核设施退役信息数据库的结构与功能设计

核设施退役工程是一项不仅需要考虑拆除（毁）设备、建筑物,还要考虑辐射影响和核废物处理的复杂工程,其拆除（毁）工作具有高危险、高污染的特点,因此建立针对核设施退役项目的信息系统辅助退役工程很有意义。本文通过收集退役活动数据(设备物资数据、源项数据、辐射剂量数据等)设计退役信息数据库,开发了基于退役数据库的信息管理系统,该系统可对数据库中各类信息数据（照片、图纸、辐射数据、时间等）进行录入、删除、修改、查询等基本操作,并根据各类数据处理流程的特点分功能模块进行相应数据信息的管理,并对不同数据信息进行分析。该系统可提升退役过程中的管理能力,优化工程安排,减少作业人员所受辐射剂量,是顺利进行退役活动的必要基础。     

Evaluation of nuclear facility decommissioning projects program-status

Major studies have been undertaken in recent years by the US Nuclear Regulatory Commission (NRC) and others on the technology, safety and costs associated with decommissioning nuclear facilities. The program described in this presentation is being undertaken by the NRC to compile and evaluate the activities of ongoing decommissioning projects. Assessment and evaluation of the methods, impacts, and costs will provide a basis for evaluating licensee's decommissioning proposals and for future decommissioning direction and regulation.Program participants include the US Nuclear Regulatory Commission (NRC) through the Office of Regulatory Research, UNC Nuclear Industries (UNC) through the Decommissioning Programs Department, and nuclear facility licensees.     

核设施退役中若干环境相关问题的探讨

核设施退役有利于消除核安全隐患,减少辐射环境风险,是环境保护的一项重要活动。本文讨论了在核设施退役过程中应重点关注的几个问题:退役目标和剂量约束值、退役过程中有关控制值的制定、放射性废物管理以及退役过程中和退役终态的监测。并结合退役项目说明了在退役实施中应该重点关注的环境相关问题。     

Factor analysis on hazards for safety assessment in decommissioning workplace of nuclear facilities using a semantic differential method

The decommissioning of nuclear facilities must be accomplished according to its structural conditions and radiological characteristics. An effective risk analysis requires basic knowledge about possible risks, characteristics of potential hazards, and comprehensive understanding of the associated cause-effect relationships within a decommissioning for nuclear facilities. The hazards associated with a decommissioning plan are important not only because they may be a direct cause of harm to workers but also because their occurrence may, indirectly, result in increased radiological and non-radiological hazards. Workers need to be protected by eliminating or reducing the radiological and non-radiological hazards that may arise during routine decommissioning activities as well as during accidents. Therefore, to prepare the safety assessment for decommissioning of nuclear facilities, the radiological and non-radiological hazards should be systematically identified and classified. With a semantic differential method of screening factor and risk perception factor, the radiological and non-radiological hazards are screened and identified.     

核设施退役的环境安全

核设施退役的环境安全是退役的最终目标,是制约整个退役活动的关键,已成为世界各国公众关注的问题。我国在核设施退役活动中,在方案设计中采取了有效的安全措施,且退役活动严格遵照预定的安全措施实施,因而退役活动对环境安全的影响完全控制在预定值以下,对公众及其后代是安全的。也提到了可能对环境安全造成影响的核设施退役活动。本文对我国已实施的几项核设施退役活动对环境安全影响进行了初步探讨,目的是为了引起有关人士的共鸣,达到深入讨论,逐步统一认识,推进我国核设施退役工作的进展。     

Comprehensive support for nuclear decommissioning based on 3D simulation and advanced user interface technologies

There is an increasing international focus on the need to optimise decommissioning strategies, driven by the anticipation of high costs and major effort for the decommissioning of nuclear facilities in the coming decades. The goals are to control and mitigate costs and negative impacts on workers, the general public, and the environment. The methods presently employed for many decommissioning tasks do not apply the latest advancements of science and technology. Therefore, there is growing interest in research and development into the adoption of novel techniques for improving safety, reducing costs, and increasing transparency.

This paper provides a comprehensive overview of the authors’ results from investigating how current and emerging technologies can be applied to enhance the international decommissioning strategy, focussing in particular on three-dimensional simulation, virtual reality, advanced user interfaces, mobile and wearable devices, and geographical information systems. Our results demonstrate that emerging technologies have great potential for supporting adoption of new instrumentation, improving data and knowledge management, optimising project plans, briefing and training field operators, and for communication, surveillance, and education in general.     

Quantification model for estimating the radiological risks of decommissioning processes in nuclear facilities

This paper proposes a model for the quantification and estimating the radiological risks of decommissioning processes in nuclear facilities. Based on fuzzy linguistic variables, the membership function and inference rules were developed for quantifying the radiological risks of nuclear decommissioning processes. Also, the fuzzy inference system was developed and the proposed method was applied to the process of concrete decommissioning. The proposed model and system is flexible in that it allows a fast-computation of the subjective expert opinion when one or several input factors change. It is believed that the suggested model and system can be applied to evaluate the safety of complex systems by only changing the variable and inputs.     

A qualitative identification and analysis of hazards,risks and operating procedures for a decommissioning safety assessment of a nuclear research reactor

Korea Research Reactor-1(KRR-1, TRIGA Mark-II type reactor), the first nuclear research reactor in Korea, is being prepared for a decommissioning. The decommissioning methods and procedures of KRR-1 ought to be based on its structural conditions and radiological characteristics. Also, a systematic approach to the decommissioning tasks must be followed by reviews and assessments of the decommissioning workers’ safety.     

A study of the decommissioning procedure of an activated structure through an evaluation of the decommissioning cost for a research reactor

As decommissioning of a research reactor and a nuclear installation requires a long period of time from the decommissioning preparation work to the site remediation, the management of the data generated during the entire period of decommissioning is one of the most important tasks. In particular, the data obtained from research reactor decontamination and decommissioning activities can be important resources securing the safety and economic feasibility for other research reactor decommissioning. The owner of the research reactor and nuclear power plant need to submit decommissioning plan to the regulatory body at the starting stage of the research reactor and nuclear installation decommissioning project. The cost plan for decommissioning and the method for assessing the amount of exposure to protect workers must be stated in the decommissioning plan.This paper introduces the DES (Decommissioning Engineering System) that can be able to manage the data generated in the process of decommissioning of the TRIGA research reactor, to calculate an amount of waste, to evaluate decommissioning cost after deriving unit work productivity factor, and to predict the decommissioning process in advance. To verify the usability of this system and data integrity through connections among the unit systems, it describes the process to calculate the decommissioning cost using the data generated in dismantling an activated bio-shielding concrete in the TRIGA research reactor.As a result of the experiment to calculate the decommissioning cost with the TRIGA research reactor structure, it was found that the calculations were done precisely without flaw as the purpose of the experiment. Therefore, the DES can not only be used for other research reactors decommissioning, but also it is expected to be applied to other research reactors in the future. As a decommissioning cost between an activated concrete and a non-activated concrete according to the method of the dismantling procedure was significantly different, a study regarding the dismantling procedure needs more research.     

Estimation on probability of radiological hazards for nuclear facilities decommissioning based on fuzzy and event tree method

This paper proposes the estimation method on probability of decommissioning hazards for nuclear facilities. Evaluation method of decommissioning hazardous accidents is based on fuzzy and event tree method. Expert’s knowledge was considered as state of the basic variable with a normal distribution, which was considered to represent the membership function. The proposed method has been successfully applied to the removal of rotary specimen rack in KRR-2.     

Software safety analysis application of safety-related I&C systems in installation phase

This work performed a software safety analysis (SSA) in the installation phase of the Lungmen nuclear power plant (LMNPP) in Taiwan, under the cooperation of INER and TPC. The US Nuclear Regulatory Commission (USNRC) requests licensee to perform software safety analysis (SSA) and software verification and validation (SV&V) in each phase of software development life cycle with Branch Technical Position (BTP) 14. In this work, 37 safety grade digital instrumentation and control (I&C) systems were analyzed by Failure Mode and Effects Analysis (FMEA), which is suggested by IEEE Standard 7-4.3.2 (2003). During the installation phase, skew tests for safety grade network and point to point tests were performed. The FMEA showed all the single failure modes can be resolved by the redundant architecture. The common mode failures can be resolved by operator manual actions via the diverse displays.     

核设施退役过程中辐射测量的一般问题

本文叙述了设施退役的阶段划分和退役过程吕辐射测量的一些问题，主要包括退役前源项调查中辐射测量的目的、内容和方法，退役施工过程中的施工辐射监测，以及退役施工结束后终态辐射检测和终态验收检测的有关问题。     

核设施退役虚拟仿真系统框架研究

退役核设施具有放射性,其退役过程危险且复杂,基于虚拟现实等技术的退役虚拟仿真系统可为退役工程提供辅助工具。本文在分析国内外研究成果的基础上,结合一专项退役工程的需求提出了该虚拟仿真系统的功能模块组成。基于软件开发技术进一步给出了系统的框架结构,并对各模块实现的相应技术进行了分析和探讨。分析中结合了计算机软硬件技术的最新研究成果,对退役中的切割、爆破、流体及放射性等的仿真技术进行了探讨。分析表明,基于普通个人计算机也可实现退役过程的全面虚拟仿真。经专家论证本方案具有可行性。     

核设施退役过程中的辐射场重构与拆除路径优化

辐射场分布和路径选择是核设施退役过程中影响工作人员吸收剂量的主要因素。针对核设施退役过程中多源项的三维辐射场,采用点核积分的方法进行重构,重构结果与蒙特卡罗程序计算结果吻合很好,验证了点核积分法的可行性。将核退役拆除路径问题抽象为一种类旅行商问题数学模型,构造不同拆除路径下所受外照射剂量对应的剂量矩阵,根据辐射防护ALARA(As Low As Reasonably Achievable)原则,利用遗传算法进行寻优。对于多源项退役拆除实例,计算给出了最优化拆除路径和三维可视化显示,并对优化效果进行了讨论。设计开发了面向核设施退役过程的辐射场重构与拆除路径优化功能软件。     

国外核设施地下管道退役的经验教训

介绍了国外核设施地下管道退役中存在的问题、管道出路的决策过程、特性调查及调查方法、测量仪器的选择,以及管道的去污、就地处置或拆除等方面的经验与教训,以期对我国的退役实践有所帮助。     

论退役策略

结合我国核设施退役实际,论述了核设施退役三种策略:立即拆除、延缓拆除和封固埋葬,以及退役策略的选择和一些主要核国家采用的退役策略。最后,对核设施退役策略的一些重要问题进行了讨论。     

核设施退役辐射检测及其仪器仪表应用

核设施退役辐射场检测技术在核设施退役的整个过程中起着非常重要的作用.较系统论述了核设施退役辐射检测的质量保证,最后从满足核设施退役工作的需要出发,评述了退役过程辐射检测仪器仪表的选择及其应用.指出国内辐射监测仪器仪表在满足核设施退役的需求上的较大差距,值得各有关方面关注.     

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。     

Final Status of the Decommissioning of Research Reactors in Korea

A decommissioning project for the Korean Research Reactors KRR-1 and KRR-2 was started in 1997 and had been carried out with the goal of completion by the end of 2008. All the facilities were dismantled and the building surfaces decontaminated. The radioactive waste was packed into 200 liter drums and 4m³ containers and temporarily stored on site until their final disposal at the national repository facility. Some of the releasable waste was freely released and utilized for non-nuclear industries. The assessment of the residual radioactivity was carried out according to the Multi Agency Radiation Site Survey and Investigation Manual (MARSSIM), and accordingly, the safety of the site release was verified. The site and buildings will be cleared for reuse for non-nuclear purposes after a review of the assessment. In this paper, the final status of the decommissioning of research reactors in Korea including dismantlement processes, waste management, and a final assessment for unrestricted use of the site and buildings as the final goal of the decommissioning project will be described.