Abstract
The paper presents the results of an experimental study to investigate the coolant interaction in adjoining fuel assemblies in the VVER reactor core composed of TVSA-T and upgraded TVSA FAs. The processes of the in-core coolant flow were simulated in a test wind tunnel. The experiments were conducted using models representing different portions of the VVER reactor core fuel bundle and consisted in measuring the radial and axial airflow velocities in representative areas within the FAs and in the interassembly space. The results of the experiments can be translated to the full-scale conditions of the coolant flow with the use of the fluid dynamics simulation theory. The measurements were performed using a five-channel pressure-tube probe. The coolant flow pattern in different portions of the fuel bundle is represented by distribution diagrams and distribution maps for the radial and axial velocity vector components in the representative areas of the models. An analysis for the spatial distribution of the radial and axial velocity vector components has made it possible to obtain a detailed pattern of the coolant flow about the FA spacer, mixing and combined spacer grids of different designs. The accumulated database for the coolant flow in FAs of different designs forms the basis for the engineering justification of the VVER reactor core reliability and serviceability. The investigation results for the coolant interaction in adjoining TVSA FAs of different designs have been adopted for the practical use at JSC Afrikantov OKBM to estimate the heat-engineering reliability of the VVER reactor cores and have been included in the database for verification of computational fluid dynamics (CFD) codes and detailed by-channel calculation codes.
Highlights
The VVER reactor core at unit 2 of the Temelin NPP has been partially refueled (Dmitriyev et al 2013b) with fuel assemblies of a new modification loaded as the replacement of the standard TVSA-T FAs
Both fuel assembly designs were developed by JSC Afrikantov OKBM
As compared with the TVSA-T fuel assemblies, the key distinction of the upgraded TVSA assembly (TVSAU hereinafter) is the use of separately installed mixing grids (MG) which ensure that the coolant mixes more intensively across the assembly, leading so to an improved performance of the new FA (Borodin et al 2006, Samoylov et al 2004, 2005, 2010, 2014, Dmitriyev et al 2012a, b, 2013a, 2014b, 2017)
Summary
The VVER reactor core at unit 2 of the Temelin NPP has been partially refueled (Dmitriyev et al 2013b) with fuel assemblies of a new modification loaded as the replacement of the standard TVSA-T FAs. As compared with the TVSA-T fuel assemblies, the key distinction of the upgraded TVSA assembly (TVSAU hereinafter) is the use of separately installed mixing grids (MG) which ensure that the coolant mixes more intensively across the assembly, leading so to an improved performance of the new FA (Borodin et al 2006, Samoylov et al 2004, 2005, 2010, 2014, Dmitriyev et al 2012a, b, 2013a, 2014b, 2017). The sensor readings were taken using a SAPHIR-22R pressure transducer with the allowable base error limit of ± 0.25%
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
