Fuzzy logic-based steam drum control system for startup of a supercritical-fast reactor

• Main Authors: Sutanto, Sutanto, Rachmadewi, Safira, Puspitasari, Ayu Jati
• Format: Conference Proceeding
• Language: English
• Subjects: Cladding; Control systems; Coolants; Cooling systems; Fast nuclear reactors; Flow velocity; Fuzzy control; Fuzzy logic; Heat exchangers; Light water; Liquid levels; Nuclear safety; Performance tests; Pressurization; Proportional integral derivative; Water level fluctuations; Water levels
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0122318

Supercritical-fast reactor is cooled by light water at high pressure of 25 MPa. It is included in t he 4th generation of nuclear reactors, and has excellent features in safety and plant efficiency. There is no phase change during the coolant cycle leading to high outlet coolant temperature. Operation of the reactor during startup is challenging due to the pressurization process from subcritical pressure to the operating state. During subcritical pressure, a separated cooling system that is composed of a steam drum, a heat exchanger, and a recirculation pump is provided to achieve stable pressurization by adjusting the liquid level of the steam drum at a constant value. This study proposes a fuzzy-based liquid level control system of the steam drum. Two signals of actual water level and change rate of the water level are taken as the inputs. Triangular functions are used for fuzzification, and the Tsukamoto method is used for inference process with an output signal of coolant flow rate dumped from the steam drum. The performance of the control is evaluated by using a startup code of the same reactor used in the previous study. The performance test of the control system shows that the water level can be kept constant as the desired value during the pressurization with a steady-state error of less than 0.02%. It is smaller than that of using a PID-type control system. The safety criterion of temperature at the cladding surface is also evaluated during the pressurization, and it is well below the limit of allowable cladding surface temperature.