Htgr power plant turbine-generator load control system

Abstract

A control system is disclosed for a high temperature gas cooled reactor power plant, wherein a steam source derives heat from the reactor coolant gas to generate superheated and reheated steam in respective superheater and reheater sections that are included in the steam source. Each of dual turbine-generators includes a high pressure turbine to pass superheated steam and an associated intermediate low pressure turbine to pass reheated steam. A first admission valve means is connected to govern a flow of superheated steam through a high pressure turbine, and a second admission valve means is connected to govern a flow of reheated steam through an intermediate-low pressure turbine. A bypass line and bypass valve means connected therein are connected across a second admission valve means and its intermediate-low pressure turbine. The second admission valve means is positioned to govern the steam flow through the intermediate-low pressure turbine in accordance with the desired power output of the turbine-generator. In response to the steam flow through the intermediate-low pressure turbine, the bypass valve means is positioned to govern the steam flow through the bypass line to maintain a desired minimum flow through the reheater section at times when the steam flow through the intermediate-low pressure turbine is less than such minimum. The power output of the high pressure turbine is controlled by positioning the first admission valve means in predetermined proportionality with the desired power output of the turbine-generator, thereby improving the accuracy of control of the power output of the high pressure turbine at low load levels.