In-service inspections and R&D of PCCVs in Japan

In Japan, the following five plants in operation use prestressed concrete c ontainment vessels (PCCVs): Tsuruga #2 (in operation in 1987), Ohi #3 and # 4 (in operation in 1991 and 1993, respectively), and Genkai #3 and #4(in op eration in 1994 and 1997, respectively). These plants have adopted the hemi spherical dome type PCCV with two or three buttresses and unbonded prestres sing system. For the above five PCCVs, lift-off tests in the in-service ins pection have been carried out 1, 3 and 5 years after the beginning of opera tion. In addition, concrete strain and temperature have been measured perio dically. This paper presents the in-service inspection methods and results of the lift-off tests and the measurement of concrete strain. The given res ults are as follows. Measured strain shows good agreement with calculated c reep and shrinkage strain, so tendon tensile force can be predicted by the design method using calculated strain, and it also matches well the results of the lift-off tests. (C) 2000 Elsevier Science S.A. All rights reserved.