Preliminary analysis of startup and acceleration transient characteristics of helium-xenon cooled reactor direct brayton cycle system

Helium-xenon cooled reactor direct Brayton cycle system has excellent application prospects in small nuclear power plants due to its light weight, high compactness and simple structure. The safe startup of reactor system is very important, so the system startup scheme is designed. In addition, reactor system may be affected by external acceleration during operation. Whether reactor system can operate normally and safely after being affected by acceleration and its influence characteristics are not clear. In order to verify the feasibility of the system startup scheme and explore the acceleration influence characteristics, the system analysis program was developed to simulate the system startup transient operating conditions and the transient operating conditions of reactor system under the influence of acceleration. In the research of acceleration influence characteristics, acceleration has different periods, amplitudes, types and directions, and the load state is divided into load change with system output power and constant load. The results show that the designed system startup scheme can start reactor system safely. Reactor system can ignore the influence of acceleration when it has load change with system output power ability. If the load remains constant, reactor system cannot ensure continuous and stable operation after being affected by acceleration, which has the risk of Loss of Flow Accident (LOFA). The relevant research results provide theoretical reference and support for the design of the reactor system startup scheme and the research on the influence characteristics of acceleration on reactor system.