Enhancing nuclear emergency response through international cooperation

Nuclear and radiological emergencies may easily become severe international emergencies requiring substantial resources in several or many states for an adequate response, which in some cases may require resources exceeding national capabilities. Through the development of a consistent, coherent and sustainable joint programme for improved and more efficient international responses to nuclear and radiological emergencies, it is believed that we could achieve a better and more cost-effective response capability for nuclear and radiological emergencies. This requires, however, that we be willing and able to establish mechanisms of assistance where information and resources are globally shared and that standardised/harmonised procedures be developed and implemented. If we are willing to make this investment, we believe that, in the long term, there will be a significant benefit for all of us.     

Off-site ignition probability of flammable gases

A key step in the assessment of risk for installations where flammable liquids or gases are stored is the estimation of ignition probability. A review of current modelling and data confirmed that ignition probability values used in risk analyses tend to be based on extrapolation of limited incident data or, in many cases, on the judgement of those conducting the safety assessment. Existing models tend to assume that ignition probability is a function of release rate (or flammable gas cloud size) alone and they do not consider location, density or type of ignition source. An alternative mathematical framework for calculating ignition probability is outlined in which the approach used is to model the distribution of likely ignition sources and to calculate ignition probability by considering whether the flammable gas cloud will reach these sources. Data are collated on the properties of ignition sources within three generic land-use types: industrial, urban and rural. These data are then incorporated into a working model for ignition probability in a form capable of being implemented within risk analysis models. The sensitivity of the model results to assumptions made in deriving the ignition source properties is discussed and the model is compared with other available ignition probability methods.     

Ongoing efforts to improve the international nuclear and radiological emergency response

It is recognised that states, through the development of a consistent, coherent and sustainable joint programme for improved and more efficient international responses to nuclear and radiological emergencies, could achieve a better and more cost-effective response capability. Enhanced efforts by IAEA member states and the IAEA secretariat to improve the implementation of the Convention on Early Notification of a Nuclear Accident and the Convention on Assistance in Case of a Nuclear Accident or Radiological Emergency have been initiated, establishing a national competent authority coordination group (NCACG) and a long-term action plan for the work.     

Development of nuclear emergency exercise programme (NEEP) in Korea

The nuclear emergency exercise programme (NEEP) is a PC-based application intended for design and planning emergency preparedness and response (EP&R) exercises for a potential nuclear emergency in Korea. The application programme allows EP&R staff to create and edit exercise scenarios based on information customised for a specific nuclear power plant's emergency plans. NEEP includes the following features: (1) step-by-step guide to developing new exercise scenario according to emergency alarm level and potential accident type, (2) database of specific plant's field exercise scenarios that can be easily modified by users, (3) generating master scenario events list and messages of exercise participants and (4) allowing the quantitative evaluation of exercise participants from the view of exercise objectives and evaluator guides. NEEP also features tools for queries, reports and visualisation that can be used to create documentation during the scenario planning and exercise evaluation processes.     

An overview of protective action decision-making for a nuclear power plant emergency

Protection of the public in a nuclear power plant emergency requires decision-makers to balance the time requirements from two chains of events: the events associated with a radiological release and the events involved with the response to that release. The management of these events is distributed among personnel at the nuclear plant, in the local community, and in state and federal agencies. All of these parties must coordinate their response to the emergency to assure that timely and effective protective response can be made by the risk area population. This article describes the process by which protective action recommendations (PARs) are developed in nuclear power plant emergency exercises and provides recommendations from research on emergency response in other types of natural and technological hazards.     

核辐射探测与应急处理机器人的小型机械臂系统设计

针对传统核辐射探测与应急处理机器人小型机械臂结构复杂、夹持物体重量小的问题,设计了一种新的机械臂抓持系统,该系统的特点是利用杠杆滑槽式手爪结构作为夹持部分,并实现了机械臂的小臂和大臂的机电一体化设计,因而机械结构简单、轻质,夹持物体重量大.仿真分析与实验结果表明,该机械臂可满足核辐射探测与应急处理机器人的应用需求.     

Regional long-term co-operation in the field of nuclear and radiation emergency preparedness

Emergency preparedness is generally covered by methodical and coordinative activities of the International Atomic Energy Agency (IAEA) in Member States of the IAEA and by the European Commission (EC) in EU Member and EU Accession Countries. However, the regional harmonisation of emergency arrangements is an important trend of emergency preparedness. The present paper gives a couple of illustrative examples for a regional co-operation in the field of emergency preparedness in Central Europe and an overview on international exercises in this region. The penultimate section contains an outlook on future activities regarding regional co-operation in Central Europe. The following topics have been suggested inter alia: the harmonisation of intervention criteria and countermeasures, co-ordination in the field of information of the public, comprehensive bi lateral and multilateral exercises, exchange of experts between the national nuclear emergency centres and inter-comparison calculations of the computer codes.     

Expert systems for emergency alarms analysis during accident situations in nuclear reactors

Expert system development is an important application of artificial intelligence. During the last few years, many successful expert systems have been developed in various fields like medical diagnosis, geological exploration, office management, etc. Expert systems is a computer software which solves reasonably complex problems where normally one needs an expert in that field to solve them.Recently efforts are being made in developing expert systems to support the operating staff in nuclear reactors. Nuclear power plant is one of the most complex engineering systems and safe and reliable operation is of primary importance. In spite of many automatic and redundant safety systems there are some occasions when the operating staff have to analyse the alarms and take further safety actions. Few of the severe accidents like Three Mile Island in USA and Chernobyl in USSR are attributed to the errors made by the operating staff and/or management. Nuclear engineers or systems analysts who may be expert in analysing an accident situation and advise corrective safety actions may not be readily available during the accident situations in the nuclear power plants. It is possible to model such expert knowledge in expert systems and this can be applied in diagnosing an accident situation like the loss of coolant accident (LOCA) and act as an additional confirmatory aid to the operating staff.Two small expert systems examples have been developed and are explained in this paper. One identifies a spurious LOCA alarm in a heavy water research reactor. The second example identifies the type of medium/small leakage (LOCA) in a coolant circuit of a PWR and suggests the subsequent safety actions. Both the examples have been developed using the expert systems shell VP-expert. They are off-line usable and user interactive. We do not propose expert system application for very fast response safety actions like reactor scram. These two small expert system examples are essentially to support the feasibility study in their applications during accident situations in nuclear power plants.     

Training for emergency management: tactical decision games.

Training of the non-technical skills that are crucial to effective management of emergency situations is an issue that is currently receiving increasing emphasis in the petrochemical sector. A case study is presented of the explosion and fires at the Texaco Refinery, Milford Haven, UK, which occurred in July 1994 (HSE, The explosion and fires at the Texaco Refinery, Milford Haven, 24 July 1994. HSE: London, 1997), with particular focus on the human factors aspects of the event. A key issue identified by the official report into this incident was the importance of emergency management training. This paper outlines a novel, low-fidelity training intervention, the tactical decision game (TDG), which is designed to enhance the non-technical skills (decision making, situation awareness, communication and co-ordination, teamwork, and stress management) required for emergency management. It is proposed that enhanced learning of these non-technical skills, through experience and directed practice following repeated exposure to TDGs, will lead to more efficient emergency management, particularly when dealing with hazardous materials.     

Off-site toxic consequence assessment: A simplified modeling procedure and case study

An assessment of off-site exposure from spills/releases of toxic chemicals can be conducted by compiling site-specific operational, geographic, demographic, and meteorological data and by using screening-level public-domain modeling tools (e.g., RMP*Comp, ALOHA and DEGADIS). In general, the analysis is confined to the following: event-based simulations (allow for the use of known, constant, atmospheric conditions), known receptor distances (on the order of miles or less), short time scale for the distances considered (order of 10's of minutes or less), gently sloping rough terrain, dense and neutrally buoyant gas dispersion, known chemical inventory and infrastructure (used to define source-term), and known toxic endpoint (defines significance). While screening-level models are relatively simple to use, care must be taken to ensure that the results are meaningful. This approach allows one to assess risk from catastrophic release (e.g., via terrorism), or plausible release scenarios (related to standard operating procedures and industry standards). In addition, given receptor distance and toxic endpoint, the model can be used to predict the critical spill volume to realize significant off-site risk. This information can then be used to assess site storage and operation parameters and to determine the most economical and effective risk reduction measures to be applied.     

The long-term management of nuclear emergencies: the principles

The long-term impact of the Chernobyl accident on the most affected populations in Belarus, Ukraine and the Russian Federation is still evident in terms of a continuing elevated level of thyroid cancer, prominent psychosocial effects, a depressed economy and a low level of well being. Some of these impacts are directly and primarily attributable to exposure to ionising radiation, while others have more complex origins and have evolved over the period since the accident. It is argued that although these latter impacts were largely unpredictable at the time of the accident, they could have been minimised had an appropriate management plan been in force. The principles underlying such a management plan for use in future accidents are enumerated. An essential component in further developing such a plan would be a thorough review of the experience of the Chernobyl accident in order to 'learn the lessons' that accident holds.     

Off-site toxic consequence assessment: a simplified modeling procedure and case study

The new "Hazardous Waste Management Regulation" was published in the Official Newspaper of the Chilean Republic on 12 June 2003, being in force 365 days after its publication (i.e., 12 June 2004). During the next 180 days after its publication (i.e., until 12 December 2004), each industrial facility was obligated to present a "Hazardous Waste Management Plan" if the facility generates more than 12 ton/year hazardous wastes or more than 12 kg/year acute toxic wastes. Based on the Chilean industrial figures and this new regulation, hazardous waste management plans were carried out in three facilities of the most important sectors of Chilean industrial activity: a paper production plant, a Zn and Pb mine and a sawmill and wood remanufacturing facility. Hazardous wastes were identified, classified and quantified in all facilities. Used oil and oil-contaminated materials were determined to be the most important hazardous wastes generated. Minimization measures were implemented and re-use and recycling options were analyzed. The use of used oil as alternative fuel in high energy demanding facilities (i.e., cement facilities) and the re-refining of the used oil were found to be the most suitable options. In the Zn and Pb mine facility, the most important measure was the beginning of the study for using spent oils as raw material for the production of the explosives used for metals recovery from the rock. In Chile, there are three facilities producing alternative fuels from used oil, while two plants are nowadays re-refining oil to recycle it as hydraulic fluid in industry. In this sense, a proper and sustainable management of the used oil appears to be promissory.     

Long-term nuclear waste management: Present status and alternatives

Long-term nuclear waste management deals with the final and irreversible stage of waste disposal, on surface and in deep geological formations (according to the waste type), when institutional surveillance is over. There are presently two main options available to deal with the wastes generated by spent nuclear fuel unloaded from reactors and containing most of the radiotoxicity produced all along the nuclear fuel cycle. Since the end of Word War II, spent-fuel reprocessing technology has gone through three different stages, ending up with considerable technical achievements and large investments (construction of large facilities, UP3 in France and THORP in the UK). However, having to face spent-fuel risings and lack of reprocessing capacities, since the mid-seventies some countries are considering the possibility of direct spent-fuel disposal without reprocessing. These two options are discussed in terms of long-term waste management. Because of the types of waste conditioning and packaging adopted with present reprocessing technology, in that case long-term safety, after a few centuries, relies completely on the geological barriers. On the other hand, long-term safety with the second option is based essentially on the retention properties of uranium oxide with respect to actinides. Finally, alternatives such as chemical partitioning of minor actinides followed by their transmutation, either in reactors or using high-energy particle accelerators, are under discussion. Apart from the standard reprocessing (after a cooling period of 3–5 years), all the other options called for a long period (50 years) of interim storage, preventing the adoption of irreversible, costly and not well proved waste management solutions, and leaving time to develop and assess these alternative methods.     

Structured information analysis for human reliability analysis of emergency tasks in nuclear power plants

Being supported by scarce empirical data, most of the performance influencing factors in human reliability analysis (HRA) have to be assessed on the basis of the analyst's knowledge on the human performance in given tasks and their context. Therefore, the outcome of HRA may only be warranted by a proper application of their knowledge based on sufficient information about the tasks and situations. However, most of the HRA methodologies, including the newly developed ones, focus on the provision of cognitive models, error mechanisms, error types and analysis method while leaving the information collection mostly in the hands of the analyst. This paper suggests structured information analysis (SIA), which helps HRA analysts in collecting and structuring such information on tasks and contexts. The SIA consists of three parts: the scenario analysis, the goal-means analysis, and the cognitive function analysis. An expert evaluation showed that this three-part information analysis allowed more expressiveness and hence more confidence on the error prediction than ASEP HRA.     

Institutional and legislative issues of emergency management policy in Russia.

The emergency management policy as an organic component of the national development policy in contemporary Russia exists only for a slight more than a decade. However, its basic trends and directions could be revealed. In the legislative area covering technological accidents involving hazardous materials these include increasing differentiation of acts in terms of issue coverage, gradual integration of legislation via enforcement of the so-called systemic (umbrella) acts and increasing incorporation of specific acts, and keeping dominance of federal emergency acts. In addition, emergency legislation and policy programs on communities' protection against major hazards drift from alleviation-oriented towards more mitigation-focused. Meanwhile, the bulk of the existing acts are still specific laws and regulations, which consider most emergency response. In institutional realms the key direction of emergency policy development involved organization and progress of the Unified State System for Emergency Prevention and Elimination of the Russian Federation (USEPE) with EMERCOM as a key coordinator and actor in handling technological hazards and accidents. The detailed analysis of USEPE organizational pattern and operation modes including institutional structure, key functions, means and forces and operation routines is provided. It is argued that the system's logic and flexible organizational framework only to some extent contribute to effective mitigation of the major emergencies and/or disasters. In no less extent it depends on the existing socioeconomic conditions, which have been for a long time unfavorable in Russia and thus seriously constrain the USEPE effectiveness. This provides for ambiguous integral evaluation of the emergency management policy in the 1990s and early 2000s.     

Technical modifications & management innovations in exporting nuclear reactor projects

As a main channel for the foreign economic cooperation of China nuclear industry, China Zhongyuan Engineering Corporation (CZEC) has been constantly engaged in technical modifications and management innovations in its exporting nuclear reactor projects. In the implementation of heavy water research reactor contract in Algeria, CZEC had established a complete and adequate design standards system in compliance with the international standards, and made significant modifications to the reference reactor in the aspects of reactor power and reactor safety, solved quite some technical issues which affected the reactor technical performance. The modifications and improvements enabled the technical parameters, safety features, reactor multipurpose application to attain to the advanced level in the world. In the 300MWe PWR NPPs in Pakistan, safety features had been updated in line with upgrading regulatory requisites. The design philosophy and technology application demonstrated CZEC’s creation and innovation on basis of constant safety enhancement of nuclear power projects. Efforts had also been made by CZEC in promoting China made equipment items and components exportation.     

基于贝叶斯网络的核电站应急电力系统安全评价

在故障树分析法(FTA)基础上提出了一种基于贝叶斯网络(BN)的核电站应急电力系统安全评价方法,比较了FTA和BN在建立安全评价模型和评价能力上的不同.该方法在应对众多影响因素上有很大优势,能进行更多有意义的分析:既能进行前向的预测推理,又能进行后向的诊断推理,可以找出影响故障的组合模式,从而能够找出系统的薄弱环节.同时采用基于Matlab的BNT软件包,大大简化了计算过程.通过对10MW高温气冷堆(HTR-10)应急电力系统的安全评价实例的分析,证明该方法是对传统的基于故障树分析的安全评价方法的有益改进.     

危险化学品安全管控与应急救援

危险是危险化学品的天然特征,安全是危险化学品永恒的主题。每一次危险化学品的安全事故,既是其本质特征使然,也与外部环境密切相关,往往在其偶发性中包含着必然性。只有在充分了解、掌握其本质特征基础上,合理设置外部条件,使其始终处于可控的安全状态,并做好安全管控和应急救援的各项准备工作,才是保障安全、防控灾害的根本方法。血的教训不可忘,要想悲剧不再重演,必须采用系统思维进行体系建设,利用先进信息通讯技术采用"互联网+"模式建立全国统一的全天候的实时动态监控体系,在规范管理、防患未然的同时,为应急救援工作提供准确信息和合理救援方案。