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Implementation of an analytical model accounting for sample inhomogeneities in REFIT. K. Kauwenberghs EC – JRC – IRMM Standards for Nuclear Safety, Security and Safeguards (SN3S). Outline. Introduction (EC - JRC- IRMM) Neutron Resonance Transmission and Capture Analysis Motivation

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Implementation of an analytical model accounting for sample inhomogeneities in refit

Implementation of an analytical model accounting for sample inhomogeneities in REFIT

K. Kauwenberghs

EC – JRC – IRMM

Standards for Nuclear Safety, Security and Safeguards (SN3S)


Outline

Outline

  • Introduction (EC - JRC- IRMM)

  • Neutron Resonance Transmission and Capture Analysis

  • Motivation

  • Initial model validation

  • Experimental model validation

  • Summary


Ec jrc irmm neutron facilities

VdG

GELINA

EC - JRC – IRMMneutron facilities

JRC-IRMM major provider in Europe of ND for nuclear energy applications


Ec jrc irmm neutron facilities1

EC - JRC – IRMMneutron facilities

GELINA

Van de Graaff

99Tc(n,) cross section

White neutron source

+

Time-of-flight (TOF)

Mono-energetic neutrons

(cp,n) reactions


Ec jrc irmm gelina

FLIGHT PATHS NORD

ELECTRON LINAC

TARGET HALL

FLIGHT PATHS SOUTH

EC - JRC – IRMMGELINA

  • Pulsed white neutron source

    • (10 meV < En < 20 MeV)

  • High resolution TOF measurements

  • Multi-user facility: 10 flight paths

  • Flight pathlengths: 10 m – 400m

  • Measurement stations with special equipment to perform:

    • Total cross section measurements

    • Partial cross section measurements

Mondelaers and Schillebeeckx, Notizario 11 (2006) 19


Ec jrc irmm gelina1

EC - JRC – IRMMGELINA

  • e- accelerated to Ee-,max ≈ 140 MeV

  • Bremsstrahlung in U-target

    (rotating & cooled with liquid Hg)

  • (  , n) , (  , f ) in U-target

  • Low energy neutrons by moderation (water moderator in Be-canning)


Neutron resonance transmission and capture analysis

Capture

Transmission

Neutron Resonance Transmissionand Capture Analysis

T : transmission

Fraction of the neutron beam traversing the sample without any interaction

Y : capture yield

Fraction of the neutron beam creating a (n,) reaction in the sample


Neutron resonance transmission and capture analysis1

Neutron Resonance Transmissionand Capture Analysis

Transmission

Capture

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Neutron resonance transmission and capture analysis2

Neutron Resonance Transmissionand Capture Analysis

Transmission

Capture

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Neutron resonance transmission and capture analysis3

Neutron Resonance Transmissionand Capture Analysis

Sample out

Sample in

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Motivation good geometry homogeneous sample

Motivationgood geometry + homogeneous sample

241Am

R(tm,E) response of TOF-spectrometer

REFIT, M. Moxon

Schillebeeckx et al., Nuclear Data Sheets 113 (2012) 3054 - 3100


Motivation heterogeneous sample

Motivationheterogeneous sample

Ignoring sample inhomogeneities:

  • Underestimation of speak

  • Overestimation of G

G


Motivation good geometry homogeneous sample1

Motivationgood geometry + homogeneous sample

  • Transmission + Capture data sample properties resonance parameters


Motivation heterogeneous sample1

Motivationheterogeneous sample

Expected transmission

  • Homogeneous sample:

  • Heterogeneous sample:

1cm

p(n') : distribution of areal density

From H. Uetsuka, et al., “Gamma Spectrometry of TMI-2 Debris” (written in Japanese), JAERI-Research 95-084.


Initial model validation

Initial model validation

  • Analytical models to account for inhomogeneities of a powder sample:

    • Kopecky et al. (ND2007)

    • LP Model (Levermore, Pomraninget al., J. Math. Phys. 27, 2526, 1986)

  • Comparison with transmission spectra produced by stochastic calculations (MC simulations)

  • LP model performs the best

35th ESARDA 2013

Becker et al., "Particle size inhomogeneity effect on NRD"


Initial model validation1

Initial model validation

  • Kopecky et al.:

    • Macroscopic model to describe the variation of the thickness

      Kopeckyet al., ND2007 , Nice , pp. 623 – 626; Schillebeeckxet al., NDS 113 (2012) 3054 - 3100

  • LP Model:

    • Microscopic model

      Levermore, Pomraninget al., J. Math. Phys. 27, 2526, 1986

35th ESARDA 2013

Becker et al., "Particle size inhomogeneity effect on NRD"


Experimental model validation

Experimental model validation

  • Experimental validation of the model

    = based on captureand transmission measurements at GELINA:

    • Cu powder samples with known grain size distribution

    • W powder samples with known grain size distribution

35th ESARDA 2013

Becker et al., "Particle size inhomogeneity effect on NRD"


Experimental model validation1

Experimental model validation

natW-powder mixed with natS-powder

(80 cm diameter, 14 g natW, 3.5 g natS)

natW-metal disc

(80 cm diameter, 14 g natW)

54th INMM 2013

Schillebeeckx et al., "Contribution of the JRC to the development of NRD"


Experimental model validation2

Experimental model validation

natW-metal disc

(80 cm diameter, 14 g natW)

54th INMM 2013

Schillebeeckx et al., "Contribution of the JRC to the development of NRD"


Experimental model validation3

Experimental model validation

natW-powder mixed with natS-powder

(80 cm diameter, 14 g natW, 3.5 g natS)

54th INMM 2013

Schillebeeckx et al., "Contribution of the JRC to the development of NRD"


Summary

Summary

  • Model accounting for inhomogeneities of a powder sample is implemented in REFIT

  • Initialvalidation of possiblemodelswith MC simulations

    LP Model performs the best

  • Experimental validation of the model with capture and transmission measurements at GELINA

    W powder samples with known grain size distribution


Implementation of an analytical model accounting for sample inhomogeneities in refit

Contributors:

B. Becker, F. Emiliani, S. Kopecky, P. Schillebeeckx

  • EC – JRC – IRMM, Geel (B)

    H. Harada F. Kitatani, M. Koizumi, H. Tsuchiya

    JAEA, Tokai-mura (Japan)

    Acknowledgement:

    Thiswork was supportedby the European Commission within the Seventh Framework Programmethrough ERINDA (FP7 – 269499).


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