SMALL LOCA DETECTIONS IN THE PRIMARY CIRCUIT OF HTR-PM BASED ON ESO

Abstract

Chinese Modular High-Temperature Gas-Cooled Reactor HTR-PM is a very promising way of energy utilization. Unlike PWR, the primary coolant of HTGR is helium, which follows the ideal gas equation. Due to the helium purification and supporting system, when the pressure of the primary circuit drops, the system will conduct gas supplement and pressure adjustment. Therefore, for the primary circuit small LOCA, it is difficult for the operator to find the problem in a short time, which leads to the leakage of radioactive helium into the containment. If the problem is handled for a long time, it will lead to the final shutdown of the reactor due to negative feedback adjustment, causing unnecessary economic losses. In view of the above problems, the amount of helium in the primary circuit really reflects whether there is an abnormal leakage of helium, but the amount of helium cannot be directly measured. On the premise of not adding additional sensors, the expanded state observer (ESO) can be used to dynamically observe the quantity change of helium in the primary circuit, which can effectively monitor the abnormal state of helium and timely reflect the occurrence of small LOCA.