As a result, there are now 1,542 fuel assemblies in the spent fuel pool, including those that were already stored there earlier.
Unit 5 had been undergoing a periodic inspection when the giant earthquake struck on March 11, 2011. All power sources, including emergency diesel generators, were lost to the subsequent tsunami, but the reactor and spent fuel pool were kept cool using generators at the adjacent Unit 6, thus avoiding a worsening of the situation.