Advanced Safety Programmable Logic Controller and Operational Programmable Logic Controller for Data Acquisition Control System of SADHANA Sodium Loop

Abstract

The SAfety Decay Heat Analysis in NAtrium (SADHANA) sodium loop is designed with two PLC controllers. All safety control interlocks are monitored by a Safety programmable logic controller (SPLC), and temperature control, including averaging ON/OFF heaters, is managed by an Operational PLC (OPLC).The decay heat exchange system of the SADHANA sodium loop is evaluated using these combined safety and operational PLCs. In the case of reactor loss of offsite and onsite power, decay heat generated in the reactor core after shutdown is removed by four Safety Grade Decay Heat Removal (SGDHR) systems [1,2,3,4,5]. Each exchanger (AHX) is located outside the reactor containment building, and a sodium loop circulation is created by natural convection [6,7,8,9,10]. The purpose of construction of SADHANA loop, with simulated models of DHX and AHX to study the performance of the SGDHR system, has been planned [11,12,13,14,15]. The SADHANA sodium loop has been commissioned, operating at isothermal temperatures of 300°C and hot temperatures of 500°C/& 550°C. The smart instrumentation and control system comprising Loop Operational Data Acquisition and Control System (LODACS) and Experimental Data Acquisition System (EDAS) are used in the SADHANA sodium loop. During the tests, LODACS personal computer and Instrumentation panel monitor loop parameters such as sodium level, leak, and pressure. In SADHANA loop DHX and AHX temperature decay heat changes monitoring by EDAS. The temperature of the pool in Test vessel 4 (TV-4) is controlled by immersion type sodium heaters via PID controllers. Currently, the loop consists of 64 surface heaters, 30 immersion type sodium heaters, and 205 thermocouples (84 Nos. of operational thermocouples and 121 Nos. of experimental thermocouples). According to the experimental thermocouples are being monitored by a separate fast data acquisition (scan rate of 10 seconds) by in-house developed software. This technical paper also describes the implementation of PLCs in different data acquisition control systems.