scholarly journals Seismic risk control of nuclear power plants using seismic protection systems in stable continental regions: The UK case

2016 ◽  
Vol 307 ◽  
pp. 377-391 ◽  
Author(s):  
Carlos Medel-Vera ◽  
Tianjian Ji
2002 ◽  
Vol 13 (2) ◽  
pp. 239-261
Author(s):  
Steve Thomas

In 1990, the privatisation of the British electricity supply industry revealed how uneconomic Britain's nuclear power plants were. The nuclear sector was withdrawn from privatisation and it seemed likely that by 2000, most of Britain's nuclear power plants would be closed. However, operating costs were dramatically reduced and in 1996, most of the nuclear plants were privatised in British Energy. Nuclear output made an important contribution to the reduction of greenhouse gas emissions and the future looked secure for the existing plants. However, the early success of British Energy was based on an inflated wholesale electricity price and by 2000, British Energy was struggling to cover its costs. The British government is now conducting a review of energy policy. The economic case for new nuclear power plants is poor but the need to meet greenhouse gas emission targets and the influence British Energy and BNFL may ensure the long-term future of the existing plants.


Author(s):  
Ф.О. Аракелян ◽  
И.П. Башилов ◽  
Ю.Н. Зубко ◽  
А.В. Николаев ◽  
Д.Г. Левченко

Рассмотрено состояние и перспективы развития атомной энергетики в связи с сейсмической и другими природнотехногенными опасностями. Анализирован опыт эксплуатации АЭС, статистика аварий на АЭС, их причины. В связи с авариями на ряде АЭС и глобальной сменой приоритетов энергетической политики в сторону возобновляемых источников энергии (ветра, солнца, гейзеров и т.п.) многие из технически развитых стран (США, Япония, Германия) заявляют о снижении роли атомной энергетики в собственных энергетических планах. Угроза опасности объединяет усилия таких стран как США, Франция, Россия, Япония, Южная Корея, Канада и Китай в сотрудничестве в области совершенствования технологий, усиления ядерной безопасности и развития ядерной инфраструктуры в странахновичках. Наиболее опасными признаны АЭС Азии, где отмечается повышенная сейсмичность. Благодаря усилиям по повышению безопасности АЭС, сделан вывод о снижении сейсмической опасности в связи с глубокой автоматизацией и передачей основных управляющих функций АЭС программному комплексу, совершенствованием алгоритмов принятия решений в случае землетрясения и других чрезвычайных ситуаций. Одна из главных целей глубоко эшелонированной защиты состоит в блокировании опасностей человеческих ошибок и сочетания отказов оборудования и ошибок операторов и распорядителей. Системы безопасности должны включаться автоматически и на некоторое время блокировать действия оператора АЭС. Эффективной защитой энергоблоков, построенных в последние десятилетия, являются герметичные оболочки (контейменты) и размещение над реактором емкости с большим количеством раствора бора, который выливается на реактор при аварии и нейтрализует радиоактивность в случае ее появления. Более детальный анализ сейсмотектонической ситуации площадок действующих АЭС мира привел к необходимости повышения ускорения безопасного останова в ряде АЭС. При проектировании АЭС недостаточно учитывать магнитуду и интенсивность предполагаемых землетрясений, для инженерных расчетов необходимо использовать конкретные параметры колебаний. Среди них важнейшее место занимает ускорение грунта, по которому можно с максимальной уверенностью судить о потенциальных нагрузках на сооружения и оборудование в зоне землетрясения. Приведена модернизированная система сейсмической защиты (ССЗ1М) энергоблоков отличающаяся надёжностью, отсутствием ложных срабатываний, стабильностью параметров во времени, защитой от внешних несанкционированных воздействий. The state and prospects of the development of nuclear energy in connection with seismic and other natural and technological hazards are considered in the article. The experience of operating nuclear power plants, statistics on accidents at nuclear power plants, and their causes are analyzed. Due to accidents at several nuclear power plants and a global change in energy policy priorities towards renewable energy sources (wind, solar, geysers, etc.), many of the technically developed countries (USA, Japan, Germany) declare a reduction in the role of nuclear energy in their energy plans. The threat of danger unites the efforts of countries such as the USA, France, Russia, Japan, South Korea, Canada and China in cooperation in the field of improving technologies, enhancing nuclear safety and developing nuclear infrastructure in newcomer countries. The most dangerous nuclear plants are located in Asia, where the increased seismicity is noted. As a result of the efforts to improve the safety of nuclear power plants, it is concluded that seismic hazard is reduced due to the deep automation and transfer of the main control functions of the nuclear power plant to the software package, improvement of decisionmaking algorithms in the event of an earthquake and other emergencies. One of the main goals of defense in depth is to block the dangers of human error and the combination of equipment failures and the errors of operators and managers. Safety systems should turn on automatically and block the actions of the NPP operator for a while. Sealed shells (containers) and placement of containers with a large amount of boron solution over the reactor, which is poured onto the reactor in the event of an accident and neutralizes radioactivity in case of its occurrence, are an effective protection for power units built in recent decades. A more detailed analysis of the seismotectonic situation of the sites of existing nuclear power plants in the world has led to the need to increase the acceleration of safe shutdown in several nuclear power plants. When designing a nuclear power plant, it is not enough to take into account the magnitude and intensity of the alleged earthquakes for engineering calculations, it is necessary to use specific vibration parameters. Among them, acceleration of the soil occupies the most important place, by which it is possible to judge with maximum confidence the potential loads on structures and equipment in the earthquake zone. The modernized seismic protection system (SSZ1M) of power units is characterized by reliability, the absence of false alarms, the stability of parameters in time, and protection against external unauthorized influences.


Author(s):  
H. Reece-Barkell ◽  
W. J. J. Vorster

Effective outage planning and implementation is critical to the efficient and safe operation of commercial nuclear power plants in the UK. Statutory outages are necessary for refuelling, for preventive and corrective maintenance when shutdown conditions are required, and for major modification and improvement projects. Outages involve the support of many companies and individuals working together and, as such, require high levels of coordination. Planning of activities before the outage is critical to the overall success of the outage. Establishing the integrity of power plant piping and pressure vessels is a key objective as part of any outage and the methodology and processes involved are the subject of this paper. Establishing the integrity of piping and pressure vessels requires an understanding of the specific threats, their relationship to the overall condition of the system, and the mitigating measures required to assure safe operation. Understanding the specific threats allows the engineering function of an organisation to advise on pipework and pressure vessel ‘Minimum Acceptable Thicknesses’ which can be used to assure integrity via comparison with thicknesses measured during outage inspections. Minimum Acceptable Thicknesses should be recorded in the outage management documentation so they are accessible during the outage implementation phase. Historically a variety of different methodologies have been used to advise on Minimum Acceptable Thickness requirements including design drawing specified minimum thicknesses, design code based required thicknesses and thicknesses calculated based on Fitness for Purpose methods. It is important that a robust procedure be applied to promote consistency of approach as regards the calculation of pipework and pressure vessel Minimum Acceptable Thickness requirements across all power station assets. An additional consideration is that of ensuring that the approach adopted is consistent with high level safety case guidance, i.e., the assessment is appropriate for the failure tolerability of the plant item. This paper provides an overview of the strategy, methodologies and processes employed to determine Minimum Acceptable Thicknesses for pipework components. These ensure that, over a specified inspection interval, were the weld/component to be defect free, it would not fail due to any of the relevant failure mechanisms, which typically are plastic collapse, creep rupture, fatigue, incremental collapse (ratcheting) or buckling. Readers of this paper will gain a valuable insight into the statutory outage process applicable to nuclear power plants in the UK. A particular focus of this paper is on the structural integrity assessments applied in a non-traditional sense prior to, during and after the statutory outage. As well as sharing a valuable insight into the assessment methodologies this paper highlights best industrial practice.


Risk Analysis ◽  
1983 ◽  
Vol 3 (3) ◽  
pp. 169-180 ◽  
Author(s):  
Stan Kaplan ◽  
Harold F. Perla ◽  
Dennis C. Bley

Energies ◽  
2016 ◽  
Vol 9 (4) ◽  
pp. 306 ◽  
Author(s):  
Guoyang Wu ◽  
Ping Ju ◽  
Xinli Song ◽  
Chenglong Xie ◽  
Wuzhi Zhong

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