Safety Analyses of IRT- Sofia LEU Core: Sensitivity Analyses of Loss of Flow Accident

Sensitivity analyses (by the PARET/ANL code) of the loss of forced flow accident because of pump stop as a result of loss of the offsite electricity supply for the IRT - Sofia are presented in this paper. These analyses are carried out because the used hydro dynamic calculation evaluation for a period during which the downward coolant flow is slowing down and stopped has very wide tolerance (from 2 to 25 sec). According to the obtained results the relation between evaluated and allowed conditions of the fuel operation does not vary significantly in the analyzed limits. Moreover for all analyzed conditions the peak cladding temperature reached in this transient is below the temperature for onset of nucleate boiling (1170C) and far below the safety limit of 4250C for the fuel cladding temperature that is fully consistent with the conclusion from the IRT - Sofia SAR for this accident. (authors)