continuous analytical performances monitoring at the on ... · overview -analytical techniques at...

IAEAInternational Atomic Energy Agency

Continuous Analytical Performances Monitoring at the On Site Laboratory Through Proficiency, Inter-Laboratory testing and Inter-comparison Analytical

Methods

J.-G. Decaillon*, G. Duhamel*, S. Dashdondog, A. Toervenyi, C.-K. Kim (IAEA)

S. Hara, S. Kato, T. Kawaguchi (NMCC)K. Matsuzawa (JSGO)

Symposium on International Safeguards 20-24 October 2014

IAEA

Overview - Analytical Techniques at OSL

Overview - Analytical Techniques at OSL

Introducing the term performance

Introducing the term performance

ITV CriteriaITV Criteria

Proficiency test

&

Inter-laboratory results

Proficiency test

&

Inter-laboratory results

ConclusionsConclusions

Outlines


IAEA

Overview: Analytical Techniques at OSL

• OSL is the third Safeguards laboratory of its kind

• IAEA operates the On-Site Laboratory jointly with NMCC (Nuclear Material Control Center)

• Main mission is to support IAEA inspection activities related to nuclear material inventory flow verification and confirmation of the operational status.

• Analysis request, sample type and concentration level drive the selection of the analytical method

• Whenever possible, the samples are measured by two independent methods (i.e. KED Vs IDMS, Pu(VI) Vs XRF-Pu)

• Least significant difference is introduced to validate the measure


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HRGS• Pu Isotopics

• U/Pu ratio

Spectrophotometry• Pu ~ g/L level

Density meter• Density

Alpha Spectrometry• Correction Pu-238

• Pu low level

AnalyticalTechniquesAnalytical

Techniques

Neutron Counter• Cm ~µg/L

K-Edge• Pu ~ 40-270 g/L

• U ~ 40-410 g/L

Thermal Ionization Mass Spectrometry (TIMS)• U ~ 1-410 g/L

• Pu~ 1-270 g/L

X-Ray Fluorescence• Pu ~ 0.5-6 g/L

• U ~ 1-10 g/L

AnalyticalTechniquesAnalytical

Techniques

Overview: Analytical Techniques at OSL


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HKED

Pros

• Fast

• Accurate

• U & Pu simultaneously

• No sample discarding issue

Cons

• Calibration effort

• No Isotopic info

• Stability of the XRF beam


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TIMS


Pros

• Robust

• Very Accurate

• U & Pu Isotopics

• Standard Equipment

Cons

• Time consuming and labor intensive (Sample preparation and separation)

• Pure Solution

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Introducing the Term Performance

• To meet the provision of safeguards objectives (Objective C) analytical methods must be accurate and precise

1

• Assessing/Judging the reliability of analytical techniques is of paramount importance2

• To meet verification regime, analytical techniques should work according to certain standards3

• Performance = serie of criteria used for making decision about the correctness of our measurement

4


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Verification is achieved by cross-checking results by two independent methods: i.e. KED vs IDMS, XRF vs Pu(VI)

Result is validated when difference

(method1 –method2) < Least Significant Difference D

� � 2 � ��

�

Introducing the term Performance


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ITV Criteria

“ITV values represent estimates of the ‘state of the practice’ which should be achievable under routine measurement conditions”*.

ITVsITVsITVsITVs

• ITVs are uncertainties

• Used as a reference of the quality of the measurement achievable

• Ur & Us are defined for each technique & element


*Excerpt of International Target Values 2010for Measurement Uncertaintiesin Safeguarding Nuclear Materials

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ITV Criteria

� � 2 � 0.18 � � 0.28 �

� � 0.67%

e.g. U concentrated solution measured by KED-U & cross-checked with IDMS. Calculation of the least significant difference


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Interlaboratory results

Off Site Shipment filament results OSL-NML

• Goals: 1. Inter Laboratory Comparison (OSL – NML): Ur, Usdetermination for both laboratory

1

• 73 Pu and 32 U loaded filaments were shipped to NML Seibersdorf2

• Data set: 2012 and 2013 inspection samples3

• Instrumentation: TRITON TIMS4


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• Samples were sent in duplicate (2 filaments loaded with same sample) to NML in order to be able to evaluate NML random error

• Results are decay corrected for better comparison

• New Agency (IFC) software package used (OPTANOVA) for evaluation of random and systematic errors

Off Site Shipment filament results OSL-NML


IAEA Symposium on International Safeguards 20-24 October 2014


Year 2013 235U/238U 240Pu/239Pu 242Pu/239Pu

Random error (OSL) 0.026 0.007 0.036

Systematic error (OSL) 0.009 0.003 0.009

Random error(NML) 0.026 0.014 0.043

Systematic error (NML) 0.009 0.005 0.011

Systematic error (OSL-NML) 0.012 0.005 0.015

Combined error 0.039 0.017 0.0580.017

Combined errors of 240Pu/239Pu, 242Pu/239Pu and 235U/238U ratios are well-below the limits given in ITV-2010 (0.18% at 1 σ)

0.0580.039

Combined Error

• Combined Errors for 240Pu/239Pu, 242Pu/239Pu and 235U/238U ratios< 0.18% (ITV-2010)

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OSL: Comparison KED-Pu vs IDMS

• Check the accuracy & performance of KED-Pu.

• No Reference material for concentrated Pu solution

• Optanova based on 53 pairs comparison (data 2012-2014)


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OSL: Comparison KED-Pu vs IDMS

-1.000

-0.500

0.000

0.500

1.000

1.500

-5 5 15 25 35 45 55IDM

S-K

ED d

iffe

ren

ce (

%)

Sample ID

2012-2014 (August)

difference IDMS-KED

New KED-Pu Cal

Symposium on International Safeguards 22 October 2014

Method Material

Uncertainty component (%rel)

ITV (%rel)

Ur Us

IDMS Pu

Glove box condition

0.15 0.1 0.18

KED-PuGlove box condition

0.3 0.3 0.42

� � 2 � 0.18 � � 0.42 �

� � 0.91%Max least significant difference

Min least significant difference

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OSL: Comparison KED-Pu vs IDMS (Optanova analysis)

Estimation of the Long-Term Systematic Error

Estimator is d% = 0.30 %

Sigma ( d% ) = 0.06 %

Absolute t-value = 5.155

Optimal Estimators for Difference IDMS KED-Pu

(a) Random Error Standard Deviation σr 0.36 % 0.25 % 0.25 %

Standard Deviation of σr sd (σr) 0.04 % 0.13 % 0.13 %

(b) Systematic Error Standard Deviation σs 0.07 % 0.05 % 0.05 %

Standard Deviation of σs sd (σs) 0.02 % 0.01 % 0.02 %

(c) sqr ( σr2 + σs

2 ) 0.36 %

sd [sqr ( σr2 + σs

2)] 0.04 %


(a) Random Error Standard Deviation σr 0.36 % 0.25 % 0.25 %Standard Deviation of σr sd (σr) 0.04 % 0.13 % 0.13 %




2 ) 0.36 %


2)] 0.04 %

Random Error

IDMS Random Error > ITV Ur (0.15%) but in the uncertainty. KED-Pu: OK


(a) Random Error Standard Deviation σr 0.36 % 0.25 % 0.25 %

Standard Deviation of σr sd (σr) 0.04 % 0.13 % 0.13 %




2 ) 0.36 %


2)] 0.04 %


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Proficiency Test

REIMEP-17uranium and plutonium amount contents typical for undiluted spent nuclear fuel input solution

uranium and plutonium amount contents typical for undiluted spent nuclear fuel input solution

U & Pu concentrationU & Pu concentration

Pu Isotopic determinationPu Isotopic determination

U Isotopic determinationU Isotopic determination

9 Laboratories participated9 Laboratories participated


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Proficiency Test

REIMEP-17: OSL detailed results vs Ref values (Pu)Reported: Certified low Certified: Certified high Relative diff %

Pu [mmol/g] 9.1751 9.1511 9.1561 9.1611 0.208

Uncertainty value 0.0205 0.005

n(238Pu)/n(239Pu) 0.04264 0.0426 0.0426 0.0426 0.119


n(240Pu)/n(239Pu) 0.4788 0.4786 0.4787 0.4788 0.020


n(241Pu)/n(239Pu) 0.1261 0.1255 0.1257 0.12560 0.296


n(242Pu)/n(239Pu) 0.1375 0.1374 0.1375 0.1375 0.025


Coverage factor (k) for all

measurand 1

Reported: Certified low Certified: Certified high Relative diff %

Pu [mmol/g] 9.1751 9.1511 9.1561 9.1611 0.208Uncertainty value 0.0205 0.005

n(238Pu)/n(239Pu) 0.04264 0.0426 0.0426 0.0426 0.119Uncertainty value 0.0006 0.00004





measurand 1

All differences are smaller than the calculated least difference. Good agreement for Pu conc & Pu isotopics with Ref values


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Proficiency Test

REIMEP-17: OSL detailed results vs Ref values (U)

Reported: Certified low Certified: Certified high Relative diff %

U [mmol/g] 0.8446 0.8429 0.8434 0.8439 0.138


n(234U)/n(238U) 0.000068 0.000064 0.000066 0.00006 4.038


n(235U)/n(238U) 0.0068 0.0068 0.0068 0.0068 -0.020


n(236U)/n(238U) 0.0000034 0.0000014 0.0000029 0.000004 16.482



measurand 1

U234/U238 & U236/U238 difference large. However difference is smaller than the least significant difference (due to large uncertainty (e.g. ~51% Unc for U236/U238 )

Unc rel ~ 2.28%

Unc rel ~ 51.7%

- Good agreement for U conc

- For U235/U238

very smalldifference

OSL Vs

Ref value


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Proficiency Test

REIMEP-17: OSL results vs others laboratories

OSL

OSL uncertainty reported as the corresponding ITV method uncertainty (IDMS-Pu LSD: 0.18%)


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OSL

Positive Bias ?

All Laboratories but one reported U concentration > Ref value


Proficiency Test

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OSL

240Pu/239Pu ratio used for IDMS calculation


Proficiency Test

IAEA


OSL


Proficiency Test

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Eqrain n°°°°12OSL: XRF & Pu(VI) results

XRF Random component determination

OSL vs Overall results

Proficiency Test

IAEA

Eqrain n°°°°12Test

sample

Plutonium content

AverageTotal

uncertaintyg.l

-1g.l

-1g.l

-1(at k=2)

1 2.321

2.341 0.1312 2.3353 2.3354 2.3585 2.359

Reported result based on 5 replicates

XRF

Ref Value: 2.358 g/L (2.129 g.Kg-1)

Reported Result based on 4 replicates

Pu(VI)

Test samplePu content

g.l-1 ** g.kg-1

12 2.3795 2.14813 2.3627 2.13294 2.3679 2.13765 2.3804 2.1489

Average = 2.3727 2.1419


Proficiency Test

IAEA

Eqrain n°°°°12 (OSL code: 12 for XRF, 15 for spectrophotometry)

OSL

ζ �� ! �"#

$�� $"#

�Zeta score

Satisfactory result when ≤ 2


Proficiency Test

IAEA

Eqrain n°°°°12: Random component determination

Ampoule n°1Repeatability test (n=19)

XRFRandom

component

UUUU(r)(r)(r)(r)====0.76 0.76 0.76 0.76 %%%%

U(r) = Standard deviation of the samples distribution

UUUU(r)(r)(r)(r)OSL vs ITVOSL vs ITVOSL vs ITVOSL vs ITV

U(r)OSL < ITV XRF

Average(n=19) = 2.3474 g/L


Proficiency Test

IAEA

Eqrain n°°°°12 (OSL code: 12 for XRF, 15 for spectrophotometry)

OSL zeta score are skewed low due to use of ITV uncertainty.

i.e. with “real uncertainty” Zeta score for XRF = -0.51 (-0.25 with ITV)


Proficiency Test

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Conclusions

• Random & systematic error for isotopic ratio are very low

• U & Pu concentrations are well in the ITV criteria

• Overall good agreement with REIMEP 17IDMS

• Random and systematic error are in the ITV criteria (<0.30%)

• Long term systematic is constant over the years and calibrationsKED


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Conclusions

• Good agreement with Eqrain ref value• Random component Ur calculated from

repeatability test better than XRF ITVXRF

• Good agreement with Eqrain ref value• Possible small positive bias (all

replicates > ref value)Spectrophotometry


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