San Onofre Nuclear Decommissioning
Controlled demolition of reactor sphere enclosure wall at San Onofre Nuclear Generating Station Unit One. Segment the top 50’ of a wall 115’ all x 3’ thick in a seismically sensitive operating nuclear environment.
Southern California Edison
Developed and implemented a controlled demolition plan in close proximity to a fuel pool, with seismic, vibration, dust/slurry control, crane capacity, and utilization constraints.
Horizontal and vertical cut lines were laid out. Diamond wire access and rigging holes were core drilled through the 3’ wall from elevated platforms. Power units were deployed on dome roof with remote control panels and diamond wire saws on elevated platforms which coupled as slurry/water control collection stations. Diamond wire sawing progression was controlled by elevation, seismic considerations and crane utilization with all blocks either rigged or anchored prior to final segmentation, and later drifted away from the spent fuel pool. In total 285 blocks (8’ x 5’ x 3’) were removed and over 1200 square feet of diamond wire sawing was completed on schedule.
Safety / Hazard Analysis
Maintaining the integrity of the spent fuel pool and protecting the operating plant infrastructure drove access, platform, diamond wire cutting, and rigging plans. The enclosed moveable platform provided safety combined with utility as a water/slurry control station. Personnel safety, plant requirements for slurry control, seismic restraints, rigging and diamond wire cutting access from only one side of the wall were all achieved.