On the inside of the sarcophagus rests the upper biological shield or UBS — a concrete slab that was thrown upwards by the reactor explosion and now rests at a 15-degree angle inside of the tomb.

石棺的内部覆盖着上层生物防护层（UBS），这是一块混凝土板，在反应堆爆炸时被抛起，现在以 15 度的角度放置在石棺内部。