Implementation of a Performance Evaluation System for Nondestructive Testing Methods

Abstract

Nondestructive Testing (NDT) is an important means to ensure structural integrity and safe operation of components in many industries, as for example nuclear power plants, aerospace or civil engineering. Within the qualification of Nondestructive Testing personnel as well as validation of NDT procedures, practical demonstrations on test blocks with realistic flaws play a key role. Adequate test pieces need to be designed according to specific criteria such as quantity, shape, orientation, size and position of the test flaws, depending on the requirements of the national codes and standards in the specific industries. The performance of the candidates and inspection systems is quantified and analyzed with respect to criteria, such as detection, positioning, characterization as well as length and height sizing of flaws. Statistic measures are applied to express the resulting accuracy and overall performance. The indication reports obtained from different candidates contain ample information, which might not appear evident at first sight. The complexity of the situation requires an intelligent extraction of the information from the data. An analysis tool IndEva was developed to handle this complexity and provide an accurate, detailed and reliable evaluation of inspection systems and personnel. Besides the plain evaluation regarding the fulfilment of the qualification requirements, critical test flaws as well as test block sections, which are likely to cause false positive indications can be identified. Statistic results display the dependency of the system performance on various parameters and parameter combinations to provide a clear picture of the performance. Country-specific evaluation standards can be applied and compared, especially with regard to the continuous improvement of the qualification methodology.