Uranium loading

After the U/Pu partition stage the uranium loaded organic phase may be back extracted with water or dilute nitric acid to give an aqueous uranium stream which passes to further purification... 

Figure 1. The bumup and generation of actinides in the robust model of a NPU reactor of OK-900 type, with the uranium loaded into the RC 302 kg, enrichment by 36% and U-Zr fuel.

Table 3. Uranium loading of selected inorganic, organic, and biological sorbents in natural sea water with a uranium concentration of about 3.3 jxg/1 the loadings refer to the dry sorbent or to its metal content U9)... 

Sorbent Functional group Uranium loading References... 

Moreover, the performance of the sorbent must be suitable for bringing it into contact with the vast volumes of sea water. Most imperative requirements pertain to the uranium uptake kinetics the sorbent should be qualified for a rapid rate of loading in order to minimize the sorbent inventory. The quantity of required sorbent material ms (tons of dry sorbent) is determined by the production rate P (tons of uranium per day) of a projected recovery plant, by the uranium loading b of the sorbent (ppm uranium per cycle based upon dry weight) and by the duration t (days per cycle) of a complete sorption-elution cycle ... 

The uranium uptake rate increases with decreasing granular size because of the specific surface enlargement. Yet, after ten days both curves show a distinct flattening. After this time, hydrous titanium oxide granules of 0.6 mm diameter attain a uranium loading of 100 ppm. The demonstrated uptake rates seem to be realistic for mechanically rather stable hydrous titanium oxide granules. 

The uranium loading of 3600 ppm amounts to less than 3 % of the total uranium capacity. A high attrition resistance of the resin beads, expected in contrast to hydrous titanium oxide, could be demonstrated in long-term experiments. Granules exposed to natural sea water in a fluidized bed for more than 6 months showed almost no attack of the outer surface however, the initial white color of the beads changed to brown, probably due to the complexation of transition metals. Uranium is mainly accumulated in a narrow surface layer of the beads. The high uranium selectivity of the resin can be deduced from Table 7. 

The uranium loading kinetics of the poly(acrylamidoxime) resin may be derived from Fig. 8. 

During the first ten days uranium loadings were between 140-200 ppm for granular sizes between 1.0-0.2 mm in diameter thus, the uranium loading kinetics for the resin is faster than for hydrous titanium oxide (Fig. 7). A further increase of the rate of uranium uptake could be achieved by using fibers of poly(acrylamidoxime) instead of granules uranium loadings of 750 ppm were obtained in natural sea water after ten days. 

Fig. 9. Uranium loading-elution cycles of the cross-linked poly(acrylamidoxime) resin Duolite ES 346 us>...

Proper conditioning of MgF for removal of impurities (mostly water) proved to be important in reducing the uranium loading of the MgF. ... 

Figure 10.9 illustrates the effect of uranium saturation of solvent on distribution coefficients, at nitric acid concentrations approximately those in the extracting and scrubbing sections. The ratio of plutonium distribution coefficient to fission products is improved at high uranium loadings, a condition sought at the feed point. 

The uranium loading of the fuel elements amounting to 7g of uranium is selected such that water ingress into the primary circuit as the result of an accident will cause a reactivity increase not higher than the accidental withdrawal of all absorbers during normal operation. 

Magnitude of coolant void coefficient (CVC) for LiF-BeF decreases with increasing uranium loading and increasing burnable poison loading... 

Density of graphite in matrix and in outer shell Heavy metal (uranium) load per ball Enrichment by (weight %)... 

Many issues are to be addressed regarding the graphite foam and fuel in the reactor. First, it has been determined that the maximum uranium loading in the foam would only fill 80% of the initially void space. 

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