Nuclear Reactor Head Segmentation
At Rancho Seco Nuclear Generating Station, we cut the reactor head into 5 pieces for shipping and burial. The reactor head was made of 8” thick carbon steel with stainless steel cladding, and a steel head flange approximately 3’ thick. Due to the size, shipping and burial costs were prohibitive.
Cutting these thicknesses requires precise set up and cutting techniques. In addition, significant internal stresses built up in the head due to high temperatures caused it to move during cutting and required compensation by adjusting set up, wire tension, and wire speed.
To provide access for cutting, the reactor head was placed on cribbing. Access holes for the wire were drilled in order to make a horizontal cut separating the dome from the flange. A vertical cut was then made to segment the dome into 2 sections. Finally, the head flange was cut into 3 separate sections.
The project was completed on schedule. Approximately 466 man hours were spent cutting with an entire dose received of 230 mrem per man. A total of 7200 square inches of steel were cut. By segmenting the head dome and head flange, the utility realized nearly $1,000,000 in savings for transportation and burial. Successful completion of this project marked the first segmentation of a reactor head utilizing a diamond wire saw.