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Ra in Water using MnO2 Resin: New Developments

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Presentation on theme: "Ra in Water using MnO2 Resin: New Developments"— Presentation transcript:

1 Ra in Water using MnO2 Resin: New Developments
Sherrod L. Maxwell, III Westinghouse Savannah River Company

2 Need for Improved Method for Ra-226, 228 in Groundwater Samples
Cation Resin experience slow flow-1 to 2 days load time potential calcium interference 1 pCi/L MDA required need large sample aliquot (1.5L) for Ra-228 via Ac-228 (gas proportional counting) Test MnO2 Resin developed by PGRF (Horwitz et al) and W. Burnett et al (FSU)

3 Ra-226 and Ra-228 in Water MnO2 Resin from Eichrom 1.25 g MnO2 Resin
1.5 liter samples + Ba-133 tracer pH adjustment to 6-7 Flow rate ~20 mL/min Vacuum box loading with inner liner ~ 1.5 hour loading speed & ability to deal with slow samples

4 Ra-226 and Ra-228 in Water Initial testing
Strip MnO2 with 20 mL 2M HCL-1% H2O2 evaporated and redissolved in 0.075M HCL Hold >30 hrs for Ac-228 ingrowth Ln-Resin tests 10 mL 0.075M HCL load + 5 mL 0.075M beaker rinse 10 mL 0.090M HCl Rinse 15 mL 0.35M HNO3 strip Had some inconsistencies that seemed related to Mn in load solution Instead, strip MnO2 with 15 mL 4M HCL-1.5% H2O2 and use…….

5 Ac-228 on DGA Resin TRU (1 mL) + DGA-Normal (2mL) stacked
TRU (U,Th removal) and DGA (Ac-228 retention) No impact from Mn on Ac-228 recovery loaded 15 mL strip solution from MnO2 resin on TRU-DGA collect load + 5 mL 4M HCL rinse for Ra-226 10 mL 4M HCL rinse-discard Discard TRU Resin Strip Ac-228 from DGA with 10 mL 0.5M HCl 100 uL Ce and 1 mL con. HF Consistent high recoveries of Ac-228

6 Slide- E. P. Horwitz, May, 2004 User’s Meeting

7 Slide- E. P. Horwitz, May, 2004 User’s Meeting

8 Ra-226 and Ra-228 in Water Evaporate load + rinse solutions from TRU-DGA Redissolve in 0.075M HCl Precipitate Ra-226 (Ra-224) using Ba sulfate 100 uL of 0.70 mg/mL Ba + 3 mL 40% sodium sulfate + 4 drops 1:1 acetic acid/place on ice 0.1 mL seeding suspension Count Ra-226 (Ra-224) by alpha spectrometry Count filter by gamma for Ba-133 tracer recovery

9 Column Loading

10 Column Stripping

11 Column Fully Stripped Collect 4M HCL-0.15% H2O2 and load to DGA

12 TRU/DGA Resin Separation

13 Ba-133 Recovery on MnO2 Resin
1 g MnO g MnO2 81% 94% 85% 90% 87% 90% 95% 92% Avg. 87% 91% Ba-133=1040 pCi in 1.5 L groundwater 20 mL/min.

14 Ra-228 by Ac-228 on DGA Ba-133 Ra-228 % Recovery % Recovery
LCS (spiked DI H2O) 62% % River smp 108% N/A River smp spk 95% % River smp spk 100% % River smp 102% N/A River smp spk 106% % River smp spk 93% % Avg = 95.1%±10.1% Ba-133= 1040 pCi, 1.5L sample, 67.8 pCi 20 mL/min.

15 Ra-226/228 Recoveries % Recovery % Recovery % Recovery
Ba-133 Ra-226 Ra-228 LCS (spiked DI H2O) 60% % % River smp 108% N/A N/A River smp spk 95% % % River smp spk 100% % 93.7% Avg = % % 1.5 L samples Ba-133=1040 pCi Ra-226 spk= 5 pCi Ra-228 spk= 20 pCi Initial Ra-228/Ac-228 using Ln-Resin low/ waited 30 hr/used DGA

16 Spiked river water sample-1500 mL
Ra-226 and Ra-228 daughters

17 Ra-226 in Groundwater % Recovery % Recovery Ba-133 Ra-226
Blank (DI H2O) 86.3% N/A LCS (spiked DI H2O) 88.6% 104% Grndwater smp % N/A Grndwater smp spk 88.6% % Grndwater smp % N/A Grndwater smp spk 92.7% % Tapwater smp % N/A Tapwater smp spk 91.2% % Avg.= 89.0% Avg = 93.8% ±6.9% Ba-133= 1040 pCi, 500 mL sample, 5 pCi Ra mg 15 mL/ min.

18 Spiked Groundwater sample-500 mL

19 Summary Ra-226 and Ra 228 using MnO2 resin Vacuum Box method Benefits
Ra-226 using barium sulfate micro-precipitation TRU/DGA Resin -Ra-228 via Ac-228 Speed and selectivity Vacuum Box method Rapid flow rates 1.5 L loaded and stripped < 2 hours Benefits Fast, easy separation (<1 hr loading for 500 mL groundwater sample) Consistent Increased productivity

20 Acknowlegments Eichrom-Larry Jassin and Anil Thakkar
W. Burnett et al, MnO2 Resin PGRF- E.P. Horwitz et al DGA and MnO2 Joyce Ray, SRS, lab technician

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