THE ESTIMATION OF SOURCE-TERM AND INTRODUCTION OF COUNTERMEASURES BASED ON DOMINANT CONDITIONS OF ACCIDENT PROGRESSION

A number of severe accident analyses for a reactor unit using VVER-440 /V213 have been performed to evaluate the source term and radiological consequences. As a tool for these analyses the STCP-M (for VVER modif ied version of Source Term Code Package) and RTARC (Real Time Accident Release Consequences) codes have been used. A set of emergency proced ures manuals for quick estimation of the source term and countermeasur es introduction during the early phase of severe accident progression have been developed at NPPRI. These manuals are based on the results o f the 54 analysed sequences, which connect known dominant conditions o f accident progression with potential leakage of the radionuclides int o the environment. Emergency procedures manuals have been elaborated f or the Crisis Centre of the Slovak Regulatory Authority and can be uti lised manually and/or on a computer with such a program module. The ma nuals have been tested and verified during several emergency drills in the Crisis Centre and are subdivided into three groups: (1) evaluatio n of the bariers integrity, (2) source term estimation and (3) estimat ion of the distances for the: countermeasures introduction. The method ology introduced above and the methods of applying the emergency proce dures are described.