[en] From March 30 through April 10, 1992, and NRC engineering team performed a special inspection at the Brunswick Steam Electric Plant. The inspection included masonry block and poured concrete walls in the building housing the diesel generators that provide emergency electrical power for the plant. The team discovered that many of the bolts in these walls which appeared to exist and provide lateral support, did not in fact exist. The bolts were apparently installed during plant construction by a subcontractor to Brown and Root. In many instances, heads cut from bolts had been attached to the angle iron that was designed to provide lateral support for the walls during an earthquake. The bolt heads made it appear that there were bolts supporting the wall, but without the bolt shanks there was no support. In the worst case, more than 85 percent of the bolts installed in one wall were either fraudulent or did not otherwise meet design requirements. For some of these bolts, the anchors had not been installed. In other cases, the bolts were too short to adequately engage the anchors. Other bolts that should have completely penetrated the walls did not. Initially, the licensee used feeler gauges inserted under the angle iron to determine whether or not the shanks of bolts were in place. In some cases, because the licensee's inspector could feel the anchor sleeve, the licensee assumed that bolt shanks were present when they were not. However, during and after NRC's special inspection, the licensee performed inspections and evaluations that were progressively more thorough. On the basis of that work, the licensee concluded that certain of the walls were not capable of performing their intended safety function and the licensee has shut down both reactors until the problem is corrected