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Nuclear Fuels CRUD Analysis

Nuclear Fuels CRUD Analysis. Analytical S trategies Yannick Suter & Helene Wolleb 24 th September 2013. Table of contents. Nuclear power plant CRUD Sampling Analysis Waste treatment. Operation Mode of a Nuclear Power Plant.

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Nuclear Fuels CRUD Analysis

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  1. NuclearFuelsCRUD Analysis Analytical Strategies Yannick Suter & Helene Wolleb 24th September 2013 Yannick Suter & Helene Wolleb

  2. Table ofcontents • Nuclear power plant • CRUD • Sampling • Analysis • Wastetreatment Yannick Suter & Helene Wolleb

  3. Operation Mode of a Nuclear Power Plant • Conversionof thermal energyreleasedfromnuclearfission • Nuclearandconventionalpart • Fissile atomicnuclei: Uranium-235 • Controlwithneutronmoderators • Nuclearchainreaction Yannick Suter & Helene Wolleb http://www.kernenergie.ch/de/akw-technik.html#anchor_ZXDVQE, 20.09.2013.

  4. Operation Mode of a Nuclear Power Plant • In Switzerland: Light waterreactors • Leibstadt: Boilingwaterreactor Yannick Suter & Helene Wolleb

  5. Operation Mode of a Nuclear Power Plant Yannick Suter & Helene Wolleb http://upload.wikimedia.org/wikipedia/commons/1/15/Boiling_water_reactor_english.svg, 20.09.2013.

  6. CRUD – Whatisit? • Deposition of solid phaseproducts on thefuelcladding • Corrosionproductsandadditionstofeedwater • Main expectedelements: Fe, Zn, Ni, Cr, Co, Cu • γ-activities: 60Co, 54Mn, 125Sb, 65Zn Yannick Suter & Helene Wolleb I. Günther-Leopold et al., Progress Report 2005–2006, Laboratory for Materials Behaviour (LWV), PSI, 13.

  7. CRUD – Problems • Magnetic CRUD: Interferencewithdeterminationofoxidethicknesslayer • Pickup of hydrogen in thecladding material • Limitingfactorforthelifetimeoffuelassemblies • Radioactivecorrosionproducts: Occupationalradiationexposure Yannick Suter & Helene Wolleb S. Abolhassaniet al., Progress Report 2005–2006, Laboratory for Materials Behaviour (LWV), PSI, 12.

  8. Radioactivity • Ionizingradiation • Eitherparticles (α, β, n, p+) orelectromagneticwaves (hard X-ray, γ) Yannick Suter & Helene Wolleb Grundlagen A, Kompetenzzentrum ABC-KAMIR, 30.07.2012.

  9. Radioactivity • Activitygivenbythenumberofdesintegrations per time [Bq = s-1] • Radiativeuptakegivenbytheabsorbedenergy dose [Gy = J/kg] • Equivalent dose andeffective dose givenasabsorbed dose multipliedwithweightingfactorsfortissueandradiation type [Sv = J/kg] • Usuallymeasuredas dose rates [Sv/h] Yannick Suter & Helene Wolleb Grundlagen A, Kompetenzzentrum ABC-KAMIR, 30.07.2012.

  10. Radioactivity • Meanannual dose in Switzerland: ~4-5 mSv • 1 Svaccountsfor a rise in cancerprobabilityby 4% • Fixed limitingvaluesforman-made radiation Yannick Suter & Helene Wolleb Grundlagen A, Kompetenzzentrum ABC-KAMIR, 30.07.2012.

  11. Sampling – General Strategy • Sampling duringannualreactorshutdown • Sampling insidethereactorcore • Fuel rodshould not bedamaged Yannick Suter & Helene Wolleb

  12. Sampling – General Strategy • Compositionof CRUD • Spatialvarianceof CRUD • Radioactivityof CRUD Yannick Suter & Helene Wolleb

  13. Sampling – General Strategy • Non-destructive in-situ measurements on CRUD difficult (e.g. EDX or XRF) • Howtoget a representative sample of CRUD? • Depth-profilingwouldrequire a solid sample Yannick Suter & Helene Wolleb

  14. Sampling – Risk Potential • Stronglyradiativeenvironment • Sample cancontainvirtuallyanyelement (in theory) Yannick Suter & Helene Wolleb

  15. Sampling – Risk Potential • Release ofradioactivematerial • Radiation uptakebyworkingstaff • Incorporationorinhalationofradioactive material • Productionofradioactivewastewhichneedsfurtherprocessing Yannick Suter & Helene Wolleb

  16. Sampling – Risk Potential • Handling insidehotcells • Special requirementsfortransportation Yannick Suter & Helene Wolleb http://www.psi.ch/media/knowledge-for-tomorrow-from-hot-cells, 20.09.2013.

  17. Sampling – Sample Preparation • CRUD isscraped off thecladdingsurfaceinsidethereactorcore • Material collectedbymembranefilters • Filters dissolved in concentrated HNO3, H2O2and HF in a microwavedigestionsystem Yannick Suter & Helene Wolleb I. Günther-Leopold et al., Progress Report 2005–2006, Laboratory for Materials Behaviour (LWV), PSI, 13.

  18. Analysis – Corrosion Layer (SIMS) • Problem: Howtoget a solid sample ofthe wall? • A solid sample wouldbemoredifficulttoquantifycorrectly • Roughprofilecouldbemadeif CRUD iscollectedfromthe same spot Yannick Suter & Helene Wolleb

  19. Analysis – ICP-MS • Liquid sample: Micronebulizer • InductivelyCoupled Plasma • Interface: Sample coneandskimmercone • Quadrupole MS • Sectorfield MS • Detection: Multiple ioncollector Yannick Suter & Helene Wolleb D. Güntheret al., SkriptAnalytischeChemie I + II, ETH Zürich, 2011.

  20. Analysis – ICP-MS Yannick Suter & Helene Wolleb http://www.chem.agilent.com/en-US/products-services/Instruments-Systems/Mass-Spectrometry/Pages/gp455.aspx, 20.09.2013.

  21. Analysis – ICP-MS • Isotopicdifferentiationpossible • Low limitsofdetection (usually ppb) • Quantificationpossible Yannick Suter & Helene Wolleb http://www.chem.agilent.com/en-US/products-services/Instruments-Systems/Mass-Spectrometry/Pages/gp455.aspx, 20.09.2013.

  22. Analysis – ICP-MS • Major problem: Interferences - Example: Isobaricinterferenceof90Sr with90Zr • Solutions: - Double-focusingsectorfield ICP-MS - ICP-MS withcollisioncell - Applicationofcouplingtechniques, e.g. ionchromatography Yannick Suter & Helene Wolleb J. S. Becker, International Journal of Mass Spectrometry2005, 242, 183-195.

  23. Analysis – ICP-MS • Issues due toradioactivity: - Nospecialsafetymeasuresforhighlydilutedsamples - Detectoristreatedasradioactivewaste Yannick Suter & Helene Wolleb .

  24. Analysis - Geiger Counter • First analysisofγ-radiation • Measuresthe dose rate [Sv/h] Yannick Suter & Helene Wolleb Automation und Messtechnik GmbH, Gebrauchsanweisung für den Dosis- leistungsmesser 6150AD, 26.10.2005.

  25. Analysis - Geiger Counter • Countingtube • An X-rayorγphotonionizes an argonatom; onlydetectsradiation in a certainenergyrange • Noinformationaboutthe radioisotopes Yannick Suter & Helene Wolleb Automation und Messtechnik GmbH, Gebrauchsanweisung für den Dosis- leistungsmesser 6150AD, 26.10.2005.

  26. Analysis – γ-Spectroscopy • Energyofγ-photons characteristicforeachradioisotope Yannick Suter & Helene Wolleb

  27. Analysis – γ-Spectroscopy Yannick Suter & Helene Wolleb http://de.wikipedia.org/wiki/Gammaspektroskopie, 20.09.2013.

  28. Analysis – γ-Spectroscopy • Energymeasurement:- Scintillationdetector (e.g. NaI)- Semiconductor (e.g. pure Ge) Yannick Suter & Helene Wolleb http://www.psi.ch/asi/radioanalytik, 20.09.2013.

  29. Analysis – γ-Spectroscopy • Energycalibrationneeded • Quantificationpossibleifcalibrationsourceofknownactivityavailable (detectorefficiency) • Usuallysmallmatrixeffects, specially in liquids Yannick Suter & Helene Wolleb

  30. Analysis – γ-Spectroscopy • Elements withoutγradiationcannotbemeasured (3H, 14C) • Not reallysuitedforactinidesα-spectroscopy • High-energyγradiationcannotbemeasured due tothe pair-effect • All β+decaysproducetheannihilationlineat 511 keV Yannick Suter & Helene Wolleb Grundlagen der γ-Spektroskopie, Kompetenzzentrum ABC-KAMIR, 14.09.2012.

  31. Waste Treatment • Strahlenschutzverordnung, Stand 2008 - Short half life: Wastestorageatproductionsite - Long half life: Collectingpointisthe PSI - PSI organizes intermediate storage Yannick Suter & Helene Wolleb

  32. Further RemarksandSummary • Reductionof CRUD • Zincinjection: Preventionofrustformation • Analysis of CRUD is essential forqualitycontrol • ICP-MS in combinationwithγ-spectroscopy • Data validation: Comparison, analysisofreferencesamples Yannick Suter & Helene Wolleb G. Ledergerber et al., J. Nuc. Sci. Tech. 2006, 43, 1006-1014.

  33. Thankyouforyourattention! Are thereanyquestions? Yannick Suter & Helene Wolleb

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