scholarly journals Research on obtaining gadolinium oxide from waste technologies for processing of uranium-gadolinium containing materials

2022 ◽  
Vol 2155 (1) ◽  
pp. 012026
Author(s):  
M K Kylyshkanov ◽  
N N Yaroshenko ◽  
G V Gusakova ◽  
A A Dorn ◽  
A A Gofman ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Solid Waste ◽  
Uranyl Nitrate ◽  
Gadolinium Oxide ◽  
Aluminum Nitrate ◽  
Technological Scheme ◽  
Waste Processing ◽  
Two Stage ◽  
Almost All ◽  
Nitrate Solutions

Abstract One of the activities of the Uranium production of JSC “UMP” is the processing of hard-to-open uranium-gadolinium-containing scraps. When processing materials of this type, after their dissolution, the gadolinium fluoride precipitation operation is carried out with the subsequent extraction purification of the obtained uranyl nitrate solutions. At the deposition stage, almost all the gadolinium contained in the scraps is transferred to the GdF3 precipitate and sent to the tailings dump as part of the solid waste. In order to determine the possibility of obtaining gadolinium oxide from waste processing of uran-gadolinium containing materials, exploratory studies were initiated. In the course of the work, various methods of obtaining gadolinium oxide were tested. A number of experiments were carried out to refine the modes of obtaining gadolinium oxide by the method of two-stage precipitation of oxalate. A technological scheme was developed, according to which a finished product was obtained, suitable for further use in the technology of obtaining uranium-gadolinium tablets of UMP JSC. The scheme consists of the following main operations: dissolution of gadolinium fluoride in a solution of aluminum nitrate, precipitation of gadolinium oxalate, washing of gadolinium oxalate in the first stage of precipitation with a solution of nitric acid, conversion of oxalate to gadolinium hydroxide, dissolution of hydroxide in a solution of nitric acid, re-precipitation of gadolinium oxalate, calcination to gadolinium oxide.

PHASE EQUILIBRIUM STUDIES FOR THE QUATERNARY SYSTEM URANYL NITRATE – ALUMINUM NITRATE – NITRIC ACID – WATER

1963 ◽  
Vol 41 (2) ◽  
pp. 531-536
Author(s):  
Robert D. Thibodeau ◽  
M. Adelman
Keyword(s):  
Phase Equilibrium ◽  
Phase Separation ◽  
Nitric Acid ◽  
Phase Diagrams ◽  
Uranyl Nitrate ◽  
Quaternary System ◽  
Aluminum Nitrate ◽  
Acid Water ◽  
Equilibrium Studies ◽  
Data Phase

The quaternary system UO2(NO3)2−Al(NO3)3−HNO3−H2O) was studied in the temperature range 0–20 °C, and the concentration range of 0–1.5 M Al(NO3)3 and 0–10 N HNO3. From the data, phase diagrams were prepared. No phase separation was evident at 30 °C and above, for the concentrations studied.

Extraction of Am(III) by benzyldibutylamine from nitrate solutions of lanthanides

1981 ◽  
Vol 46 (1) ◽  
pp. 194-200 ◽  
Author(s):  
Marta Vojtíšková ◽  
Věra Jedináková ◽  
Libor Kuča
Keyword(s):  
Nitric Acid ◽  
Nuclear Fuel ◽  
Organic Phase ◽  
Spent Nuclear Fuel ◽  
Optimum Conditions ◽  
Separation Factors ◽  
Nitrate Solutions

Benzyldibutylamine is a suitable extractant for the separation of Am(III) and Ln(III) from the acidic nitrate solutions. The effect of lanthanides and yttrium on the extraction of Am(III) has been followed under the conditions modelling the content of these components in the spent nuclear fuel. The separation factors αAm/Ln were evaluated for the optimum conditions found for the separation of Am(III) from the lanthanides. The coextraction of nitric acid and water into the organic phase is discussed.

Increasing Operational Efficiency in a Radioactive Waste Processing Plant

2009 ◽  
Author(s):  
T. W. Turner ◽  
S. N. Watson
Keyword(s):  
Radioactive Waste ◽  
Solid Waste ◽  
Management Practices ◽  
Operational Efficiency ◽  
Processing Plant ◽  
Waste Processing ◽  
Long Term Storage ◽  
Below Ground ◽  
Pass Through ◽  
Intermediate Level Radioactive Waste

The solid waste plant at Harwell in Oxfordshire, contains a purpose built facility to input, assay, visually inspect and sort remote handled intermediate level radioactive waste (RHILW). The facility includes a suite of remote handling cells, known as the head-end cells (HEC), which waste must pass through in order to be repackaged. Some newly created waste from decommissioning works on site passes through the cells, but the vast majority of waste for processing is historical waste, stored in below ground tube stores. Existing containers are not suitable for long term storage, many are already badly corroded, so the waste must be efficiently processed and repackaged in order to achieve passive safety. The Harwell site is currently being decommissioned and the land is being restored. The site is being progressively delicensed, and redeveloped as a business park, which can only be completed when all the nuclear liabilities have been removed. The recovery and processing of old waste in the solid waste plant is a key project linked to delicensing of a section of the site. Increasing the operational efficiency of the waste processing plant could shorten the time needed to clear the site and has the potential to save money for the Nuclear Decommissioning Authority (NDA). The waste processing facility was constructed in the mid 1990s, and commissioned in 1999. Since operations began, the yearly throughput of the cells has increased significantly every year. To achieve targets set out in the lifetime plan (LTP) for the site, throughput must continue to increase. The operations department has measured the overall equipment effectiveness (OEE) of the process for the last few years, and has used continuous improvement techniques to decrease the average cycle time. Philosophies from operational management practices such as ‘lean’ and ‘kaizen’ have been employed successfully to drive out losses and increase plant efficiency. This paper will describe how the solid waste plant at Harwell has continuously increased the throughput of RHILW, which should lead to significant programme savings.

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