Global engineered heavy-lifting company Mammoet has successfully extracted a 540-tonne nuclear reactor vessel at the shutdown Crystal River Unit 3 pressurised water reactor site in Florida.
Contracted by leading decommissioning of shutdown nuclear facilities company Orano USA, Mammoet shifted the entire reactor vessel and ‘internals’ – the reactor vessel’s internal components – in three parts for accelerated decommissioning. The removal of the reactor vessel is part of the accelerated decommissioning of the facility, which began generating electricity in 1977.
According to Mammoet, during decommissioning, all parts of a nuclear reactor are segmented, packaged, and shipped in up to 80 transports, which is time-and-cost-intensive with repeated processes and regulatory requirements.
Orano developed and patented a process known as ‘optimised segmentation’, which first segments, extracts and separates underwater the reactor vessel’s internal components into categories based on their radioactivity using the U.S. Nuclear Regulatory Commission’s low-level waste classification system: A, B, C, Greater-than-Class-C (GTCC).
The A, B, and C internals waste was precisely repacked inside the emptied vertical reactor vessel to optimize the segmentation of the entire reactor vessel into three pieces for transportation and disposal. Using a custom-installed strand jack system spanning the inside of the reactor containment building, Mammoet’s crew carefully lifted the two heaviest reactor vessel segments out of the reactor well and then lowered each one down through the reactor building into a customised package on the ground level for transport to final disposal.
Mammoet’s team had prior knowledge of the facility after previously completing a steam generator replacement at the same location. This knowledge, combined with early involvement with Orano to plan the process and provide a workable solution for handling the reactor parts, was crucial to execution using the optimised segmentation method, according to the heavy lifting specialist. In an industry first, this project marks the first time that this method was performed, with Mammoet’s Project Manager, Sidney King, praising the efficiency of the operations team.
“Mammoet put together an expert team with decades of nuclear experience to assemble and operate the TLD/HTS strand jack system for our client,” he said. “Execution of the lifts were performed flawlessly, and it is exciting to see the experience, technical expertise, and Mammoet’s innovative thinking come together to be a part of this historic moment in nuclear decommissioning.”
Mammoet has regularly been involved with the nuclear industry since the early 1970s providing its engineering and heavy lifting expertise to plants across the globe, as underscored by its 2016 operation to safely enclose the damaged Chernobyl reactor.
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