| 摘要 |
<p>In order to reduce the time required for removal and replacement of a reactor vessel closure head, previously used studs for securing the closure head are replaced with a reduced member of larger diameter bolts located in radial slots in vessel and head flanges. All bolts are provided with individual hydraulic tensioning and tilting devices mounted on the head flange. The devices are operated simultaneously to preload the bolts and to actuate the bolts and the devices to an inclined position to permit the head to be removed when the tension load on the bolts is released.</p> |
