A second hydrogen blast occurred at the Fukushima Daiichi nuclear plant in northern Japan at 11 a.m. local time March 13, but the explosion in the reactor building of Unit 3 left the primary containment vessel intact, says the the International Atomic Energy Agency. The unit’s control room remains operational, says the IAEA. A hydrogen gas blast at Unit 1 on Saturday destroyed that unit’s containment building’s outer shell but also did not damage the core reactor building, say Japanese officials. Late on March 13, officials of the Tokyo Electric Power Co. (TEPCO) were attempting to reduce the concentration of
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.