The development of accidental neutron dose assessment method by radioactive analysis

This study was carried out as a step of the personal monitoring program for the rapid and correct assessment of exposure dose in case of probable accident in the research reactor and, if necessary, for the preparation of the basic data for the first-aid medical treatment of an accidentally exposed person. At the possible location for neutron over exposure (TRIGA MK-III T2 Experimental Hole), the neutron spectra were calculated from the radioactivation technique of multiple foils and the radioactivity of Na-24 in the blood serum was measured after neutron irradiation. The neutron and the gamma exposure dose were measured by using the TLDs at the same location and the dose conversion factor was determined from the relation between the specific radioactivity of Na-24 in the blood and the neutron exposure dose. The Na content in the blood of an average Korean was 1.85 mg/ml and that of blood sample irradiated in this experiment appeared to be 1.83 mg/ml. The dose conversion factor was determined to be 0.6566 [Sv mg-23Na/Bq-24Na] for the calculation of neutron exposure dese. On the condition of the 1.5 MW operation and the 1 hr irradiation, the ratio of neutron to gamma dose within the T2 experimental hole was found to be about 4 and the total exposure dose measured 0.56 Sv. (author)