General Engineering Laboratories Use of Eichrom Resins for Bioassay Pa-231 Bob Timm - GEL Tim Chandler - GEL Bill Burnett - FSU Mike Schultz - PerkinElmer

General Engineering LaboratoriesGeneral Engineering Laboratories

Use of Eichrom Resins for Use of Eichrom Resins for Bioassay Pa-231Bioassay Pa-231

Bob Timm - GELBob Timm - GEL

Tim Chandler - GELTim Chandler - GEL

Bill Burnett - FSUBill Burnett - FSU

Mike Schultz - PerkinElmer Mike Schultz - PerkinElmer Instuments, ORTECInstuments, ORTEC


OutlineOutline

What is ProtactiniumWhat is Protactinium Pa-231 procedure developmentPa-231 procedure development ConclusionsConclusions


ProtactiniumProtactinium

Originally called "protoactinium", Pa is one of Originally called "protoactinium", Pa is one of the rarest and most expensive naturally-the rarest and most expensive naturally-occurring elementsoccurring elements

Pa-231 has a fast fission cross section nearly Pa-231 has a fast fission cross section nearly the same as the same as 239239PuPu

Pa(V) forms a very stable, water-soluble Pa(V) forms a very stable, water-soluble complex with fluoridecomplex with fluoride

Pa(IV) forms insoluble fluoridesPa(IV) forms insoluble fluorides Two naturally-occurring isotopes: Two naturally-occurring isotopes: 234234Pa and Pa and

231231PaPa


Pa-231Pa-231

PARENTPARENT U-235 half-life 7x10^8 yrs decays to Th-231U-235 half-life 7x10^8 yrs decays to Th-231 Th-231 half-life 25.52 hrs decays to Pa-231Th-231 half-life 25.52 hrs decays to Pa-231 Pa-231 half-life 3.3x10^4 yrsPa-231 half-life 3.3x10^4 yrs DAUGHTERDAUGHTER Ac-227 Ac-227 Actinium Actinium 100.0 %100.0 %


HistoryHistory

Method for Environmental developed by Burnett Method for Environmental developed by Burnett and Yeh. (1995)and Yeh. (1995)

The earlier procedure was only concerned with The earlier procedure was only concerned with interferences from naturally occuring interferences from naturally occuring radionuclides. radionuclides.

A method for Bioassay was required. Bioassay A method for Bioassay was required. Bioassay samples could contain artificial radionuclides.samples could contain artificial radionuclides.

Made the decision to try developing method Made the decision to try developing method using a single column method. using a single column method.


Development ObjectivesDevelopment Objectives

Try an analysis on TRU Resin and start Try an analysis on TRU Resin and start determining corrective steps.determining corrective steps.

Begin making corrections to procedure Begin making corrections to procedure based on results of testing.based on results of testing.

Finalize procedure.Finalize procedure.


Load Solution for Test 1Load Solution for Test 1

Perform a Ca(PO4) Precipitation on DI Perform a Ca(PO4) Precipitation on DI water containing Nat Th, Nat U, Pu-239, water containing Nat Th, Nat U, Pu-239, Am-241 and Pa-231.Am-241 and Pa-231.

Followed procedure on next slide.Followed procedure on next slide.


Test-12 mL 9M HCl10 mL 4M HCL20 mL 0.1M HCl

10 mL 2M HNO320 mL 8M HNO3 - 1M Al(NO3)3

(~90-95%)

345

21

56 Th

Pa

TRU.

Resin

1-4 (discard)

Pa Elution 20 mL 0.1M HCL - 0.1M HF

6


Test 1 ResultsTest 1 Results

Only about 50% Protactinium recoveries Only about 50% Protactinium recoveries with ~100% Plutonium and small with ~100% Plutonium and small amounts of Thorium (Up to 10%) visible amounts of Thorium (Up to 10%) visible in spectrum. in spectrum.

Analyzed the fractions just before the Analyzed the fractions just before the Protactinium Elution and determined the Protactinium Elution and determined the remainder of the Protactinium was in remainder of the Protactinium was in the Thorium elution. the Thorium elution.


Test 2Test 2

Decision made to elute Thorium with 1M Decision made to elute Thorium with 1M HCL instead of 0.1M HCL to increase HCL instead of 0.1M HCL to increase Protactinium recovery. Protactinium recovery.

Decision to use a TiCl3 solution to elute Decision to use a TiCl3 solution to elute Plutonium when eluting Americium. Plutonium when eluting Americium. Added 0.5 mL of TiCl3 to 20 mL of 4M Added 0.5 mL of TiCl3 to 20 mL of 4M HCL.HCL.



Test-22 mL 9M HCl20 mL 4M HCL - 0.5 mL TiCl320 mL 1M HCl


(~90-95%)

345

21

56 Th

Pa

TRU.

Resin

1-4 (discard)


6


Test - 2 ResultsTest - 2 Results

Plutonium was separated as expected Plutonium was separated as expected and Protactinium recoveries increased to and Protactinium recoveries increased to near 90%. near 90%.

We tested the procedure one additional We tested the procedure one additional time adding the same actinides as before time adding the same actinides as before but added Np-237 as well. Unfortunately but added Np-237 as well. Unfortunately Np-237 followed Pa through the Np-237 followed Pa through the procedure and gave a new challenge.procedure and gave a new challenge.


Test 3Test 3

Added UTEVA column to remove Neptunium Added UTEVA column to remove Neptunium and provide additional Uranium and Thorium and provide additional Uranium and Thorium clean up.clean up.

Load solution changed to 2.5M HNO3 / 0.1M Load solution changed to 2.5M HNO3 / 0.1M Ferrous Sulfamate. Added 1 mL of 1.0 M Ferrous Sulfamate. Added 1 mL of 1.0 M Ascorbic Acid to reduce Fe. This is optimal for Ascorbic Acid to reduce Fe. This is optimal for Neptunium (IV) retention on UTEVA while Neptunium (IV) retention on UTEVA while Protactinium stays in the +5 oxidation state.Protactinium stays in the +5 oxidation state.



Test-32 mL 9M HCl

20 mL 4M HCL - 0.5 mL TiCl3

20 mL 1M HCl

10 mL 2.5 M HNO3 (2x)

20 mL 2.5M HNO3 / 0.1 M FeS / Asc Acid

3 4

5

2

1

6

Pa

TRU.

Resin

1-5 (discard)


UTEVA.

Resin

1 2

6



80 to 90% of the Neptunium was removed by the 80 to 90% of the Neptunium was removed by the UTEVA. UTEVA.

We have not identified exactly why the We have not identified exactly why the Neptunium is not fully separated by the UTEVA Neptunium is not fully separated by the UTEVA resin. We have ruled out column overloading of resin. We have ruled out column overloading of any sort by adding a TEVA column to the any sort by adding a TEVA column to the sequence and still seeing Neptunium sequence and still seeing Neptunium interferance.interferance.

One possibility is phosphate interferance with One possibility is phosphate interferance with Neptunium’s retention on UTEVA. (see next slide)Neptunium’s retention on UTEVA. (see next slide)


Sensitivity to POSensitivity to PO44

UTEVA.Resin TRU.Resin


Test - 3 Results cont’dTest - 3 Results cont’d

Another thought was to separate Another thought was to separate Neptunium using spectral separation.Neptunium using spectral separation.

~84% of the energy lines can be used ~84% of the energy lines can be used which do not have Neptunium interferance which do not have Neptunium interferance with them.with them.


Spectral Separation of Np-237 Spectral Separation of Np-237 from Pa-231from Pa-231

0

0.1

0.2

0.3

0.4

0.5

Energy (MeV)

Abu

ndan

ce Np-237

Pa-231


Oxalic Acid rinseOxalic Acid rinse

Began testing to see if the separation of Began testing to see if the separation of Neptunium and Protactinium on TRUResin Neptunium and Protactinium on TRUResin was possible using oxalic acid. was possible using oxalic acid.

We loaded Neptunium and Protactinium We loaded Neptunium and Protactinium onto a TRU Column and performed a rinse onto a TRU Column and performed a rinse with 1M HCL/0.015 M Oxalic acid. with 1M HCL/0.015 M Oxalic acid.

Neptunium did not show up in the Neptunium did not show up in the Protactinium rinse. We proceeded with Protactinium rinse. We proceeded with Test-4.Test-4.


Test-42 mL 9M HCl20 mL 4M HCL - 0.5 mL TiCl3

15 mL 1M HCl / 0.015 M Oxalic Acid


34

5

21

7

7(Pa)

TRU.

Resin

1-6 (discard)


6 10 mL 1M HCl



Tracer yields were ~50% and spectrums were Tracer yields were ~50% and spectrums were free of interfering actinides. free of interfering actinides.

Approximately 15% of the Pa tracer came off Approximately 15% of the Pa tracer came off with the 10 mL rinse of 1M HCL. No other with the 10 mL rinse of 1M HCL. No other actinides were detected. This rinse can be actinides were detected. This rinse can be combined with the Pa elution to obtain tracer combined with the Pa elution to obtain tracer yields of ~65%.yields of ~65%.

The remaining Protactinium tracer came off The remaining Protactinium tracer came off with the oxalic acid rinse containing with the oxalic acid rinse containing Neptunium.Neptunium.


Test 5Test 5

Increased the molarity of HCL with the Increased the molarity of HCL with the Oxalic acid rinse to 2M HCL. Our thought Oxalic acid rinse to 2M HCL. Our thought was that maybe the total volume of 1M was that maybe the total volume of 1M HCL rinses was causing the Protactinium HCL rinses was causing the Protactinium to elute early. The Thorium will still elute to elute early. The Thorium will still elute with the 2M HCL rinse.with the 2M HCL rinse.


Test-52 mL 9M HCl20 mL 4M HCL - 0.5 mL TiCl3

15 mL 2M HCl / 0.015 M Oxalic Acid


34

5

21

7

7(Pa)

TRU.

Resin

1-6 (discard)


6 10 mL 1M HCl



Tracer yields were ~95%. Spectrums had Tracer yields were ~95%. Spectrums had 1% of the Np-237 added. No other 1% of the Np-237 added. No other actinides were present.actinides were present.

Two tests are currently in progress. Two tests are currently in progress. a.) Increase the Oxalic rinse to 0.03M a.) Increase the Oxalic rinse to 0.03M

Oxalic acid.Oxalic acid. b.) Perform the oxalic acid rinse under b.) Perform the oxalic acid rinse under

HNO3 conditions.HNO3 conditions.


ConclusionsConclusions

Eichrom Resins can be effectively utilized to Eichrom Resins can be effectively utilized to separate Protactinium from other actinides for separate Protactinium from other actinides for alpha measurements.alpha measurements.

Np-237 if present may interfere. We can Np-237 if present may interfere. We can resolve this interference with spectral resolve this interference with spectral separation or by using an oxalic acid rinse.separation or by using an oxalic acid rinse.

A Ce(OH) method of co-precipitation is A Ce(OH) method of co-precipitation is necessary for alpha counting. Flouride co-necessary for alpha counting. Flouride co-precipitations will not work with Pa(V).precipitations will not work with Pa(V).

Documents

General Engineering Laboratories Use of Eichrom Resins for Bioassay Pa-231 Bob Timm - GEL Tim Chandler - GEL Bill Burnett - FSU Mike Schultz - PerkinElmer