Failure of the cooling systems allowed pressure to build up beyond the design capacity of the reactors.

冷却系统的失效使压力升高，超过反应堆的设计能力。

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This prolongs the reactors core life by preventing the embrittlement of the steel of the pressure vessel, with some reactors being designed to last between 40 and 50 years.

通过防止压力窗口钢质的脆化，从而延长了核反应堆芯的寿命，有些反应器寿命更是长达40-50年。

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Early on Saturday Tepco said it had lost the ability to control pressure at the No. 1 and 2 reactors.

星期六的早些时候，电力公司说在1号和2号反应堆的压力已经失控。

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Solid-fuel reactors are atomic pressure cookers, with the constant danger of high-pressure ruptures, meltdowns, and the forceful ejection of radioactive material into the environment.

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Sea water is being pumped into the reactors by special high pressure fire extinguisher hoses to prevent a nuclear meltdown.

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Cooling systems to the reactors were knocked out, fuel rods overheated, and attempts to release pressure in the chambers led to explosions in the buildings housing the reactors.

BBC: Japan nuclear: Tepco halts Fukushima cooling plan