Control

Overall Control Theory

The basic control theory applied for the OPEN100 plant will follow the same strategy used in larger PWRs and utilize a sliding reactor average temperature (Tavg) control mode. The Tavg control mode averages the hot leg and cold leg temperatures of the RCS and adjusts the core power levels to maintain a set value based on the main steam pressure. This has proven to be the best approach to delivering power to the turbine while maintaining the core temperatures at optimal operating levels.

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Human-Machine Interface

The Human-Machine Interface or HMI is the collection of digital screens that display the plant’s operating status on control room screens for operators. The screens provide a graphical layout of various systems and present key data points that give clear and immediate feedback on each system. The screens can be monitored from any of several screens available in the control room so that if one screen is unavailable, data can be displayed on an alternate panel.

 
 

Computer System Functions

Like large PWRs, the OPEN100 Computer System Functions include sensor data collection, performance reporting and control response. The sensor data collection is to both trigger plant control actions and to analyze/report plant performance. Plant control actions may include opening or closing a valve, turning on or off a piece of equipment, varying equipment load levels, etc. Engineers and/or operators use the reported data to fully understand the operating conditions of the plant. All data can be accessed over a network via the remote monitoring system.

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Nuclear Steam Supply System Process Supervision

The NSSS Process Supervision System monitors all critical nuclear system data collected and analyzes performance such as reactor output, core neutron flux and temperature distribution and deviation from expected results. It also calculates current and postulated operating conditions based on system operating trends. The secondary (BOP) systems that impact directly operation of NSSS systems are also monitored for trends and potential impacts.

 

Digital Radiation Monitoring System

The digital radiation monitoring system is a dedicated system that monitors and collects data from the radiation monitors installed throughout the plant. Any potential leak path from the NSSS systems is monitored by means of various types of monitors that alert the operation staff to the presence of radionuclides in the air or process streams. Most alarms alert staff to initiate corrective actions to alleviate the situation while others could require a plant shutdown.

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                  is a project of the Energy Impact Center, a Washington, DC based research institute focused on climate restoration.