If the reactor core became exposed to the external environment, officials would likely began pouring cement and sand over the entire facility, as was done at the 1986 Chernobyl nuclear accident in the Ukraine, Peter Bradford, a former commissioner of the U.S. Such an explosion would enhance the spread of radioactive contaminants. At that point, the uranium and dangerous byproducts would start escaping into the environment.ДЄt some point in the process, the walls of the reactor vessel - 6 inches (15 centimeters) of stainless steel - would melt into a lava-like pile, slump into any remaining water on the floor, and potentially cause an explosion much bigger than the one caused by the hydrogen. Next, it would eat through the floor of the already-damaged containment building.

If the temperature inside the Fukushima reactor vessel continued to rise even more - to roughly 4,000 degrees Fahrenheit (2,200 Celsius) - then the uranium fuel pellets would start to melt.ДЄccording to experts interviewed by The Associated Press, any melted fuel would eat through the bottom of the reactor vessel. The blast destroyed the exterior walls of a building, but did not breach the steel housing enveloping the reactor there, officials said. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS Tepco / X80001ДЄ similar radiation increase was seen Saturday during venting at the No. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS.

REUTERS/TEPCO/Handout (JAPAN - Tags: DISASTER ENERGY) FOR EDITORIAL USE ONLY. Tokyo Electric Power Co also said fuel may have been damaged by falling water levels at the Daiichi facility, one of its two nuclear power plants in Fukushima, some 240 km (150 miles) north of Tokyo. Japanese authorities battling to contain rising pressure in nuclear reactors damaged by a massive earthquake were forced to release radioactive steam from one plant on Maafter evacuating tens of thousands of residents from the area. 1 at the Fukushima Daiichi nuclear plant after an explosion that blew off the upper part of the structure is seen in this handout photo released by Tokyo Electric Power Company (TEPCO) in Fukushima Prefecture, northeastern Japan, March 12, 2011. Released steam raised radiation levels above safety limits outside the Unit 3 reactor Sunday, TEPCO officials said, adding they informed the government of an 'emergency situation.' Still, they said, there was no immediate threat to human health.Д®dano said the radiation levels later fell. The Unit 2 reactor, though shut down by the quake, was not in the same trouble. On Sunday TEPCO released air containing radioactive materials for more than 2 hours and injected water at the Unit 3 nuclear reactor container vessel to reduce pressure and temperature to save the reactor from a possible meltdown.Д¬ritical core cooling systems failed at both reactors. Tokyo Electric Co., or TEPCO, Saturday began pouring seawater and boric acid into its Fukushima Daiichi power plant Unit 1 reactor, whose core partially melted.

Nuclear reactor meltdown in japan 2011