Robots are used for decontamination and dismantling work at a nuclear fuel reprocessing plant that has become a waste furnace

Located in the northernmost part of England and adjacent to Scotland, Cumbria State has a soap reprocessing plant that reprocesses spent nuclear fuel from nuclear power plants. The reprocessing plant which began operation in 1997 starts its dismantling in November 2018, but many robots are introduced for decontamination and demolition work of nuclear waste with high radiation level And it seems.

Inside Sellafield's death zone with the nuclear clean-up robots - BBC News
https://www.bbc.com/news/business-46301596

The soap (THORP) reprocessing plant is a facility named after "Thermal Oxide Reprocessing Plant" meaning "Thermal Oxide Reprocessing Plant", owned by the Nuclear Decommissioning Agency, a British official government agency Then, Serafield Corporation has operated it. In the facility, we have received sales of 9,000 million pounds (about 1.3 trillion yen) by accepting spent nuclear fuels inside and outside the UK and producing MOX fuel, but operation finished in November 2018.

The biggest problem of the nuclear facility which became the decommissioning furnace is how to disassemble and dispose of the waste polluted by the high radiation level, so that problem is waiting for the demolition work of the soap reprocessing plant It is. It is said that when 4 siebelts (4000 mSv) are exposed to the whole body at a time, it is said that half of the exposed people die due to bone marrow injury, but human beings disassemble the nuclear fuel carried into the reprocessing plant and re- The dose level of the equipment "Head End Shear Cave" that prepares for processing reaches 280 sievert per hour.

In order to prevent the radiation from leaking to the outside, windows for looking inside the facility are fitted with glass with a thickness of 1 m or more, which contains lead. Of course, it is not a situation that human beings are inside, so most of the work is handled by a robot that operates remotely.

The robot has already been put in the facility and we are working on the inside cleaning work with careful operation by the operator. We are continuing to wash away adhering pollutants with water and acid, and ultimately plan to decontaminate to a contamination level where human beings can enter and work. Melanie Brownridge of Nuclear Abolition Measures Agency (NDA), which manages dismantling of nuclear power plants, says, "We need to keep looking for excellent equipment to more efficiently decontaminate facilities."

These robots were developed for the dismantling of the facility, and various types of large and small are prepared according to the application. The robot is in charge of decontaminating the inside of the pool that continues to cool the spent nuclear fuel, which is reflected in the following movies.


Also, drone is used for this work. It is said that a method of periodically drone a drone inside the building and mapping the radiation level in the facility for use in decontamination work has been adopted. The technology of Blue Bear which is in charge of work seems to be utilized also for decontamination work of Fukushima nuclear power plant in Japan.

Surprisingly, the environmental group "Greenpeace" has a high interest in dismantling work of this soap reprocessing plant. Greenpeace, which developed harsh criticism at the time of construction of the facility, says that it has a policy of promoting the abolition of other nuclear facilities by using the dismantling know-how of this facility.

Dismantling of the soap reprocessing plant began, and initial decontamination work is expected to take about three years. However, it is considered that decommissioning work waiting before that takes time on the level of decades. It is estimated that dismantling of the facility will be finally completed between 2075 and 2095, and this cost is estimated to be 4 billion pounds (about 6 trillion yen) in 2018 as monetary value.

And, of course, we are also waiting for the problem of how to finalize high level nuclear waste generated by dismantling. In the UK, we are setting a policy of geological disposal to store waste in concrete and drum cans in the underground rock formations, but the actual final disposal site has not been decided at all.

Half a century has passed since practical use of "nuclear energy" which was touted as "infinite energy", mankind will face the same problem one after another when operation stop of the old facility begins. An era will come when the world needs to narrow down its wisdom from now on to the question of who and how to keep managing nuclear waste that needs to be managed at several hundreds of years from the tens of thousands of years level.