Taking stock of component condition

In an increasingly competitive marketplace, power providers can afford nothing less than accurate, economical condition assessment. This is particularly true for thick-section steel components such as turbine rotors and pressure vessels, which become brittle with long-term exposure to high temperatures and, in nuclear reactor vessels, neutron bombardment. One solution is the small punch test, a miniature-specimen, nondestructive technique that provides direct, accurate measurement of metal toughness. Performing the small punch test at different temperatures allows determination of a material's small punch transition temperature, the temperature at which a heated brittle (low energy to failure) sample becomes ductile (high energy to failure). The small punch test has demonstrated its ability to support condition assessment that relies on direct, accurate, unit-specific determination of fracture toughness. Savings accrued throughout the power industry could be substantial, as the small punch test helps utilities realize the economic benefits of operating power plants well beyond their design or previously planned lifetimes.