US 4,056,362 A · System for disposing of radioactive waste

Abstract

A system for disposing of radioactive waste material from nuclear reactors by solidifying the liquid components to produce an encapsulated mass adapted for disposal by burial. The method contemplates mixing of radioactive waste materials, with or without contained solids, with a setting agent capable of solidifying the waste liquids into a free standing hardened mass, placing the resulting liquid mixture in a container with a proportionate amount of a curing agent to effect solidification under controlled conditions, and thereafter burying the container and contained solidified mixture. The setting agent is a water-extendable polymer consisting of a suspension of partially polymerized particles of urea formaldehyde in water, and the curing agent is sodium bisulfate. Methods are disclosed for dewatering slurry-like mixtures of liquid and particulate radioactive waste materials, such as spent ion exchange resin beads, and for effecting desired distribution of non-liquid radioactive materials in the central area of the container prior to solidification, so that the surrounding mass of lower specific radioactivity acts as a partial shield against higher radioactivity of the non-liquid radioactive materials. The methods also provide for addition of non-radioactive filler materials to dilute the mixture and lower the overall radioactivity of the hardened mixture to desired Lowest Specific Activity counts. An inhibiting agent is added to the liquid mixture to adjust the solidification time, and provision is made for adding additional amounts of setting agent and curing agent to take up any free water and further encapsulate the hardened material within the container.

Claims36

Dependent claims

A system for solidifying a slurry of radioactive waste material into a solid plastic matrix of cured polymer having radioactive waste particles distributed throughout, comprising

a supply tank adapted to contain a polymerizable setting agent in liquid form,
a catalyst tank adapted to contain a curing agent for said setting agent in liquid form,
a receiving tank adapted to contain solidified radioactive waste material and formed with an inlet thereto,
manifold means connected to said supply and catalyst and receiving tanks,
slurry pump means interposed in said manifold means and adapted for connection to a source of liquid slurry containing radioactive waste material,
catalyst pump means in said manifold connected to pump said curing agent from said catalyst tank,
setting agent pump means in said manifold connected to pump setting agent from said supply tank,
said pump means being formed to pump proportioned amounts of said setting agent and said curing agent and said radioactive slurry into said receiving tank for regulating the specific activity radiation characteristics per unit of volume of the materials in said tank,
radioactivity control means connected to said pump means and responsive to specific activity levels in said system to regulate pump speed thereby to maintain the specific radioactivity level of the material in said receiving tank at no more than a predetermined Low Specific Activity rating,
a first mixing means connected to said pumping means and formed for intermixing said setting agent and said radioactive slurry before delivery to said receiving tank,
and a second mixing means positioned at the inlet to said receiving tank and formed for intermixing said curing agent with the intermixed setting agent and slurry from said first mixing means as they enter said receiving tank.

8 more elements

Dependencies are inferred from the claim text.

System for disposing of radioactive waste

Life of this patent

System for disposing of radioactive waste

Life of this patent

Abstract

Claims36