Method and apparatus for improved removal and retention of radioactive particulates from fluids

A multistage apparatus for filtering a fluid to remove radioactive particulates from the fluid comprising:

• a re-usable first stage filter consisting of a first filter housing and a first radiation resistant and cavitation erosion resistant porous filter element, where the first filter housing and the porous filter element are designed to withstand an internal pressure of up to 150 psid, a particulate-laden fluid supply means consisting of a first inlet conduit accommodating a flow rate of <150 to 600 gpm, said supply means being fluidically connected to a region inside the porous filter element, through which fluid flows and upon which particulates are collected, and a particulate-free fluid discharge means consisting of a first outlet conduit, said first outlet conduit fluidically connected to the region outside of the porous filter element, with the first inlet conduit and the first outlet conduit collectively providing the first filtration flow path used during filtration of a fluid containing radioactive particulates;
• means of periodically regenerating the first stage filter by supplying backwashing fluid to the first stage filter at 1 to 10 gpm with a second inlet conduit fluidically connected to the region inside of the first stage filter housing and outside of the first porous filter element;
• and a backwashed fluid and particulate discharge means consisting of a second outlet conduit fluidically connected to the region inside of the first porous filter element upon which radioactive particulates have been filtered, the second inlet conduit and the second outlet conduit collectively providing a second backwash flow path for fluid through the first stage filter used during backwashing of captured radioactive particulates;
• a second stage filter consisting of a second filter housing and a second radiation resistant porous filter element designed to withstand a differential pressure of up to 3000 psid across the second porous filter element, a particulate-laden backwash fluid supply means consisting of a third inlet conduit forming a flow path for fluid and particulates backwashed from the first stage filter, said flow path accommodating flow rates from 1 to 10 gpm, and said supply means being fluidically connected through the wall of the second filter housing) to the region inside of the second porous filter element, through which fluid flows and upon which backwashed particulates are captured, and a particulate-free fluid discharge means consisting of a third outlet conduit, said third outlet conduit fluidically connected through the second filter housing) wall to the region outside of the second porous filter element, said second stage filter including flanges or connectors used to detach and remove the second stage filter from the multistage filtration apparatus;
• a pumping system comprising a pump between the first stage filter and the second stage filter fluidically connected to the first stage filter with the second outlet conduit and to the second stage filter via the third inlet conduit, said pump designed to provide fluid at a pressure between 150 and 1000 psig and at a flow rate between 1 to 10 gpm;
• and
• at least one ultrasonic transducer incorporated into the first stage filter assembly.