Standards Development

Scope

This International Standard applies to runners of reaction turbines, regardless of their size and capacity. These may include radial turbines such as Francis turbines, as well axial turbines such as Kaplan and propeller turbines, including diagonal turbines, in all possible configurations. In the case of turbine runners with adjustable blades, the internal mechanical components of the blades’ adjustment mechanism are excluded from this document.

This document outlines the recommended methodologies for conducting a fatigue assessment of turbine runners. It encompasses several key aspects, such as defining the load events to be considered during the assessment, determining stresses for each of these load events, as well as the detailed approaches for assessing fatigue for new and existing runners. Additionally, it includes manufacturing and quality assurance requirements that must be complied with to achieve the desired material fatigue properties and effectively apply the proposed fatigue assessment methodologies. This document also covers best practices for analyzing on-site strain gauge measurements performed on existing runners to evaluate their fatigue life.

The purpose of this document is to provide guidelines to assess fatigue in new and existing turbine runners. It does not specify if a fatigue assessment must be performed or not for a given runner. However, it includes an annex that provides guidance to evaluate the necessity of realizing a fatigue assessment or not for a given runner. The methods described in this document can also be used for remaining life assessments of in-service runners. However, caution should be exercised as the assessed runner materials’ fatigue properties and quality level could differ from the prescriptions found in the manufacturing and quality assurance section of this standard which have been defined for new runners.