73 Sierverts/Hr Radiation Inside Reactor 2 Containment Vessel at #Fukushima I Nuke Plant

Not that surprising, but here's how Yomiuri Shinbun (3/28/2012) puts it:

東京電力は２７日、福島第一原子力発電所２号機の格納容器内の線量を事故後、初めて直接測定し、最高で毎時７３シーベルトだったと発表した。

TEPCO announced on March 27 that they directly measured the radiation levels inside the Containment Vessel at Fukushima I Nuclear Power Plant for the first time since the accident had started, and the maximum level was 73 sieverts/hour.

　事故後に測定した最高線量で、人が被曝(ひばく)すれば１分弱で嘔吐(おうと)などの症状が発生し、約８分で死に至る。東電は「容器内での人の作業は不可能で、内部の状況を把握するためには、高い放射線に耐える機器開発が必要になる」としている。

It is the highest level measured after the accident. If one is exposed to radiation at this level, the radiation sickness including vomiting starts in less than one minute, resulting in death in about 8 minutes. TEPCO says "It is impossible for human workers to work inside the CV. In order to fully understand the condition inside, it will be necessary to develop equipments that withstand high levels of radiation."

　調査は２６日に内視鏡を挿入した配管に、線量計を入れて測定した。壁面から５０～１００センチの場所で計８か所測り、線量は毎時３１～７３シーベルトだった。定期検査中の格納容器内の線量に比べ、１０万倍以上高い。格納容器内に溶け落ちた核燃料や、格納容器内に拡散した放射性物質による放射線の影響と見られる。

The radiation survey was done by inserting the dosimeter through the same pipe that had been used for the endoscope on March 26. 8 locations were measured, at 50 to 100 centimeters off the inner wall of the Containment Vessel. The radiation levels were 31 to 73 sieverts/hour. The levels are more than 100,000 times as high as the levels during a regular maintenance. It is probably due to the melted core that has dropped to the CV and radiation from the radioactive materials that have dispersed inside the CV.

The dosimeter was capable of measuring up to 1,000 sieverts/hour radiation. 19 TEPCO workers and 16 Toshiba workers spent one hour, receiving maximum 1.69 millisievert per person for the work.

As you can see from the TEPCO's handout below, all the measurements were above the grating, and the radiation levels 100-centimeter off the wall were higher than those at 50 centimeters.

From TEPCO's handout for the Press in English, 3/27/2012:

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