Patent ID: 6885719
Filing Date: 2005-04-26
Classification: G21D,Y02E

Abstract:
1. A method for grouting a decommissioned reactor vessel, said reactor vessel having a predetermined amount of residual water in a bottom portion thereof, said method comprising the steps of: forming a first, water-absorbent cement grout by mixing: flowing a selected amount of said water-absorbent cement grout into said bottom portion of said reactor vessel so that said water-absorbent particulate material absorbs excess water from said grout as said grout intermixes with said residual water; said selected amount of said water-absorbent cement grout being limited to an amount approximately sufficient to fully absorb said predetermined amount of residual water in said reactor vessel; allowing said first, water-absorbent cement grout to set so as to form a first layer of cementitious fill that incorporates said residual water; forming a second, lightweight cellular cement grout by mixing: flowing said lightweight cellular cement grout into said reactor vessel atop said first layer of cementitious fill in which said residual water has been incorporated; and allowing said second, lightweight cellular cement grout to set so as to form a second, relatively lighter layer of cementitious fill in an upper portion of said vessel.