The story begins, in a sense, in classrooms around the world, where students are taught that the rate of decay of a specific radioactive material is a constant.

这个事情要从世界各地的教室里说起，在那里学生学习到特定核素的衰变速率是恒定的。

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The concept of heat threshold is brought forward for the melting process of radioactive source with constant heat rate.

针对恒释热率热源接触熔化，提出了热量阈值的概念。

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Physicists have long held the view that the rate of breakdown - or decay - for any given radioactive substance is constant.

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But if physicists at Stanford and Purdue are correct in their findings, the whole theory of constant radioactive decay rates could be thrown out the door.

FORBES: Radioactive Decay Rates May Not Be Constant After All

The enormous heat generated by the radioactive fuel in the reactor core needs a constant flow of cold water.

FORBES: Second Explosion Damages Another Japanese Nuclear Reactor