A second reactor containment vessel at Japan's Fukushima Daiichi nuclear power plant was believed to be emitting radioactive fumes after possibly bursting open, the Japanese government announced today (see GSN, March 15).
The apparent breakage in the No. 3 reactor's containment vessel was announced one day after the nation announced a possible similar breach to the site's No. 2 reactor container, the New York Times reported. The probability of "severe damage" to the No. 3 reactor vessel was "low," Japanese Chief Cabinet Secretary Yukio Edano said (Tabuchi/Bradsher, (New York Times, March 16).
The reactor No. 2 containment vessel's seeming rupture -- possibly caused by one of four hydrogen explosions to hit the Fukushima facility in recent days -- might be filling the reactor's larger containment building with radioactive steam capable of bursting open the structure, the Washington Post yesterday quoted experts as saying (Washington Post, March 16). The blast might also have compromised a reactor cooling component at the No. 2 reactor as well as the reactor's suppression pool, which is designed to reduce pressure by converting steam into water, the Asahi Shimbun reported (Asahi Shimbun, March 16).
The nuclear plant was crippled by Friday's 9.0-magnitude earthquake, which also produced a devastating tsunami. Officials have said the events probably caused no fewer than 10,000 deaths.
Tokyo Electric Power, which operates the facility, said it had increased the number of personnel at the site from 50 to 100 after earlier withdrawing 700 workers, the Times reported. Employees pulled back from the plant for 45 minutes at one point, but kept water moving into the No. 1, No. 2 and No. 3 reactor sites in an effort to prevent components and fuel from overheating. Untreated material could melt down or lead to new explosions, potentially allowing a massive release of radioactive material into the environment (Tabuchi/Bradsher, New York Times).
The radiation that prompted the pullback likely came in white clouds emitted from one of the reactor sites, the Associated Press reported on Wednesday (Talmadge/Yuasa, Associated Press I/Yahoo!News, March 16).
The Fukushima plant has six reactors. Prior to the possible break at the No. 3 reactor, authorities' focus had been on a section of the No. 4 building that contains spent fuel rods in cooling ponds and on an area of the No. 2 reactor used for cooling and collecting cesium, iodine and strontium, Reuters reported.
The effects of the continuing crisis have been widespread. The government has urged roughly 140,000 residents within an 18-mile exclusion zone of the plant not to go outdoors. Nations such as France and Australia are calling for nationals to exit Japan, and there are concerns about what so far have been low levels of radiation in Tokyo (Saoshiro/Fujioka, Reuters I, March 16).
"Japanese authorities have informed the IAEA that the evacuation of the population from the 20-kilometer zone around Fukushima Daiichi has been successfully completed," the International Atomic Energy Agency said. "The Japanese authorities have also advised that people within a 30-[kilometer] radius to take cover indoors. Iodine tablets have been distributed to evacuation centers but no decision has yet been taken on their administration" (International Atomic Energy Agency release, March 16).
The French nuclear safety organization ASN declared on Tuesday the situation should be designated a six on the INES classification of atomic events, according to Reuters. The ranking system has seven tiers, with a level seven being the most severe. The Japanese government issued its latest designation on Saturday, placing the crisis at level four.
"This is a slow-moving nightmare," said physicist Thomas Neff of the Massachusetts Institute of Technology.
Intense radiation at the Fukushima site scuttled plans for a helicopter to lift water into the No. 3 reactor building, which was broken open by one of the explosions, Reuters reported. The facility's administrator characterized problems at the No. 3 reactor, which used a fuel blend with converted weapons plutonium, as its "priority" (see related GSN story, today).
Authorities were set to train a water cannon on one of the reactor areas in a bid to cool used nuclear fuel, and personnel were scrambling to remove obstructions that were preventing the creation of a pathway to the No. 4 reactor for fire engines. That reactor area's status was "not so good," the operator indicated (Saoshiro/Fujioka, Reuters I, March 16).
Japan sighted a second fire at the No. 4 reactor, but visual evidence of the conflagration vanished within 30 minutes, Tokyo informed the International Atomic Energy Agency (Fredrik Dahl, Reuters II, March 16).
Workers were pumping water into the buildings of reactors No. 5 and No. 6 in an effort to cool spent fuel in storage there (Saoshiro/Fujioka, Reuters I).
Japan informed the International Atomic Energy Agency "the water level in Unit 5 had decreased to 201 [centimeters] above the top of the fuel," a 40-centimeter decrease in four hours, the U.N. nuclear watchdog said in a statement.
"Officials at the plant were planning to use an operational diesel generator in Unit 6 to supply water to Unit 5," the agency said (International Atomic Energy Agency release).
Authorities were weighing the option of firing water and boric acid at the plant in a last-resort effort to cool reactor components, AP reported on Tuesday.
Seventy percent of the No. 1 reactor site's fuel rods might have suffered harm, the Japanese government indicated. One-third of another reactor area's fuel rods had been affected, Kyodo News reported.
"We don't know the nature of the damage, and it could be either melting, or there might be some holes in them," atomic safety agency spokesman Minoru Ohgoda said (Associated Press II/Google News, March 15).
Japanese government sources said they were in discussions with U.S. armed forces on potential assistance at the facility, Reuters reported (Saoshiro/Fujioka, Reuters I).
Meanwhile, Russian government sources on Wednesday rebuffed suggestions that radiation from the Japanese facility might spread to eastern Russia, RIA Novosti reported (RIA Novosti, March 16).