumptions made in the modeling of neutron damage in graphite. These include different scattering cross sections and damage weighting functions. It is concluded that, although apparently significant differences exist between the available graphite damage response functions, their net effect is not significant in determining EDND. Therefore, confidence in past calculations has been improved and continued use of existing methods is supported.