Validation of WWER-440/213 Thermohydraulic Model for TRACE Computer Code Based on RNPP-1 Incident Data

This paper describes the main steps and results of preparing WWER-440/213 model for TRACE system thermohydraulic code to be used in further deterministic analysis calculations. As the basis for developing the model, the previously developed RELAP5/Mod.3.2 input deck was used. As a first step, the thermohydraulic components of input deck were automatically converted to TRACE format using SNAP utility. Then, necessary manual adjustments and additions were implemented to incorporate the safeguards actuation logic and operation of various plant controllers into the model. A set of validation calculations was performed for various transients (abnormal operation events) that had actually occurred at Rivne NPP Unit 1 to confirm that the TRACE model is capable of reproducing adequately the response of nuclear power plant with WWER-440/213 reactor. The results for one of validation calculations (Loss of normal power supply with reactor scram and additional failures) are provided as an example. Comparison of calculation results with plant measured data demonstrate acceptable agreement for the main plant parameters. To extend the scope of model validation, the cross-code comparison between TRACE and RELAP5 results is planned to be performed for a number of representative design-basis accident scenarios. (author)