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1

Uranium oxides. Specific surface measurement by nitrogen adsorption  

International Nuclear Information System (INIS)

Determination of the specific surface of uranium oxides: UO_2 and U_3O_8 using a simplified equation derived from the Brunauer, Emmett and Teller theory. The method is suitable for samples having a surface between 6 to 50 m"2.

2

Production of pure yellow cake by ion-exchange processes employing sulphate elution  

International Nuclear Information System (INIS)

Recovery of uranium by ion-exchange processes from impure acid leach liquors is described, which produce a concentrated and pure eluate employing 10% sulphuric acid elution. In situations where resin is loaded to 45 g/ltr or more the acid consumption at ambient temperature is less than 4 kg of H_2SO_4 per kilogram of U_3O_8. Precipitation with an alkali such as ammonia or magnesia produces a yellow cake of high purity. (author).

1979-06-08

3

Measurement of reactor tube cladding thickness by x-ray fluorescence spectrometry  

International Nuclear Information System (INIS)

An x-ray fluorescence spectrometer was designed and fabricated which nondestructively determines the thickness of aluminum cladding at small suspected thin spots in the inner or outer surface of actinide reactor tubes. The analysis method is based on the difference in absorption of actinide L/sub #alpha#/ and L/sub #beta#/ fluorescent x-rays in passing through the cladding. Calibration plots of the logarithm of the L/sub #beta#//L/sub #alpha#/ x-ray intensity ratio versus cladding thickness are linear to at least 40 mils for U-Al, U_3O_8-Al, and PuO_2-Al substrates. Accuracy and precision of the experimentally determined cladding thickness and evaluated for both uranium and plutonium substrates. Experimental thickness data are reported for 618 quality assurance analyses on six Mark 41 PuO_2-Al target tubes. An x-ray fluorescence cladding thickness monitor operated with a computer-controlled fluoroscope ...

1978-01-01

4

Crystallohydrate forms of trisubstituted uranyl orthophosphate  

International Nuclear Information System (INIS)

The conditions of production and the stability regions have been studied for the following crystallohydrates of trisubstituted uranyl orthophosphates: (UO_2)_3(PO_4)_2x6H_2O, (UO_2)_3(PO_4)_2x4H_2O, and (UO_2)_3(PO_4)_2xH_2O. Their thermal stability has been studied. It is shown that thermal dehydration of high-water hydrates at 220-240 deg C gives (UO_2)_3(PO_4)_2xH_2O. The anion composition and crystal structure of the compound remain constant up to 1000 deg C. The mixture of the composition of U_3O_8xU_3(PO_4)_4 is the final product of decomposition at 1000 deg C. The thermodynamic constants of dehydration processes have been calculated. A conclusion has been made about the polymer structure of the compound in which water is located between the uranylphosphate layers.

5

Direct denitration and recycling of PFBR MOX liquid waste from dissolution test using microwave heating method  

International Nuclear Information System (INIS)

Full text: Dissolution test (DT) is one of the important specifications of PFBR MOX fuel. It is a macro homogeneity test used to ascertain that the dissolution of spent fuel will be easier during reprocessing. The DT specification limit for PFBR MOX fuel is ? 1.0 wt.% residue of the whole pellet when it is dissolved in HNO3 under reflux conditions. For this test, sintered MOX pellet is dissolved in reflux condition in 60 ml of 12M HNO3 for 10 hours. This test is carried out for each batch and during complete MOX campaign a lot of MOX waste in liquid form is being generated. This liquid waste is in clean form and U and Pu is required to be recovered from the clean waste. Different methods like direct denitration, precipitation and solvent extraction are available but either the product is not of good quality for pelletization or secondary liquid wastes are generated. Microwave denitration is a faster and cleaner method which has different heat transfer mechanism and temperature profile ...

2010-11-24

6

Production of yellow cake from rock phosphate deposits and its characterization  

International Nuclear Information System (INIS)

This study was carried out mainly to produce uranium trioxide (UO_3), with the standard of commercial specifications from rock phosphate deposits in eastern part of Nuba mountains, south Kurdufan state. A simplified hydrometallurgical procedure has been adopted for production of yellow cake from the ore. Elemental analysis has shown that the ore is rich in Ca and deficient in elements of potential interest such as Fe, Cu and Zn. Uranium content in ore, phosphoric acid and purified yellow cake (UO_3) obtained with different precipitants was analyzed using alpha-spectrometry. On the average, the activity concentration of uranium in ore corresponds to 82 #+-# 24 ppm (0.10%). From the data of pregnant liquor, it was observed that the addition of KCIO_3 as an oxidant improves the dissolution of uranium from the ore by almost 20%. Data has also indicated that the yellow cake purified by hydrogen peroxide has higher concentration of uranium by 44.5% over the one purified by TBP extraction. ...

2002-01-01