Now they're telling us...
Yomiuri Shinbun (in Japanese, link added; 1:21AM JST 3/24/2011):
Haruki Madarame, chairman of the Nuclear Safety Committee [link is in Japanese; their last update on their English site update was in February] which advises the Japanese government on the safety regulations for the nuclear power industry in Japan, spoke for the first time on March 23 evening since the earthquake that triggered the nuclear accident at Fukushima I Nuclear Power Plant.
Asked about the damage to the Reactors at Fukushima I Plant, the chairman said, "(After the hydrogen explosion), the fuel rods in the Reactor No.1 are assumed to have melted to a significant degree. Compared to the Reactors No.2 and 3, the situation in the Reactor No.1 is the most severe." The temperature and the pressure of the reactor core continue to rise abnormally, and the situation is getting very dangerous. He disclosed "We are considering releasing the valve to let the steam out of the Reactor Pressure Vessel (RPV) in order to prevent the destruction [of the RPV]."
The fuel rods in the Reactors No.1, 2, 3 have been exposed, and the operation to pour sea water into the reactor cores continues. On March 32, The Reactor No.1's core temperature rose to 400-degree Celsius, exceeding the design temperature (302-degree Celsius), but the successive pouring of water has since lowered the temperature. However, the pressure continues to build inside [the RPV]. Chairman Madarame said they will decide on March 24 whether to release the steam from the RPV.
Mr. Madarame is another graduate from the nation's elite Tokyo University. At least he majored in nuclear science.