核事故产生的放射性废水处理方法研究进展

核事故会对人们生命安全及环境健康造成巨大危害。为最大限度地控制放射性物质的传播扩散,放射性废水的有效处理和处置应当引起我们足够的重视。本文总结了切尔诺贝利核爆炸、日本福岛核泄漏对放射性废水的处理经验,列举了美国、英国等国推荐使用的有效处理方法,并对吸附法、离子交换法、膜分离法以及联用工艺的研究进展进行了概述,为我国建立和完善核事故放射性废水处理和处置方案提供借鉴。     

An emergency response intercomparison exercise using a synthetically generated gamma-ray spectrum

Although high resolution gamma ray spectrometry serves as the primary analytical technique in emergency response situations, chances for laboratories to practice analysing the type of spectra that may be expected in the early phase of such a situation are limited. This problem is more acute for laboratories in countries that have no nuclear facilities. The analysis of synthetically generated spectra may serve as a useful surrogate for actual spectra; this paper reports the results of a multilateral intercomparison exercise conducted using such a spectrum. Results indicate that the laboratories involved appear to have no problems identifying radioactive isotopes that regularly appear in national and international intercomparisons or exercises. However, some problems are evident for isotopes that are less often encountered which may, however, occur during the early phases of a nuclear accident. Isotopes prone to true coincidence summation proved also to be difficult with regard to correction of activities in some cases. The synthesized spectrum constituted a useful means of comparative analysis of complex spectra multilaterally without the impracticalities of using a sample drawn from a reactor.     

Radiochemistry at the University of Missouri-Columbia: A joint venture with chemistry,nuclear engineering,molecular biology,biochemistry, and the Missouri University Research Reactor (MURR)

Summary The United States, the Department of Energy (DOE) and its National Laboratories, including the Pacific Northwest National Laboratory (PNNL), are facing a serious attrition of nuclear scientists and engineers and their capabilities through the effects of aging staff. Within the DOE laboratories, 75% of nuclear personnel will be eligible to retire by 2010. It is expected that there will be a significant loss of senior nuclear science and technology staff at PNNL within five years. PNNL's nuclear legacy is firmly rooted in the DOE Hanford site, the World War II Manhattan Project, and subsequent programs. Historically, PNNL was a laboratory where 70% of its activities were nuclear/radiological, and now just under 50% of its current business science and technology are nuclear and radiologically oriented. Programs in the areas of nuclear legacies, global security, nonproliferation, homeland security and national defense, radiobiology and nuclear energy still involve more than 1,000 of the 3,800 current laboratory staff, and these include more than 420 staff who are certified as nuclear/radiological scientists and engineers. This paper presents the current challenges faced by PNNL that require an emerging strategy to solve the nuclear staffing issues through the maintenance and replenishment of the human nuclear capital needed to support PNNL nuclear science and technology programs.     

Implementing quality assurance in an R&D environment at the Belgian Nuclear Research Centre – SCK·CEN

If we agree that quality assurance (QA) in R&;D indeed provides added value, just how do we show the public that such a QA system is operating well? At the Belgian Nuclear Research Centre (SCKÖbullet CEN), where a QA system has been implemented by various laboratories in accordance with the EN 45001 standard within the general framework of ISO 9001 at the institutional level, several laboratories have already been accredited. At the request of one of our customers the Belgian Agency for Radioactive Waste Management (NIRAS/ONDRAF), we implemented a quality system for research projects related to the characterization, treatment and processing of radioactive wastes in view of disposal. We obtained accreditation for this research in 1999. In this paper, we discuss the implementation of our QS and important issues related to the overall management of the QA system, broken down into three parts: organizational, technical and project-specific quality elements such as the QA plan and internal communication.     

Nuclear analysis applications in cooperative texas forensic investigation program

For the past two years, a cooperative nuclear forensic investigation program has been in operation in the Nuclear Reactor Laboratory at the University of Texas at Austin. An essential partner in this program has been the Crime Laboratories of the Texas Department of Public Safety, Under this program, both routine analyses of typical physical evidence samples and comprehensive survey analyses of classes of materials with forensic importance have been carried out. Both radioisotope-excited nondispersive X-ray fluorescence and multielement instrumental neutron activation analyses have been used, the first technique for screening incoming samples and performing macro-constituent analyses and the second for performing quantitative trace element analyses. Close coordination of routine analyses with the Crime Laboratories has provided supportive and complementary analyses of physical trace evidence samples for the preparation of investigative results. Carefully selected survey projects, such as the trace element characterization of safe platers and shotgun pellets described in this paper, have contributed to the development of background data available for forensic analysis in other laboratories.     

Documentation of a model action plan to deter illicit nuclear trafficking

Theft, illegal possession, smuggling, or attempted unauthorized sale of nuclear and radiological materials remains a worldwide problem. The Nuclear Smuggling International Technical Working Group (ITWG) has adopted a model action plan to guide investigation of these cases through a systematic approach to nuclear forensics. The model action plan was recently documented and provides recommendations concerning incident response, collection of evidence in conformance with required legal standards, laboratory sampling and distribution of samples, radioactive materials analysis, including categorization and characterization of samples, forensics analysis of conventional evidence, and case development including interpretation of forensic signatures.     

Further development of a graduate program in nuclear and radiochemistry at the University of Texas

Over the last three years we have developed a very robust nuclear and radiochemistry program at The University of Texas at Austin. The cornerstone of support was the DOE Radiochemistry Educational Award Program (REAP) that was awarded from 2002–2005. A second award for the period of 2005–2008 was just received. This award has enabled us to support many educational activities from vanguard classroom instruction, to laboratory enhancements, to research activities at the graduate and undergraduate levels. Both traditional radiochemistry and advanced topics in nuclear instrumentation have been supported. Various DOE university programs, national lab funding and IAEA fellowship grants, have allowed the Nuclear and Radiation Engineering Program at the University of Texas to be at the forefront of nuclear and radiochemistry educational and research activities and help secure the next generation of needed expertise.     

Radioactivity in monitoring materials processing

Monitoring of the concentration of actinides in process streams and waste materials can be effectively carried out by detecting and measuring their radioactive emissions. Such monitoring techniques lead to more efficient control of the process, and also aid in the minimisation of losses to the waste and better accounting of the nuclear materials. This paper provides an overview of some of the techniques such as on-line alpha monitoring, passive and active neutron assay and gamma counting, and also describes the monitoring systems which have been developed in our laboratory for use in a reprocessing plant.     

Study Characteristics of New Concrete Mixes and their Mechanical,Physical, and Gamma Radiation Attenuation Features

Ordinary concrete and those of different compositions are regarded as suitable material in many applications concerning with gamma and neutron radiation shielding purposes. They are widely used in nuclear power plant, medical facilities, nuclear shelters, and for radioactive materials transportation as well as storage of radioactive wastes. In this study four different concrete mixes were prepared with the following different types of coarse aggregates: dolomite, barite, goethite, and steel slag. The effect of changes in the fine aggregates, selected to be 50 % local sand and 50 % limonite with addition of 10 % silica fume (SF) and 10 % fly ash (FA) by replacement of the total cement weight, on the performance of the samples was also investigated. To examine the performance of such samples for radiation shielding applications, a set of physical, mechanical, and radiation attenuation properties was studied and compared with those of ordinary concrete. This investigation includes compressive strength, slump test, bulk density, ultrasonic pulse velocity test, and gamma rays attenuation measurements for the different samples. A verification of the experimental results concerning the radiation attenuation measurements was performed using WinXcom program (Version 3.1). The experimental results revealed that all concrete mixes; goethite‐limonite concrete (G.L), barite‐limonite concrete (B.L), steel slag‐limonite concrete (S.L) and dolomite concrete (D.C) have good physical and mechanical properties that successfully satisfying them as high performance concretes. In addition the barite‐limonite and the steel slag‐limonite have the higher γ‐ray attenuation coefficients at low and high energy range and hence have a better radiation shielding. The obtained results from WinXcom program calculations showed a good agreement with the experimental results concerning γ‐ray attenuation measurements for the studied concrete mixes.     

Environmental monitoring program around Rokkasho nuclear fuel cycle facilities

Three commercial nuclear fuel cycle facilities, a reprocessing plant, an uranium enrichment plant and a low level radioactive waste disposal center, have been constructed or are in partial operation at Rokkasho-mura in Aomori prefecture, about 700 km north of Tokyo. A monitoring program has been settled on the modulation between Japan Nuclear Fuel Ltd. (JNFL) and Aomori Prefectural Govemment. The basic goal of environmental monitoring is to make sure that the dose equivalent received by the public, living around the facilities, is much lower than the annual dose equivalent limit. The target is as follows: (1) to estimate the dose equivalent received by the public, (2) to understand the accumulation of radioactive materials in the environment and (3) to estimate the influence on the environment due to unexpected release from the nuclear facilities and to make judgement for the enforcement of routine monitoring or not. This paper describes the contents of the monitoring program such as the object of nuclides, measuring/sampling point, kinds of samples etc.     

Law enforcement tools available at the Savannah River Site

A number of nuclear technologies developed and applied at the Savannah River Site in support of nuclear weapons material production and environmental remediation can be applied to problems in law enforcement. Techniques and equipment for high-sensitivity analyses of samples are available to identify and quantify trace elements and establish origins and histories of forensic evidence removed from crime scenes. While some of these capabilities are available at local crime laboratories, state-of-the-art equipment and breakthroughs in analytical techniques are continually being developed at DOE laboratories. Extensive experience with the handling of radioactive samples at the DOE labs minimizes the chances of cross-contamination of evidence received from law enforcement. In addition to high-sensitivity analyses, many of the field techniques developed for use in a nuclear facility can assist law enforcement personnel in detecting illicit materials and operations, in retrieving of pertinent evidence and in surveying crime scenes. Some of these tools include chemical sniffers, hand-held detectors, thermal imaging, etc. In addition, mobile laboratories can be deployed to a crime scene to provide field screening of potential evidence. A variety of portable sensors can be deployed on vehicle, aerial, surface or submersible platforms to assist in the location of pertinent evidence or illicit operations. Several specific nuclear technologies available to law enforcement and their potential uses are discussed.     

Advances in the development of a dissolution method for the attribution of iridium source materials

Journal of Radioanalytical and Nuclear Chemistry - To assist in nuclear forensic investigations, new techniques are required to evaluate radioactive materials that may be discovered outside of...     

Nuclear, chemical, and physical characterization of nuclear materials

The goal of nuclear forensics is to establish an unambiguous link between illicitly trafficked nuclear material and its origin. The Los Alamos National Laboratory (LANL) Nuclear Materials Signatures Program has implemented a graded “conduct of operations” type analysis flow path approach for determining the key nuclear, chemical, and physical signatures needed to identify the manufacturing process, intended use, and origin of interdicted nuclear material. This analysis flow path includes both destructive and non-destructive characterization techniques and has been exercized against different nuclear materials from LANL’s special nuclear materials archive. Results obtained from the case study will be presented to highlight analytical techniques that offer the critical attribution information.     

Development of ultrahigh energy resolution gamma spectrometers for nuclear safeguards

We are developing superconducting ultrahigh resolution gamma-detectors for non-destructive analysis (NDA) of nuclear materials, and specifically for spent fuel characterization in nuclear safeguards. The detectors offer an energy resolution below 100 eV FWHM at 100 keV, and can therefore significantly increase the precision of NDA at low energies where line overlap affects the errors of the measurement when using germanium detectors. They also increase the peak-to-background ratio and thus improve the detection limits for weak gamma emissions from the fissile Pu and U isotopes at low energy in the presence of an intense Compton background from the fission products in spent fuel. Here we demonstrate high energy resolution and high peak-to-background ratio of our superconducting Gamma detectors, and discuss their relevance for measuring actinides in spent nuclear fuel.     

State of practice and emerging application of analytical techniques of nuclear forensic analysis: highlights from the 5th Collaborative Materials Exercise of the Nuclear Forensics International Technical Working Group (ITWG)

The Nuclear Forensics International Technical Working Group (ITWG), a community of nuclear forensic practitioners who respond to incidents involving nuclear and other radioactive material out of regulatory control, completed its fifth Collaborative Materials Exercise in 2017 (CMX-5). Forensic laboratories from 19 countries and one multinational organization aimed to advance nuclear forensic science and improve international cooperation in the event of a nuclear material security incident. In all, over 30 analytical techniques were utilized to investigate the samples, many techniques applying novel methods or offering improvements in turnaround time. An objective review of the state of practice and emerging application of analytical techniques of nuclear forensic analysis based upon this exercise is provided.

     

Potential application of aluminum phosphate binder in the treatment of waste containing strontium: effects of SrO content on structures and leaching stabilities of aluminum phosphate solidified systems

Journal of Radioanalytical and Nuclear Chemistry - Solidification of radioactive waste containing strontium is a significant procedure in the nuclear waste treatment and disposal. In this research,...     

Investigation on the radiolytic stability of polybenzimidazole-based polymeric resins for the recovery of lanthanides,actinides, palladium from aqueous medium

Journal of Radioanalytical and Nuclear Chemistry - Radiolytic stability of polymeric resins is an important aspects in nuclear materials processing. The different dosage of gamma radiation was...     

Nuclear forensics—metrological basis for legal defensibility

The admissibility of nuclear forensics measurements and opinions derived from them in US Federal and State courts are based on criteria established by the US Supreme Court in the case of Daubert v. Merrell Dow and the 2000 Amendment of Rule 702 of the Federal Rules of Evidence. These criteria are being addressed by new efforts that include the development of certified reference materials (CRMs) to provide the basis for analytical method development, optimization, calibration, validation, quality control, testing, readiness, and declaration of measurement uncertainties. Quality data is crucial for all stages of the program, from R&D, and database development, to actual casework. Weakness at any point in the program can propagate to reduce the confidence of final conclusions. The new certified reference materials will provide the necessary means to demonstrate a high level of metrological rigor for nuclear forensics evidence and will form a foundation for legally defensible nuclear chemical analysis. The CRMs will allow scientists to devise validated analytical methods, which can be corroborated by independent analytical laboratories. CRMs are required for ISO accreditation of many different analytical techniques which may be employed in the analysis of interdicted nuclear materials.     

Nuclear science education in Taiwan, 1956–1992

The nuclear science education has been established in Taiwan at the College of Nuclear Science, National Tsing Hua University since 1956, the only one among 123 universities and colleges in Taiwan where nuclear-related education is offered. The Nuclear/Radiochemistry program, with nine faculty members, offers bachelor's, master's, and doctorate degrees in Nuclear Science. Lectures and lab classes of nuclear chemistry, radiochemistry, and allied branches in health physics, nuclear instruments, nuclear engineering, nuclear medicine, radiation biology, and environmental monitoring are given to the 17 undergraduate students and 33 postgraduate students currently registered. Support from the well-developed local nuclear power industry and government agencies is converged with rapid growth rate toward the Nuclear/Radiochemistry program; the 1992 annual research contracts for the program amounted over one million US dollars. Careerplacement program for graduates is developed to orientate them into the local nuclear power utilities as well as agricultural, medical, industrial, academic, and govemmental sects where nuclear chemists and radiochemists at all levels are desperately needed.