Vol.9 No.2 AASP17 (125-126-127-128-129-130-131-132-133-134-135-136-137-138-139-140-141-142) NT85 |
|||||
Academic Articles | |||||
Regular Paper | Vol.9 No.2 (2017) p.118- p.125 | ||||
Performance Based Maintenance Concept to Optimize Inspection Schedule |
|||||
Masayuki KAMAYA1,* | |||||
1 Institute of Nuclear Safety System, Inc., 64 Sata, Mihama-cho, Fukui 919-1205, Japan |
|||||
Abstract | |||||
This study is aimed at proposing a new maintenance concept; performance based maintenance (PBM). In a flaw tolerance assessment, time duration until the next inspection is determined by crack growth prediction assuming material degradation such as stress corrosion cracking and fatigue. In most cases, the crack growth prediction is excessively conservative and no cracking is found by inspections. The fact of no indication by inspections implies that cracks have not grown to more than a detectable size for the inspection technique applied. In the PBM concept, this inspection result is considered in determining the next inspection schedule. In this study, applicability of the PBM concept was shown for fatigue degradation of stainless steel components in a pressurized water reactor primary water environment. The relationship between crack depth and number of cycles obtained in the author’s previous study was used for the crack growth prediction. Then, crack growth for a postulated fatigue crack was predicted considering strain gradient in the depth direction caused by thermal loading. It was shown that the duration until the next inspection could be optimized based on the inspection result together with the crack growth curve. A longer operation time before the inspection resulted in a longer duration until the next inspection. | |||||
Keywords | |||||
Performance-based maintenance, fatigue, crack growth, maintenance, inspection schedule | |||||
Full Paper: PDF
|
|||||