Rapid Determination of Pu
in Steel Samples$1--
6XPPDU\ RI 0HWKRG   Plutonium is separated and measured from 1-2 gram steel samples. Samples are digested
with concentrated nitric, hydrochloric, and hydrofluoric acids. The digestate is evaporated to dryness, the residue
dissolved in HNO3/H3BO3, and a CaF2/LaF3 precipitate is used to concentrate the Pu and remove matrix. An optional
NaOH fusion may also be performed, post sample digestion, to dissolve concrete or stone included in the sample anddeal more rigorously with refractory Pu. Plutonium is separated from matrix impurities and potentially interfering
radionuclides in the sample using 2 mL cartridges of Eichrom TEVA Resin. Plutonium is measured by alpha
spectrometry following rare earth fluoride microprecipitation onto Eichrom Resolve filters. The chemical recovery of Pu,
determined by 242Pu tracer, was 90–99%. Measured values of Pu typically agreed to within 7-8% of reference values for
16 hour count times. The minimum detectable activity for Pu in 2 g samples with 16 hour count times was 0.25 mBq/g.
A single operator can prepare batches of 12 samples for)LJXUH6DPSOH3UHSDUDWLRQ
the measurement of Pu in less than 8 hours.
Add 1-2 g steel sample to Teflon beaker*.
5HDJHQWV*If using optional fusion, omit HF/H3BO3 and use Zr crucible.
TEVA Resin, 2 mL Cartridges (Eichrom TE-R50-S)
Nitric Acid (70%)
Add 242Pu tracer, 5 mL 70% HNO3,
Hydrochloric Acid (37%)
20 mL 37% HCl, and 5 mL 49% HF.
Hydrofluoric Acid (49%) or Ammonium Bifluoride
Digest on Hotplate to dryness.
Lanthanum Carrier (10 mg/mL)
Cerium Carrier (10 mg/mL)
Add 1 mL 70% HNO3,
Deionized Water 1.25M Ca(NO3)2242
Optional
NaOH
Fusion.
10 mL 37% HCl, and 1 mL 49% HF.
2M Al(NO3)3
Pu TracerAdd
15-20gNaOH.
Boric acid
NaNO2
Digest on Hotplate to dryness.
Fuse
at600Cfor
20min.
Ascorbic Acid
30% H2O2
10-20% (w:w) TiCl3 in HCl
Add 5 mL 3M HNO3-0.25M H3BO3
DissolveinDIwater.
3.2M (NH4)2HPO4*
and 5 mL 37% HCl.
Transferto250mLc-tube.
Sodium Hydroxide*
Digest on Hotplate to dryness.
Dilute to 100 mL. Add 2 mL
1.25M Ca(NO3)2, 5 mg La, andAdd 25 mL 1M HCl. Warm to dissolve.
(TXLSPHQW
8.5 mL 3.2 M (NH4)2HPO4.
Transfer to 250 mL centrifuge tube.
Vacuum Pump
Repeat 2 additional times.
Centrifuge
Centrifuge. Decant
Muffle Furnace*
Dilute to 170 mL with 0.01M HCl. Add 2 mLsupernate. Dissolve ppt. inHot Plate
1.25M Ca(NO3)2,5 mg La, and 3 mL 20% TiCl3.
80 mL 1.5M HCl.
Analytical Balance
Teflon Beakers (Zr Crucibles*)
50 mL and 250 mL Centrifuge Tubes
Alpha Spectrometry System
Vacuum Box (Eichrom AR-24-BOX or AR-12-BOX)
Cartridge Reservoir, 20 mL (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)

Add 25 mL 49% HF. Mix Well. Allow to sit 20 min.
Centrifuge. Discard supernate.
Dissolve precipitate in 7 mL 3M HNO3-0.25M
H3BO3, 6 mL 8M HNO3, 7 mL 2M Al(NO3)3. Mix.
Warm if necessary. Centrifuge. Check for solids.
Continue to Pu Separation.

)LJXUH/RDG6ROXWLRQ3UHSDUDWLRQDQG3OXWRQLXP6HSDUDWLRQ(1) Ensure samples are cooled toroom temperature.
(2) Add 1.25 mL of 1.5M ascorbic
acid. Mix well. Wait 5-10 minutes.

(4) Precondition 2 mL TEVA Resinwith 5 mL 3M HNO3.

(7) Rinse sample tube
with 5 mL 8M HNO3 +50 PL 30% H2O2.

(11) Strip Pu with 15 mL 0.1M HCl0.05M HF-0.01M TiCl3.**If preparing alpha sources byelectrodeposition, replace TiCl3 withRongalite or hydroxylamine.

(3) Add 1 mL of 3M NaNO2.
Mix well. Wait 5-10 minutes.

(6) Load sample.

(10) Dispose of (4) to (9) as waste.

TEVA(8) Add tube rinse to TEVA Resin.
(9) Rinse TEVA Resin sequentiallywith:- 15 mL 3M HNO3 (U decon.)- 20 mL 9M HCl (Th)- 5 mL 3M HNO3(18) Rinse filter
funnel with 3 mL
DI water and 2 mL
100% ethanol.
(19) Draw vacuum
until filter is dry.

(20) Remove filter fromfunnel assembly and(12) Add 50 ug Ce carrier and 0.5 mLmount filter on stainless
30% H2O2 to all samples. Mix well.
steel planchet with 2-sided tape.
(13) Add 1 mL 49% HF. Mix well. Wait
15-20 minutes.
(14) Set up Resolve® Filter Funnel onvacuum box.
(15) Wet filter with 3 mL 80% ethanol
followed by 3 mL DI water.

(16) Filter sample.
(17) Rinse sample tube with 5 mL DI
water and add to filter.

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

Method Performance for Pu in Steel Samples
SampleReferenceDetailsreplicates (mBq/sample)
238Pu in 2 g Steel5
37.0
239Pu in 2 g Steel
524.5
239Pu (refractory) in 2 g Steel
524.5239 Pu in 5 g Steel
437.0

Measured(mBq/sample)
37.7 + 1.6
24.4 + 1.6
23.4 + 0.9
38.3 + 1.0

Average 242Pu tracer% Diff.
% Yield
4.2
89.3 + 2.3
6.6
96.5 + 3.4
3.8
98.9 + 6.6
2.6
92 + 14

5HIHUHQFHV1) Sherrod L. Maxwell, Brian K. Culligan, Jay B. Hutchison, Robin. C. Utsey, Ralf Sudowe, Daniel R. McAlister, “Rapid
method to determine plutonium isotopes in steel samples,” J. Radioanal. Nucl. Chem., 314(2), 1103-1111 (2017).
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