要防止铀中的衰变热熔解堆心，必须用水冷却。

To keep the decay heat in the uranium from melting the core, you have to keep water on it.

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关闭核反应堆时，需要打开安全阀门释放蒸气，然后用水冷却堆心。

To shut down a reactor, safety valves are opened to release the steam and water is used to then to cool down the reactor core.

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贝杰隆说，不得不让人担心的是堆心仍然存在衰变热，而这将会持续几天。

'What you have to worry about is the decay heat that is still in the core that will last for days,' Bergeron said.

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