1. M. Koestlbauer, V. Nizhnik SGTS/TND G. Sheppard SGCP/CTR
Application of Lanthanum Bromide Detectors for the IAEA Safeguards Verification
M. Koestlbauer, V. Nizhnik SGTS/TND
G. Sheppard SGCP/CTR

2. Limitations of Ge and NaI detectors
Germanium (Ge) detectors
Slow time shaping: unsatisfactory performance in high background (count rate) applications, like recycled uranium enrichment measurement. High dead-time.
Requires Liquid Nitrogen (LN) cooling: long cooling/preparation time before start of measurement
Certain facilities do not allow LN use due to safety reasons
LN dewar maks detector more bulky: limited portability
Sodium Iodide (NaI) detectors
Poor resolution:
bad Peak-to-Compton background ratio
Non-resolving/overlaping gamma peaks
Poor linearity and temperature stability

3. LABR: Key Parameters Performance
Lanthanum Bromide (LABR) – scintillation gamma detector
Room temperature operation (no LN need, fast instrument preparation for the measurement, convenience in use, excellent portability)
2-3 times better energy resolution versus NaI: 5% vs 10-12% at 185keV
High and fast light output (high count rate capability; low dead-time)
Good linearity and temperature stability
% DT
Ge vs LaBr dead-time
Spectra of SIL uranium standard taken with LABR and NAID
Count Rate kcpsc
U-235 peaks

4. Uranium Bottle Verification System (UBVS) RRP
Recycled Uranium stored in containers of big bottle type:
Avoid to use LN cooling: LN cooled Ge detector is not applicable
Very high background from U-232 daughter products (high counting rate): high dead-time effects; Electrically Cooled Germanium System (ECGS) is not applicable
238keV peak from Pb-212 (daughter of U-232): peaks overlapping and influence on 185keV area determination in NAID spectra
Accumulation of U-232 daughter products with time
Recycled Uranium Spectrum for NAID
185keV
238keV Pb-212
RIO 1
RIO 2

5. LaBr vs NaID Verification Results for UBVS
Required RSD 4.5%
NAID performance
Average OID %
Avg. Uncertainty 4.8 %
LABR performance
Average OID -2.7%
Avg. Uncertainty 2.6 %
UBVS Measurement with LABR
Average over the measurement campaign

6. Fuel Rods Verification
Standard measurement setup:
NaI detector with V-shape collimator: calibration constant is rod diameter dependent
2 ROI method for 185keV area determination: background variation sensitive
No attenuation correction: cladding material type and thickness sensitive
No burnable poison correction: sensitive to presence of Gd/Er/Dy burnable poison and its concentration
Need for calibration for each combination of Rod Diameter, Cladding Type and Thickness, Burnable Poison Type and Concentration.
Hundreds of calibration standards and corresponding measurements to establish calibrations for the whole range of combinations of fuel rods parameters

7. LaBRod: LaBr for Rods Method F Verification
Monte-Carlo Modeling (Corrections)
Fuel Pellet Diameter (D), mm 7.5 – 14.0
Cladding Thickness (Th), mm 0.0 – 3.0
Cladding Type (K): Zr, SS, Al
LaBRod Software Development
Automatic Reporting in PDF format
Instrument-Collimator Setup
Category A (Oct 2011)

8. Fuel Rods Verification
Fuel Rods Enrichment Verification Results at a Fuel Fabrication Plant
Average value of OID and Measurement Uncertainty for the verification campaign
Average OID, rel. % -0.9%
Average Unc., rel.% 1.00%
RSD-ITV 2010, rel.% 3.2 %

9. Fuel Pellets Verification
Standard measurement setup:
NaI detector with Al spacer: poor Peak-to-Compton background ratio; long counting time
Instrument Calibration– Monte-Carlo calculations at the HQ prior sending equipment to the field: no possibility to calibrate the instrument in the field, when operator introduces new pellets design
No burnable poison correction: sensitive to presence of Gd/Er/Dy burnable poison and its concentration
Need to recall instrument back to the HQ if a calibration for a new pellet design is needed
Standard measurement time is s

10. LaBPel: LaBr for Pellets Method F Verification
Monte-Carlo Modeling (Corrections)
LaBPel Analysis Software Development
Ext. Diameter (D), mm 7.0 – 16.0
Pellet Height (H), mm 0.0 – 3.0
Internal hole (Din): % D
Instrument-Collimator Setup
UO2 Fuel Pellet
Plastic Holder
LaBr Crystal
+ Automatic Reporting in PDF format
Collimator Assembly
Category A (Oct 2011)

11. Fuel Pellets Verification
Enrichment measurement of fuel pellets during the training course (CIE at Bulk Handling Facilities 2011)
Average OID, rel.%:
Detector %
Detector %
Average Unc., rel.%:
Detector %
Detector %
Typical Sigma historical: 4-5%
OID, %
Average value of OID and Measurement Uncertainty for the verification campaign