2021 International Conference on Automation, Control and Mechatronics for Industry 4.0 (ACMI), 8-9 July 2021, Rajshahi, Bangladesh 978-1-6654-3843-8/21/$31.00 ©2021 IEEE Investigation on Steam Flow in a Secondary Circuit of a VVER-1000 Power Plant Abstract— The objective of this paper is to determine the efficiency of the designed plant as well as identify the main technical parameters that affect the overall efficiency of the plant by using MATLAB 2018a software and X-Steam function file for the required iterative thermodynamic calculation. Here the generic design of Vodo-Vodyanoi Energetichesky Reaktor; Water-Water Power Reactor (VVER- 1000) reactor is used. This study is for investigation on steam flow in a secondary circuit of a VVER-1000 power plant. It represents a nuclear power plant design based on some given parameters such as power, condensate temperature, feed water temperature, condensate pressure, feed water pressure, various extraction pressure, deaerator pressure, enthalpies of a drainage system, enthalpies of heaters inlet and outlet, the parameters of heating plant etc. It includes several steps including calculation of the number of regenerative heaters and their connection to different components as well as developing equations for the power unit. For validation equations of different flows are developed for each equipment in the secondary circuit for the purpose of determining the unknown flow rates and then overall plant efficiency is determined and then observed if is within the range of 30-35%. Keywords— VVER-1000, secondary circuit, deaerator, feed pump, efficiency Index Terms— Rankine cycle, secondary circuit. I. INTRODUCTION A nuclear power plant is a thermal power station with a nuclear reactor is considered to be a heat source. Heat is used to produce steam, which drives a steam engine attached to an electricity generator, as is characteristic in thermal power plants. Here Rankine cycle is used to produce steam in this secondary circuit. All around the world most common types commercial Light Water Reactor (LWR) is Pressurized Water Reactor (PWR) which mainly consists of two different circuit: primary circuit for single phase flow and secondary circuit for double phase flow. Usually, pressure and temperature in PWR on steady state condition are 15MPa and 315 ̊[1]. VVER-1000 is a Russian reactor which is also well-known PWR type reactor, which is used to produce steam which generates turbine. The secondary loop of VVER -1000 consist of a steam generator, turbine, condenser, heater deaerator etc [2]. For algorithm development & evaluation of thermodynamic parameter Matlab, Xsteam and water steam pro are used. By using different equations a secondary circuit is designed and different flow rates are developed to determine the efficiency. Here Matlab is used to calculate No of regenerative heater ,their pressure, temperature, enthalpy. Along with hand calculation Matlab is used for accuracy. And also the validation part where the thirty one unknown flow rate are calculated are done by using Matlab. By using different equations a secondary circuit is designed and different flow rates are developed to determine the efficiency. Xsteam is a matlab function used to calculate steam and water property [3].It can calculate enthalpy by using pressure and temperature. WaterSteamPro is a set of programs for calculating properties of water, steam, gases and gases mixtures .With WaterSteamPro one can calculate thermophysical properties specific volume, enthalpy, entropy, internal energy, speed of sound, isochoric and isobaric heat capacity, Joule-Thomson coefficient, kinematic and dynamic viscosity, Prandtl number, thermal conductivity, surface tension, etc. of water/steam. The pressurized high temperature water from primary circuit brought the heat from the fission process in the reactor core and Steam generator is used to exchange the heat. Steam generators are heat exchangers used to transform water into steam from heat generated in a nuclear reactor core. They connect between the primary and secondary coolant loops in pressurized water reactors (PWR).The primary-side fluid is liquid water at the high pressure, and the fluid on the secondary side is saturated water-steam mixture at the pressure twice as low. A special attention is given to preserving the boundary between the contaminated water in the primary reactor coolant system and the water-steam Sk.Farjana Hassan 1 Dept of Nuclear Science and Engineering (NSE) Military Institute of Science and Technology Dhaka, Bangladesh farjana857@gmail.com Farzana Binthe Farooq 1 Dept of Nuclear Science and Engineering (NSE) Military Institute of Science and Technology Dhaka, Bangladesh farzanafarooq317@gmail.com Md Muzahidul Islam 1 Dept of Nuclear Science and Engineering (NSE) Military Institute of Science and Technology Dhaka, Bangladesh muzahidislam1517@gmail.com Md Ghulam Zakir 1 Dept of Nuclear Science and Engineering (NSE) Military Institute of Science and Technology Dhaka, Bangladesh zakir@nse.mist.ac.bd Md. Sadman Anjum Joarder 2 Dept of Mechanical Engineering Rajshahi University of Engineering & Technology (RUET) Rajshahi-6204, Bangladesh ullash24140@gmail.com