This study proposes a method for^(99)Mo production via electron accelerator irradiation of a natural-uranium-bearing liquid molten salt target,with advantages including low nuclear proliferation risk,online extraction...This study proposes a method for^(99)Mo production via electron accelerator irradiation of a natural-uranium-bearing liquid molten salt target,with advantages including low nuclear proliferation risk,online extraction capability,and low construction costs.The approach primarily produces^(99)Mo through photofission of uranium(~95%),specifically^(238)U(γ,f).Secondary neutrons,originating from photonuclear interactions or fission processes,contribute minimally(~5%)to^(99)Mo production owing to their high energies and low fission cross sections.Key parameter analyses revealed that fluoride salt systems exhibit higher^(99)Mo yield.Their performance stems from high bremsstrahlung energy loss rate and superior photon yield,making them optimal molten salt target materials.To maximize photofission and photoneutron cross sections while minimizing highenergy gamma ray shielding requirements,an electron beam energy range of 40-80 MeV is recommended.To suppress local hot spots and prevent molten salt boiling,flow conditions were introduced to enhance convective heat transfer,effectively reducing the peak temperature.At a flow velocity of 0.5 m/s and under 80 MeV energy conditions,the maximum system temperature is only 808.9 K,which is significantly lower than the boiling point of 1773 K.Under optimized parameters,the maximum annual production capacity of~(99)Mo reaches 4486.49 Ci,sufficient for millions of diagnostic procedures and equivalent to 16.37% of China's projected demand for 2030.This method provides a viable pathway for stable,large-scale^(99)Mo production.展开更多
Albira SI小动物单光子发射断层显像-X线计算机体层成像仪(SPECT-CT)是单光子放射性药物临床前研究的先进影像工具,其质量控制及检测性能是图像质量和实验数据可靠性的基本保障。为评价Albira SI SPECT-CT设备应用的真实性、可靠性,采...Albira SI小动物单光子发射断层显像-X线计算机体层成像仪(SPECT-CT)是单光子放射性药物临床前研究的先进影像工具,其质量控制及检测性能是图像质量和实验数据可靠性的基本保障。为评价Albira SI SPECT-CT设备应用的真实性、可靠性,采用临床常用单光子核素^(99m)Tc对Albira SI小动物SPECT-CT进行季度性质量控制,同时进行测量结果的线性、稳定性、偏差的检测,并初步尝试小动物骨代谢扫描。结果表明,该设备与放射性活度之间线性关系良好,稳定性强,与常用活度测量设备测量结果差异较小。Albira SI小动物SPECT-CT能够准确反映单光子核素^(99m)Tc的放射性活度分布,小鼠骨代谢显像效果好,适用于临床前放射性药物研究。本研究中建立的系统研究SPECT-CT性能的方法可为类似设备的操作提供方法学依据。展开更多
基金supported by the National Natural Science Foundation of China(Nos.12435012,12175300,and 12475185)Shanghai Natural Science Foundation(No.24ZR1478500)Nuclear energy development project(HNKF202210(24))。
文摘This study proposes a method for^(99)Mo production via electron accelerator irradiation of a natural-uranium-bearing liquid molten salt target,with advantages including low nuclear proliferation risk,online extraction capability,and low construction costs.The approach primarily produces^(99)Mo through photofission of uranium(~95%),specifically^(238)U(γ,f).Secondary neutrons,originating from photonuclear interactions or fission processes,contribute minimally(~5%)to^(99)Mo production owing to their high energies and low fission cross sections.Key parameter analyses revealed that fluoride salt systems exhibit higher^(99)Mo yield.Their performance stems from high bremsstrahlung energy loss rate and superior photon yield,making them optimal molten salt target materials.To maximize photofission and photoneutron cross sections while minimizing highenergy gamma ray shielding requirements,an electron beam energy range of 40-80 MeV is recommended.To suppress local hot spots and prevent molten salt boiling,flow conditions were introduced to enhance convective heat transfer,effectively reducing the peak temperature.At a flow velocity of 0.5 m/s and under 80 MeV energy conditions,the maximum system temperature is only 808.9 K,which is significantly lower than the boiling point of 1773 K.Under optimized parameters,the maximum annual production capacity of~(99)Mo reaches 4486.49 Ci,sufficient for millions of diagnostic procedures and equivalent to 16.37% of China's projected demand for 2030.This method provides a viable pathway for stable,large-scale^(99)Mo production.
