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Title: Tests of alternative reductants in the second uranium purification cycle

Abstract

Miniature mixer-settler tests of the second uranium purification cycle show that plutonium cannot be removed by hydroxylamine-hydrazine (NH/sub 2/OH-N/sub 2/H/sub 4/) because the acidity is too high, or by 2,5-di-t-pentylhydroquinone because HNO/sub 3/ oxidizes the hydroquinone. Plutonium can be removed satisfactorily when U(IV)-hydrazine is used as the reductant.

Authors:
Publication Date:
Research Org.:
Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.
OSTI Identifier:
5418183
Report Number(s):
DP-1548
TRN: 80-010400
DOE Contract Number:
AC09-76SR00001
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; PLUTONIUM; SOLVENT EXTRACTION; REDUCING AGENTS; URANIUM; HYDRAZINE; HYDROXYLAMINE; PURIFICATION; REPROCESSING; SPENT FUELS; ACTINIDES; AMINES; ELEMENTS; ENERGY SOURCES; EXTRACTION; FUELS; MATERIALS; METALS; NITROGEN COMPOUNDS; NUCLEAR FUELS; ORGANIC COMPOUNDS; REACTOR MATERIALS; SEPARATION PROCESSES; TRANSURANIUM ELEMENTS; 050800* - Nuclear Fuels- Spent Fuels Reprocessing

Citation Formats

Thompson, M.C. Tests of alternative reductants in the second uranium purification cycle. United States: N. p., 1980. Web. doi:10.2172/5418183.
Thompson, M.C. Tests of alternative reductants in the second uranium purification cycle. United States. doi:10.2172/5418183.
Thompson, M.C. Thu . "Tests of alternative reductants in the second uranium purification cycle". United States. doi:10.2172/5418183. https://www.osti.gov/servlets/purl/5418183.
@article{osti_5418183,
title = {Tests of alternative reductants in the second uranium purification cycle},
author = {Thompson, M.C.},
abstractNote = {Miniature mixer-settler tests of the second uranium purification cycle show that plutonium cannot be removed by hydroxylamine-hydrazine (NH/sub 2/OH-N/sub 2/H/sub 4/) because the acidity is too high, or by 2,5-di-t-pentylhydroquinone because HNO/sub 3/ oxidizes the hydroquinone. Plutonium can be removed satisfactorily when U(IV)-hydrazine is used as the reductant.},
doi = {10.2172/5418183},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu May 01 00:00:00 EDT 1980},
month = {Thu May 01 00:00:00 EDT 1980}
}

Technical Report:

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  • A wide range of miniature mixer-settler tests were conducted to determine the source of iron and sulfur contamination in the uranium product stream (''1EU'') of H Canyon's 2nd Uranium Cycle. The problem was reproduced on the laboratory scale mixer-settlers by changing the feed location of ferrous sulfamate from stage D4 to stage D1. Other process variables effected no change. It was later determined that ferrous sulfamate (FS) solids had plugged the FS line to stage D4, causing FS to backup a ventline and enter the Canyon process at stage D1. Pluggage was almost certainly due to precipitation of FS solidsmore » during extended process downtime. During the search for the root cause, tests showed that FS solids were quite small (1-10 mm), and a portion of them could bypass the current Canyon prefilter (3-mm). Also, additional tests were done to find an alternate means of reducing and thereby removing plutonium and neptunium from the uranium product. These tests showed that FS was a more effective reductant than either ascorbic acid or a hydroxylamine nitrate (HAN) / dilute FS combination.« less
  • Defense Waste Processing Facility - Engineering (DWPF-E) has requested the Savannah River National Laboratory (SRNL) to perform scoping evaluations of alternative flowsheets with the primary focus on alternatives to formic acid during Chemical Process Cell (CPC) processing. The reductants shown below were selected for testing during the evaluation of alternative reductants for Sludge Receipt and Adjustment Tank (SRAT) processing. The reductants fall into two general categories: reducing acids and non-acidic reducing agents. Reducing acids were selected as direct replacements for formic acid to reduce mercury in the SRAT, to acidify the sludge, and to balance the melter REDuction/OXidation potential (REDOX).more » Non-acidic reductants were selected as melter reductants and would not be able to reduce mercury in the SRAT. Sugar was not tested during this scoping evaluation as previous work has already been conducted on the use of sugar with DWPF feeds. Based on the testing performed, the only viable short-term path to mitigating hydrogen generation in the CPC is replacement of formic acid with a mixture of glycolic and formic acids. An experiment using glycolic acid blended with formic on an 80:20 molar basis was able to reduce mercury, while also targeting a predicted REDuction/OXidation (REDOX) of 0.2 expressed as Fe{sup 2+}/{Sigma}Fe. Based on this result, SRNL recommends performing a complete CPC demonstration of the glycolic/formic acid flowsheet followed by a design basis development and documentation. Of the options tested recently and in the past, nitric/glycolic/formic blended acids has the potential for near term implementation in the existing CPC equipment providing rapid throughput improvement. Use of a non-acidic reductant is recommended only if the processing constraints to remove mercury and acidify the sludge acidification are eliminated. The non-acidic reductants (e.g. sugar) will not reduce mercury during CPC processing and sludge acidification would require large amounts of nitric acid (and subsequently larger reductant additions) unless a reducing acid is also used.« less
  • Experiments are described which show that the ruthenium decontamination factor in the uranium purification cycle of a TBP process can be substantially improved by heating the feed with hydrazine nitrate. (auth)
  • This report presents a preliminary assessment of the quality of existing information available for the evaluation of potential environmental impacts resulting from large-scale implementation of a thorium-based fuel cycle. The report's purpose includes (1) assistance in the development of a hazard assessment policy for the Nonproliferation Alternative Systems Assessments Program (NASAP) sponsored by the Department of Energy, and (2) identification of areas in which further research is necessary to allow detailed evaluation of the environmental hazards associated with thorium fuel cycles in general. Both the hazard assessment data base and the available assessment methodology are evaluated. While this report doesmore » not present coverage of all issues pertaining to practical thorium fuel cycles and pertinent literature, it is an attempt to specify those issues likely to appear to be significant during an exhaustive hazard analysis.« less
  • Experimental studies and evaluation were performed of the performance of the 1B Electropulse Column, the second plutonium cycle, and the third plutonium cycle under the proposed coprocessing flowsheet. Both pilot-plant and plant scale electropulse columns were tested for uranium electrolytic reduction efficiency. Both columns obtained the same efficiency which demonstrates that the design of the Electropulse Column is sufficient for the coprocessing flowsheet. Pilot plant-scale tests demonstrated the proper functioning of the second and third plutonium cycles under coprocessing conditions. Comparisons of column uranium profile data with those predicted by the SEPHIS computer porgram show good agreement at the stream-endmore » points, but the program does not accurately predict the column concentration profiles. The reason for this disagreement is believed to be continuous phase backmixing.« less