Dates: February 25 – March 1, 2019
Booth #: Bronze Sponsor
Location: The Banff Center | Banff, Alberta, Canada
ASME STS-1 provides guidelines for the design, fabrication, and erection of steel stacks, however there are no specific guidelines for the assessment of guyed steel stacks already in service. Furthermore, existing literature regarding the proper re-tensioning of guy wires is scarce or nonexistent. This presentation summarizes the effect of guy wire spacing, position, tension pattern, and operating and shutdown tension settings on the structural response of a guyed steel stack. Field tension measurements and laser scans are used to refine a finite element model of the stack. A performance-based methodology for lateral deflection is proposed to guide fitness-for-service assessments and mitigation implementation.
Pipe wall loss due to Flow Accelerated Corrosion (FAC) is currently recognized as a serious safety concern for both nuclear and fossil power plants. The nuclear utility industry began detailed analysis of FAC related failures after the Surry Unit 2 FAC failure that occurred on December 9, 1986. The fossil utility industry began serious consideration following the February 12,1995 Pleasant Prairie Unit 1 FAC failure. The NRC requires all nuclear plants to have an FAC program.
The mandatory Chapter VII on the Operations and Maintenance of covered piping systems (CPS), first published in the ASME B31.1 Power Piping Code in December 2007, recognizes FAC as one of degradation mechanisms that must be part of a Fitness-for-Service (FFS) program. This presentation details one utility’s experience in setting up an FAC program on its boiler feed water pump discharge piping (FWD). It includes brief descriptions of the program including initial testing of select locations. The results of this testing are discussed including the results and recommendations.