de la S ection T hermique de capture l A méricium 241 par M esure inté GRA le dans MINERVE P Leconte CEA SPRCLEPh A Gruel B Geslot CEA SPExLPE L Mathieu CNRSCENBG ID: 1034743
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1. AMSTRAMGRAM AMélioration de la Section Thermique de capture l’Américium 241 par Mesure intéGRAle dans MINERVEP. Leconte CEA (SPRC/LEPh)A. Gruel, B. Geslot CEA (SPEx/LPE)L. Mathieu CNRS/CENBGA. Plompen, P. Siegler IRMMNEEDS meeting, Paris, 07-08 january 2016
2. | PAGE 2CEA | 10 AVRIL 2012OUTLINEContextDesign of the experimental programPreliminary resultsConclusions
3. CONTEXTCollaborative frameworkNEEDS ProjectCEA + IRMM + CNRSImprovement of thermal capture xs of Am241 to solve integral vs microscopic inconsistenciesCHANDA/WP12 ProjectCIEMAT + CEA + IRMMWork on samples of common interest for consistent measurement by TOF and oscillation techniques: Am241 and Tc99I3PCEA + EDF + AREVAImprovement of nuclear datafor the validation of the APOLLO2/JEFF3.1.1 code package3NEEDS meeting, Paris, 07-08 january 2016
4. CONTEXTCurrent status of evaluations and covariances241Am thermal capture99Tc thermal captureJEF-2.219.1 bJEFF-3.122.8 bJEFF-3.221.0 bENDF/B-VII.0ENDF/B-VII.1JENDL-4.022.8 ± 1.2 b20.0 ± 1.2 b23.6 b241Am and 99Tc capture are involved in several situationsReactivity of MOX assemblies (Am)Cycle length (both)Burn-Up Credit (both)Both isotopes show differences higher than 5% on the thermal valueNEEDS meeting, Paris, 07-08 january 20164
5. | PAGE 5CEA | 10 AVRIL 2012OUTLINEContextDesign of the experimental programPreliminary resultsConclusions
6. Samples from IRMM (Geel, Belgium)7 americium oxide in Al2O3 matrix + 3 « dummies » (Al2O3 only)10 technetium oxide (without matrix)Samples from past MINERVE programmesBurn-Up Credit (natUO2 + 99Tc)OSMOSE (natUO2 + 241Am)10 cm1 cm6NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMSample availability 30 mg 241Am / sample 1g 99Tc / sample 2g 99Tc 60 – 200 mg
7. Main goalHighest precision (so sensitivity) on the thermal capture cross-section of 241Am and 99TcTarget uncertainty on integral capture cross section: <3%Reactivity worth measurements by the pile-oscillation technique Mesurements in an over-thermalized spectrumLattice with a water hole at the centerNew configuration of the MINERVE reactorMAESTROAMSTRAMGRAMExp. zone:7NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMCore configuration
8. Overall reactivity worth energy distribution8NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMSensitivity calculations
9. Lattice neutronic characterizationActivation foils (Au, In, Ni…)(238U capture rate / total fission) ratioγ-spectrometry on fuel pins aroundthe water holeIntegral xs measurementsOscillations (reactivity effect)Neutron activation (capture rate measurement)Fission cross section ratio measurements 241Am/235U-> special fission chambers with absolute mass deposit calibration9NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMExperimental techniques
10. So…… heterogeneous designs… have to fit in a single common device… in which we can pile-up samples… that must be easy to handle… and must remain watertight watertight sample holder+ aluminum wedges for axialpositionning new oscillating rodlarger diameter, watertight new central devicealuminum cylinder10NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMMechanical design
11. Am and calibration samplesNew containers for:void samples (ref.)Al2O3 samples (ref.)Calibration samples+ Al wedges of differentssizes11NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMMechanical design
12. Tc samplesNew containers for:void samples (ref.)+ special Al wedgesof different sizes12DESIGN OF THE EXPERIMENTAL PROGRAMMechanical design
13. Calibration samplesTo avoid the determination of absolute reactivity worrth, all measurements are normalised with calibration samples Must be neutron standard isotopes+ to fullfill our mechanical constraints must be:easy to manufacture as metallic foilsnot too expansive…GoldUsually used in past programsEasy to manufactureEasy to handleOther isotope ?Lithium was chosen13NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMMechanical design
14. 1st step: critical configurationFind the number of fuel elements that will fullfill all safety criteriaskeff all absorbers outControl rods reactivity worthkeff of exp. lattice surroundedby graphite%fission in breeding zone3 types of fuel assemblies 3% UO2 fuel pins90% and 93% MTR assembliesKeep as possible the core symmetry Based on MCNP calculations14NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMNeutronic design
15. 2nd step: samples reactivity worthRange of measurement Δρ ≈ 1 to 10 pcm Typical uncertainty of ±0.01 pcmMC direct calculations numerical CV ≈ 3 pcm on keffFor Am and TcMCNP calculations for safety purposes (no choice in the masses)Results were controled with the newlyimplemented IFP-perturbation method in TRIPOLI4For Au and LiCalculations for mass determination MC T4 IFP calculations15NEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMNeutronic design
16. 16Reactivity worth of samplesIRMM samples7 241Am containersMCNP, direct calculation: -2.1 ± 3 pcmTRIPOLI4, IFP-perturbation calculation: -2.08 ± 0.02 pcm10 99Tc containersMCNP, direct calculation: -18.4 ± 3 pcmCalibration samples (10 mm)7 natAu disk (thick. 0.25 mm)TRIPOLI4, IFP-perturbation calculation: -11.7 ± 0.2 pcm7 natAu disk (thick. 0.125 mm)TRIPOLI4, IFP-perturbation calculation: -6.4 ± 0.1 pcm5 natLi disk (thick. 0.6 mm)TRIPOLI4, IFP-perturbation calculation: -10.6 ± 0.2 pcm7 natLi disk (thick. 0.2 mm) -5.9 ± 0.1 pcmNEEDS meeting, Paris, 07-08 january 2016DESIGN OF THE EXPERIMENTAL PROGRAMNeutronic design
17. | PAGE 17CEA | 10 AVRIL 2012OUTLINEContextDesign of the experimental programPreliminary resultsConclusions
18. PRELIMINARY RESULTS (1/2)18241Am resultsNEEDS meeting, Paris, 07-08 january 2016
19. PRELIMINARY RESULTS (2/2)1999Tc resultsNEEDS meeting, Paris, 07-08 january 2016
20. | PAGE 20CEA | 10 AVRIL 2012OUTLINEMotivation for new measurements on Am and TcDesign of the experimental programPreliminary resultsConclusions
21. CONCLUSIONS 21AMSTRAMGRAM: a challenging programUnusual sample size and massLots of mechanical devices to design (most of them from scratch) Experiments are ongoing till end of februaryA future experimental phase is under consideration Supplying of an Am241 source for neutron activation experimentManufacturing of a flat fission chamber for capture and fission measurementswith the same sampleA possible extension to the fast energy range with TAPIRO (ENEA)Transport of Am caps to TAPIRO forneutron activation experimentsNEEDS meeting, Paris, 07-08 january 2016