The Future of Radiological Protection


A Study for Dose Impact of MCR Operators in Nuclear Power Plants Under ICRP 30 and ICRP 60

Author(s): Seung-Chan Lee
( Korea Hydro Nuclear Power Co., KHNP-CRI)



Impact evaluation on tritium in Korean heavy water reactor was performed. The purpose of this study is to find the dose suitability for Tritium, Iodine, Xe and Kr. Another purpose is to find the contribution of Tritium during NPP operator's dose in Main Control Room of Design Basic Accident of NPP.

In this study, DCF (Dose Conversion Factor) is ICRP 30 and ICRP 60. From this condition, some sensitivity analysis is carried out by simulation code RADTRAD 3.03 and ARCON96. These codes are approved from US NRC for the safety analysis of Nuclear Power Plants. Analysis condition is under considering the core coolant pipe break of Heavy Water Reactor.
In order to recover the NPP state, some operator operation is carried out by the signal of DBA.

In this moment, the operators reside in MCR (Main Control Room) against the DBA to response the NPP States. RADTRAD 3.03 simulates the accident of NPP and ARCON96 simulates the diffusion of fission products. MCR operator's dose effects are different between ICRP 30 and ICRP 60.

Noble gas is reduced in dose calculation and Tritium contribution is very small in dose effects. In the effect of tritium, it had an effect of less than 1% comparing with external dose and less than 2% comparing with internal dose. In this study, every calculation is carried out by assumption of no deposition of fission products on the wall surface, pipe and concrete. This conservation increase the TEDE of Tritium, Noble gas (Xe and Kr) and Iodine.
Otherwise, in condition of deposition coefficient 0.01, RADTRAD's calculation results make 5~10% reduction of TEDE. In ICRP 60, I suggest that ICRP60's radio nuclides deposition should be studied in concrete material, metal pipe material, structure material and so on. Exact deposition coefficient allow the accurate and optimized TEDE dose calculations to be performed.

Keywords: ICRP 30; ICRP 60; TEDE; ARCON96; RADTRAD