Time dependence of ESR signal of irradiated alanine dosimeter

It is very important to assess the cable which generally depending on environment conditions like temperature and radiation dose rate. Radiation level has been assessed by RHRI in cooperation with Wolsong Unit 1. and Youngkwang Unit 1. The assessment method of radiation level is that First, install alanine dosimeter at the location of interest in times of pre-scheduled maintenance period then, after one or two fuel cycles, retrieve and analyze the dosimeters by use of ESR dosimetric system. The Alanine dosimeter were installed 38 place at the Wolsong Unit 1 and 30 place and the Youngkwang Unit 1. Measurements of the ESR signal amplitude of γ-irradiated alanine has signal variations in the signal amplitude within days after irradiation. The characteristics of ESR signal, especially signal decreasing time and pattern, would be different on the ranges of dose quantity, but the range we are interested in is low dose range less then about 5Gy. In most case of dose assessing for measurement of cable aging, the dose range is very low, this study give us good information about proper measurement time after alanine dosimeter was taken out from NPP