I. HISTORY AND DEVELOPMENT

Visual examination or testing (VT) is a method of nondestructive testing that has been neglected for much of its industrial application life. VT was the first nondestructive test (NDT) method used in the nondestructive testing industry, but was last method to be formally acknowledged. Development of the visual method as an independent entity was fostered by the Electric Power Research Institute (EPRI) Nondestructive Examination (NDE) Center in the early 1980s. This was the result of the development of a training program for visual examination technology that included 120 hours of formal training. The need was prompted by the American Society of Mechanical Engineers, specifically Section XI Rules for Inservice Inspection of Nuclear Power Plant Components. The program was designed to qualify personnel as visual examiners. Examination personnel scrutinizing the general condition of components were to comply with the requirements of the American Society for Nondestructive Testing, Recommended Practice No. SNT-TC-1A. Visual examination of components for general mechanical and structural conditions was to satisfy the requirements of ANSI N45.2.6. This standard was codified via the U.S. Federal Regulations, Title 10, Code of Federal Regulations, Part 50, requiring nuclear power plants to meet certain requirements for licensing. ASME sectored the visual examination into four categories based on the scope of inspection. The categories are classed as VT-1, VT-2, VT-3, and VT-4. VT-1 addresses the condition of a component, VT-2 the location of evidence of leakage, VT-3 the general mechanical and structural conditions of components and their supports, and VT-4...