Patent ID: 6076958
Filing Date: 2000-06-20
Classification: B01F

Abstract:
A method for stirring a radioactive material in a vessel having a combination of liquid and solid substances until that combination turns into a liquid slurry that can be pumped out of the vessel, the vessel having a vessel opening, said method comprising the steps of:providing an impeller mixer assembly having a first folding blade assembly disposed at an end of a mixing shaft assembly, said mixing shaft assembly rotatable by motor means and said folding blade assembly having an open position and a folded position;inserting the end of said mixing shaft assembly having said folding blade assembly disposed at the end in its folded position through the vessel opening and locating the folding blade assembly at a predetermined depth in radioactive material to be stirred;rotating said impeller shaft assembly by said motor means to a predetermined speed and causing said folding blade assembly to enter the open position from its folded position and mixing the combination of liquid and solids to a pumpable slurry;pumping the slurry out of the vessel until the vessel is empty;causing said impeller mixer assembly to stop rotating by said motor means so that said folding blade assembly returns to its folded position; andremoving the end of said impeller mixer shaft assembly from the vessel through the vessel opening.