Vattenfall has developed special gripping tools with which to remove more than 600 barrels of low- and intermediate-level waste from six storage pits at the decommissioned Brunsbüttel nuclear power plant in Germany.
The company demonstrated the technology yesterday during a visit to Brunsbüttel by Robert Habeck, energy transition minister of Germany's northernmost region of Schleswig-Holstein.
|One off the gripping tools undergoes acceptance testing (Image: Vattenfall)
A total of 632 steel drums are currently stored in six pits within the plant's storage area. These drums contain radioactive wastes from the plant's waste water treatment system. This includes filter resins used to keep the water as clean as possible, as well as evaporator concentrates - dried residues from the waste water treatment.
The pits and the barrels were not intended for the long-term storage of such wastes. However, with the delayed completion of the Konrad repository - now expected between 2021 and 2025 - the waste has been stored within them longer than expected.
In 2014, Vattenfall examined the pits and the barrels within them using a specially developed camera. Some of the barrels were found to have been damaged. The company has since developed various gripping tools for handling the barrels according to the degree of damage to them. A crane will be used to lift the barrels out of the pits.
"We found that special gripping tools would be required for lifting some of the barrels when emptying the pits to ensure easy and safe handling," said Vattenfall's Jens Seyer. "As there were no tools for this application, they had to be specially designed and manufactured for it."
He added, "After extensive acceptance and functional tests, as well as cold handling under quasi-real conditions, we are confident that these tools are ready for use."
Vattenfall expects to begin removing barrels from the pits at the end of this month and to complete the task by mid-2018.
Once removed, the contents of the barrels containing filter resins will be transferred to final storage containers. Meanwhile, those barrels containing evaporator concentrates will be dried in a drying plant and then the entire barrels will be placed in final storage containers.
The single-unit Brunsbüttel plant was among the eight oldest German reactors taken out of service in March 2011. The 771 MWe boiling water reactor had been idle since 2007 following a grid-facilitated trip. Vattenfall - which owns a 66.7% stake in the plant with EOn holding the remaining 33.3% - applied in late 2012 to decommission that plant and the approval process is under way.
Researched and written
by World Nuclear News