Mammoet strand jacks aid nuclear reactor decommissioning

Mammoet crews assisted client Orano USA with the extraction of the sectioned 540-tonne nuclear reactor vessel (RV) at the shutdown Crystal River Unit 3 pressurized water reactor site in Florida. The removal of the RV is part of the accelerated decommissioning of the facility, which began generating electricity in 1977.

Extraction of part of a nuclear reactor using Mammoet’s strand jacks.

Mammoet said that typically, 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 ‘optimized segmentation’, which first segments, extracts and separates underwater the reactor vessel’s internal components, the “internals,” 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 RV 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 RV segments out of the reactor well and then lowered each one down through the reactor building into a customized package on the ground level for transport to final disposal.

“Mammoet put together an expert team with decades of nuclear experience to assemble and operate the TLD/HTS strand jack system for our client,” said Sidney King, project manager, Mammoet. “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.”