Publisher Summary This chapter focuses on Quality Assurance (QA), which is an essential aspect of good management. QA can be implemented through the definition and the realization of a Quality Assurance Program (QAP). The QAP is an integral part of the plant design. It provides a disciplined approach to all activities affecting quality. The establishment and the implementation of a QAP for a nuclear plant are essential. An organization having overall responsibility for a nuclear power plant is responsible for the establishment and the implementation of the overall QAP for that plant. Some aspects that can be included in QAP are: procedures, necessary instructions, and drawings. The QA activities are fundamental, to attain safety in a plant. The QA method has been demonstrated in many sectors of production and service activities. It has been the most effective and efficient means to obtain the desired quality. In many production sectors, it has replaced the method of product control, substituting it with the control of the process that originates the product itself.