Haghighi shad - Ofough Consulting Engineers (Eng. Sec)-Boushehr
Sharifi - Amirkabir Univeristy (PHD, Nuclear Eng)

In this paper total Exposure effective dose caused by release of airborne radioactive material due to leakages with an equivalent diameter of 100 mm & more from the primary to the secondary Circuit is investigated. In this accident noble gases are released with a fraction of 98% into the containment’s atmosphere and from there with a volume fraction of 1% in to the neighboring environment . the radioactive doses are calculated by the AIRDOSE code. This program uses the Gaussian distribution model for contaminate dispersion. Hilsmeier-Gifford atmospheric dispersion parameters are used in this model . in addition a computer program named SIGHG for estimation of standard deviation in vertical & horizontall directions also a program for accident conditions was development Exposure’s of receptor from passage of Gamma rays radioactive cloud or the so called “air submersion & inhalation of radionuclides during this passage time are considered & also exposure from ground shine of radioactive material which deposited on the ground is considered as route’s of exposure. In this accident the maximum and minimum effective dose on the body, was calculated to accurse in West-South – West (WSW) and South – East (SE) sectors respectively. Dispersion coefficient of shore – time periods (urgent phase dose) is obtained from Hilsmeier – Gifford equations for an effective source height of 100m. the maximum & minimum . total Exposure effective dose received to member of the public is 5.1 & 3.8 m Sv in WSW sectors respectively. These values are in good agreement with result of DOZAM code [10]. The maximum concentration (x/O) is predicted to be 3.3e-5 sec/m3 & happen at a wind velocity of U=1m/s in the weather class A at a distance of 600m from the stack which is in good agreement with the amount of 3e-5sec/m3 reported in preliminary report on safety assurance (PSAR) for BNPP[1.10]

Dose assessment - Exposure - Loss of Coolant Accident , Total Effective Dose Equivalent (TEDE)-Release of Airborne Radioactive Material - Atmospheric Dispersion Model - Exposure pathway's