电渗析处理模拟放射性废物焚烧工艺废水的实验研究

放射性废物焚烧系统在运行过程中会产生一定量的低放工艺废水。废水处理时,其所含Cl-会对蒸发设备造成腐蚀,含HCO3-对离子交换柱产生解吸作用,影响放射性核素吸附的效果。对此,研究建立了一套电渗析处理系统,进行了NaCl溶液直流脱盐实验和循环脱盐实验、阴离子选择透过性实验、模拟工艺废水的电渗析处理实验,确定了工艺流程和操作参数。结果表明:模拟废水经处理后非放射性物质含量满足国家排放标准,产生的浓缩液达到废水处理平衡浓度,符合工艺废水处理要求。     

辐照加工宝石的放射性测量研究

利用辐照进行天然宝石改色,能显著提升宝石的观赏价值和商业价值。但经反应堆辐照后的宝石含有人工放射性核素,会对相关人员产生照射。本文利用γ能谱分析方法对辐照宝石进行了直接放射性测量。采用实验和蒙特卡罗模拟相结合的方法分析了辐照宝石的几何结构、密度对其γ能谱测量准确性的影响,得到探测效率与能量、样品质量的修正公式,从而实现了无需磨制过程的辐照宝石放射性的γ能谱准确测量。     

建材产品中放射性的研究

应用γ能谱仪和最小二乘法解析谱方法,研究了31种地板砖中放射性核素的含量,发现不同地板砖中U、Th、Ra和^40K的放射性含量有较大的差别,少数产品的含量甚至超出了国家规定的建材放射卫生防护标准。     

220Rn子体结合态放射性气溶胶粒径分布实验研究

放射性气溶胶粒径分布是评价环境中Rn、Tn子体所致呼吸道内照射剂量的重要参数.采用CR-39作探测器,ThB作示踪粒子,反推计算得到了Tn子体结合态气溶胶的中位径(CMD)和方差(GSD).在广东省阳江市(高本底地区)进行的现场测量结果表明,CMD分布为30～130 nm,GSD分布为1.9～3.3.与北京大学技术物理楼的实验结果相比较可知,潮湿的农村的CMD较小,且环境越潮湿,CMD一般会越小.另外,通风对气溶胶粒径的影响也很明显,砖房在通风状况好的情况下有较大的CMD.砖房的CMD普遍比水泥房间的小.     

放射性树脂微球的制备研究

肝癌外照射治疗受正常肝组织耐受量的影响而被认为无效。原因是肿瘤杀伤剂量在120Gy以上，而正常肝组织接受剂量30Gy即可引起放射性肝炎。因此，肝癌内照射治疗（介入放射治疗）逐渐引起人们的关注。多种途径应用不同放射性核素的内照射治疗不断被应用到动物及临床试验中，并取得了一定疗效。     

秦山核电二期工程厂址建筑物群对气态放射性排放物扩散影响的实验研究

在环境风洞中，对于一定的模拟区域和气态污染物排放源，通过释放示踪气体做大气扩散模拟实验，是当今环境空气质量评价与研究的一个有效途径。本文通过风洞模拟实验，对秦山核电二期工程厂址建筑物群周围的流场特征和烟羽弥散规律进行了研究，给出了一个估算复杂建筑物周围地面空气中污染物浓度分布的计算模式     

镅的器壁吸附及其对扩散池实验的影响

针对北山地下水介质中镅（Am）在花岗岩内的扩散池实验中出现的Am在器壁上的吸附现象进行研究和分析。对扩散池实验的监测结果表明,母液内Am活度随时间显著降低。通过对可能产生该现象的几种原因进行分析和实验验证,确定了Am在器壁上的吸附损失是导致母液内Am活度降低的首要原因。Am在器壁上的吸附行为主要由Am的赋存形态决定。由于Am的赋存形态常随pH变化而改变,因此,pH对Am的器壁吸附行为影响很大。通过对可能降低Am器壁吸附损失的措施进行分析和探索,结果表明,对于像Am一样的强吸附性核素,不宜选择扩散池法研究其扩散行为。     

秦山核电二期工程厂址建筑物群对气态放射性排放物扩散影响的实验…

在环境风洞中，对于一定的模拟区域和气态污染物排放源，通过释放示踪气体做大气扩散模拟实验，是当今环境空气质量评价与研究的一个有效途径。本文通过风洞模拟实验，对秦山核电二期工程厂址建筑物群周围的流场特征和烟羽弥散规律进行了研究，给出了一个估算复杂建筑物周围地面空气中污染物浓度分布的计算模式。     

Stainless steel containers for the storage of low and medium level radioactive waste

Corrosion investigations have been performed on the austenitic structural steel AISI 304L, in comparison with the structural steel AISI 316L, in an aerated and a de-aerated solution, which was leached from low and medium level radioactive waste. On the basis of measured potentio-dynamic anodic polarization curves and the results of cyclic polarization tests, it was found that both types of steel, as well as the corresponding welds, had a high pitting potential and a high protective potential, which means that they have a strong tendency to form a compact and corrosion-resistant passive film. The repassivation capability of both types of steel prevents the occurrence of stress corrosion cracking at the level of concentration of chloride ions which corresponds to the described type of waste, whereas absorbed atomic hydrogen does not reduce toughness or cause hydrogen embrittlement. The results of the research work confirmed that it is possible to use AISI 304L structural steel for the construction of containers for the temporary, 30-year storage of low and medium level radioactive waste.     

中放废液的远红外蒸发处理技术研究

本文研究了用远红外蒸发技术处理中放废液的工艺条件及影响因素。探讨了远红外加热器的加热距离、系统负压、废液的pH值对各种核素(~(137)Cs、90Sr、~(147)Pm、~(95)Zr-~(95)Nb)和1AW废液的蒸发速率和去污因数影响。并对本所0.7吨中放废液进行了实际处理,二次蒸汽冷凝液的放射性浓度为1×10~(-9)Ci/l,浓缩倍数35,蒸残液已近半固体状态,需要进一步固化处理。     

高放废物地质处置安全全过程系统分析研究进展

高水平放射性废物(以下简称“高放废物”)地质处置安全全过程系统分析是对处置库长期安全的综合性系统分析。本文论述了安全全过程系统分析的概念及近20年发展情况,强调了其在高放废物地质处置库规划、选址、设计、建设、运行、关闭和关闭后等各阶段的重要性。以国际原子能机构(IAEA)和经合组织核能署(NEA)技术文件为主,阐述了安全全过程系统分析的背景、安全策略、评价基础、安全评价及综合等核心组成部分,列举了其应用中管理和技术方面的12个关键点,分析了芬兰、瑞典、美国和法国的研究应用现状,并对我国放射性废物地质处置安全全过程系统分析的发展及应用现状进行了探讨。     

放射性废物处置安全全过程系统分析及有关问题的探讨

本文根据IAEA第SSG-23号安全导则,对放射性废物处置安全全过程系统分析及其在英国、法国、美国、芬兰、瑞士、瑞典等国家放射性废物处置中的应用情况作了概括性的介绍。结合我国放射性废物处置管理的现状,对我国处置场的环境影响评价和安全分析中存在的主要问题进行了探讨。为促进我国安全全过程系统分析工作的全面开展,建议加快制定相关标准,将“安全全过程系统分析”作为我国放射性废物处置的许可条件,在景象开发、长期演变、坚稳性、不确定性、管理系统等方面加强研究。     

自碎式消污液清除室内壁面放射性粉尘试验研究

针对室内壁面放射性污染粉尘控制与清除的难题,提出一种自碎式消污液进行放射性污染控制与清除方法,研发了专用的喷射器、碎片回收器和自碎式消污液,对专用设备的作业性能进行了测试,两种设备的作业性能均较好地满足使用要求。为检验研发的自碎式消污液对放射性粉尘的污染控制与清除效果,采用铀矿粉为目标粉尘,设计进行了自碎式消污液对混凝土、玻璃和大理石三种介质表面放射性粉尘的去污试验。结果表明,自碎式消污液对于混凝土、玻璃和大理石表面的放射性粉尘的去污率可以达到85%以上。验证了自碎式消污液对放射性粉尘的去污效果,可为工程应用提供参考。     

Experimental study on the direct contact condensation of steam jet in the passive safety injection tank

The direct contact condensation and subsequent thermal mixing by the injected steam jet onto a quiescent coolant inside a tank were examined experimentally to simulate the phenomena in passive safety injection systems. Specifically, the influence of the steam injection velocity was studied. Even though the total flow rate of injected steam was unchanged, the pressure inside the tank increased quickly at the larger nozzle diameter. Additionally, at a larger nozzle diameter, the thickness of the thermal mixing zone decreased because the amount of direct contact condensation decreased. For the in-depth study on the role of the nozzle size for the thermal mixing, the particle image velocimetry method was used to understand the flow field of water inside the tank. The visualization results demonstrated the formation of a flow field in the coolant due to the expansion and contraction of the steam–air mixture boundary. Furthermore, the thermal mixing zone was found to be closely related to the penetration depth. Finally, a variety of penetration models were examined and compared against the experimental observation. The correlations based on the steam condensation approach under-predicted the penetration depth, whereas the approach that considers the momentum of non-condensable gas gave the reasonable prediction capability.     

气动式脉冲液体射流泵性能实验研究

实验研究了喷嘴直径为5 mm,扩散管直径分别为5、7 mm,提升高度为6.7 m的气动式脉冲液体射流泵的性能。结果表明:料桶内的液面高度对气动式脉冲液体射流泵的效率、扬程、输送量影响甚微,而随着操作压力的增加,脉冲液体射流泵的效率、扬程、输送量也增大。证明了在本实验条件下,最佳喷嘴间距与喷嘴直径之比为0.8～2.0范围内,并讨论了不同喷嘴间距所对应的最低操作压力条件。     

A comparative study of engineering options for the disposal of high-level radioactive waste with regard to thermal effects and chemical degradation

The disposal of high-level radioactive waste in deep geological repositories requires stable and foreseeable physical conditions over very long time scales. During this period, the chemical stability of both the natural and the engineered barriers is governed by thermally activated processes. These in turn are driven by the heat pulse generated by the nuclear decay of waste products. The technical concept to cap the temperature peak in the repository is thus an important aspect for the proof of safety of disposal facilities. It is shown that densely stocked repositories, as currently foreseen in several countries, do not necessarily represent the optimal choice with regard to temperature effects, long-term reaction kinetics and chemical degradation of components. It is suggested that the optimization of the temperature peak rather than the fulfillment of cut-off conditions for peak temperature should be a cardinal issue in engineering concepts.     

Experimental study on the sub-atmospheric loop heat pipe passive cooling system for spent fuel pool

As one kind of the natural circulation cooling system, loop heat pipe is promising in improving the safety of the nuclear power station since it is passive and has no electricity driven components. A novel heat pipe cooling system is designed for passively removing the residual heat released by the spent fuel stored in the spent fuel pool (SFP) under the accidental conditions such as the station blackout. This system is characterized by its large-diameter and long-length evaporator. Its working fluid is water and it's sub-atmospheric. To test such system's heat transfer performance and get to know its thermo-fluid dynamics, a test facility for a simplified heat pipe made of one evaporator tube and one condenser has been developed. The heat transfer rate of the simplified heat pipe is obtained in a wide range of conditions covering the potential working conditions in spent fuel pool. Moreover, it's found that heat pipe with such a large-diameter and long-length evaporator is vulnerable to be unstable. The periodic state mode is more likely to happen when the heat source temperature, the air velocity or the volumetric filling ratio is low. Furthermore, the effects of hot water temperature, the air velocity and the filling ratio of the water in the circulation system have been analyzed.     

低中放废物处置FEPs清单建立的方法研究

识别所有影响处置场长期安全的有关因素,即特征(Features)、事件(Events)和过程(Processes)(FEPs),是处置场安全全过程系统分析的关键过程之一。我国目前低中放固体废物处置场环境影响评价中未开展低中放处置场的FEPs识别和景象开发。本文拟以某处置场为例,对如何建立我国的低中放废物处置FEPs清单进行了初步的探讨。