1. Proceedings
  2. I3M
  3. 2021
  4. MAS
  5. 10.46354/i3m.2021.mas.009

SURET calculation of a new type of nuclear fuel assembly having spacer grid with mixing vane

  • a Áron Vécsi , 
  • b Gábor Házi
  • a,b Centre for Energy Research, Konkoly-Thege M. Street 29-33., Budapest, HU-1121, Hungary
Cite as
Vécsi A., Házi G. (2021). SURET calculation of a new type of nuclear fuel assembly having spacer grid with mixing vane. Proceedings of the 20th International Conference on Modeling & Applied Simulation (MAS 2021), pp. 72-76. DOI: https://doi.org/10.46354/i3m.2021.mas.009

Abstract

A new type of fuel assembly will be introduced at Paks Nuclear Power Plant in order to improve its fuel economy. The new fuel rods and its cladding are thinner than the ones used now and some of the spacer grids will be supplemented by mixing vanes to intensify the mixing in the assembly. Before starting a new fuel cycle with the new design, subchannel calculations have to be carried out to prove that the application of the new fuel will not result in the violation of operational limits during the fuel cycle.
To simulate the behavior of mixing vanes we used our SURET (SUbchannel REactor Thermohydraulics) subchannel analysis code, which has been developed based on COBRA 3c (Rowe, 1973). SURET differs from COBRA by the solution of the energy equation and it makes it possible to locally modify the resistance factors of the spacer grids to model the mixing vanes.
SURET input file has been created to the new fuel design and benchmark calculations have been carried out to prove that SURET is able to provide reasonably accurate solutions for the new geometry. Calculations were verified by separate effect tests and validated by comparing its results with the ones obtained by CFD calculations. In this paper we demonstrate that the calculation results of SURET follow reasonably well the temperature field calculated by CFD.
SURET has been also developed for online calculations applying more advanced algorithms for matrix inversion and optimizing the inner calculations. With these changes, we could reduce the running time from minutes to less than 2 seconds.

References

  1. OK “Gidropressz” (2018). “Second generation VVER-440 assembly with optimized water-uranium ratio” Második generációs VVER-440 kazetta együttes optimalizált víz-urán aránnyal. 463.10 D7, 2018. 07.
  2. Rowe, D.S. (1973). COBRA IIIC: digital computer program for steady state and transient thermal-hydraulic analysis of rod bundle nuclear fuel elements. Battelle, United States, March 1973.
  3. Zsíros, G., Dr. Tóth, S. (2018). “Thermohydraulic investigation of VVER-440 assembly supplemented by mixing vane” Keverőfüles távtartóráccsal szerelt VVER-440 köteg termohidraulikai vizsgálata. BME NTI-872/2018. 2018. 12. 01.