Development of the calorimetry target on second neutral beam injection beam line of HL-3 device

Abstract

BackgroundIn neutral beam injectors (NBIs) of Tokamak device, the calorimetric target is one of the most important water-cooled components, responsible for receiving and measuring beam power. In addition, by using a built-in thermocouple array, the temperature rise at different positions of the target plate can be monitored in real-time, thereby obtaining the power density distribution of the extracted ion beam or neutral beam.PurposeThis study aims to develop a calorimetric target for the neutral beam injector in the HL-3 device, which can meet the requirements of target plate lifting and thermal load absorption.MethodsA linear push rod mechanism was applied to the design of the calorimetry target to achieve lifting and lowering, and a "W" - shaped target plate structure was adopted to achieve absorption of neutral beam energy. According to the design parameters, the fluid calculation module of Ansys Workbench was employed to simulate the temperature distribution of the calorimetry target under full power operation.ResultsCalculation results show that the maximum temperature rise of the calorimetry target is 526.4 ºC when the deflecting magnet is opened under full power operating conditions, and the temperature can be lowered to room temperature within 30 s, satisfying the requirements for the use of the beam line.ConclusionsThe successfully developed calorimetric target of this study meets application requirements on second neutral beam injection beamline of HL-3 device, providing references for further engineering design of calorimetric targets in other NBIs.

Keywords

• neutral beam injectors
• calorimetric target
• finite element calculation