This was by any measure

Fukushima; Hydrogen explosion; Common mode failure; Loss of cooling; Fault tree
1. Introduction
After the Three Mile Island and Chernobyl accidents research in learning from failures has resulted in recommendations, for becoming learning organisations, specifically addressed to the nuclear power sector [11]. Unfortunately, these have not been matched with guidance on how this could be achieved [35]. One unique feature of nuclear power plants is that they Tipranavir are initially designed for a very long operational life, typically sixty years. This poses major challenges such as those of having to cope with technical developments, new safety requirements and sustaining skills and competencies, over two or three generations of staff [35].
1.1. The evolution of the disaster
On 11 March 2011 Japan suffered its worst ever recorded earthquake, known as the Great East Japan Earthquake. It was classified as a seismic event of magnitude 9.0, with maximum measured ground acceleration of 0.52 g (5.07 m/s2). The epicentre was 110 miles E.N.E. from the Fukushima-1 reactor site, where Reactor Units 1, 2 and 3 were operating at power. On detection of the earthquake all the units shutdown (tripped) safely.