Extremely deadly radiation reading, huge hole found in grate under Fukushima No. 1 reactor vessel

The Japan Times

The radiation level in the containment vessel of reactor 2 at the crippledFukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, oTokyo Electric Power Co. Holdings Inc. said Thursday. The reading means a person could die from even brief exposure, highlighting the difficulties ahead as the government and Tepco grope their way toward dismantling all three reactors that suffered core meltdowns in the March 2011 disaster. Tepco also announced that, based on image analysis, it has discovered a 2-meter hole in the metal grating beneath the pressure vessel inside reactor 2's containment vessel, and discovered a portion of it is warped. The hole could have been caused by melted fuel penetrating the vessel after the March 11, 2011 mega-quake and massive tsunami triggered a station blackout that crippled the plant's ability to keep the reactors cool. The new radiation level, described by some experts as "unimaginable," far exceeds 73 sieverts per hour, the previously highest radiation reading monitored in the interior of the reactor.


Tepco finds gaping hole in grate under containment vessel, potential fuel debris at Fukushima No. 1 power plant

The Japan Times

The radiation level in the containment vessel of the No. 2 reactor at the defunct Fukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, operator Tokyo Electric said Thursday. Tokyo Electric Power Company Holdings Inc. also announced that, based on image analysis, it has discovered a 2-meter hole in the metal grating beneath the pressure vessel inside the No. 2 unit's containment vessel, and detected that a portion of it is warped. According to Tepco, the blazing radiation reading was taken near the entrance area in the space just below the pressure vessel, which contains the reactor core. The previously high was 73 sieverts per hour. The hole could have been caused by melted fuel penetrating the vessel after a mega-quake and massive tsunami triggered a station blackout that crippled the plant's ability to keep the reactors cool on March 11, 2011.


Fukushima radiation levels hit record high

Daily Mail - Science & tech

Radiation levels inside a stricken reactor at Japan's Fukushima nuclear plant have hit a record high. Levels are now so high that they could kill off robots sent in to probe the reactors. The development casts doubt over how the disaster-hit facility will be safely dismantled in the future. Radiation levels inside a stricken reactor at Japan's Fukushima nuclear plant have hit a record high. Levels are so high that they could kill off robots sent in to probe the reactors.


High radiation readings complicate Fukushima robot strategy at unit 2

The Japan Times

The high radiation estimates in the No. 2 reactor of the stricken Fukushima No. 1 nuclear plant will probably force a rethink of the nationalized utility's robot-based strategy for locating its molten fuel. According to an analysis of Thursday's abbreviated probe, the radiation in the primary containment vessel is about 650 sieverts per hour, more than the 530 sieverts estimated late last month, Tokyo Electric Power Company Holding Inc. said. That level could kill a person quickly and indicates the fuel likely burned through the pressure vessel during the meltdown and is somewhere nearby. Tepco, as the utility is known, halted Thursday's robot after its camera went dark. The company suspects the problem was caused by the radiation.


Tepco's biggest hurdle: How to remove melted fuel from crippled Fukushima reactors

The Japan Times

Six years after the triple meltdown at the Fukushima No. 1 nuclear power plant, recent investigations underneath the damaged reactor 2 using cameras and robots came close to identifying melted fuel rods for the first time. Experts say getting a peek inside the containment vessel of reactor 2 was an accomplishment. But it also highlighted how tough it will be to further pinpoint the exact location of the melted fuel, let alone remove it some time in the future. The biggest hurdle is the extremely lethal levels of radiation inside the containment vessel that not only prevent humans from getting near but have also crippled robots and other mechanical devices. Safely removing the melted fuel would be a best-case scenario but the risks and costs should be weighed against the option of leaving the melted fuel in the crippled reactors, some experts said.