Maintenance of Prestressed Concrete Containment Vessels in a Nuclear Power Plant

Abstract

The main feature of a prestressed concrete containment vessel (hereinafter referred to as “PCCV”) is that unbonded tendons, which are not bonded to the structure, are used because the tension of the tendon needs to be measured in periodical in-service inspection (hereinafter referred to as “ISI”) to ensure that the performance of the power plant is maintained during the service life. This report describes the results of measurement of the tension of the tendon, which has been performed as an activity to maintain the PCCV in Ohi Nuclear Power Plant (hereafter referred to as Ohi “NPP”) Units 3 and 4 of Kansai Electric Power in the past twenty some years since the construction of the PCCV, the changes in the standards and guidelines for the maintenance of the PCCV in Japan, as well as the discussion of non-destructive test-based methods for estimating the strength of high-strength concrete used for the PCCV and the development of a hydraulic shim-type load cell-based system for the measurement of the tension of the tendon, taking into account the ease of non-destructive testing, etc.