Modelling the behaviour of a control-element blade during irradiation

Research output: Contribution to journalArticle

Abstract

The control-rod elements in a boiling-water reactor contain natural boron carbide (B4C) powder, used as neutron-absorber material and clad in stainless-steel blades. During in-reactor service, the internal production of helium gas and point defects in neutron-irradiated boron carbide cause swelling which can induce significant contact stresses in the blade causing, eventually, stress-corrosion cracking of the blades. In this work, a finite-element analysis of a control-rod blade consisting of B4C powder and stainless-steel cladding has been performed using ADINA. An algorithm for the finite-element calculation of a porous material such as B4C powder has been developed and which models both swelling and consolidation behaviour of B4C powder. The Drucker-Prager constitutive law has been used to model the consolidation effect. The model has been verified with an analytical solution for a simple geometry. A number of cases with B4C powder in contact with stainless steel and using the actual blade design have been studied for which contact stresses, the displacements and the effective stresses are calculated. Finally, the model has been used to predict the deformation of the blade during irradiation under B4C swelling and irradiation-induced creep of stainless steel.

Details

Authors
External organisations
  • Luleå University of Technology
  • ABB Corporate Research
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Sciences
  • Mathematics
Original languageEnglish
Pages (from-to)1113-1127
Number of pages15
JournalComputers & Structures
Volume64
Issue number5-6
Publication statusPublished - 1997
Publication categoryResearch
Peer-reviewedYes
Externally publishedYes