1. Actinide Analysis from Large- Volume Seawater Samples Bill Burnett & Guebuem Kim Department of Oceanography Florida State University and Phil Horwitz PG Research Foundation

2. Acknowledgments Pavel Povinic, Jerry LaRosa IAEA Marine Environment Laboratory, Monaco PG Research Foundation

3. 3 Marine Environment Laboratory Monaco

4. Need for Large Volumes zActivities of fallout Pu in the open sea very low — on order of 0.01 mBq/kg! zTo obtain good precision with reasonable count times (~1 week) requires volumes on the order of 100-400 liters! zHow can we preconcentrate/separate actinides efficiently from such a large volume?

5. MnO 2 Co-precipitation Seawater, 100-400 liters Acidify to pH 2, add Pu/Am tracers, stir/hold For 100L sample, add 35 mL sat KMnO 4 (~2.1g); Pu-->Pu(VI), org oxid, purple color Adjust pH to 8-9 with NaOH Add 0.5M MnCl 2 (2x vol of KMnO 4 ); --> MnO 2 ppt, dark brown 2MnO 4 - + 3Mn 2+ + 2H 2 O = 5MnO 2 + 4H + Re-adjust pH to 8-9 as necessary Stir occasionally to keep MnO 2 suspended for few hours Allow Mn0 2 (Pu, Am) ppt to settle overnight Pump supernatant into clean tank for Cs, Sr processing Drain MnO 2 slurry from bottom tap Seawater MnO 2 Suspension MnO 2 ppt (Pu, Am) ~4400 mg! supernatant Cs, Sr centrifuge/ filter

6. Transferring Water and MnO 2 Supernatant seawater transferred from one plastic tank to another via pumping — this will be used for 90 Sr and 137 Cs. MnO 2 suspension withdrawn from bottom of conical-shaped plastic tanks — processed for Am and Pu.

7. Fe(OH) 3 ppt Dissolve MnO 2 w (~2L) 2M HCl + (~20-40 mL) NH 2 OH. HCl (0.1g/mL) Add 50 mg Fe 3+ as FeCl 3 --> yellow Add (~1.5L) 2M NaOH to decrease acid conc. Add ~2mL NH 2 OH. HCl to reduce Fe 3+ --> Fe 2+ Pu*-->Pu 3+ ; colorless soln Add 20 mL NaNO 2 (0.1g/mL); Fe 2+ --> Fe 3+ ; Pu 3+ --> Pu 4+ Add 2M NH 4 OH to pH = 8-9; ppt Fe(OH) 3 Boil ~5 min to improve coagulation of Fe(OH) 3 ppt Adjust pH to 6-7 w 1M HCl to hold Mn in soln Let cool, settle, centifuge Fe(OH) 3 suspension, filter supernatant, dissolve ppt in acid for separation MnO 2 ppt (Pu, Am) Mn 2+ soln (Pu, Am) Mn 2+, Fe 2+ soln (Pu 3+, Am 3+ ) Fe(OH) 3 ppt (Pu, Am) Chemical separations

8. Collection of Fe(OH) 3 ppt Fe(OH) 3 is ppt and allowed to settle in 10-liter glass beakers Supernatant from Fe(OH) 3 suspension filtered through a 0.45  m filter

9. 2-Column Separation: Part 1 U/TEVA TRU 1 1 2 2 Resin® Resin® [Discard or to SrResin] 12 U, Th, Np Am, Pu

10. Actinide Separation: Part 2 U/TEVA Resin® 1 2 3 12 Np, Th U 3 1 2 9M HCl 3 5N HCl - 0.05 H2C2O4 0.01M HCl 2.5M HNO3 2.5M HNO3 - 0.1M NaNO2 2.5M HNO3 1 2 9M HCl 3 4 4M HCl 0.1M NH4HC2O4 or 4M HCL + 0.1M H2Q TRU 1 1 2 2 Resin® 4 3 Discard Am Pu 3 4

11. Results: Irish Sea Water * IAEA Intercomparison (Povinic, pers. comm.)

12. Am Spectrum

13. Pu Spectrum

14. Summary & Future Plans zMnO 2 /Fe(OH) 3 ppt effectively concentrates actinides from large volumes. zUTEVA/TRU effectively and easily separates Pu/Am from Fe(OH) 3 matrix. zInvestigate use of Diphonix for actinide preconcentration from large volumes.