Abstract
This article uses the letters and notices issued by the China National Nuclear Safety Administration on fastener quality incidents as the main line to review the process of fastener quality incidents from clues, investigation to handling. Based on the problems encountered in the process of handling this incident, the improvement direction and improvement measures for strengthening the quality management of fasteners were analyzed from the elements of quality assurance, design, procurement, manufacturing, installation, non-conformance management, inspection and testing, and documents. The design of nuclear power plants should clarify the classification and marking of fasteners, and the design of fasteners should be as universal and standardized as possible, and specifications and models should be reduced. Procurement should focus on supplier evaluation, limit the lowest bidding price, prevent cutting corners, etc.; manufacturing should set up witness points for key links, inspect the quality assurance system while witnessing; pay attention to the factory inspection of fasteners, and it is recommended to increase the re-inspection of fasteners before storage or use. Fasteners managed by equipment category are not recommended to be classified as bulk materials, but they still need to be re-inspected. Fastener re-inspection standards should take into account the requirements of different reactor types and different specification systems. Re-inspection should not only focus on mechanical properties, but also pay attention to the re-inspection of fastener surface quality. The re-inspection unit shall have a certain degree of credibility or be bound by nuclear safety regulations. The idea of establishing a professional nuclear industry fastener supply and testing platform was proposed.
