Effluent, alpha activity

A comparison of the activity in the effluent from the above process with the activity in the "feed" solution is shown in Table III for an experiment in which a Mtanate column was used at approximately 100% capacity. Only Ru and a small amount of residual alpha activity were detected in the effluent. 

Figure 2. Alpha activity in the effluent from the separation column as measured by the flow-through alpha detector during a typical run...

Discharge of dewatering effluents from underground uranium mines and runoff from uranium mine tailings piles have contaminated surface waters and aquifers in New Mexico with elevated levels of gross alpha activity and uranium (NMHED 1989). The concentration of uranium in mine discharge water in New Mexico was 31,500 pg/L (equivalent to 22,680 pCi/L assuming the uranium content is natural uranium)... 

Mound Facility Low-Risk Waste. Approximately 3 x 105 l of low-level waste are generated weekly at the Mound Facility. This particular waste stream is essentially local hard water which has been demineralized and then used in various chemical processes involving the radionuclides 238Pu and 233U. The first step in decontaminating the low-risk wastes entails addition of small amounts of calcium and iron salts followed by addition of NaOH to pH 11.5 to precipitate iron and calcium hydroxides and carbonates. The clarified effluent from the precipitation step is then passed through a 200 micrometer sand filter to yield a solution containing, typically, 0.1+ d/min/m alpha activity. 

The criteria used in designing the full-scale treatment system were based on data obtained from a pilot-plant study using a 0.38 m dia. by 0.6l m high bed of bone char operated at a rate of about bO Z/mln. Feed to the column contained an average 0.18 nCi/ alpha activity while the effluent contained about 0.09 nCi/ total alpha. This bed of bone char satisfactorily decontaminated 2.1 x 105 Z of feed before saturation. 

Effluent solution from the ion exchange column is passed through an in-line alpha-detector which activates a count-rate meter and recorder outside the cell. Inside the detector/ the liquid flow is passed adjacent to a Mylar film-covered window/ which separates the liquid from the silicon diode detector. 

Description Polymer-grade ethylene is oligomerized in the liquid-phase reactor (1) with a catalyst/solvent system designed for high activity and selectivity. Liquid effluent and spent catalyst are then separated (2) the liquid is distilled (3) for recycling unreacted ethylene to the reactor, then fractionated (4) into high-purity alpha-olefins. Spent catalyst is treated to remove volatile hydrocarbons and recovered. The table below illustrates the superior purities attainable (wt%) with the Alpha-Select process ... 

---