Member: Fukushima, nuclear power will not have a similar accidents in China
5:59 local time on November 22, Japan coast of Fukushima Prefecture a 7.4-magnitude earthquake and subsequent tsunami warning issued.
Heart of life at the same time, Fukushima, public concern for 2011 earthquake and tsunami caused nuclear power plant accident, did the nuclear leak? And to be concerned about the safety of China's nuclear power plants. To this end, we asked experts for all secret nuclear safety situation in China.
Different from Fukushima, safer
Japan media, Fukushima daini nuclear power units, the third fuel-rod pools cooling once the earthquake stops. Then Japan claimed the Office of nuclear safety, the unit spent fuel pool cooling function has resumed before 8 o'clock local time, is not a nuclear leak.
Good news is, Japan quake caused no serious casualties and nuclear accident, but some are worried that China's nuclear power plants could withstand a similar to the impact of natural disasters?
Cnnc nuclear power expert, academician Ye Qizhen, told reporters: "in addition to the selection process of the geological conditions other than strict, solely on the nuclear power plant itself, we can have confidence in the safety of nuclear power plants in China. ”
In fact, 5 years ago Japan's Fukushima nuclear plant and very different from China's nuclear power plants.
Said Ye Qizhen, first are boiling water reactors at the Fukushima. Boiling water reactor power plant work processes--the coolant (water) from the lower part of the reactor core flows, rising along the core process, getting heat from the fuel rods, the refrigerant into a mixture of steam and water, through steam separators and steam dryer, separated high temperature steam to drive steam turbine generator. And the Fukushima nuclear plant was built in the 70 's of the last century, technology is relatively low.
Pressurized water reactor, pressurized water reactor with 3 barriers: the fuel cladding, containment, pressure boundary. Fuel breaks, radioactive substances can be masked in pressure boundary, or in a loop.
But the steam from a boiling water reactor loop wore out, but also through the containment, so boiling water reactor 3 barrier is not complete. It is boiling water reactor loop with characteristics of the secondary loop is not isolated, about 5 years ago a large amount of radioactive material leaked at the Fukushima.
In this regard, PWR type which has many advantages, and China's nuclear pressurized water reactors.
"China is one of the characteristics of the development of nuclear energy has advantages. Because we are the most advanced technology at that time, there is a very mature technology base, so not a place we consider poor or lack of experience and detours. "Ye Qizhen said.
He said: "security, China's nuclear power development has never been ignored. China has to some degree considered the impact of serious accidents, and severe accident response. ”
For example, there are hydrogen elimination system in qinshan nuclear power plant, a system with hydrogen-oxygen compound, did not reach the explosion before they combined, so there is no 5-year former Fukushima hydrogen explosion risk.
Technological breakthroughs, security can be guaranteed
Of course, China's nuclear power development has been the introduction of the technology of others while they stopped. From two to three generations, change is one of the biggest indicators safety goal is improved by an order of magnitude. Core melting in other words, a major accident, one order of magnitude lower probability of effects of environmental accidents.
Said Ye Qizhen, first complete prevention of serious accidents and mitigation measures is to eliminate the accident prevention in the bud. Accidents are usually caused by equipment failure, so we have redundancy to improve equipment reliability.
"Redundancy means, like fire-fighting system of the building, not only do I have a fire extinguisher, I have several, one will not open, opened another, more reliable is it? "Ye Qizhen said.
For example the third generation nuclear power technology in China "Hua long, first" are two forms of security systems, active and passive. A security system called dynamic, in the event of accident, will soon be able to eliminate the accident. If no power, just like Fukushima lost all power, move up, "Hua long, first" there is passive safety systems, and can be maintained in a safe condition.
Ye Qizhen said told reporters: "this is ' active and passive ' advantage. Dynamic, because of its dynamic role and quickly eliminate accidents; passive because it is carried out in accordance with the laws of nature do not need external power, able to ensure the security of back. So we adopted two combines the advantages of the method. ”
Ill come, "Hua long, first" double containment was designed. What security level is that double containment can be achieved?
"Against large commercial aircraft impact. "Ye Qizhen said.
You read that right, design of double containment "Hualong first", not only the magnitude 9 earthquake-resistant, outer layer can also prevent such as A380 aircraft collision, explosion, lining to prevent radioactive accidents.
"' Hua long first ' is in the original nuclear power development on the basis of summarizing using mature experience and mature technology, has taken some fundamental, innovative and improved technology, such as active and passive, double containment, accident prevention, so it is a very reliable product. "Ye Qizhen said.
More about nuclear security be assured
"Nuclear is based on all of the industry on the basis of continuous improvement in the industry in China, nuclear power equipment manufacturing level compared to qualitative changes in thirty or forty years ago. "Ye Qizhen said.
China now China nuclear power equipment localization rate to 85%~90%, equipment, key equipment in the domestic manufacturing, such as a pressure vessel, steam generator, steam generator, etc.
"Chinese-made equipment in the production process, we adhere to the highest international standards of manufacture to the highest standards to test. We will not be vague on this issue, China's nuclear power equipment are quite reliable. "Ye Qizhen said.
He also stressed that the operation of nuclear power plants, the World Association of nuclear operators WANO indicators for each of the organizations with 8 ~10 assessment of nuclear power plants.
According to this assessment, China's nuclear power plants within the top 50, and even some years some power stations rank first or second. In other words, the operation of nuclear power plants in China very well, are recognized at the international level.
Ye Qizhen, told reporters: "China has always adhered to the highest international safety standards for the design of nuclear power plants, building nuclear power plants, running nuclear power plants, China's nuclear power plants are safe. Because some of our technical route and the technical measures, ensures that no similar Fukushima and similar to the Chernobyl accident. ”
He said that if China built power plants, more aware of the measures taken by the nuclear power plant in China, will be able to address nuclear safety concerns.
"I work in the nuclear industry for close to fifty or sixty years, twenty or thirty years in the nuclear power field, after so many years of practice, I have confidence in China's nuclear security. "Ye Qizhen said.
China National Nuclear Corporation also contributed to this article.
(Editors: Zhong Qinghui UN660)
2016-11-28 16:13:15
Surging news
院士：中国核电不会有类似福岛的事故
当地时间11月22日5时59分，日本福岛县近海发生7.4级地震，随后海啸预警发布。
在心系生命的同时，公众不免担心福岛曾因2011年地震和海啸导致核电站事故，这次有没有核泄漏？进而关心中国核电站的安全性。为此，记者采访相关专家，为大家揭秘中国核安全现状。
不同于福岛，我们更安全
据日本媒体报道，福岛第二核电机组第三号燃料棒储存池在地震中一度出现冷却停止。随后日本原子能安全厅声称，这一机组废燃料池已于当地时间8时前恢复冷却功能，并未发生核泄漏。
值得庆幸的是，日本此次地震没有造成严重伤亡和核泄漏事故，但有人会担心中国的核电站能否经受住类似的自然灾害的冲击？
中核集团核电专家、中国工程院院士叶奇蓁告诉记者：“除了选址过程对地质条件的严格把关以外，单就核电站自身而言，我们完全可以对中国核电站的安全有信心。”
其实，5年前日本福岛发生核事故的核电站和中国的核电站有很大区别。
叶奇蓁说，首先福岛核电站是沸水堆。沸水堆核电站工作流程是——冷却剂（水）从堆芯下部流进，在沿堆芯上升的过程中，从燃料棒那里得到了热量，使冷却剂变成了蒸汽和水的混合物，经过汽水分离器和蒸汽干燥器，用分离出的高温蒸汽来推动汽轮发电机组发电。而且福岛核电站建于上世纪70年代，技术水平相对较低。
再看压水堆，压水堆有3道屏障：燃料包壳、压力边界、安全壳。燃料假如破了，放射性物质就可被屏蔽在压力边界里，还是在一回路里面。
但是沸水堆的蒸汽要从一回路穿出去，同时也穿过安全壳，所以说沸水堆的3道屏障不完整。正是沸水堆一回路跟二回路不隔离的特点，带来了5年前福岛核电站大量放射性物质泄漏的可能。
就这方面而言，压水堆堆型具有优势,而中国核电也以压水堆为主。
“中国核能的发展特点之一是有后发优势。因为我们采用的都是当时最先进的技术，有一个很成熟的技术基础，所以不至于在某一个地方由于我们考虑不周或者经验不足而走弯路。”叶奇蓁说。
他说：“安全性，中国的核电发展从来没有忽视过。中国已经在一定程度考虑了严重事故的影响，以及严重事故的应对措施。”
例如，在秦山核电站里有消氢系统，这一系统将氢跟氧复合，没有达到爆炸浓度之前就把它们复合了，因此不会出现5年前福岛核事故时氢爆的危险。
技术突破，安全性能大有保障
当然，中国的核电发展不会一直引进别人的技术而自己却止步不前。从二代到三代，改变最大的一个指标就是安全目标提高了一个量级。也就是说发生堆芯熔化，发生大型事故、影响环境事故的概率要低一个量级。
叶奇蓁说，首先是严重事故的完整预防和缓解措施，预防是尽量把事故消除在萌芽状态。事故一般是设备故障引起的，因此我们把设备的可靠性冗余度提高了。
“冗余度的意思，就像大楼里面的消防系统，我不仅有一个灭火器，我有几个，一个打不开，另外一个可以打开，更加可靠是不是？”叶奇蓁说。
例如中国的三代核电技术“华龙一号”就有两种形式的安全系统，能动加非能动。一个叫能动的安全系统，一旦出现事故，很快就能把事故消除。而一旦没动力，就像福岛核事故那样失去全部电源，动不起来了，“华龙一号”还有非能动的安全系统，还是能够把堆维持在安全状态。
叶奇蓁说告诉记者：“这就是‘能动加非能动’的优势。能动，由于它的动力作用，快速地消除事故；非能动，由于它是按照自然规律进行，不需要外界的动力，能够确保后面的安全。所以我们采用了两个优势结合起来的方法。”
厉害的来了，“华龙一号”还设计了双层安全壳。那么双层安全壳能达到什么安全水平？
“防商用大飞机冲撞。”叶奇蓁说。
你没有看错，设计了双层安全壳的“华龙一号”，不仅可抗9级地震，外层还可以防如A380那类大飞机冲撞、爆炸等，里层可以防放射性事故。
“‘华龙一号’是在原有的核电发展基础上进行总结，利用成熟的经验、成熟的技术，采取了一些根本性的、创新性的改进技术，像能动加非能动、双层安全壳、严重事故预防等，所以它是一个非常可靠的产品。”叶奇蓁说。
多多了解，核电安全请放心
“核是建立在所有的工业基础上，中国的工业水平在不断提高，核电设备制造水平相比三四十年前有质的变化。”叶奇蓁说。
中国现在核电设备的中国国产化率达到了85%~90%，大设备、关键设备都在国内制造，比如压力容器、蒸汽发生器、汽轮发电机等。
“中国国产设备的生产过程中，我们坚持用国际最高标准来制造，以最高标准来检验。我们不会在这个问题上含糊，所以中国的核电设备是相当可靠的。”叶奇蓁说。
他同时强调，关于核电站运行，世界核电运营者协会WANO组织用8项~10项的指标对每个核电站进行考核。
按照这个考核，中国的核电站差不多都在前50名以内，甚至有的年份有的电站还排到第一或者第二。换句话说，中国的核电站管理运行得很好，在国际上都是被认可的。
叶奇蓁告诉记者：“中国一向坚持以最高的国际安全标准来设计核电站、建造核电站、运行核电站，中国的核电站是很安全的。因为我们采取的技术路线以及所采取的一些技术措施，都确保了不会发生类似福岛和切尔诺贝利类似的事故。”
他说，大家只要多了解中国所建造的电站、多了解中国核电站所采取的措施，就可以打消核电安全方面的担心。
“我在核行业工作了快五六十年了，在核电领域也有二三十年，经过这么多年的实践，我对中国核电的安全完全有信心。”叶奇蓁说。
中国核工业集团公司对本文亦有帮助。
(责任编辑：钟庆辉 UN660)
2016-11-28 16:13:15
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