Dooms Day Device... is broken.

During a power test of the Large Hadron Collider sprung a leak of liquid helium. The leak was in one of the power bus that transfers the massive amounts of electricity needed to power the LHC. To use this power more efficiently it is transferred through superconducting niobium–titanium cables, which need to be cooled to 1.9 Kelvin or -271.3°C. This is where the liquid helium leaked from. When the helium leaked the cables could not withstand the load of almost 8,000 amps. The current began to arch and subsequently destroyed near by parts of the machine. Some nearby magnets where destroyed and the vacuum chamber was punctured. The current was so powerful that the wire was vaporized. Scientists at CERN, the European Organization for Nuclear Research, are confident that an accident like this will not happen again. Measures will be taken to ensure that electrical fluctuations in the bus will be monitored more closely. This is important because the LHC cannot be simply switched off, it takes nearly a minute for heating coils and bypass circuits to discharge the power stored inside the magnets.

http://www.nature.com/news/2008/081029/full/news.2008.1194.html?s=news_rss