An emergency diesel generator(EDG) manufactured by a French company Wartsila SACM is a tandem type engine and consisted of two 10 cylindered diesel engines on each side. The maintenance manual provided by the manufacturer recommends that engine bearing be inspected every 15 years. However, it is difficult to inspect them because the manhole located in the lower compartment of the engine is too small for maintenance worker to access engine internals. Furthermore, the EDG should be disassembled and then overturned to inspect bearings unlike other EDG type. Such process will take longer period time than ordinary maintenance period. So it is not possible to inspect the main engine bearing and crank shaft during a routine or scheduled maintenance. In this paper, five methods are proposed and estimated to resolve the problem and the optimal maintenance method is chosen among them. The proposed optimal maintenance plan makes it possible to perform proper maintenance during regular maintenance period and to lower maintenance cost considerably.

In this study, the specific 3-dimensional plant model is developed to check the physical interference of structures and components which cross each other, and to reduce the interference errors occurred between interconnecting parts. Based on 3D model, the construction schedule is reviewed by 4D simulation to avoid construction activity overlapping. Also, the layout simulation of a large capacity crane is implemented to relieve interference on the run-time of a large capacity crane.

In this study, an analytical study on the effect of the support structure deflection on the impact test result was carried out to set up the accurate impact test method. Various impact analyses of the CEDM(control element drive mechanisms) impact test were performed using LS-DYNA commercial FE program. Finally, the effect of the boundary condition of the support structure and impact loading duration were investigated.

The new technologies such as modularization are developed to secure competition against oversea NPP for APR+ Plant. To reduce the construction period, the SC structure and Half-SC structure modules were respectively applied to exterior wall and slab of the APR+ IRWST. In this paper, partitioning Methods of IRWST module, constructability and construction schedules were analyzed. Consequently, it is concluded that the construction period can be reduced by applying IRWST modules to NPP Construction.

The ex-vessel steam explosion may occur when, during a severe reactor accident, the molten core pours into the water in the reactor cavity. These dynamic loads on the cavity wall could potentially lead to the significant failure of the cavity wall. But the phenomenon like this steam explosion includes big uncertainty in estimating the impulsive pressure loading of RCB. In this study, risk based integrity assessment method of the NPP structure subjected to steam explosion load was suggested to capture these uncertainties involved during the structural integrity assessment of the Nuclear power plant.

In this paper, the improvement methods of working platforms arrangement for NPP(Nuclear Power Plant) construction has been reviewed to enhance the construction accessibility. The working platforms will be enlarged and added because of accessibility of the hi-capacity crane for installation of the SC module and the combined module. The vertical elevator and the working tower have been also proposed to increase construction accessibility. It is concluded that the improvement of constructability is possible based on the consultation of construction company.