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JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 1
Particle Analysis –Finding the Needle in the Haystack
Nicole Nicole ErdmannErdmann, Magnus Hedberg, Magnus Hedberg
Nuclear Safeguards and Security Unit Nuclear Safeguards and Security Unit -- ITUITU Available from: www.CartoonStock.com
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 2
Nuclear Safeguards & Security Unit
Traditional Safeguards Isotope & Element Assay- Nuclear material accountancy (owner)- Independent verification (Euratom, IAEA,...)
LISEURATOM
Strengthened Safeguards Particle HPTA Method
- Verify “completeness” of declaration (Add. Protocol)
- Absence of undeclared activities
Illicit trafficking and nuclear forensics- Detection Chemical Analysis- Source attribution Macroscopic Parameters
Microscopic ParametersReference Data
?
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 3
Support for DG-TREN and IAEA
Examples of JRC/ITU support to DG-TREN and the IAEA:• Management of the On-site laboratories at La Hague and Sellafield for DG-TREN.• Analysis of HPTA SIMS samples and training of staff for DG-TREN and the IAEA. • Analysts from ITU provided in-field
analytical measurement support to joint DG-TREN/IAEA inspection teams at European fuel fabrication plants.
• Analysis of nuclear samples for DG-TREN and the IAEA.
• Support to the IAEA’s operation at Rokkasho and Training of IAEA staff for work at Rokkasho OSL.
25 year celebration of EC support to the IAEA (2006)
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 4
Strengthened Safeguards - HPTA
Basis of the High Performace Trace Analysis (HPTA) method:
Fine particulate material or aerosols are often released in trace amounts during the handling of nuclear material→ they are representative of the original material→ their composition provides specific information about the source→ they are highly mobile and can be found in many locations at a facility
• They are not detected by conventional techniques and pose no health risk
• It is difficult to clean up and remove the released particles
• Samples taken at a facility that has been operated over a long period can provide an insight into the entire history of the operation
→ Highly sensitive techniques required! SEM picture of uranium particles. (H. Thiele – ITU)
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 5
Swipe sampling
• Swipe Samples are taken by Safeguards Inspectors at the facilities
• At IAEA/Euratom headquarters, samples are anonymised, coded, then sent to the analytical labs
→ Analytical lab has no info of sample origin !!!!
www.iaea.org
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 6
Why measure single particles?→ To obtain information that gets lost/obscured by measuring the bulk average:• particle-particle change in chemical composition• particle-particle change in isotopic composition
The Analytical Challenge
(3) U3O8 hexagons
(1) PuO2 platelets
(2) PuO2 rods
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 7
The Analytical Challenge
Main objectives in particle analysis:
• Search through millions of particles to find the particles of interest (“needle in the haystack”)
• Perform analysis under strict time pressure
• Precise and accurate measurements of isotopic ratios on smallest particles possible
Particle distribution. (Resolution 1050x and 3500x).
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 8
Isotopic Analysis of Uranium Particles– Method and equipment
Particle isotopic analysis with SIMS. (Cameca 4FE6)
Particle analysis
Preparation of HPTA samples for SIMS at the ITU Clean Laboratory.
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 9
Principle of SIMS:• bombardment of sample with high-
energy ion beam• detection of secondary ions
Analytical information:• Mass spectrum (= isotopic fingerprint)• Ion image• Depth profiles, etc
Particle analysis
m/z=238
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 10
Particle analysisIsotopic analysis of particles from a swipe sample (enrichment plant for power reactor fuel)
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 11
New developments
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IMS 4F
• Aim to constantly improve the performance of particle analysis
• Measure not only major isotopes (235U/238U) but also minor isotopes (236U, 234U, they contain information about uranium origin and production process)
• Large Geometry (LG) SIMS significantly improves timeliness, sensitivity and quality of the data
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IMS 1270
Cameca 1280 LG-SIMS. Cameca 4F 236/235 data + background interference.
Cameca 1280 236/235 data (interference free)
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 12
Detailed LG-SIMS evaluation
• Detailed evaluation of LG-SIMSperformance by ITU
→ Significant improvement in sensitivity and accuracy of minor isotope data
• Results have recently been published
• Results have been provided to IAEA
Y. Ranebo et al.” Improved isotopic SIMS measurements of uranium particles for nuclear safeguard purposes”, J. Anal. At. Spectrom., 2009, 24, 277 - 287
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 13
Particle analysis
Main conclusion:
• A change towards LG-SIMS will significantly improve the quality and reliability of the particle analysis
• Finding a uranium particle in a matrix of other material is approximately 10 times faster
• The sensitivity of the instrument will also improve about 10 times, allowing for smaller particles to be analysed
• In total, the switch from SG-SIMS to LG-SIMS is a major step forward for the work of verifying the absence of non-declared nuclear activities
Both ITU and the IAEA’s laboratories are planning to establish LG-SIMS facilities in the near future.
JRC-ITU Karlsruhe - 19 March 2009 Nuclear Security 14
Further Improvements in particle analysis
Three ongoing projects to improve particle analysis:
1. Investigate the fundamental mechanisms in uranium aerosol particle release and mobility for optimising the sampling techniques.
Improve sampling.
Automated software for SIMS
Improve sample preparation.
2. Improve sample preparation methods to enhance the sensitivity in finding the U particles of interest in a large matrix of other materials.
3. Ongoing development project with the company Cameca to create a new dedicated software package for SIMS analysis that will significantly improve the performance on particle analysis.