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.A lead-based reactor with employing heat pipes as passive residual heat removal system (PRHRS) for longterm decay heat removal was designed. Three-dimensional computational fluid dynamics (CFD) software FLUENT was adopted to simulate the thermal-hydraulic characteristics of the PRHRS under Station-Black-Out (SBO) accident condition. The results showed that heat in the core could be removed smoothly by the PRHRS, and the core temperature difference is less than 20 K.

Background: Percutaneous intervertebral radiofrequency thermocoagulation (PIRFT) and sinuvertebral nerve ablation (SVNA) are commonly used clinical treatments for discogenic low back pain (DLBP). However, they have been reported to have low efficacy rates of approximately 16.5%-26.5%, especially in the medium to long term., Objectives: To investigate whether PIRFT combined with SVNA can reduce pain and improve clinical outcomes in patients with DLBP., Study Design: This is a prospective study., Setting: All data were from Honghui Hospital in Xi'an., Methods: Following the inclusion and exclusion criteria, 195 patients were enrolled in this study and randomly divided into 3 groups of 65 patients each and treated with PIRFT+SVNA, PIRFT, or SVNA. Postoperative follow-ups were done at one week, one month, 3 months, 6 months, and 12 months. The demographic characteristics, relevant surgical information, and observed complications of all groups were recorded. The efficacy of the surgeries was evaluated using the visual analog scale (VAS), Oswestry disability index (ODI), and modified Macnab criteria., Results: In total, 167 patients, comprising 81 men and 86 women (aged 28-75 years), were included in this study and completed postoperative follow-ups. There were 54 patients in the combined PIRFT and SVNA (PIRFT+SVNA) group, 58 patients in the PIRFT group, and 55 patients in the SVNA group. All groups were comparable because there were no significant differences in gender, age, disease duration, follow-up time, surgical segments and presence of high-intensity zones of the groups (P > 0.05). In addition, the efficacy of the PIRFT+SVNA group was significantly higher than that of the PIRFT and SVNA groups as assessed by the modified Macnab criteria (P = 0.032). Surgery was successfully completed in all 3 groups, and VAS and ODI improved at all postoperative time points in all 3 groups compared to the preoperative scores. The differences between the VAS and ODI scores preoperation and 12 months postoperation were not statistically significant between all 3 groups. However, at one week, one month, 3 months, and 6 months after surgery, the VAS and ODI scores were lower in the PIRFT+SVNA group compared to the PIRFT and SVNA groups. The difference in VAS scores among the 3 groups was most significant at one week postoperation, and the difference in ODI scores was most significant at one month postoperation. The VAS and ODI improvement rates of the 3 groups showed significant improvement at one week, one month, 3 months, and 6 months postoperation (P < 0.05). There was no significant difference among the 3 groups at 12 months postoperation (P > 0.05)., Limitations: This study was limited by its small sample size in a single-center study., Conclusions: In DLBP, the sinuvertebral nerve (SVN) is the main nerve involved in the lumbar disc pain signaling pathway, and compared with PIRFT and SVNA alone, combined PIRFT and SVNA treatment may provide more satisfactory pain relief and functional improvement at an early stage.