Finite Element Modelling to Investigate the Mechanisms of CRUD Deposition in PWR

Research output: Chapter in Book/Report/Conference proceedingConference contribution

  • External authors:
  • Jiejie Wu
  • Andy Banks
  • Andrew Powell
  • Lara-Jane Pegg

Abstract

Corrosion Related Unidentified Deposition (CRUD) in PWR may cause severe issues, such as Tube Support Plate (TSP) blockage, fuel cladding cracking, and subsequently increased radiation doses for workers. The primary objective of this work is to develop an all-inclusive deposition model, which will reproduce the morphology and elucidate the contributing electrokinetic mechanisms. In this paper the development and verification of a model of the streaming current linking the potential distribution and the fluid flow behaviour using the Finite Element Method (FEM) is presented. In the model, coupled anodic and cathodic regions were found at the inlet of a pipe restriction, associated with a region of recirculating flow following the front facing step (FFS). The corresponding current densities and overpotential at the metal/solution interface were calculated. The coupled anode and cathode may explain the observed deposition process – generating deposits at the front facing step first, followed by a region free of deposits and then repeating ripples of deposited material. At the restriction outlet, a cathode was found which balances the current loops. In this paper, the simulated initiation and propagation processes of the electrokinetic deposition are presented.

Bibliographical metadata

Original languageEnglish
Title of host publication18th International Conference on Environmental Degradation in Nuclear Power Systems and€“ Water Reactors
DOIs
Publication statusPublished - 2017