2007 International RERTR Meeting

Abstracts and Available Papers Presented at the Meeting

Investigation of Approximations in Thermal- Hydraulic Modeling of Core Conversions

Patrick L. Garner and Nelson A. Hanan
Nuclear Engineering Division, Argonne National Laboratory
9700 South Cass Avenue, Building 208, Argonne, Illinois, 60439, USA

ABSTRACT

Neutronics analyses for core conversions are usually fairly detailed, for example representing all 4 flats and all 4 corners of all 6 tubes of all 20 IRT-3M or -4M fuel assemblies in the core of the VVR-SM reactor in Uzbekistan. The coupled neutronics and thermal-hydraulic analysis for safety analysis transients is usually less detailed, for example modeling only a hot and an average fuel plate and the associated coolant. Several of the approximations have been studied using the RELAP5 and PARET computer codes in order to provide assurance that the lack of full detail is not important to the safety analysis. Two specific cases studied are (1) representation of a core of sametype fuel assemblies by a hot and an average assembly each having multiple channels as well as by merely a hot and average channel and (2) modeling a core containing multiple fuel types as the sum of fractional core models for each fuel type.

 

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