Modelling of pellet-cladding interaction in thermal reactor fuel pins using the Sleuth computer code

This Paper describes the modelling of pellet-cladding mechanical interaction (PCI) in thermal reactor fuel pins using the Sleuth Computer code. The code is based on the fundamental physical mechanisms causing PCI (differential thermal expansion, fuel swelling, cladding creep-down, etc.) coupled with an estimate of strain concentrations over fuel cracks. It uses the classical 1 1/2 dimensional method which subdivides the fuel both axially and radially. While Sleuth was originally developed to predict PCI failure/survival, it has evolved into a general fuel performance code. The latest version, Sleuth 86, which is a modular form with mnemonic variable names, has proved to be an ideal vehicle for testing new sub-models which have been required as the experimental data base has been expanded. (author)