Development of 'Temporary standards for maximum permissible content of 134Cs and 137Cs in food products intended for population feeding' (April 1987)

After the Chernobyl accident a control over the radiation content in food products was established in Bulgaria. A mathematical model was developed for control level elaboration for the late phase of the accident when the main contamination factors were 134Cs and 137Cs. The effective equivalent dose (EED) absorbed by internal irradiation with contaminated food was determined. The individual body features, way of feeding and the extent of contamination of the food products are taken into consideration. The model is presented in a matrice form. The task of standartization consists in creating of such matrices of the control levels for radionuclide contents in different food products, in which the corresponding elements of EED to be equal or smaller of the elements of the matrices for corresponding dose limits of EED. Simplifying assumptions are made and some limiting conditions are determined: calculation of the dose coefficient at 26 April 1987, dividing of the whole population into 9 groups according to the age and the intensity of the physical labour, splitting of the food products in 18 classes, ration of feeding according to recomendation of the Ministry of Health (1980), supplemented by extrapolation for the group under 1 year, dose limit for all groups 2 mCw/y etc. The approximate solution is made by the help of software DOSA for multichannel analyzer IIV-90. The control levels determined in this way are given; they correspond to the annual dose from external irradiation when food products in the range of 1-4 mSw to 2.4 mSw have been consumed. 3 refs