Low Enriched Uranium Control Applicable to a Range of Potential 99 - - PowerPoint PPT Presentation

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Low Enriched Uranium Control Applicable to a Range of Potential 99 - - PowerPoint PPT Presentation

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LA-UR-14-24630 Low Enriched Uranium Control Applicable to a Range of Potential 99 Mo Production Processes I. May 2014 Mo-99 Topical Meeting, June 24-27, Washington D.C . UNCLASSIFIED Operated by Los Alamos National Security, LLC for the U.S.

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Operated by Los Alamos National Security, LLC for the U.S. Department of Energy's NNSA

UNCLASSIFIED

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Low Enriched Uranium Control

Applicable to a Range of Potential

99Mo Production Processes

  • I. May

2014 Mo-99 Topical Meeting, June 24-27, Washington D.C.

LA-UR-14-24630

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NRC Regulations, Title 10 – Nuclear Material Accountancy Requirements

  • >10,000 g of 235U containing materials enriched up to

20.00 % is deemed to be special nuclear material of moderate strategic significance.

– http://www.nrc.gov/reading-rm/doc-

collections/cfr/part074/part074-0041.html

  • Establish and maintain a measurement control program

so that for each inventory period the SEID (Standard Error of Inventory Difference) is less than 0.125 percent

  • f the active inventory

– http://www.nrc.gov/reading-rm/doc-

collections/cfr/part074/part074-0045.html

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Davis and Gray Titration

  • Destructive analysis

method for quantitative uranium measurement

  • Titration method used

extensively for the analysis of uranium in nuclear materials

  • M. Bickel, J. Nucl. Mater.,

246 (1997), 30-36

  • W. Davies and W. Gray,

Talanta, 11 (1964), 1203

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Technique for Uranium Analysis - Visible Spectroscopy

  • Uranyl absorption spectra – can be applied

to uranium concentration measurement in solution

  • 𝐵 = 𝜁𝑑𝑚

–

A= absorbance

–

𝜁= molar absorptivity (M-1 cm-1)

–

c= concentration (M)

–

l= path length, cm

  • lmax (peak max, nm) and 𝜁 (molar

absorptivity) vary with chemical composition

  • A small aliquot of sample (e.g. 50 L) and

dilute in excess of either 1 M HNO3 or H2SO4 (2000 L)

16 14 12 10 8 6 4 2 Molar Absorptivity (L mol

  • 1cm
  • 1)

480 440 400 360 Wavelength (nm) 1 M nitric acid 1 M sulfuric acid

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Molar Absorptivity of Uranium(VI) Determined from Matrix of Standard Uranium Solutions

  • The molar absorptivity
  • f uranium(VI) in 1.0 ±

0.1 M H2SO4 at 19.5 ± 1.7 °C is 13.736 ± 0.026 cm–1 M–1 at 419.5 nm.

  • Accurate molar

absorptivity values could be obtained for a wide range of chemical matrices

0.4 0.3 0.2 0.1 0.0 Abs419.5nm 0.0300 0.0200 0.0100 0.0000 [Uranium] (M)

Abs419.5nm= m·[U] + b (y = m·x + b) Weighted least squares fit results: m = 13.736 ± 0.026 b = 0.0001 ± 0.0002

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Assay Method Accuracy Testing (151.2 gU/L, 0.6353 mol/L)

  • The white lines represent 1

standard deviation of the known molar uranium concentration based

  • n gravimetric data from solution

preparation.

  • The square and circle points are

the uranium concentrations measured by the spectroscopy assay method using 90 or 50 µL uranium aliquots, respectively.

  • The error bars are the standard

deviations in these measurements.

  • Difference between known and

measured values all < 0.7 %. For the 90 µL assays.

0.640 0.638 0.636 0.634 0.632 0.630 0.628 0.626 [U] (M) 3.0 2.0 1.0 Solution Replicate Number

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Density Measurements on pH1 Uranium Sulfate Solutions

1.26 1.24 1.22 1.20 1.18 1.16 1.14 U/HSO4 Solution Density (g/mL) 60 40 20 Temperature (°C) 183.6 gU/L 154.3 gU/L 142.5 gU/L 133.4 gU/L 105.5 gU/L 1.22 1.21 1.20 1.19 1.18 1.17 U/HSO4 Solution Density (g/mL) 60 50 40 30 20 10 Temperature (°C) 154.3 gU/L 142.5 gU/L 133.4 gU/L

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Analysis of Contaminants

and Impurities

Raman Spectroscopy Detection

  • f Nitrate in 143 gU/L (pH 1)

Uranium Sulfate Solution Impact of Cr(III) on the uranium spectroscopy technique

1600 1400 1200 1000 800 600 400 200 Raman Intensity 1100 1000 900 800 Wavenumber (cm

  • 1)

143 g/L U sulfate 0.12 % NaNO3 0.24 % NaNO3 0.52 % NaNO3 1.37 % NaNO3 2.79 % NaNO3 HSO4

  • NO3
  • SO4

2-

ClO4

  • UO2

2+

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Chemical Process for the Recovery of Fission Molybdenum-99

  • 99Mo recovery and purification processes
  • Initial solid target dissolution step undertaken

using acid or base (MDS Nordion use a HNO3 dissolution process)

  • HEU to LEU conversion: - increase in no. of solid

targets, processing runs & waste volume

  • Most currently operating flow sheets are not well

suited to the recycle of uranium

  • LEU solution target concepts linked to the

application of titania based sorbents for 99Mo recovery (uranyl nitrate in dilute HNO3 is a potential fuel solution)

  • Alumina is the ‘Industry Standard’ sorbent

http://nucleus.iaea.org/HHW/Radio pharmacy/VirRad/Eluting_the_Gen erator/Generator_Module/Design_p rinciples/index.html

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99Mo Retention on Alumina –

Impact of Uranium Concentration

http://www.rertr.anl.go v/Web2002/2003Web /Wilkinson.html. See also D.C. Stepinski et al. in IAEA-TECDOC-1601, 2008 (P73)

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“Inventive Application” of Individual Separation Processes

  • 1. a. Evaporation and addition of HNO3
  • b. Target dissolution in HNO3.
  • 2. i) Lower soln. temp. and/or evaporate

under reduced pressure to crystallize

  • ut uranium. ii) Separation of

crystalline phase from solution.

  • 3. Preparation of final uranium product,
  • ption for recycle/reuse.
  • 4. Remove excess nitric acid and add

water to obtain the desired uranium and nitric acid concentration.

  • 5. Recovery of a Mo-99 product using an

alumina column.

http://en.wikipedia.org/wiki/File:Uranyl_nitrate.jpg

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Experimental Validation

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Crystallization Process Removes Most of the Uranium

Mo-99

Solution Crystals

LEU

Solution Crystals

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Crystallization Provides a Purified Uranium Nitrate ‘Product’

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Alumina Column Separation Recovers the 99Mo

14 12 10 8 6 4 2

pH

10 9 8 7 6 5 4 3 2 1

Column Fraction

0.01 0.1 1 10 100

Activity(µCi/ml)

Mo-99

Example fission product

Feed solution contained 'low' uranium concentration

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Acknowledgements

Analysis of Uranium

  • D. Rios & S. D. Reilly (LANL)
  • J. Driscoll (SHINE Medical

Technologies)

  • The NNSA Global Threat

Reduction Initiative (GTRI) Uranium Crystallization Process

  • A.S. Anderson, R. Copping,

G.E, Dale, D.A. Dalmas, M.J. Gallegos, L.A. Hudston, C.T. Kelsey IV, M. Mocko, S.D. Reilly, D. Rios, F.P. Romero and K.A. Woloshun

  • LANL Laboratory Directed

Research & Development – Exploratory Research project