The development of VVER-440 core models for supporting of information and analytic center
Information and analytic center (IAC) was created for the purpose of emergency response at Rostechnadzor. Working groups, which also include staff from SEC NRS, operate at IAC of Rostechnadzor. The tasks of these groups are state assessment of NPP units during the accident and accident development prediction.
It is necessary to determine efficiency of reactivity control rods and reactivity coefficients at the current moment of campaign for the models for the rapid assessment in case of severe accident or during the emergency training. Determine the efficiency of reactivity control rods requires in case of re-criticality.
That report is dedicated to the development of the core models of NPP with VVER-440 units for current campaigns.
These models are intended for the purpose of IAC to perform reactor core neutron-physical characteristics calculation for the models for the rapid assessment and for NPP with VVER-440 type units licensing.
VVER-440 core models will be used at IAC in case of the accident or during the emergency response training in the following way:
- obtaining necessary information about energy-producing of the accident unit from the operation organization (in effective full power days); it’s necessary to transmit the calculated values of fuel assembly’s energy-production in the core at the basis of regular operation of IAC;
- performing calculation of current campaign from the beginning until the beginning of the accident using DESNA code; determination efficiency of reactivity control rods and reactivity coefficients at the current moment of campaign in order to use it in models for the rapid assessment of critical safety functions` status; determination burnup arrays that can be used for three-dimensional fields of radionuclides determination in the core for the fast-running fission product release model.
These developed models will be coupled with models for the rapid assessment of critical safety functions` status in case of reactivity accident simulation, that requires three-dimensional core model.
Verification of developed models was carried out by comparison the DESNA code calculation results with project calculation results. Verification shown, that developed models are correct.
The DESNA code calculation results and the verification results are given in the report.Full version (russian)