Wachs Services and the NASA Glenn Plum Brook Station Decommissioning Story
In early August 2003, ‘Wachs Technical Services” removed three components known as Horizontal Beam Tubes. These tubes were metal pipes that ran through the side of the reactor vessel wall adjacent to the reactor’s core box and were used in experiments when the reactor was operational. Because these tubes contained a significant portion of the radiation remaining in the reactor vessel, NASA made their removal the first order of business during segmentation.

The Wachs crew removed the tubes in the manner they had practiced — remotely — operating specially articulated tooling, while looking into camera monitors to minimize exposure. The crew used a special air-activated table device to guide the tubes out of the side of the reactor and into one of the quadrants (Quadrant D) of the reactor Facility. Then the worker used a specially designed, remotely operated band saw to cut through the tubes, after which an overhead crane lifted the cut pieces out of the quadrant and into a stainless steel liner. The crew used a remote device to insert a stainless steel plug into the hole in the reactor wall and made use of a special Cask Transfer System (involving the large capacity crane, cart mounted on trolley-like tracks) to move the external ends of the Horizontal Beam Tubes into a dedicated area of Quadrant A. There they underwent further size reduction and temporary storage in the liner. The crew moved the “hotter” ends — the ones that had been inside the reactor tank in a specialized storage cask.

Mock-up Testing, Training and Safety
Mock-up training is critical to reactor components disassembly and removal. Wachs Technical Services regularly designs and/or modifies machinery and produces specialized tooling and mock-ups at its shop in North Carolina.

At NASA Glenn Plum Brook Station
During mock-up training workers become extremely proficient. Wachs made extensive training use of the Mock-up Reactor (MUR) that once operated conterminously with the test reactor. In the case of the Beam Tubes, technicians were able to reduce the amount of time it took to do the task and therefore reduce the overall time spent in the radiation environment. Cutting the tubes, re-capping the vessel, lifting the tube pieced (by crane) and packing the pieces into liners and shipping casks were maneuvers controlled via video cameras and directed by robotics.

Identify the best cutting technology and tooling required for components and material being cut.
Wachs Identified the cutting technology and tooling best suited for the components and material. Most of the segmenting tools must be specifically designed and fabricated because of the small space in which they’ll be used. Wachs test tools and allows operators to train by using them on mock-ups in their North Carolina facility. Lessons learned from these mock-up exercises are used by the Wachs on-site tool engineers making machine design enhancements in anticipation of actual segmentation.