Experts warned of underestimation as nuclear crisis unfolds

By Yo Tong on March 15, 2011
Fukushima Daiichi Nuclear Power Plant after the second explosion on 14 March. Image by DigitalGlobe.

Two new explosions rocked the Fukushima Daiichi Nuclear Power Plant yesterday, after being damaged by last Friday's traumatic earthquake and the subsequent tsunami. Experts are worried that the crisis is more severe than the estimation given by Japanese authorities.

Although Japanese authorities maintained the rating of the Fukushima nuclear disaster on level 4 (out of seven) of the International Nuclear Event Scale (INES). This level refers to an “accident with local consequences.” US Energy Secretary Steven Chu said Wednesday (EDT) that early reports indicated that the incident in Fukushima Daiichi Nuclear Power Plant could be “very significant, perhaps beyond Three Mile Island meltdown” (level 5 in INES) in 1979.

Goto Masashi, former Toshiba engineer who specialized in designing containment vessels of reactors, had warned of the risk posed by Mixed oxide fuel rods, which contain plutonium and uranium, in reactor No. 3. The radiation data of Tokyo Metropolitan government only covered Iodine 131 and  Caesium 137, according to a NHK report on 16 March.

French Nuclear Safety Authority (ASN) said the accident at Fukushima Daiichi Nuclear Power Plant could be classed as level six in INES, one level lower than that of Chernobyl disaster in 1986, according to Reuters. ASN Chairman Andre-Claude Lacoste said the concrete vessel around the No. 2 reactor, designed to contain radioactive debris, is “no longer sealed.”

At 06:14 on 15 March (Japan local time), an explosion occurred at reactor No. 2 of Fukushima Daiichi Power Plant, Japan's Nuclear and Industrial Safety Agency (NISA) confirmed. It is thought that the suppression pool container is damaged. Prime Minister Naoto Kan urged people within a 20-30 km radius from the Plant to stay indoors.

At the same time, an explosion occurred at the building which housed reactor No. 4. It is believed to be a hydrogen blast. No. 4 reactor went into regular maintenance mode when the earthquake occurred on 11 March and is not operational.

Subsequently, at 09:38, a blast occurred on the fourth floor of the building which housed reactor No. 4, TEPCO reported. It is believed that the blast started at the recycling pump which supplied water to the reactor. TEPCO said at 13:00 that the fire is extinguished.

In the English version of the press release by TEPCO, people were informed that “a loud explosion was heard from within the power station (Unit 4 Nuclear Reactor Building)” yet in the Japanese version, the explosion was underplayed as being “a loud noise” (大きな音).

Japan's Chief Cabinet Secretary Edano Yukio said in a press briefing that according to monitoring data of Daiichi Power Plant, radiation near reactor No. 3 increased to 400 Millisievert (400000 Microsievert) per hour at 10:22, and radiation near reactor No. 4 and area between No. 3 and No. 2 reached 100 Millisievert per hour and 30 Millisievert per hour respectively. It was confirmed that this level of radioactivity is harmful to human beings.

Later, radiation at the front gate of Daiichi Power Plant dropped to 596.4 Microsievert per hour at 15:30, Japan's Chief Cabinet Secretary Edano Yukio said in a press briefing. Meanwhile, the temperature of reactors No. 5 and 6 “somewhat increased,” Edano said.

Radiation in Russian port city of Vladivostok, about 800km northwest of Fukushima Daiichi Nuclear Power Plant, were slightly higher at 13:00 compared to six hours before. However, it stayed within normal levels, Reuters reported, citing Russia's regional interior ministry.

In a separate development, at 22:35, an earthquake with a magnitude of 6.1 occurred in Shizuoka Prefecture, according to U.S. Geology Surveys. Japan Meteorological Agency later said it is not clear whether the earthquake is related to the 9.0 earthquake that hit Japan on March 11. Hamaoka Nuclear Power Plant, which is located about 90km southwest of epicenter and situated on a fault line, is in normal operation, IAEA said.

The international community is preparing for the worst. U.S. Federal Aviation Administration said Tuesday night that it was prepared to take action, including the rerouting of Japan-bound flights should the nuclear crisis worsen, Reuters reported.

Deutsche Lufthansa AG rerouted its Tokyo flights to the southern-Japanese cities of Nagoya and Osaka, citing risk of nuclear fallout, according to Bloomberg.

Meanwhile, Austria is moving its embassy from Tokyo to Osaka, citing unstable conditions in vicinity of the Fukushima Daiichi Power Plant.

China is organizing a large-scale evacuation of its citizens from northeastern Japan for the same reason, according to an emergency notice by the Chinese Embassy in Japan.

The Chinese Embassy in Japan and the Chinese Consulate General in Niigata are arranging coaches to Miyagi, Fukushima, Ibaraki and Iwate Prefectures to gather their citizens and send them to Niigata and Narita airports, before securing flights to China, the notice said. No charter flight is arranged for the moment.