In the U. S., reactors shut down for refueling typically retain most of their fuel in the thick steel reactor pressure vessel that provides much more protection against a radioactive release.

在美国，如果反应堆因补充燃料而关闭，一般来说，在厚重的钢质反应堆压力容器内仍会存有大多数燃料，因为这个容器可提供更多保护，防止辐射泄漏。

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Perform Fuel System Pressure Release Procedure as described in this Group.

按本单元的说明执行燃油系统压力释放程序。

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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