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As the last step of the nuclear fuel cycle, nuclear waste reprocessing is essential to the safe utilization and sustainable development of the nuclear industry and nuclear energy. Vitrification is currently internationally recognized as the best solution for the treatment of high-level radioactive waste, and it is also the only high-level waste disposal method that realizes engineering applications. The cold crucible induction melting (CCIM) vitrification technology is one of the key research directions of high-level waste liquid vitrification technologies. As an important part of the cold crucible, the bottom affects the magnetic permeability, sealing, strength and leakage process of the cold crucible. In order to improve the pouring efficiency during cold crucible melting process, the magnetic induction intensity near the discharge port needs to be enhanced. The effects of the design of the crucible bottom on the magnetic induction intensity and electromagnetic loss inside the cold crucible were studied. The 3D electromagnetic induction models of cold crucibles with different bottom structures were established by using the AC/DC module of COMSOL Multiphysics software. The simulation results show that changing the number of slits has little effect neither on the magnetic field inside the crucible, nor on the magnetic field and the electromagnetic loss at the bottom of the crucible. The slit width of crucible bottom increasing from 5 mm to 20 mm, the magnetic flux density inside the crucible increases by about 4%, and the electromagnetic loss of the glass melt domain in the crucible increases by about 1.7 kW (the proportion increased by about 6%). Increasing the length of the slits from 90 mm to 115 mm, the magnetic flux density near the center of the crucible bottom increases by 0.1-1.25 mT, and the electromagnetic loss of the glass melt near the bottom increases by 1.6% (about 0.4 kW). Accordingly, the magnetic permeability and the heating efficiency of the cold crucible can be improved by increasing the slit width. The magnetic induction intensity near the discharge port can be improved by increasing the length of the slits, thereby improving the leakage efficiency. In practical applications, it is not only necessary to improve the heating efficiency of the cold crucible, but also to avoid the leakage of the glass melt at the bottom of the cold crucible during the melting process. Therefore, the structural design of the cold crucible bottom needs to comprehensively consider factors such as the magnetic permeability, the heating efficiency, the strength of the crucible and the processing of water-cooled components inside the slits.

Aim: This study aimed to assess the overall status of burnout in nurses in China on a national scale and investigate the demographic characteristics related to burnout and the relationships between demographics, job satisfaction and burnout. Methods: This was a national cross‐sectional study conducted by the Chinese Nursing Association between July 2016 and July 2017. Data were collected using a structured, self‐administered questionnaire. Results: A total of 51 406 registered nurses in 311 Chinese cities completed the questionnaire. Fifty per cent of the participants suffered burnout, and 33.8% of nurses had high scores on emotional exhaustion, 66.6% had high scores on depersonalization and 93.5% had low scores on personal accomplishment; 16.2% reported a high level of job satisfaction, only 0.4% was satisfied with their jobs and 70.7% intended to leave their jobs. Marital status, educational level, income and years of working experience affected job burnout. Nurses with a high level of burnout were more likely to have a high degree of job dissatisfaction and intend to leave their jobs. Conclusion: We found a high prevalence of burnout among nurses in China. Nursing managers need to pay more attention to job burnout and its influencing factors. Interventions to reduce nurse burnout should be implemented. SUMMARY STATEMENT: What is already known about this topic? Burnout is a prolonged response to chronic job‐related stress and it has a negative effect on job satisfaction and quality of nursing care. What this paper adds? The prevalence of burnout among nurses working in China is high.Marital status, educational level, income and years of working experience affect job burnout.Nurses with a high level of burnout have high job dissatisfaction and intend to leave. The implications of this paper: Nursing supervisors and managers need to be more aware of the high prevalence of job burnout among nurses in China.Interventions should be undertaken to prevent or reduce nurse burnout. [ABSTRACT FROM AUTHOR]