THIS CHAPTER ACQUAINTS the user of this manual with background information so that a better understanding of the complexities of regulations and their need in the maintenance of the nuclear power facility is achieved. The following subjects will be briefly discussed: 1. The reasons for the initial coating work, including that done in the primary containment structure. 2. The relationship between the coating work accomplished during the construction phase and the concerns of the emergency coolant system/engineered safety systems of light water nuclear power plants.