Nuclear fuels crud analysis
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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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Nuclear fuels crud analysis

NuclearFuelsCRUD Analysis

Analytical Strategies

Yannick Suter & Helene Wolleb

24th September 2013

Yannick Suter & Helene Wolleb


Table of contents

Table ofcontents

  • Nuclear power plant

  • CRUD

  • Sampling

  • Analysis

  • Wastetreatment

Yannick Suter & Helene Wolleb


Operation mode of a nuclear power plant

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.


Operation mode of a nuclear power plant1

Operation Mode of a Nuclear Power Plant

  • In Switzerland: Light waterreactors

  • Leibstadt: Boilingwaterreactor

Yannick Suter & Helene Wolleb


Operation mode of a nuclear power plant2

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.


Crud what is it

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.


Crud problems

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.


Radioactivity

Radioactivity

  • Ionizingradiation

  • Eitherparticles (α, β, n, p+) orelectromagneticwaves (hard X-ray, γ)

Yannick Suter & Helene Wolleb

Grundlagen A, Kompetenzzentrum ABC-KAMIR, 30.07.2012.


Radioactivity1

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.


Radioactivity2

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.


Sampling general strategy

Sampling – General Strategy

  • Sampling duringannualreactorshutdown

  • Sampling insidethereactorcore

  • Fuel rodshould not bedamaged

Yannick Suter & Helene Wolleb


Sampling general strategy1

Sampling – General Strategy

  • Compositionof CRUD

  • Spatialvarianceof CRUD

  • Radioactivityof CRUD

Yannick Suter & Helene Wolleb


Sampling general strategy2

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


Sampling risk potential

Sampling – Risk Potential

  • Stronglyradiativeenvironment

  • Sample cancontainvirtuallyanyelement (in theory)

Yannick Suter & Helene Wolleb


Sampling risk potential1

Sampling – Risk Potential

  • Release ofradioactivematerial

  • Radiation uptakebyworkingstaff

  • Incorporationorinhalationofradioactive material

  • Productionofradioactivewastewhichneedsfurtherprocessing

Yannick Suter & Helene Wolleb


Sampling risk potential2

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.


Sampling sample preparation

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.


Analysis corrosion layer sims

Analysis – Corrosion Layer (SIMS)

  • Problem: Howtoget a solid sample ofthe wall?

  • A solid sample wouldbemoredifficulttoquantifycorrectly

  • Roughprofilecouldbemadeif CRUD iscollectedfromthe same spot

Yannick Suter & Helene Wolleb


Analysis icp ms

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.


Analysis icp ms1

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.


Analysis icp ms2

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.


Analysis icp ms3

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.


Analysis icp ms4

Analysis – ICP-MS

  • Issues due toradioactivity:

    - Nospecialsafetymeasuresforhighlydilutedsamples

    - Detectoristreatedasradioactivewaste

Yannick Suter & Helene Wolleb

.


Analysis geiger counter

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.


Analysis geiger counter1

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.


Analysis spectroscopy

Analysis – γ-Spectroscopy

  • Energyofγ-photons characteristicforeachradioisotope

Yannick Suter & Helene Wolleb


Analysis spectroscopy1

Analysis – γ-Spectroscopy

Yannick Suter & Helene Wolleb

http://de.wikipedia.org/wiki/Gammaspektroskopie, 20.09.2013.


Analysis spectroscopy2

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.


Analysis spectroscopy3

Analysis – γ-Spectroscopy

  • Energycalibrationneeded

  • Quantificationpossibleifcalibrationsourceofknownactivityavailable (detectorefficiency)

  • Usuallysmallmatrixeffects, specially in liquids

Yannick Suter & Helene Wolleb


Analysis spectroscopy4

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.


Waste treatment

Waste Treatment

  • Strahlenschutzverordnung, Stand 2008

    - Short half life: Wastestorageatproductionsite

    - Long half life: Collectingpointisthe PSI

    - PSI organizes intermediate storage

Yannick Suter & Helene Wolleb


Further remarks and summary

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.


Thank you for your attention

Thankyouforyourattention!

Are thereanyquestions?

Yannick Suter & Helene Wolleb


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