Nondestructive Testing (NDT) is a technology that evaluates parts and materials for conditions and flaws that could affect their integrity. Effective NDT depends on the knowledge and skills of the technician. Flaws can affect the serviceability of the material or structure, so NDT is important in guaranteeing safe operation as well as in quality control and assessing plant life. The flaws may be cracks or inclusions in welds and castings, or variations in structural properties which can lead to loss of strength or failure in service.