The estimation on the dose reduction effects due to the replacement of stellite materials

The Korean nuclear power plants(KNPPs) have been remarkably successful in reducing workers radiation exposures over the past thirteen years. Despite this dose reduction, challenges for the nuclear power plants remain. Also the individual exposure limits have been tightened in ICRP-60 and there will be increased requirements for special maintenance work as plants age. So the vigorous efforts will be required to meet the goals at nuclear power plants. The replacements of stellite materials to low or free cobalt materials offer the best opportunity of continuing the downward in occupational radiation exposure