Study of impact of the AP1000® reactor vessel upper internals design on fuel performance

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

11 Scopus Citations
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Author(s)

  • Yiban Xu
  • Michael Conner
  • Kun Yuan
  • Milorad B. Dzodzo
  • Zeses Karoutas
  • And 6 others
  • Steven A. Beltz
  • Sumit Ray
  • Teresa A. Bissett
  • Ching-Chang Chieng
  • Min-Tsung Kao
  • Chung-Yun Wu

Detail(s)

Original languageEnglish
Pages (from-to)128-134
Journal / PublicationNuclear Engineering and Design
Volume252
Publication statusPublished - Nov 2012
Externally publishedYes

Abstract

One aspect of the AP1000® 1 reactor design is the reduction in the number of major components and simplification in manufacturing. One design change relative to current Westinghouse reactors of similar size is the reduction in the number of reactor vessel outlet nozzles/hot legs leaving the upper plenum from three to two. With regard to fuel performance, this design difference creates a different flow field in the AP1000 reactor vessel upper plenum (the region above the core). The flow exiting core and entering the upper plenum must turn 90°, flow laterally through the upper plenum around support structures, and exit through one of the two outlet nozzles. While the flow in the top of the core is mostly axial, there is some lateral flow component as the core flow reacts to the flow field and pressure distribution in the upper plenum. The pressure distribution in the upper plenum varies laterally depending upon various factors including the proximity to the outlet nozzles. To determine how the lateral flow in the top of the AP1000 core compares to current Westinghouse reactors, a computational fluid dynamics (CFD) model of the flow in the upper portion of the AP1000 reactor vessel including the top region of the core, the upper plenum, the reactor vessel outlet nozzles, and a portion of the hot legs was created. Due to geometric symmetry, the computational domain was reduced to a quarter (from the top view) that includes of the top of the core, of the upper plenum, and of an outlet nozzle. Results from this model include predicted velocity fields and pressure distributions throughout the model domain. The flow patterns inside and around guide tubes clearly demonstrate the influence of lateral flow due to the presence of the outlet nozzles. From these results, comparisons of AP1000 flow versus current Westinghouse plants were performed. Field performance information from current Westinghouse plants will be shown to demonstrate an experience base of acceptable core lateral flows. From this experience base and the AP1000 CFD results, acceptability of the AP1000 upper plenum design on the fuel performance of the AP1000 fuel design will be demonstrated. © 2012 Elsevier B.V. All rights reserved.

Citation Format(s)

Study of impact of the AP1000® reactor vessel upper internals design on fuel performance. / Xu, Yiban; Conner, Michael; Yuan, Kun et al.
In: Nuclear Engineering and Design, Vol. 252, 11.2012, p. 128-134.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review