Robot designed in UK to help assess damaged Fukushima reactor

The remotely operated device will collect pebble-like debris that was deposited at the bottom of the reactor containment vessel after the meltdown caused by the earthquake and tsunami in March 2011. 

According to Jacobs, a prototype of the device has passed factory acceptance and performance tests to meet the requirements of Mitsubishi Heavy Industries (MHI), which is leading the project to develop the tool. The company expects to build a radiation resistant version of the robotic tool following selection in Japan.

“This is a prime example of how we are combining innovative engineering and deep nuclear knowledge to help decommissioning agencies meet the challenge of transforming legacy sites into a safe end state,” said Jacobs Energy, Security & Technology senior vice president Karen Wiemelt.

The exact nature of the debris is currently unknown, and examination of the retrieved debris samples will provide crucial data for the next steps in the clean-up and decommissioning of the Fukushima reactors.

The robotic tool had to meet over 300 functional, operational, performance and geometric requirements. It also had to be small enough to enter the damaged containment vessel and pick up sand and pebbles up to 10mm in size by deploying a bucket-style retrieval device.

In trials a remote operator guided by images from a built-in camera will need no more than eight minutes to insert the device into the containment vessel and retrieve samples, minimising the impact of radiation damage on the functioning of the device.  

MHI implemented this project through the International Research Institute for Nuclear Decommissioning, supported by funding from Japan's Ministry of Economy, Trade and Industry.