LABVIEW. Two-phase heat transfer phenomena that occur on plate-type narrow channel on BETA Test Loop is important to be studied, particularly in the event of loss of coolant accident (LOCA) in the PWR type of Nuclear Power Plant. To support this study, an adequate instrumentation system is required primarily to improve the reliability and safety of the operator that has been done manually by designing a valve opening automation in the test loop based on the coolant temperature. The design is aimed to obtain an automatic valve control instrumentation system that can ease the researchers to conduct the experiment using the BETA Test Loop. The design activity was started by determining interfaces associated with the physical quantities such as the NI 9213 thermocouple to monitor the temperature and the N 9476 (digital I/O) to turn the heater on and off. After assembling those interfaces together as a single unit of automation control system, then a control program was developed using the LabVIEW 2011 software. The test result shows that the regulation of the coolant temperature at 55-60 C can be reached in 28 minutes starting from the room temperature and the heating system is “off” and back to “on” again at the minute of 98. Therefore, the automation system of the opening valve in the primary cooling system can be used for the experiment activity in the BETA Test Loop.