1. One-Column Separation and Analysis of Isotopic Am and Pu in Soil Samples Nidal M. Jadalla, Eberline Services, Albuquerque, NM Anil Thakkar, Eichrom Technologies, Inc.

2. Objective Develop an efficient, reliable, and cost- effective method to analyze isotopic americium and plutonium in soil samples.

3. First Approach 1-Sample Preparation (500 C Furnace and Microwave Digestion) 2-Digested sample in ~200 ml of 1M HN03 solution 3-Add NH 4 OH to precipitate Fe in the sample 4-Centrifuge and collect the precipitate 5-Dissolve precipitate in 3M HNO 3 - 1.0M Al(NO 3 ) 3. Add ascorbic acid. 6-Condition TRU Resin 3M HNO 3 7-Charge sample. 8-Oxidize to Pu +4 with 2M HNO 3 -0.1M NaNo 2 solution 9-Elute Am with 4M HCl 10-Elute Pu with 25 ml 4M HCl-0.833 ml 20% TiCl 3 11-Prepare Source by NdF 3 precipitation.

4. Problems Low americium chemical recoveries in soil (particularly with high iron content) Isotopic Th frequently appears in the plutonium spectrum (Th-228/Pu-238 overlapping).

5. Current Method: 1-Sample Preparation (500 C Furnace and Microwave Digestion) 2-Digested sample in ~200 ml of 1M HNO3. Add Ca carrier and oxalic acid. Precipitate calcium oxalate with NH 4 OH at pH 3-4 3-Dissolve precipitate in 3M HNO 3 - 1.0M Al(NO 3 ) 3 4-Condition TRU Resin 3M HNO 3 5-Charge Sample. 6-Oxidize to Pu +4 with 2M HNO 3 -0.1M NaNo 2 solution 7-Elute Am with 4M HCl 8-Elute Pu with 25 ml 4M HCl-0.833 ml 20% TiCl 3 9-Prepare Source by NdF 3 precipitation.

6. Low Am-243 Chemical Recovery Frequent problem in soil matrix when TRU resin is used. Possible reason: Matrix effect (Presence of Fe +3 ). Proposed solution: Precipitate as calcium oxalate to eliminate matrix interference

7. Thorium in Pu Spectrum Sample is being Digested. Thorium is retained on column and a small but noticeable fraction elutes with Pu. Proposed Solution: 1- Sample leaching instead of digestion. 2- Add a 25 ml rinse of 4M HCL-0.1M HF to remove remaining Th.

8. Procedure: Sample Prep. (1) Leach 1 g of Soil 40 ml HNO 3. Heat and stir 4 hrs (2) Transfer to C-tubes. Decant into 500 ml beaker (3) Volume to 500 ml with DI H 2 O. Stir and heat (4) Add oxalic acid and calcium carrier (5) Bring to PH=3 using NH 4 OH. Stir for 30 more min (6) Let precipitate settle and decant. Wash precipitate (7) Heat precipitate At 500 C for 6 hr (8) Aqua Regia. Digest with HNO 3 (9) Dissolve in 20 ml 3M HNO 3 - 1.0M Al(NO 3 ) 3

9. Procedure: TRU Resin AmPu Load Solution 10 ml 2M HNO 3 - 0.1M NaNO 2 20 ml 4M HCl 25 ml 4M HCL- 0.1M HF 25 ml 4M HCl-0.8333 ml TiCl3

10. Results:Th Interference Sample ID Original Th228 (dpm/g) Th228 in Pu Fr. Digestion No HCl-HF Soln. Th228 in Pu Fr. Digestion Add HCl-HF Soln Th228 in Pu Fr. Leaching Add HCl-HF Soln 048-13.7970.6010.0200.004 048-22.9640.4890.0210.003 048-33.2460.5120.0180.004 Average DF NA6.2170916

11. Results: Chemical Recoveries Sample IDPu (New)Pu (Old)Am (New)Am (Old) 47-0166%68%81%47% 47-0255%76%80%23% 47-0377%85%78%5% 47-0459%81%83%51% 47-0554%79%76%32% 47-0667%86%80%22% 47-0761%58%79%29% 47-0874%78%83%43% 47-0963%72% 15% 47-1061%77% 51%

12. Results: Precision and Accuracy ID Pu-239 Result (Bq/Kg) Pu-239 Ref Value Rec.Pu-238 Result Pu- 238 Ref Value Rec.Am- 241 Resul t Am-241 Ref Value Rec. MAPEP- 02- S9#59 72.372.999.2%33.533.3100.6%43.343.599.5% MAPEP- 02- S9#59 Dup. 73.772.9101%34.833.3104.5%42.143.596.8%

13. Conclusions Modified procedure significantly improves Am chemical recovery Modified procedure reduces Pu tracer recovery by an average of 10-15% Th-228 may interfere in Pu spectrum unless leaching and additional rinse to the TRU column is added.