Nuclear power plant containment shell is a large-volume pre-stressed reinforced concrete silo-shell structure to prevent radioactivity, and is the most important protected object in special condition.

核电站安全壳是防止放射性物质向环境释放的大体积预应力混凝土筒壳结构，是特殊环境条件下的重点防护目标。

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In like manner, I believe that reactors should be designed such that an earthquake of any magnitude could not destroy the reactor or its containment shell, further that if the reactor core was to start to melt down, the melt down itself would shut the reactor down and, at the very worst, the reactor would entomb itself with no potential release of radiation into the environment.

FORBES: A Year After Fukushima Meltdown, Is Nuke Power Any Safer?

Shell has also been asked to build a containment device in case it is needed.

BBC: Shell claims progress on North Sea oil leak

The damage occurred during a test of what Shell says would be the first-ever containment system deployed in Arctic waters.

FORBES: After Mishaps, Shell Dials Back Arctic Oil-Drilling Plans