There are around twenty branches in a Nuclear Power Plant that operate to maintain the plant and one of the most important branches of them is ‘Safety and Reliability’. Approximately forty percent of the investment is paid to ensure the safety and reliability of the plant. Goal of this research work is to estimate reliability of a mechanical system which is chosen as Hydroaccumulator System of VVER type reactor. Getting the reliability, we will be trying to improve the system and enhance its reliability. To do so, firstly, reliability is calculated from a ‘prototype reactor’s’ hot loop which is located at Obninsk Institute for Nuclear Power Engineering (INPE). Thus, calculations were done and its applications being known, then finally these formulas and experiences are being used to calculate and improve the Hydroaccumulator System’s design along with its reliability to increase the safety of the NPP.

Vibrational data monitoring system is designed to observe, detect and study any vibration caused in the NPP working cycle by different factors. The objective of the work is to analyze vibrational monitoring data of the primary circuit installation of VVER reactor to acquire knowledge of the characteristics of equipment vibration. Data has been collected using displacement sensors and pressure fluctuation sensors attached to the equipment. Data processing is carried out in R software. The work gives an overall idea of the vibrational data processing, visualization and how to present it by different graphics which will help the NPP operator for taking necessary steps.