TEPCO to introduce new device for measuring Fukushima fuel debris

27 September 2015

Tokyo Electric Power Co. will introduce as early as in fiscal 2016 a new device that can accurately measure the contents of fuel debris remaining in the Nos. 1, 2 and 3 units at the crippled Fukushima Daiichi nuclear power plant in Fukushima Prefecture.
With fuel very likely to have deteriorated due to the disaster, TEPCO needs to obtain a clear grasp of its condition in order to proceed safely with removal.
After analyzing the device survey results in detail, TEPCO will decide on how to remove the fuel debris, a procedure said to be the biggest challenge in the decommissioning process.
The Japan Atomic Energy Agency is currently developing the new device and is discussing when to introduce it with TEPCO. The instrument, to be operated by remote control, will comprise a main body part of optical fiber several millimeters in diameter and a measuring component.
The attached figure shows an image of the fuel debris survey.
The device, which will be constructed to withstand high radiation levels, will be placed in reactor pressure vessels and other parts of the units. Camera and sensor functions will be attached to the tip of the optical fiber, and a laser will be generated through the optical fiber when the device approaches fuel debris. The debris content will then be analyzed based on plasma emission.
(Translated by Kyodo News)