Luminescent monitoring of metal dititanium triphosphates as promising materials for radioactive waste confinement

The potential use of luminescent probes for control over the structural state of MTi₂(PO₄)₃ double metal phosphates as host materials for radioactive waste confinement is examined. Luminescence spectra of pure and metal (Al, In, V) and rare-earth (Pr, Sm, Dy) doped MTi₂(PO₄)₃ (M = Li, Na, K) phosphate compounds (in crystalline and related amorphous forms) under X-ray, VUV (synchrotron radiation), UV and visible light excitations are analyzed. Electronic structure and absorption spectra of NaTi₂(PO₄)₃ crystals are calculated by the full-potential LAPW method. The origin of the self and impurity emission bands of MTi₂(PO₄)₃ materials is defined. It was shown that nitrogen laser with 337.1 nm generation wavelength is the most effective excitation source for remote monitoring of incorporation of various types of waste elements into MTi₂(PO₄)₃ hosts and for control over states of these hosts during storage of radioactive waste.     

Service-oriented architecture for an overall radioactive waste package record management system

In Taiwan, there are a few radioactive waste package record management systems independently implemented by radioactive waste generators, operators of waste management facilities, transport organizations and storage facilities. To claim compliance of a radioactive waste package record meets with waste acceptance criteria for disposal, an overall radioactive waste package record management system which records and tracks all relevant information, from raw waste characteristics, through changes related to waste processing, to final checking and verification of waste package parameters should be constructed in accordance with IAEA recommendation. Service-Oriented Architecture (SOA) is widely accepted as a new paradigm for integrating heterogeneous systems in an effective way. It has formed a new trend being adopted by organizations in mitigating legacy system problems as in to maximizing interoperability, reusability and flexibility. Based on the current radioactive waste management processes, this paper proposes a three-tier SOA for the further overall radioactive waste package record management system design.     

Regulatory control of the German radioactive waste management system

In Germany, all radioactive materials are controlled from their origin to their final disposal or release. This is in accordance with the IAEA draft Convention on the Safety of Radioactive Waste Management. A Waste Control System has been developed and is now available. Although the IAEA and EU regulations allow disposal outside the country of origin this philosophy is not in compliance with the present German disposal concept. As a consequence, Germany will not grant licences for the import of radioactive waste for final disposal or for export for disposal in a foreign country. Thus, unconditional clearance is a prerequisite if the final destination is outside Germany. However, Germany will closely follow all international developments in the field of radioactive waste disposal.     

The EIX process for radioactive waste treatment

The use of an electric potential in place of chemical reagents to elute ion-exchange media by ion migration, as well as perform redox and pH changing reactions is of considerable importance in simplifying subsequent processing stages, such as, the recovery or disposal of the concentrate. The process has become known as Electrochemical Ion Exchange (EIX). By making multiple and complete use of ion exchange capacity in this way, large volume reduction factors can be achieved for only <5% (depending on the feed concentration) of the energy required for evaporation.

AEA Technology has developed EIX over the last decade from concept to pilot demonstration, and during the last five years has gained vast experience in the design, build and operation of pilot systems (often as one stage integrated into a larger processing plant) for a variety of applications. The principal application areas for EIX relate to the removal/recovery of metals from aqueous streams[1]. These include: the decontamination of streams produced by Pressurised Water Reactors (PWRs) and the separation of radioactivity from tank waste storage facilities, the selective removal and recovery of precious metals from metal refining operations and base metals from electroplating rinse waters, the treatment of hospital waste (active) streams and the removal of silver from photographic wash waters[2]. The process has also been used successfully to remove toxic heavy metals, such as arsenic, from drinking water supplies.

The technology has proven to be both robust and reliable. Direct comparison with ion exchange and evaporation has demonstrated significant cost savings for the majority of applications listed above.     

基于WebGIS的北山高放废物处置地学信息系统的研究

讨论了WebGIS技术,选择GeoServer和PostgreSQL等开源软件来搭建WebGIS系统,采用Web浏览器、WebGIS服务器和数据服务器三层构架。将使用ASP.NET技术开发基于WebGIS的北山高放废物处置地学信息系统,使用户通过Internet,以图形化的方式方便地浏览、操作和分析北山地区各种地学信息,从而实现高效的地学信息共享,为北山地学信息的管理决策提供科学依据。     

某同位素生产线放射性废气处理系统设计

为确保某同位素生产线项目产生的气态放射性流出物能满足排放标准,根据释放源项及气体流量,对比了加压衰变法与滞留床吸附法的优缺点。借鉴国内核电站放射性废气处理系统的工艺设计,提出了“碱洗+冷冻除湿+吸附干燥+活性炭滞留”联合工艺。文章中详细介绍了处理工艺流程、主要设备的参数设计及滞留床活性炭用量的优化计算,对废气处理装置的功能、系统流程、系统配置、布置方案等进行阐述,给出装置总体设计方案。装置设计完毕后进行了相应的试验,单床滞留时间4.6 h(以Kr-85计),优于设计值。干燥装置压降在216~274 Pa之间、滞留装置单床压降在183~310 Pa之间,均满足设计指标要求,在安全性、经济性和可实施性方面作到了较好的综合平衡。     

双通道人工放射性气溶胶监测系统设计

人工放射性气溶胶的监测环境较为复杂,有时甚至要在地下洞库、坑道或地下核设施测量,其环境中氡及其子体产物的浓度高达10~3-10~4 Bq·m~(-3)。在高氡钍环境下,氡钍能峰拖尾导致其放射性计数影响了人工气溶胶道址计数,进而影响人工放射性气溶胶的探测下限。本文研制了一种适合在高氡环境下工作的常压、真空双通道人工气溶胶监测仪。虽然常压测量通道测量准确度较差,但响应速度快,可以弥补真空测量通道测量准确但响应速度慢的缺点。本仪器对大气环境中钚、铀气溶胶检测的响应时间快,在有人工核素泄露的情况下最快30 min内可以得到测量结果,理论探测下限可达到10~(-4)-10~(-3) Bq·m~(-3),可验证探测下限为铀0.1 Bq·m-3、钚0.02 Bq·m~(-3),适用于各类需要对人工核素进行无人监测的高氡环境场所。     

CPR1000机组固体废物处理系统及其调试

CPR1000核电机组固体废物处理系统负责电站运行期间产生的各类固体放射性废物的收集、贮存及处理,系统涉及水泥固化、混凝土固定、超级压缩处理等废物处理工艺。本文就系统处理源项、系统工艺流程、系统调试启动进行介绍,并着重就CPR1000机组固体废物处理系统与目前国内其它电站的差异性进行论述,对其存在的不足及后续系统改进优化提出合理化提议。     

国外高放废物地质处置库地下实验室环境监测与影响评价浅析

系统分析芬兰ONKALO地下实验室环境监测要素和因子,梳理美国尤卡山高放废物处置库环境影响评价工作内容,与我国拟建地下实验室进行对比分析,为我国相关研究及后续处置库环境影响评价提出工作建议。     

加压贮存和活性炭吸附在核电站放射性废气处理中的应用

加压贮存和活性炭吸附是目前国内处理压水堆核电站放射陛废气最常用的两种方法。以大亚湾核电站和田湾核电站的放射性废气处理系统为例,并结合国内其他核电机组同类系统,分别介绍这两种方法在国内核电站的应用情况,并分析它们各自的优缺点：加压贮存系统结构简单但设备体积庞大,适合处理流量变化较大的放射性废气;活性炭吸附具有安全性高,操作简单的特点,适合于处理流量较小的放射性废气。     

环境γ剂量率及放射性气溶胶连续监测系统

通常环境核监测系统主要对γ剂量率进行连续监测，而气溶胶的监测仍然以人工定时取样测量为主。介绍了一种环境核监测设备，在对γ剂量率进行连续监测的同时，实现了放射性气溶胶取样、测量和数据处理的自动化过程。     

高放废物地质处置中的工程材料

凡人类从事于与核材料有关的许多生产、生活活动均可能产生不同活度的放射性废物.高放废物由于具有放射性水平高、发热量大、核素寿命长等特点,其安全处置倍受全球科学家和广大公众所重视.目前深地质处置被国际上公认为处置高放废物的最有效可行的方法.借鉴已有研究成果,我国采用多重工程屏障系统(包括废物固化体、废物罐及其外包装和缓冲/回填材料)和适宜的地质围岩地质体共同作用来确保高放废物与生物圈的安全隔离.参照国际上该领域的研究成果,结合我国处置概念,本文就高放废物地质处置中的工程材料(废物固化体、废物罐、外包装、缓冲材料、回填材料),以及其材料选择、设计要求和研究重点等进行了总结.     

江苏省城市放废库辐射环境监测水平研究北大核心CSCD

随着核技术在各领域的广泛应用,辐射环境的安全受到越来越多的重视。以江苏省城市放废库为研究对象,从2015年起连续对放废库进行辐射环境监测6年。对放废库周围的γ辐射空气吸收剂量率,水源水中总α、总β以及土壤中放射性核素进行了监测,并对辐射监测结果进行了分析。研究结果表明γ辐射空气吸收剂量率敏感点范围为59.0~96.5 nGy/h,源库四周范围为81.92~103.32 nGy/h;水源的总α和总β范围分别为0.90×10^(-2)~5.87×10^(-2)Bq/L和3.00×10^(-2)~16.00×10^(-2)Bq/L。γ辐射空气吸收剂量率的变化主要与源库的距离和废源的管理有关;水体中放射性水平变化主要与年降水量有关;土壤中核素的变化主要与放射性气溶胶有关。所有变化均在本底范围内涨落,对环境几乎没有影响,可以确保辐射环境安全。     

Characterization and storage of radioactive zeolite waste

For the safe storage of zeolite wastes generated by the treatment of radioactive saline water at the Fukushima Daiichi Nuclear Power Station, this study investigated the fundamental properties of herschelite adsorbent and evaluated its adsorption vessel for hydrogen production and corrosion. The hydrogen produced by the herschelite sample is oxidized by radicals as it diffuses to the water surface and thus depends on the sample's water level and dissolved species. The hydrogen production rate of herschelite submerged in seawater or pure water may be evaluated by accounting for the water depth. From the obtained fundamental properties, the hydrogen concentration of a reference vessel (decay heat = 504 W) with or without residual pure water was evaluated by thermal–hydraulic analysis. The maximum hydrogen concentration was below the lower explosive limit (4%). The steady-state corrosion potential of a stainless steel 316L increased with the absorbed dose rate, but the increase was repressed in the presence of herschelite. The temperature and absorbed dose at the bottom of the 504 W vessel were determined as 60 °C and 750 Gy/h, respectively. Under these conditions, localized corrosion of a herschelite-contacted 316L vessel would not immediately occur at Cl^? concentrations of 20,000 ppm.     

我国核电厂流出物监测和辐射环境监测标准体系研究

为了适应我国核电快速发展新形势下环境辐射安全监督管理要求,并更好地指导核电厂的流出物监测和辐射环境监测工作的开展,需要对现有监测标准体系进行梳理和分析,推动标准体系的完善。本文分析了目前我国核电厂流出物监测和辐射环境监测标准的技术要求,提出了我国现行标准体系需要补充和修订的标准清单及修订和完善的建议,为加强和完善我国核电厂流出物监测和辐射环境监测的监督管理提供参考借鉴。     

An improved segmented gamma scanning for radioactive waste drums

In this paper, the equivalent radius of radioactive sources in each segment is determined by analyzing the different responses of the two identical detectors, and an improved segmented gamma scanning is used to assay waste drums containing mainly organic materials, and proved by an established simulation model. The simulated radioactivity distributions in homogenous waste drum and an experimental heterogeneous waste drum were compared with those of traditional segmented gamma scanning. The results show that our method is good in performance and can be used for analyzing the waste drums.     

Shielded containers for radioactive waste using recycled contaminated metals

A family of shielded containers constructed of recycled contaminated lead and stainless steel from the US Deptartment of Energy (DOE) stockpile have been developed as a joint effort by the Idaho National Engineering and Environmental Laboratory and Lockheed Martin Energy Systems-Oak Ridge. The containers were designed primarily for the transportation and storage of 30- or 55-gallon drums of remote handled transuranic solid waste (RH-TRU). The use of recycled construction materials fulfills two purposes: (1) waste transportation and storage and (2) a reduction in the quantity of contaminated metals that require both storage and disposal. Currently, the DOE complex has millions of pounds of contaminated lead and stainless steel. Non-linear, dynamic finite element analyses were used to simulate the drop tests onto a rigid surface required for US Deptartment of Transportation (DOT) 7A Type A certification. During and after these tests, the container contents must remain within the container and shielding must not be reduced. Loads in the major connections and strains in the stainless steel and lead were monitored as a function of time during dynamic impact analyses for three simulated drop orientations. Results were used to optimize the final design. Stainless steel and lead were found to have maximum strains well below ultimate levels except at an impact corner where additional deformation is acceptable. The predicted loads in the connections indicate that some yielding will occur but the containment and shielding will remain intact. The results provide assurance that the containers will pass the required DOT certification tests. The methods used can be applied to other waste shipping containers allowing for optimization of designs without the expense of actual impact testing.