Finite element simulation of Pellet-Cladding Interaction (PCI) in nuclear fuel rods

Modelling of iodine-induced stress corrosion cracking in CANDU fuel

“…The critical crack volume V c can be simplistically modelled as a right cylindrical cone, with a typical crack base width of d c $ 5 lm [32], and a crack length equal to the sheath thickness, i.e., t clad = 0.43 mm. Hence, 3 gives a critical volume of $2.8 Â 10 À9 cm 3 . Substituting Eq.…”

“…During the early 1970s, occurrence of fuel failures in CANDU fuel at the Pickering and Douglas Point Nuclear Generating Stations was observed during sustained power ramps [3,4]. This led to the development of an improved re-fuelling scheme to minimize the hoop stress in the sheathing during the power ramp manoeuvre, and the introduction of a (chemical) barrier coating of graphite (CANLUB) on the internal surface of the sheath.…”

“…This led to the development of an improved re-fuelling scheme to minimize the hoop stress in the sheathing during the power ramp manoeuvre, and the introduction of a (chemical) barrier coating of graphite (CANLUB) on the internal surface of the sheath. The search for PCI mitigation, particularly for Boiling Water Reactors, also resulted in the mid 1970s in the development of barrier fuel with a thin, pure zirconium layer on the inside surface of the tubing [3,4]. Consequently, detected current failure rates are typically less than ten per million rods in operation [4].…”

Axisymmetric whole pin life modelling of advanced gas-cooled reactor nuclear fuel

“…Most work in recent years has focussed on water cooled systems [2][3][11][12][13]. Marchal [11] showed through 3D modelling of PCI, in the CAST3M FE code, that the while pellet fracture did produce stress concentrations in the cladding there was also a significant stress remaining in the fuel fragment. These pellet fragments had sufficient remaining stresses that later interaction with the cladding through friction contact produced further radial cracking.…”

“…Walker also shows that a failure of this size was sufficient to cause a two orders of magnitude reduction in the number of pellet cracks to propagate in the adjacent cladding. Most work in recent years has focussed on water cooled systems [2][3][11][12][13]. Marchal [11] showed through 3D modelling of PCI, in the CAST3M FE code, that the while pellet fracture did produce stress concentrations in the cladding there was also a significant stress remaining in the fuel fragment.…”