Abstract: Nuclear safety level system is the nerve center of whole nuclear power plant for safe operation control. The core component of circuit is printed circuit board assembly that directly affecting about its operation stability. This article aims at the surface cleanliness of the printed circuit board assemblies, and analyzes the necessity and importance of cleaning process in the production process of printed circuit board assembly, so as to ensure that there will not be reliability problems such as the decrease of surface insulation resistance and electrochemical migration caused by ion residue during using due to cleaning problems. Through the investigation comparison and experimental analysis of several cleaning solvents, the most suitable solvent materials for cleaning nuclear level printed circuit board assembly are determined.

Key words: nuclear safety level; printed circuit board assemblies; cleanliness