1. Search for a Long Hidden Isotope or How a Fast Pu-Separation Helped Solve the Puzzle
Dr. Carola A Laue
Heavy Element Nuclear and Radiochemistry Group,
Lawrence Berkeley National Laboratory
Eichrom Industries, Inc. - Western Workshop Pleasanton, CA May 25, 1999

2. Acknowledgement actively involved in procedure development
Ralf Sudowe, Ken Gregorich and Darleane Hoffman
actively involved in repetitive separations during on-line experiment
Diana Lee, Jeb Adams, Michael Lane, Chris McGrath, Dawn Shaughnessy, Dan Strellis, Eric Sylwester and Philip Wilk
DOE for the financial support
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

3. Neutron-Deficient ActinidesZ N 91 92 93 94
131
133
135
137
139
141
Pu228 ?
Pu229 ?
Pu230 ?
Pu m
Pu m
Pu h
Pu m
Np225 ?
Np ms
Np s
Np s
Np229 4 m
Np m
Np m
Np m
Np m
Np d
U222 1 ms
U ms
U ms
U ms
U ms
U m
U m
U m
U d
U d
U a
U E5 a
Pa221 6 ms
Pa222 3 ms
Pa ms
Pa s
Pa s
Pa m
Pa m
Pa h
Pa d
Pa d
Pa E4 a
Pa d
Th ms
Th ms
Th ms
Th s
Th s
Th m
Th m
Th d
Th a
Th a
Th E4 a
Th h
a-decay
b+/EC-decay
b--decay
spontaneous fission
undiscovered 90
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

4. Why could 231Pu hide so well ?
Theoretical predictions for 231Pu decay half-life: min, Ea: MeV
Production reaction
cross section are small
interferences due to simultanously produced neighboring elements
Chemical separation needs to be fast, selective and efficient
Detection technology, data processing
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

5. Plutonium Separation - but Why Fast
Identification of the unknown, short-lived plutonium isotopes, 231Pu
Characterization of poorly known plutonium isotopes: 232Pu, 230Pu, 229Pu and 228Pu
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

6. Plutonium Separation - but Why Fast
1 Jaeger et al., Z. Phys. 258, 337 (1973), 2 Moeller et al, t2.lanl.gov, * Hatsukawa et al., Phys. Rev. C 42, 642 (1990)
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

7. Way of Plutonium Production - Reason for an Especially Selective Pu-Separation+
charged particle emission
neutron evaporation
3He2+
233U
[236Pu]*
231Pu
5 n
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

8. Schematic of Target and Transport System at the LBNL 88-Inch Cyclotron
oven
Helium
Nitrogen cooling gas
BEAM
150 mm
L I M target system
collection site
vacuum
Pt disk
KCl + He
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

9. Plutonium Separation - but Why Especially Selective
Pu231 ?
? EC
Pu m
80% EC
20% a
6.60, 6.54
? a
Np m
2% a
6.26
U m
U m
6.86
7.06
6.68
6.59
85% a
6.47
6.42
Pa m
Th s
Th s
7.32
7.28
7.17
7.00
Ac m
6.646
6.661
Ra ms
Ra ms
7.68
7.99
7.46
Fr ms
Rn ms
Rn ms
7.314
8.67
8.05
At ms
Po s
Po ms
8.026
Bi m
7.45
8.78
207Pb, stable
208Pb, stable
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

10. Experimental Criteria
time > 10 min
sample matrix KCl aerosol
interferences neptunium, uranium thorium, protactinium actinium
data acquisition a-spectrometry
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

11. Separation Development
classical method
TTA extraction
Anion exchange
solid phase extraction
TEVA-resin®
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

12. Separation Development
TEVA-resin®: TEtraVAlent actinide resin
by EIChroM Industries Inc.
Material: inert support, Amberchrom CG-71ms, impregnated with undiluted AliquatTM.336 [40 % (w/w)] - mixture of trioctyl and tridecyl methyl ammonium chlorides
Principle: SPE or liquid-liquid anion exchange extraction chromatography with one liquid phase stationary on an inert support
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

13. TEVA resin® - HCl and HNO3 k’ dependencies for selected elements
Graphs are scanned from E.P.Horwitz et al., Anal. Chim. Acta 310, 63 (1995)
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

14. Conditions Evaluated
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

15. Plutonium Elution Behavior from TEVA-resin®
Chemical yield for the first 5 FCV, as collected during the on-line experiment:
43 ± 4 % ± 7 %
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

16. Separation Factors Achieved
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

17. Plutonium Separation Procedure Developed
dissolution with
50 L 2 mol/L HNO3
aerosol sample
elution of U(VI), Np(V), Pa(V) and trivalent ions
TEVA resin®
column
2 mol/L HNO3
6 mol/L HCl
elution of Th(IV)
Pu -elution by reduction
to Pu(III) using HI/HCl
Pu fraction
time of
whole procedure: ~8 min
evaporation step: ~4 min
evaporation
-counting
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

18. Summed a-spectrum of 100 individually separated Pu-samples
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

19. Results Identification of 231Pu successful Confirmation of 232Pu data
t1/ min, Ea 6.72 MeV, 10% a-branch
Confirmation of 232Pu data
t1/ min, Ea 6.60 MeV
First determination of cross sections for
232Pu mb at 36 MeV 3He2+
231Pu nb at 42-to-47 MeV 3He2+
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999

20. Future Work Extend statistical evaluation of chemical procedure
Achieve shorter separation times
Automation
Transfer into applied research
Dr. Carola A Laue, LBNL-NSD Eichrom Western Workshop Pleasanton, CA May 25, 1999