Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Takei, Hayanori
Journal of Nuclear Science and Technology, 45 Pages, 2025/06
The Japan Atomic Energy Agency is working on the research and development of an accelerator-driven nuclear transmutation system (ADS) for transmuting minor actinides. This system combines a subcritical nuclear reactor with a high-power superconducting proton linear accelerator (JADS-linac). One of the factors limiting the advancement of the JADS-linac is beam trips, which often induce thermal cycle fatigue, thereby damaging the components in the subcritical core. The average beam current of the JADS-linac is 32 times higher than that of the linear accelerator (linac) of the Japan Proton Accelerator Research Complex (J-PARC). Therefore, according to the development stage, comparing the beam trip frequency of the JADS-linac with the allowable beam trip frequency (ABTF) is necessary. Herein the beam trip frequency of the JADS-linac was estimated through a Monte Carlo program using the reliability functions based on the operational data of the J-PARC linac. The Monte Carlo program afforded the distribution of the beam trip duration, which cannot be obtained using traditional analytical methods. Results show that the frequency of the beam trips with a duration exceeding 5 min must be reduced to 27% of the current J-PARC linac level to be below the ABTF.
Takei, Hayanori
Journal of Nuclear Science and Technology, 61(8), p.1075 - 1088, 2024/08
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)In the proton linear accelerator (linac), the proton beam is unexpectedly interrupted due to the electrical discharge originating from the radio frequency, failure of the device/equipment, or other factors. Do these beam trips occur randomly? Conventionally, it has been implicitly assumed that beam trips occur randomly. In this study, we investigated whether beam trips in the linac of the Japan Proton Accelerator Research Complex (J-PARC) occur randomly to estimate the beam trip frequency in a superconducting proton linac for an accelerator-driven nuclear transmutation system. First, the J-PARC linac was classified into five subsystems. Then, the reliability function for the operation time in each subsystem was obtained using the Kaplan-Meier estimation, a reliability engineering methods. Using this reliability function, the randomness of beam trips was examined. Analysis of five-year operational data for five subsystems of the J-PARC linac showed that beam trips occurred randomly in some subsystems. However, beam trips did not occur randomly in many subsystems of the proton linac, including the ion source and the acceleration cavity, the primary subsystems of the proton linac.