TEPCO workers carried out efforts at the Fukushima Daiichi Unit 1 reactor to drill a hole through the concrete containment and steel containment liner in order to insert a camera to investigate where the melted nuclear fuel may be currently located and how much water is being provided to cool it.
Four feet from the drilling location radiation levels hovered around 2 millisieverts per hour, but jumped to 10 millisieverts per hour on the drilling surface. Once the hole was opened workers measured the radiation levels on the inside edge of the drilled opening and found the radiation levels were over 200 millisieverts per hour.
TEPCO did not provide any observations related to the radiation levels detected by noted that they planned to conduct further research as planned.
Source: TEPCO
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