AN-1433

Rapid Determination of Actinides
in Emergency Air Filter Samples

Summary of Method U, Pu, Np, Am and Cm are separated and concentrated from air filters. Samples are digested
in Teflon beakers once with HNO3-H2O2-HF and then several times with HNO3-H2O2. After evaporating to dryness fromHNO3-H3BO3 to complex any residual fluoride, actinides are valence adjusted and separated on stacked 2mL cartridgesof Eichrom TEVA and TRU resins. Actinides are measured by alpha spectrometry following CeF3 microprecipitation onto
Eichrom Resolve® Filters. Chemical yields of tracers averaged from 94+12% for 242Pu, 87+6% for 243Am, and 67+32%
for 232U. Poor 232U recoveries in some samples were traced to insufficient mass of Ce carrier in the source preparation
step. Recovery of 232U improved upon increasing to 100ug of Ce carrier. Measured values typically agreed to within 10%of reference values. Sample preparation for batches of 12 samples can be completed by a single operator in <8 hours.
Alpha spectrometry count times will depend on detection limit and data quality objectives.
Reagents
TEVA Resin, 2mL Cartridges (Eichrom TE-R50-S)
TRU Resin, 2mL Cartridges (Eichrom TR-R50-S)
Iron carrier (50mg/mL Fe, as ferric iron nitrate)
242Pu (or 236Pu if meas. Np), 243Am and 232U tracers
Oxalic acid/Ammonium oxalate
Ce carrier (1mg/mL)
Deionized water
2M Al(NO3)3
10% (w:w) TiCl3
HNO3 (70%)
HCl (37%)
HF (49%) or NaF
Boric acid
H2O2 (30%)
NaNO2Denatured ethanol
Sulfamic Acid
Ascorbic Acid

Equipment
Vacuum Box (Eichrom AR-24-BOX or AR-12-BOX)
Cartridge Reservoir, 20mL (Eichrom AR-200-RV20)
Inner Support Tubes-PE (Eichrom AR-1000-TUBE-PE)
Yellow Outer Tips (Eichrom AR-1000-OT)
Resolve Filters in Funnel (Eichrom RF-DF25-25PP01)
50mL Centrifuge Tubes
Centrifuge
Heat Lamp
Hot Plate
Analytical Balance
250mL Teflon beakers
Stainless Steel Planchets with adhesive tape
Alpha Spectrometry System
Vacuum Pump

Figure 1. Sample Preparation
Air Filter + tracers in Teflon beaker.
Wet ash to dryness with 3mL 70% HNO3,
3mL 30% H2O2 and 5mL 49% HF.
Wet ash to dryness with
3mL 70% HNO3 and 3mL 30% H2O2.
Wet ash to dryness with
3mL 70% HNO3 and 3mL 30% H2O2.
Wet ash to dryness with
3mL 70% HNO3 and 3mL 30% H2O2.
Add 3mL 3M HNO3 –0.25M H3BO3.
Evaporate to dryness.
Dissolve residue in 6mL 6M HNO3
and 6mL 2M Al(NO3)3.
Cool samples to room temperature.
Fix valence states. Mix between each addition of:
0.5mL 1.5M sulfamic acid, 10uL 50mg/mL Fe,
1.5mL 1M ascorbic acid, 1mL 3.5M NaNO2.

Figure 2. Actinide Separation on TEVA - TRU*
(1) Precondition stacked 2mLTEVA-TRU with 10mL
3M HNO3.
(2) Load sample solution.
(3) Rinse sample tube with
5mL 6M HNO3. Add tube
rinse to cartridges.**(4) Rinse cartridges with 5mL
3M HNO3.
(5) Separate TEVA and TRU
cartridges.

TEVATRU(11) Add 0.5mL of 10% TiCl3 to each U
sample for CeF3 ppt.
(12) Add 50-100ug Ce carrier to allsamples. Mix well. Add 1mL 49%
HF. Mix well. Wait 15-20 minutes.
(13) Set up Resolve® Filter Funnel onvacuum box.
(14) Wet filter with
3mL 80%ethanol followedby 3mL DIwater.

(6) Rinse TEVA cartridge with:-15mL 3M HNO3
-20mL 9M HCl( remove Th)-5mL 3M HNO3(15) Filter sample.
(7) Strip Pu(Np) from TEVA with 20mL
0.1M HCl-0.05MHF-0.01M TiCl3.
(16) Rinse sample
Add 0.5mL 30% H2O2 fortube with 5mL DI
additional U decon. during CeF3
water and add tofilter.
(8) Strip Am/Cm from TRU with
15mL 4M HCl. Dilute to 30mL
and add 0.2mL 30% H2O2.
(9) Rinse TRU with 15mL 4M HCl0.2M HF. (Th removal)(10) Strip U from TRU with 15mL
0.1M ammonium bioxalate.

(19) Remove filter from funnel
assembly and mount filter on
stainless steel planchet with
2-sided tape.

(20) Dry filter under heat lamp for
3-5 minutes.
(21) Measure actinides by alpha
spectrometry.

(17) Rinse filter funnel with 3mL DI
water and 2mL 100% ethanol.
(18) Draw vacuum until filter is dry.

*89/90Sr can also be measured by placing a 2mL Sr Resin cartridge below DGA and following the separation scheme inapplication note AN-1434**Adding 50uL of 30% H2O2 to the 6M HNO3 tube rinse can help improve U recoveries and decontamination in the Pu/Npfraction.

References
1) Sherrod L. Maxwell, Brian K. Culligan, Gary W. Noyes, “Rapid separation method for actinides in emergency air filter
samples,” Applied Radiation and Isotopes, 68(12), 2125-2131 (2010).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

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