CTLGroup was retained by First Energy, to develop special processes to evaluate the containment vessel at the Davise Besse Power station as part of their relicensing commitments to the Nuclear Regulatory Commission. These commitments involved evaluating the in-place condition of the containment vessel in several hard to reach areas.
CTLGroup developed methods of demolishing concrete 5-feet thick to expose the containment vessel at its deepest point to investigate the current condition of the containment vessel and evaluate if there was any ongoing corrosion or the presence of any contaminated water from other systems in the plant. CTLGroup also developed a process for concrete demolition in the annular space between the containment vessel and the shield building. Both processes required full scale mockups, demonstration of the penetrating depth of existing non-destructive testing equipment, evaluation of different demolition techniques so as to properly remove concrete but not harm the containment vessel, and development of formal procedure documents meeting the First Energy quality standards. CTLGroup evaluated concrete samples removed from the structure in our laboratory for multiple properties under the direction of a third party firm with a license to receive material from nuclear facilities.