04-12-2010 纽约时报：对AP1000新设计安全的质疑 作者：马修，瓦尔德
图片提供：Courtesy Arnold Gundersen, Fairewinds Associates
插图告诉我们核污染事故是怎样在西屋新设计的核反应堆AP1000容器内发生的。
南方公司和其合作伙伴，将用83亿美元的联邦贷款担保，在靠近奥古斯塔和佐治亚州处，兴建两个新的核反应堆，而反对者却质疑核反应堆设计的细节问题。
这种核反应堆由西屋公司设计称AP1000，还计划为其他几个核电站提供他们的设计，但尚未完全被美国核安全管理委员会的批准。
这种新的设计据称它的安全性要远远超过现有的核电站设计，它能确保由于没有电力供应而将导致核芯熔化的意外事故中，能够借助自然重力而冷却发热的水泵阀门和管道。这个概念取名为AP1000,AP就是非动能（高级被动）的意思。（1000是指额定输出功率为1000兆瓦，实际的输出功率为1145兆瓦。）
一个关键的设计特点是一个不寻常的壳结构。其中一个是独立的钢穹顶，130英尺高，四周围绕保护外层屏蔽壳结构，顶上配有一个紧急水箱。
该委员会已引起关注安全屏蔽壳是否将强大到足以在地震中生存。西屋电气公司提交了一份详细的报告和计划，今年五月将证明该安全屏蔽壳是足够牢固的。
但是在周三（4月6日），阿尼冈德森，核工程师若干反核团体委托，发布的一份报告提出了不同的看法。
在这份报告中，他们指出，安全壳由一个钢衬和混凝土穹顶组成，但有时钢衬已生锈。
根据西屋电气公司新的设计，钢衬垫与混凝土现在分开，让空气流通之间，所以内部的钢结构温度下降是依靠了自然冷却。但如果钢铁生锈，先生冈德森说：这个作用就失效了。
在新的设计，他说，金属隔板和钢衬垫间直接有空气流动，这些金属隔板上会有水气凝结。在海岸边，是咸水凝结，在内陆，这将像冷却塔蒸发水凝结。检查钢铁是否生锈，他说，将是困难的。
如果因为圆顶生锈而发生事故，市民受核电站释放的辐射剂量，是10倍于原子能能管理委员会的最高限制，先生冈德森说。不用绘图通过烟囱效应出去的圆顶清新的空气，设计将释放放射性污染物。
沃恩吉尔伯特，作为西屋电气发言人，对先生冈德森的评估有争议。
吉尔伯特先生说，穹顶将是高品质的钢制成是1.75英寸厚。 （大多数现有的穹顶有钢衬八分之三或半英寸厚。）
安全壳结构“是旨在排除，避免腐蚀，''吉尔伯特先生说。 “万一会有一些腐蚀，它会很容易地确定视察，并加以纠正。''
冈德森先生的报告费用由地方和国家的团体，包括地球，蓝岭环保协会联盟，美国佛罗里达州绿党和南卡罗来纳州的塞拉俱乐部章朋友的组合。
New York Times Tuesday, April 12, 2011 Environment
April 21, 2010, 3:27 pm
Critics Challenge Safety of New Reactor Design
By MATTHEW L. WALD
Courtesy Arnold Gundersen, Fairewinds Associates
Illustration of how an accident might unfold in the containment vessel of a Westinghouse AP1000 nuclear reactor.
As Southern Company and its partners, armed with federal loan guarantees of $8.3 billion, move toward construction of two new reactors at a site near Augusta, Ga., opponents are taking aim at the design details.
The reactor, the Westinghouse AP 1000, is also planned for several other locations, but has not yet been fully approved by the Nuclear Regulatory Commission. It is intended to be far safer than existing plants, ensuring that there will be no fuel melting in an accident by relying for its cooling on forces like gravity and natural heat flow instead of pumps, pipes and valves. That concept gives the AP 1000 its name, for Advanced Passive. (The 1,000 refers to the power rating in megawatts, although the actual power output is a less picturesque 1,154.)
A critical feature of the design is an unusual containment structure. One part is a free-standing steel dome, 130 feet high, surrounded by a concrete shield building and topped with a tank of emergency water.
The commission has raised concerns about whether a shield building would be strong enough to survive an earthquake. Westinghouse submitted a detailed report last month and plans another in May to demonstrate that the building is adequate.
But on Wednesday, Arnie Gundersen, a nuclear engineer commissioned by several anti-nuclear groups, released a report suggesting a different hazard.
In existing plants, he pointed out, the containment consists of a steel liner and a concrete dome, but sometimes the steel liner has rusted through.
In the new Westinghouse design, the liner and the concrete are now separated, to allow air to flow between them, so the temperature inside the steel structure will be kept down by natural forces. But if the steel rusts through, “there is no backup containment behind it,’’ Mr. Gundersen said.
In the new design, he said, metal baffles bolted to the steel direct the air flow, and those baffles are a spot where moisture from the atmosphere could collect. At coastal plants, salty water could collect, and inland, it would be evaporating water from the cooling towers. Inspection, he said, would be difficult.
If the dome rusted through and an accident occurred, the plant could deliver a dose of radiation to the public that is 10 times higher than the N.R.C. limit, Mr. Gundersen said. Instead of drawing fresh air past the dome through a chimney effect, the design would expel radioactive contaminants.
Vaughn Gilbert, a spokesman for Westinghouse, disputed Mr. Gundersen’s assessment.
Mr. Gilbert said that the dome would be made of high-quality steel that is 1.75 inches thick. (Most existing domes have a steel liner three-eighths or half an inch thick.)
The containment structure “is designed to preclude and avoid corrosion,’’ Mr. Gilbert said. “In the unlikely event that there would be some corrosion, it would be readily determined in inspections, and remedied.’’
Mr. Gundersen’s report was paid for by a combination of local and national groups, including Friends of the Earth, the Blue Ridge Environmental Defense League, the Green Party of Florida and the South Carolina chapter of the Sierra Club.
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