Preliminary study of derivation and suitableness of default values OIL1 and OIL2 recommended by IAEA for PWR accidents

This paper introduces the definition of operational intervention level (OIL) and the derived process of default values of OILs recommended by IAEA. Then this paper focused on the reasonableness of two parameters, R1(ratio of dose rate from inhalation to ambient dose rate) and R2 (ratio of thyroid dose rate to ambient dose rate from inhalation of iodine), which is assumed in derived process of default OIL1 and OIL2 for PWR reactor accidents. For the source terms of PWR accidents described in WASH-1400 and France severe accident, the average values of R1 and R2 in the same accident series derived by the calculating program of Inter RAS are close to the presumptive values. The results also indicated the rationalization of the default OIL1 and OIL2. The impact of meteorological conditions and distance on values of R1 and R2 is smaller than accident source terms (The ratio of the maximum to minimum of R1 and R2 at different distances in accident of PWR1-PWR7 equals to two approximately; The deviation to default values of R1 and R2 recommended by IAEA is about fifty percent in different meteorological conditions in accident of PWR1-PWR6). So the default OILs should be corrected or recalculated during a real accident. (authors)