~(222)Rn/~(220)Rn子体连续测量仪研制

实验研制了基于α能谱法的~(222)Rn/~(220)Rn子体连续测量仪。该仪器采用微孔滤膜采样,采用PIPS探测器与α能谱测量技术实现~(222)Rn、~(220)Rn子体的α粒子计数与测量。实验测试表明:在不更换滤膜的前提下,可实现~(222)Rn/~(220)Rn子体的活度浓度及潜能的有限次连续测量;测~(222)Rn、~(220)Rn子体活度浓度的下限为10 Bq/m~3,~(222)Rn子体活度浓度为100 Bq/m~3时的测量合成不确定度优于10%。     

氡室^222Rn／^220Rn采样的实时监测与控制系统设计

提出了以Intel 51系列单片机为控制核心的.222Rn/220Rn采样监测与控制系统设计方案.硬件部分对传感器、A/D转换器件、USB芯片、键盘和数码显示芯片、光耦隔离与直流泵驱动芯片的选择和使用进行了详细介绍,并给出了电路设计简图;软件部分包括上下位机软件,分别通过Visual Basic语言和汇编语言实现数据采集转换及直流泵流量控制,并采用PID控制算法对泵流量稳定性进行改善,给出了程序流程图.     

丝网扩散组模拟测量222Rn/220Rn子体在人体呼吸道沉积的研究进展

氡及其子体所致的公众集体剂量占天然电离辐射剂量的份额约55％,氡对人体内照射的主要剂量贡献是它们的子体。本文简要介绍了环境中。^222Rn／^220Rn子体气溶胶的主要特性,概述了丝网扩散组测量^222Rn／^220Rn子体气溶胶粒径分布的基本原理,总结了利用丝网扩散组模拟测量。^222Rn／^220Rn子体在人体呼吸道沉积的研究进展。展望此领域,应当进一步细化呼吸道中气溶胶的沉积模型以更加准确地测量评价,且亟需开发适用于现场大范围调查的测量手段。     

密闭空间氡浓度垂直分布规律的实验研究

为了验证氡浓度可能存在垂直分布规律,通过被动式测氡法——活性炭盒测氡法开展了氡浓度垂直分布规律的验证性研究。结果表明,在该实验场所的0．04m至3．01m处氡浓度从73．12Bq／m3降至51．89Bq／m3,初步验证了氡浓度上低下高的垂直分布规律。之后,在同一场所又进行了一次实验,实验结果再次验证了之前的结论。该规律对地下建筑内的工作人员的剂量评价工作开展具有一定的指导意义。     

利用组件式GIS开发砂岩型铀矿综合评价信息系统

组件式GIS具有功能灵活、使用方便等特点,适合于开发地学领域专业GIS应用系统。在铀资源勘查评价过程中,计算机应用系统已成为必不可少的有力工具,而且应具备专业处理、海量数据的管理与存储、空间分析、可视化与制图输出等功能。提出了基于ArcGIS Engine开发砂岩型铀矿铀资源综合评价信息系统的技术路线,利用ArcGIS Engine可以方便快速地实现GIS功能,因此,开发人员能将大部分精力致力于专业功能的开发。开发出的系统运行稳定、功能灵活、具有较强的专业性。     

Development of an integrated methodology in support of remaining life assessment of Co-60 based gamma irradiation facilities

An integrated approach has been developed for the remaining life assessment of an irradiation facility. The probabilistic safety assessment (PSA) was performed for the plant to develop the quantified indicators of safety for various situations. PSA results were used to identify and prioritize the systems and components for deterministic assessment. The insight developed from various accidents world over has also been used as an input to investigate the likelihood of such failures and assessment of safety provisions against such failures. This paper discusses development of safety indicator in details and touches upon the other aspects as and when required. The objective is that the extended life of the facility should be predicted in a manner that likelihood of accident is low. As far as Cobalt-60 based Gamma Irradiation Facilities are concerned a survey of available literature shows that this study is unique in three respects; (a) it is for the first time that such a comprehensive re-assessment work has been performed on an irradiation facility. (b) In this study an integrated framework has been developed and applied for safety reassessment of Gamma Irradiation Plant (ISOMED) for Sterilization of Medical Products) one of the oldest, category - II type Cobalt-60 based Gamma Irradiation Facilities in the world and (c) A procedure has been developed in support of regulatory re-licensing and life extension of the Cobalt-60 based Gamma Irradiation plant. Based on this study eleven recommendations dealing with system retrofitting, change in operation and maintenance practices and further testing and qualification to get added confidence as part of life extension programme. Even though this study recommended life extension of ten years the first regulatory clearance of three years was given by the regulatory agency.     

Development of Three-Dimensional Numerical Model for 222Rn and Its Decay Products Coupled with a Mesoscale Meteorological Model II. Numerical Analysis on the Increase in Gamma Dose Rate Observed in the Coastal Area of Fukushima Prefecture

A three-dimensional Eulerian numerical model for ²²²Rn and its decay products coupled with a mesoscale meteorological model, MM5-TMNR, is applied to investigate the mechanism of the naturally induced increase in gamma dose rate observed at the coastal area of Fukushima prefecture in October 2002. The results obtained by MM5-TMNR are verified by comparisons with observed wind, precipitation and gamma dose rate to be adequate for examining the mechanism. The unusual increase in gamma dose rate is observed by the combination of the synoptic-scale (about 2000 to 5000 km horizontally) transport of natural radionuclides due to the inflow of cold air mass from the Asian Continent and the meso-_-scale (about 20 to 200 km horizontally) precipitation process within the coastal area of Fukushima prefecture. The contribution rate of natural radionuclides from the Asian Continent to the increase in gamma dose rateis estimated to be more than 60%.     

表皮生长因子血药浓度^125I标记示踪法的建立

采用＾１２５Ｉ标记示踪结合三氯醋酸（ＴＣＡ）沉淀法，测定兔血浆中表皮生长因子（ＥＧＦ）的浓度，本文法最小检出量３．０μｇ／Ｌ回收率为（９７．８０±４．９４）％，日内变异系数ＣＶ为（３．２３±２．０４）％，血浆在１２．５－４００μｇ／Ｌ浓度范围内呈良好的线性关系，ｒ＝０．９９９０。本法与酶联免疫吸附分析法（ＥＬＩＳＡ）对兔血浆样品的测定结果基本一致，但前法测定值略高于后者。     

Nuclear design of an integrated small modular reactor based on the APR-1400 for RO desalination purposes

The United Arab Emirates lacks conventional water resources and relies primarily on desalination plants powered by fossil fuels to produce fresh water. Nuclear desalination is a proven technology, cost-competitive, and sustainable option capable of integrating the existing largescale desalination plants to produce both freshwater and electricity. However, Small Modular Reactors(SMRs) are promising designs with advanced simplified configurations and inherent safety features. In this study, an Int...     

基于多层流模型的核电站警报分析系统的开发

开发了基于多层流模型(MFM)的核电站警报分析系统。系统通过在复杂的故障状态下自动识别主要根本原因,能够减轻运行人员的工作负荷。另外,由于多层流模型提供了一组蕴涵因果关系的图形符号,操作维护人员可以通过符号分析来验证诊断结果,从而可以提高警报分析过程的可理解性以及维护工作的可靠性。取自RELAP5/MOD2的19组数据用于评价系统性能。仿真实验结果显示了该系统在停堆前具有较好的及时检测和诊断故障的能力。     

Use of Al2O3 layer as a dielectric in MOS based radiation sensors fabricated on a Si substrate

The use of Al₂O₃ dielectric in MOS based radiation sensors has been investigated. Their response has been compared with conventional MOS capacitors with a SiO₂ dielectric. The study includes gamma radiation effects with dose up to 4 Gy. The effect of radiation has been determined from the valance band shift in C-V curves. The amount of charge induced by the radiation has been calculated and compared with the response of MOS capacitors with SiO₂ with the same and different thicknesses. Fading properties have been studied and compared. Results show that MOS capacitors with Al₂O₃ dielectric exhibit sensitivity greater than that obtained from MOS capacitors with SiO₂. This higher sensitivity is attributed to higher trapping efficiency in the Al₂O₃ layer.     

Simulation of SBLOCA based on an Improved Choked Flow Model for RELAP5/MOD3 Code

This paper is a continuation of the present author’s previous publication dealing with a new choked flow model for two-phase flow. The model based on a hyperbolic one-dimensional two-fluid model, where in the momentum equations the terms representing the interfacial pressure difference has been included in lieu of the virtual mass force terms. The new choked flow model is an improvement upon the choked flow model of the current RELAP5/MOD3 code, which itself is based on the Trapp–Ransom method. The author compares the predictions of this improved model with Trapp–Ransom model and Henry–Fauske model, for an assumed flow in a vertical pipe. The author simulates a typical PWR system with a hypothetical SBLOCA as well, and compares the system behaviors predicted by RELAP5/MOD3, based on the aforementioned choked flow models. He shows that the improved choked flow model leads to better predictions.     

Development of an in situ Raman spectroscopic system for surface oxide films on metals and alloys in high temperature water

In order to directly analyze the structure of oxide films on metals and alloys in high temperature water conditions, an in situ Raman spectroscopic system has been developed, utilizing Ar-laser with sapphire/diamond window assemblies as a part of an Alloy 690 autoclave. The performance of the developed in situ Raman spectroscopic system was verified using high purity NiO, NiFe₂O₄, Cr₂O₃, and NiCr₂O₄ powders. Obtained reference Raman spectra in room temperature air environment agreed well with published results. The developed Raman system has been applied for the characterization of the surface oxide films of a nickel-base Alloy 600 in typical primary water conditions of pressurized water reactors (PWRs); water with 1000 ppm boron and 2 ppm lithium at a pressure of 18 MPa and temperatures ranging up to 350 °C. In situ Raman spectra were collected for Alloy 600 in PWR water conditions at different temperatures up to 350 °C, while the specimens were heated and then cooled. In this study, NiO, Cr₂O₃, and NiCr₂O₄ phases were observed for Alloy 600 in PWR water conditions, in reasonable agreement with earlier results of ex situ studies.     

Method for converting in-situ gamma ray spectra of a portable Ge detector to an incident photon flux energy distribution based on Monte Carlo simulation

A matrix stripping method for the conversion of in-situ gamma ray spectrum, obtained with portable Ge detector, to photon flux energy distribution is proposed. The detector response is fully described by its stripping matrix and full absorption efficiency curve. A charge collection efficiency function is introduced in the simulation to take into account the existence of a transition zone of increasing charge collection after the inactive Ge layer. Good agreement is obtained between simulated and experimental full absorption efficiencies. The characteristic stripping matrix is determined by Monte Carlo simulation for different incident photon energies using the Geant4 toolkit system. The photon flux energy distribution is deduced by stripping the measured spectrum of the partial absorption and cosmic ray events and then applying the full absorption efficiency curve. The stripping method is applied to a measured in-situ spectrum. The value of the absorbed dose rate in air deduced from the corresponding flux energy distribution agrees well with the value measured directly in-situ.     

AP/CAP核电厂爆破阀药筒驱动装置输出性能试验方法与装置开发

根据AP/CAP核电厂爆破阀的试验大纲,需要对爆破阀药筒驱动装置进行输出性能试验,为完成试验开发了专用试验装置。介绍了AP/CAP核电厂爆破阀药筒驱动装置输出性能试验的原理、方法以及试验装置的开发内容。开发的试验装置点燃爆破阀药筒驱动装置产生高温气体,通过采集装置内包容的气体压力数据、绘制并分析压力-时间曲线,对药筒驱动装置的输出性能进行评价,并针对不同类型与规格的药筒驱动装置分别进行了测试。结果证明,该试验装置适用于多型号规格的爆破阀药筒驱动装置的试验,且性能可靠、操作方便。     

Development of an evaluation parameter for physical protection in INPRO and its case study on Republic of Korea’s PWRs

Evaluation parameters (EP), including evaluation scales (ES), for assessing a physical protection status of an INS (innovative nuclear system) in the INPRO have been developed; and a case study on the Republic of Korea’s (ROK) PWRs, using the developed EPs, has been performed. The INPRO proliferation resistance (PR) and physical protection (PP) methodology (developed by the IAEA) is comprised of a BP (basic principle), a UR (user requirement), a CR (criterion) and an IN (indicator). In the case of the INPRO methodology for PR, an EP and an ES that may facilitate the evaluation process are provided with definitions in the manual; but they are not given for the area of PP. In this study, we have developed parameters which can be used to evaluate the PP status for both an INS and an existing nuclear power plant. The developed EPs and ESs contain all the possible components that may affect the PP status. They were made based on an IN and acceptance limits that are specified in the manual. The evaluation tables are provided for some EPs such as material type, insider attack and vulnerability tests to increase the reliability of the evaluation. A case study on this methodology had been performed on the ROK’s PWRs. The results showed that the physical protection status of the ROK’s PWRs satisfied most of the EPs; however, some parameters such as the DBT, and the QA system did not meet the requirements. It has been seen through the case study that the EPs and the ESs developed are very useful for evaluating the physical protection status of a nuclear facility.     

Advantages and disadvantages of nuclear reactions used in reactors or cyclotrons,in addition to a theoretical study based on photodisintegration on natural indium for 111Ag production

Production routes were recorded on available reactions for ¹¹¹Ag production from nuclear reactors or cyclotrons using a natural palladium target based on ¹¹⁰Pd（n, γ） and ¹¹⁰pd（d, n） reactions, respectively.^natCd（γ,x） based on ¹¹⁰Cd（γ, p） has also been studied as a prospective reaction for the production of ¹¹¹Ag. Unfortunately, these nuclear reactions are difficult to utilize because, in some cases, they reduce the specific activi...     

Advantages and disadvantages of nuclear reactions used in reactors or cyclotrons,in addition to a theoretical study based on photodisintegration on natural indium for 111Ag production

Production routes were recorded on available reactions for ¹¹¹Ag production from nuclear reactors or cyclotrons using a natural palladium target based on ¹¹⁰Pd（n, γ） and ¹¹⁰pd（d, n） reactions, respectively.^natCd（γ,x） based on ¹¹⁰Cd（γ, p） has also been studied as a prospective reaction for the production of ¹¹¹Ag. Unfortunately, these nuclear reactions are difficult to utilize because, in some cases, they reduce the specific activi...     

Impact of spread in minor actinide data from ENDF/B-VII.0, ENDF/B-VI.8, JENDL-3.3 and JEFF-3.0 on an IAEA-CRP FBR benchmark for MA incineration

Under an IAEA Coordinated Research Project (CRP), an FBR Model has been designed to study feasibility of incineration of long-lived minor actinides (MA). The predictions depend on the accuracy of the nuclear data used. There are several evaluations for actinide nuclear data, produced based on state-of-the-art procedures, but substantial deviations persist among them. The effect of spread in the MA nuclear data over a few recent evaluations, on the predicted material and Doppler worths of the FBR model, has been estimated and presented in this paper.