A parallel slide gate valve (PSGV) is a critical component of a combined cycle power plant (CCPP). It is located
between the heat recovery steam generator (HRSG) and the steam turbine. The PSGV acts as a stop or shut-off valve
under high temperature and high pressure operating conditions. Therefore, its performance and structural integrity must
be ensured in the valve design. Among the components of PSGV, a disc holder is connected to a stem and moves the
valve disc vertically by closing and opening the valve. In this paper, the elastic-plastic analysis and structural integrity
evaluation for the disc holder is performed according to the local failure assessment described in the ASME B&PVC
VIII-2, where the plastic strain calculated from the elastic-plastic stress analysis is used in the method. In addition, an
improved design is suggested based on the evaluation results, resulting in an increased stem thrust satisfying the
required level of safety compared with the initial disc holder.