In a nuclear test, all of the energy is suddenly (within milliseconds) released in the form of heat from a relatively small volume surrounding the thermo - nuclear device.

在核试验中，能量瞬间(毫秒内)爆发，在热核装置附近以热的形式和相对小的体积表现出来。

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SEOUL, South Korea (AP) The first satellite launched from South Korean soil is working normally, officials said Thursday, a day after Seoul achieved its space milestone amid high tensions over archrival North Korea's recent threat to test a third nuclear device.

NPR: SKorea: Satellite Working Normally, Sending Data

South Korean officials have said that activity at the Punggye-ri site indicates preparations for another nuclear test after North Korea exploded a nuclear device there on Feb. 12.

WSJ: Pyongyang Threatens to End Venture

For several weeks South Korean officials have said that activity at the Punggye-ri site indicates preparations for another nuclear test after North Korea exploded a nuclear device there on Feb. 12.

WSJ: North Korea Suspends Operations at Kaesong Industrial Complex