反应堆退役废金属高压水去污废水回用工艺研究

用高压水射流去污将反应堆退役废金属再循环再利用，会产生相当数量的放射性废水。回用这部分放射性废水可节省放射性废水处理费用，从而降低废金属去污的成本。高压水去污废水中的放射性主要来自于其中的固体颗粒。为此回用废水就要将水中固体颗粒去除。选用离心分离工艺可达到此目的。     

反应堆退役放射性废金属的熔炼处理

反应堆退役将产生大量放射性废金属。熔炼处理可使其减容、再循环再利用。以大量减少放射性废物处置量。回用绝大部分金属．熔炼处理有减容、整备、包容放射性核素、降低比活度、便于放射性监测等优点和产生二次废物、对一些放射性核素的去污效果不理想等缺点．因此，采用这项工艺要预先用其它去污工艺去污，预计去污效果和落实再循环再利用的去向，还必须有效控制二次废物．     

高压水清洗技术在反应堆退役工程中的验证试验

在反应堆退役工程中使用高压水清洗技术对反应堆工艺运输水池、工艺房间、密闭水池和一些特殊设备进行了清洗去污。通过施工前的工程验证试验及工程施工，取得了高压水清洗技术应用于大型核设施去污的1套技术数据。同时针对特殊情况进行了技术改进，使该技术在核设施退役领域中得到进一步完善。     

高压水射流技术在反应堆水池去污中的应用

介绍了某压水堆核电厂反应堆换料水池应用高压水射流去污的工作情况。通过对比去污前后的放射性污染水平,验证了高压水射流技术在反应堆换料水池清洗去污中的效果。     

反应堆退役放射性废金属的熔炼处理

反应堆退役将产生大量放射性废物金属,熔炼处理可使其减容、再循环再利用,以大量减少放射性废物处置量,回用绝大部分金属。熔炼处理有减容、整备、包容放射性核素、降低比活度、便于放射性监测等优点,但会产生二次废物、对一些放射性核素的去污效果不理想等缺点。因此采用这项工艺要预先用其他去污工艺去污,预计去污效果和落实再循环再利用的去向,还必须有效控制二次废物。     

退役核设施中废金属的熔化和回用

[《核欧洲和世界浏览》1994年第1—2期第58页报道] 从核设施的退役中,可以得到大量已被沾污和已被活化的钢和有色金属。鉴于许多国家现在没有,或只有有限的处置放射性废物的能力,这些材料作为放射性废物来处置将会有许多问题。所以,将这些材料重新熔化或去污并加以重新使用是很有益的。     

哈德姆内克核电站的退役去污工作

【英国《国际核工程》 1998年 12月报道】　康涅狄格扬基原子动力公司 (CY)的哈德姆内克 (Haddam Neck)核电厂已经进入退役阶段。在退役的准备过程中 ,该厂选择了西门子公司 (Simens) HP CDRD D UV工艺进行全系统去污。CY开发了一种独特的应用方法 ,它应用主要的电厂设备进行去污 ,而不是用外部去污设备进行去污。CY于 1996年 12月宣布进入退役运行阶段 ,在按 AL ARA(尽可能低地排放放射性废物 )进行了一次仔细的评估后 ,管理人员决定在移走任何主要部件前进行全系统去污工作 (FSD)。其目的是将最初系统的剂量率减少到原来的 1/ …     

重水研究堆退役废物再利用研究

实现废物再利用是废物最小化的重要措施之一,从废物流中将有潜在利用价值的物料分离出来实现再利用可大幅减少对环境的影响。本文以中国原子能科学研究院重水研究堆退役为实例研究了放射性废物再利用问题。通过全面分析和计算重水研究堆在退役期间产生的各类废物,得出具有一定数量的物料有潜在的利用价值,可直接或经适当处理后再利用在其他行业领域中。研究表明,通过采取废物最小化控制措施（如废物分类和废物流分离等）,采用适当的去污技术和执行清洁解控要求,至少可使重水研究堆退役过程中产生的几十吨钢铁、10 t铝材和5 t重水实现再利用。     

核设施退役产生的污染物料的再循环再利用

简要阐述了核设施退役过程产生的主要污染物料）））金属和混凝土的再循环和再利用情况,包括染物料的产生情况、再循环再利用途径、再循环再利用可参考的标准,以及几种污染物料的再循环再利用技术,以期对我国今后核设施退役产生的污染物料的管理提供技术支持。     

退役密封放射源回收再利用现状及存在问题探讨

越来越多的退役放射源对环境造成了很大的压力,对可再利用密封放射源的回收再利用也越来越得到有关部门的重视。本文介绍了我国目前使用的常见密封放射源种类、拥有数量情况,退役或闲置密封放射源的处置及回收再利用现状;并分别就可回收再利用的退役^60Co远距离治疗源、^137Cs工业辐射源、^60Co伽马刀治疗源在本公司再利用的现状,对不能再利用的密封放射源整备收储做了简单介绍;同时针对在退役密封放射源回收再利用领域存在的问题提出建议。     

Sensitivity of Physics Parameters for Establishment of a Burned CANDU Full-Core Model for Decommissioning Waste Characterization

The sensitivity of parameters related with reactor physics on the source terms of decommissioning wastes from a CANDU reactor was investigated in order to find a viable, simplified burned core model of a Monte Carlo simulation for decommissioning waste characterization. First, a sensitivity study was performed for the level of nuclide consideration in an irradiated fuel and implicit geometry modeling, the effects of side structural components of the core, and structural supporters for reactive devices. The overall effects for computation memory, calculation time, and accuracy were then investigated with a full-core model. From the results, it was revealed that the level of nuclide consideration and geometry homogenization are not important factors when the ratio of macroscopic neutron absorption cross section (MNAC) relative to a total value exceeded 0.95. The most important factor affecting the neutron flux of the pressure tube was shown to be the structural supporters for reactivity devices, showing an 10% difference. Finally, it was concluded that a bundle-average homogeneous model considering a MNAC of 0.95, which is the simplest model in this study, could be a viable approximate model, with about 25% lower computation memory, 40% faster simulation time, and reasonable engineering accuracy compared with a model with an explicit geometry employing an MNAC of 0.99.     

Verification of Source Term Estimation Method against Measured Data for Decommissioning Waste from a CANDU Reactor

The method for the establishment of an equilibrium core model proposed in the previous paper and the source term calculation method proposed in this paper for the characterization of decommissioning waste were verified by comparing the nuclide inventory estimated by MCNP/ORIGEN2 simulations with the measured nuclide inventory according to a chemical assay in an irradiated pressure tube discharged from Wolsong Unit 1 in 1994. At first, the time-average pseudoequilibrium full-core model of Wolsong Unit 1 was developed on the basis of the previously proposed modeling method for the activation of in-core and ex-core structural components. Then, the application level of the neutron flux and cross section in the radionuclide buildup calculation were compromised. Fourteen major actinides and fission products were considered to represent the irradiated fuel condition, and a geometry simplification was also introduced in the burned full-core model for MCNP simulation. The assumption of a constant neutron flux and capture cross section as a function of the irradiation time was applied in the radionuclide buildup calculation in ORIGEN2. As a result, the values estimated from the analysis system agreed with the measured data within a difference range of 30%. Therefore, it was found that the MCNP/ORIGEN system and source term characterization method proposed can be viable to estimate the source terms of the decommissioning waste from a CANDU reactor.     

废旧金属回收冶炼的辐射监测管理探讨

剖析了两起发生在废旧金属回收冶炼中的典型放射性污染事故,在分析放射性废旧金属来源和我国现状的基础上,提出了废旧金属回收冶炼的辐射监测应当进行分级管理和加强口岸辐射监测,以及目前亟待解决的几个问题。     

Surface Decontamination of Chemical Agent Surrogates Using an Atmospheric Pressure Air Flow Plasma Jet

An atmospheric pressure dielectric barrier discharge (DBD) plasma jet generator using air flow as the feedstock gas was applied to decontaminate the chemical agent surrogates on the surface of aluminum, stainless steel or iron plate painted with alkyd or PVC. The experimental results of material decontamination show that the residual chemical agent on the material is lower than the permissible value of the National Military Standard of China. In order to test the corrosion effect of the plasma jet on different material surfaces in the decontamination process, corrosion tests for the materials of polymethyl methacrylate, neoprene, polyvinyl chloride (PVC), polyethylene (PE), phenolic resin, iron plate painted with alkyd, stainless steel, aluminum, etc. were carried out, and relevant parameters were examined, including etiolation index, chromatism, loss of gloss, corrosion form, etc. The results show that the plasma jet is slightly corrosive for part of the materials, but their performances are not affected. A portable calculator, computer display, mainboard, circuit board of radiogram, and a hygrometer could work normally after being treated by the plasma jet.     

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。     

Liquid Metal Extraction for Removal of Molybdenum from Molten Glass Containing Simulated Nuclear Waste Elements

Laboratory-scale experiments for removing Mo and MoO3 from molten borosilicate glass were performed using liquid Cu as an extractant. Removal of Mo from the simulated HLW glass containing oxides of Nd, Fe, Zr, Mo, Sn, Ni, Sr, Cd, Ru, and Se was also performed, and the fractions of these elements transferred into Cu were examined. Mixtures of Cu anda ternary SiO₂-B₂O₃-Na₂O glass containing metallic Mo or MoO₃ were heated in an alumina crucible at 1,673K in an Ar environment. The amounts of Mo and MoO₃ added to 10 g of the ternary glass were fixed at 0.1 and 0.15 g, respectively. As for the glass containing metallic Mo, more than 90% of Mo was extracted into liquid Cu. Spherical Cu metal buttons containing Mo formed on the bottom of the crucible when Cu was added at more than 10 times that of Mo on a mass basis. Removal of Mo from the glass containing MoO3 was also achieved by the addition of Si as a reducing agent for the reduction from MoO₃ to Mo. The fraction of Mo extracted into liquid Cu depended on the molar ratio of Si to Cu added to the glass. The fraction increased up to 84% with an increase in the molar ratio of Si/Cu. However, the excess addition of Si may enhance the chemical interaction between the metal phase and the glass phase, and some of the metal phase containing Mo remained in the glass phase without forming a metal button. The optimum molar ratio of Si/Cu that produces the highest removal fraction was found to be approximately 0.5. Almost the same removal fraction of 88% was obtained from the simulated HLW glass under the condition of Si/Cu = 0.5. Nearly 100% of Ru was extracted into Cu with Mo, while Sr, Zr, and Nd were hardly extracted and remained in the glass.     

Control of a High Temperature Supercritical Pressure Light Water Cooled and Moderated Reactor with Water Rods

The plant system of a supercritical pressure light water reactor (SCR) is once-through direct cycle. The whole coolant from the feedwater pumps is driven to the turbines. The core flow rate is less than 1/7 of that of a boiling water reactor. In the present design of the high temperature thermal reactor (SCLWR-H), the fuel assemblies contain many water rods in which the coolant flows downward. The stepwise responses of the SCLWR-H are analyzed against perturbations without a control system. Based on these analyses, a control system of the SCLWR-H is designed. The pressure is controlled by the turbine control valves. The main steam temperature is controlled by the feedwater pumps. The reactor power is controlled by the control rods. The control parameters are optimized by the test calculations to satisfy the criteria of both fast convergence and stability. The reactor is controlled stably with the designed control systems against various perturbations, such as setpoint change of the pressure, the main steam temperature and the core power, decrease in the feedwater temperature, and decrease in the feedwater flow rate.