Delayed signatures of underground nuclear explosions.
Delayed signatures of underground nuclear explosions.
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DOI：
10.1038/srep23032
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发表时间：
2016-03-16
影响因子：
4.6
通讯作者：
Chipman VD
中科院分区：
文献类型：
--
作者：
Carrigan CR;Sun Y;Hunter SL;Ruddle DG;Wagoner JL;Myers KB;Emer DF;Drellack SL;Chipman VD
地下核爆炸 (UNE) 发出的放射性核素信号受到周围水文地质状况的强烈影响。与非遏制爆炸相比，遏制的效果之一是延迟爆炸产生的放射性氙到达表面，并延长其可探测期。通过现场规模的示踪剂实验，我们评估了前 UNE 遗址的重要运输特性。我们观察了在实际传输条件下由于气体从爆炸后烟囱迁移而导致的表面信号特征。背景氡气信号被发现对空腔加压高度敏感，这表明局部氡气异常可能是秘密 UNE 的一个指标。计算机模拟利用从实验中获得的传输特性来跟踪烟囱中的放射性氙同位素及其向地表的迁移。他们表明，被破裂的安全壳包围的烟囱的行为就像一个泄漏的化学反应堆，因为它对同位素演化的影响引入了以前未考虑到的对核产量的依赖。这种放射性氙同位素的演化模型通过 2013 年朝鲜民主主义人民共和国 (DPRK) 的 UNE 的放射性氙大气观测得到了验证。我们的模型产生的结果与同位素观测相似，核产量与地震估计相当。
Radionuclide signals from underground nuclear explosions (UNEs) are strongly influenced by the surrounding hydrogeologic regime. One effect of containment is delay of detonation-produced radioxenon reaching the surface as well as lengthening of its period of detectability compared to uncontained explosions. Using a field-scale tracer experiment, we evaluate important transport properties of a former UNE site. We observe the character of signals at the surface due to the migration of gases from the post-detonation chimney under realistic transport conditions. Background radon signals are found to be highly responsive to cavity pressurization suggesting that large local radon anomalies may be an indicator of a clandestine UNE. Computer simulations, using transport properties obtained from the experiment, track radioxenon isotopes in the chimney and their migration to the surface. They show that the chimney surrounded by a fractured containment regime behaves as a leaky chemical reactor regarding its effect on isotopic evolution introducing a dependence on nuclear yield not previously considered. This evolutionary model for radioxenon isotopes is validated by atmospheric observations of radioxenon from a 2013 UNE in the Democratic People’s Republic of Korea (DPRK). Our model produces results similar to isotopic observations with nuclear yields being comparable to seismic estimates.