The Argonne EBWR was a fully operational prototype test reactor built to demonstrate an integrated plant design using direct cycle boiling reactor as a heat source. Initial operation began in 1956 and reached a maximum capacity of 100 MW (t) before it was de-fueled in 1967.
The reactor vessel was completely supported by the flange which had a smaller inside diameter than the main reactor body. This situation required us to begin the segmentation from the bottom of the 24 foot long reactor vessel and work up. In fact, the first cut included the largest in-place tre-panning operation ever performed in the energy industry. This cut facilitated the removal of the reactor vessel lower bowl, nine control rod tubes and four forced circulation inlet pipe stubs, through the smaller reactor vessel flange opening.
The remaining vessel was segmented into 6 rings created by performing circumferential cuts on the 7 foot diameter reactor vessel. Each cut was made by a specially designed and fabricated split frame portable field lathe with a hydraulic power geared transmission and dual parting slides.
In addition to the vessel segmentation, all of the connecting nozzles had to be machined extremely close to the reactor vessel’s outside diameter to avoid conflict with the reinforced concrete cavity. These operations were performed with standard precision field machining equipment. The 8 foot 9 inch diameter cavity liner and lower shield plug were also segmented. Both components were lined with lead and, therefore, could only be cut with a cold process which would not jeopardize the health of the decommissioning team. A power feed milling table was implemented to segment rectangular pieces that fit directly into the burial cask.