Investigation into the in-box LOCA consequence and structural integrity of the KO HCCR TBM in ITER

Korea has developed a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) and its auxiliary system in ITER. In parallel with its design, safety analysis has performed including accident analysis with the selected reference accidents. Among them, the effect of in-box LOCA to the structural integrity of the TBM was investigated. From the transient analysis of the GAMMA-FR on the in-box LOCA, it is found that the pressure of the internal TBM can be increased up to 8 MPa with the same pressure of the operating coolant through the Tritium Extraction System (TES) and He purge lines in the TBM. Structural analysis with ANSYS code for TBM was performed with this condition and it is confirmed that the TBM can endure and it does not affect the ITER machine by the failure.     

中国氦冷固态实验包层模块In-box LOCA事故分析研究

中国氦冷固态实验包层模块(CN HCCB TBM)将在ITER 2号窗口进行测试,在测试期间,聚变中子和TBM内部材料发生核反应,产生氚和其他放射性物质。考虑到ITER的运行和工作人员与公众的安全,在进入ITER测试之前需要进行事故安全分析。本文应用MELOCR对HCCB TBM及其氦冷系统(HCS)进行建模,开展了TBM增殖区冷却板流道破口事故(In-box LOCA)安全研究,并对泄压罐体积,破口面积,隔离阀关闭延迟时间等关键参数进行敏感性分析。结果表明:在保守假设流道全破裂的工况下,box压力超过其压力限值4 MPa,而单根流道和5根流道破裂的工况下,box均未超过其压力限值;安装泄压罐和改变隔离阀关闭延迟时间能够有效的控制box压力。     

Code development for analyzing transient behaviors induced by the in-box LOCA of liquid blanket in hydrogen fusion energy systems

Blanket is the strategic component in hydrogen fusion energy system, converting nuclear energy of hydrogen nuclei to thermal energy which could be further transported for the production of electricity. In order to investigate blanket transient behaviors induced by the in-box LOCA (Loss of Coolant Accident), a code named LBBFoam for high pressure compressible multi-phase flow is developed based on OpenFOAM, which is capable of simulating accident-induced pressure wave propagation in the blanket module. Two classic one dimension shock tube cases were simulated to verify the code. With this code, three scenarios with 8 MPa helium injection into PbLi in a blanket-like container were analyzed to capture pressure oscillation and bubble transportation characteristics. It is found that the maximum pressure in the PbLi zone exceeds and even doubles the helium injection pressure due to the reflection and superposition of pressure waves. This suggests that the traditional structural safety design limits of helium cooled PbLi blanket, which is usually set as the operating pressure of helium coolant, would be too low considering pressure wave superposition. This code will provide an assessment tool for the structural safety of blanket.