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NSEN 619 by G. Beitel

3/31/2012. NSEN 619 by G. Beitel. 2. Handouts. CD Handout CD glass articlesAnalysis of Thorp Glass.pdf Japanese ResearchPNNL-SRP Glass Tutorial.pdfGlass composition.xls Glass composition worksheetFrench vitrification.pdf WV experience.pdf Information on West Valley waste treatmentImmobilizat

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NSEN 619 by G. Beitel

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    1. 3/31/2012 NSEN 619 by G. Beitel 1 NSEN 619 HLW - Class 9 Mid-term Exam Silicate Pyramid Solution Term Paper Pu-238/(Pu-239+Pu-240) ratio More on Glass Glass Composition and Corrosion

    2. 3/31/2012 NSEN 619 by G. Beitel 2 Handouts CD Handout CD glass articles Analysis of Thorp Glass.pdf Japanese Research PNNL-SRP Glass Tutorial.pdf Glass composition.xls Glass composition worksheet French vitrification.pdf WV experience.pdf Information on West Valley waste treatment Immobilization in Glass summary.pdf DOE ESMP discussion of vitrification Advantages of Vitrification.htm Natural Analog Japan.pdf 2 page summary of naturB Plantlog work Glass corrosion - Hand.pdf Hand is a well known glass scientist Glass corrosion - Pain.pdf Glass corrosion.pdf B Plant_Filters.pdf Article of interest after we had the Sr-Cs Recovery lectures Thorp.ppt Copies of a Thorp article CentCont.ppt Nice slides on Centrifugal Contactors Calcine Vitrification.pdf Plus a many others INEEL EIS History of Nuclear Handbooks

    3. 3/31/2012 NSEN 619 by G. Beitel 3 Class Notes and Handouts CD - provided PAPER 2004 assignment.doc Solution of Silicate Pyramid.doc Analysis of Thorp Glass.pdf A few thoughts about glass.doc Glass corrosion - Hand.pdf Glass corrosion - Pain.pdf

    4. 3/31/2012 NSEN 619 by G. Beitel 4 Mid-term exam Cs-Sr Na(CO3)2 Metathesis to convert sulfates into carbonates, SrCO3 being one of the most insoluble HLW 1 - 10 Ci/gal 500 1900 Ci/gal fresh defense HLW Cs separation, NaTB, PTA, Ion exchange, Solvent-Solvent extraction (CSEX) Analogs MWD/MTIHM - Burn up Remember all of the criteria for HLW

    5. 3/31/2012 NSEN 619 by G. Beitel 5 Pu-238/(Pu-239+Pu-240) ratio Physics of fission processes or neutron interactions (reactors, bombs, neutron irradiation) determines the 238/239 ratio. It is man-made only Once produced, the ratio cannot be changed by natural or chemical processes (except by decay, but Pu-238 decays with ?1/2 = 87 y) Therefore isotopic ration is an origin marker like DNA

    6. 3/31/2012 NSEN 619 by G. Beitel 6 Pu-238/(Pu-239+Pu-240) ratio From IDB, and Internet: INTEC 60 average 182 for high burnup HEU SRP 34 Commercial spent fuel average 5.6 WVDP 4 LWR overall average 2.5 Northern Hemisphere Fallout 0.30 Sellafield 0.29 NTS lagoon 0.14 Weapons Grade (IDB - RFETS TRU) 0.026 Hanford 0.017 Therefore if you know the ratio, you can guess the point of origin

    7. 3/31/2012 NSEN 619 by G. Beitel 7 THORP Thermal Oxide Reprocessing British reprocessing plant http://www.globalsecurity.org/wmd/world/uk/sellafield.htm Only commercial reprocessing facility except for France Only reprocessing facility for hire Recovers Pu and Uranium and fabricates MOX fuel, MOX = Mixed U/Pu oxides Direct vitrification of HLW

    8. 3/31/2012 NSEN 619 by G. Beitel 8 Glass Glass Data and Commercial Glass making (Mosers Paper) Handout papers on Glass Todays lecture is based on articles in Vol. 333 of Materials Research Society Scientific Basis for Nuclear Waste Management XVII (1993) Page numbers and author references are to that book. The PNNL-SRP Glass Tutorial contains much the same material (540 pages of slides)

    9. 3/31/2012 NSEN 619 by G. Beitel 9 Minerals The stability of silicates The silicate tetrahedron The structures of silicates Why silicates can accommodate many different ions Why glass accommodates even more

    10. 3/31/2012 NSEN 619 by G. Beitel 10 Glass phase diagram

    11. 3/31/2012 NSEN 619 by G. Beitel 11

    12. 3/31/2012 NSEN 619 by G. Beitel 12 Glass Composition Choice of waste form Corrosion mechanisms

    13. 3/31/2012 NSEN 619 by G. Beitel 13 Mosers Glass paper Reasonable discussion of the conflict between Aluminosilicate and borosilicate glass p. 21. Good description of glass making and some history Good collection of glass data from the 60s and 70s from PNL Tables. OK attempt to discuss glass composition vs. minerals Good discussion of the impact of changing composition pages 24 - 28

    14. 3/31/2012 NSEN 619 by G. Beitel 14 Glass Paper by Cunnane and Allison Choice of Glass as a waste form is to allocate the full requirement of 60 CFR 116 to the Waste Form The approach is to demonstrate that glass corrosion rate is low enough to satisfy that. Composition of Glass is consistent with Chemical Compositions of HLW Borosilicate glass was chosen because it has good product reliability, lower melting temperature and lower volatility at melt temperature than aluminosilicate

    15. 3/31/2012 NSEN 619 by G. Beitel 15 SRP Article Glass Composition Approach to predicting containment Glass Weathering parameters Surface Area Temperature Pressure Composition Water pH

    16. 3/31/2012 NSEN 619 by G. Beitel 16 Weathering of Glass Mechanism Exchange of Alkali metals with H+ Silicic acid Diffusion of Alkalis to the gel layer Expected values of corrosion.

    17. 3/31/2012 NSEN 619 by G. Beitel 17 Release math Fraction of glass corroded per y = F = RA/W Where R= corrosion rate in g/m2/y, W = wt, A = exposed glass surface area. Fraction, fi of radionuclide released per year = F/(RF)i This reduces to evaluating R, estimating A, and knowing (RF)i

    18. 3/31/2012 NSEN 619 by G. Beitel 18 Corrosion Mechanism, Fig 2, page 6 (Cunnane) Surface Area Time dependence Relationship to boron Rates - Forward and Saturation

    19. 3/31/2012 NSEN 619 by G. Beitel 19 Results Table 1, page 10 3E-3 g/m2 d ~ 1g/ m2 y -- In 10,000 y it would corrode 1cm. Is this reasonable? 1 mm/millennium Figure 4, page 11

    20. 3/31/2012 NSEN 619 by G. Beitel 20 Glass Corrosion (note: Key portions of these two papers will be provided) Article on Page 107 Processes Surface layers Rate limiting steps Article on page 145 Significance of thermodynamics Glass composition Mineral phases Significance of S/V Surface to Volume Ratio (m-1)

    21. 3/31/2012 NSEN 619 by G. Beitel 21 Corrosion rates

    22. 3/31/2012 NSEN 619 by G. Beitel 22 Significance of corrosion rates Density of glass is ~2 1 m3 has a mass of 2 x 106g A corrosion rate of 1 g/m2d, if attacking a single face will dissolve a m3 glass block in 2 x 106d = 5500 y Corrosion rates less than 0.05 g/m2d will give a life time of the order of 100,000 y

    23. 3/31/2012 NSEN 619 by G. Beitel 23 Waste life times Corrosion rates measured at 90 C, After first 500 years, the temperatures will drop to about ambient or maybe <40 C (See the 1972 NAS SRP report I provided in Class 3). This will commensurately drop corrosion rate by 2 or 3 orders of magnitude Maximum radius of glass log is 0.30 m Container (waste package) must last 1000 y It can easily be argued that, for any corrosion rate less than 0.02 g/m2d, measured at 90 C will be less than 10-5/y after 1000 year. These last two bullets are the 10 CFR 60 criteria Furthermore, the corrosion rates are generally determined on the basis of dissolution of the glass matrix. Solubility of actinide oxides is generally 1 to 3 orders of magnitude less than that of glass.

    24. 3/31/2012 NSEN 619 by G. Beitel 24 Corrosion rates of various glasses

    25. 3/31/2012 NSEN 619 by G. Beitel 25 Relative release rate from glass

    26. 3/31/2012 NSEN 619 by G. Beitel 26 Corrosion mechanism Alkalis dissolve and go into solution in the surrounding water. Acid can attack =SiO-M and dissolve the M, where M is any metal, the =SiO-M becomes a silanol group =SiO-H Base can attack =SiO-Si= and break the silicate network and produce silicic acid, for example H4SiO4 Silicic acid has a number of forms: A group of seven hydrated forms of SiO2, including the following silicic acids: tetra, H2Si4O9, meta-di, H2Si2O5, meta-tri, H4Si3O8, meta, H2SiO3, ortho-tri, H8Si3O10, ortho-di, H6Si2O7 and ortho, H4SiO4. The latter formula is often written as Si(OH)4. Silicic acids and silicate anions polymerize through formation of multiple Si-O-Si bonds. The polysilic structure can be linear or cyclic and is not uniform in size.

    27. 3/31/2012 NSEN 619 by G. Beitel 27

    28. 3/31/2012 NSEN 619 by G. Beitel 28 Dissolution behavior

    29. 3/31/2012 NSEN 619 by G. Beitel 29

    30. 3/31/2012 NSEN 619 by G. Beitel 30 Dissolution as a function of pH

    31. 3/31/2012 NSEN 619 by G. Beitel 31 Oxidation-Reduction Glass is a highly oxidized material However, since it is really a solution, it can exist with a shortage of oxygen and hence be a reduced glass. For example, let us be melting glass and then add some powdered iron into the molten glass. The state of oxidation is traditionally measured in terms of the ratio of Fe(II)/Fe where Fe is the total iron content, and Fe(II) is valence +2 iron. In fact most of the other iron will be in the +3 state.

    32. 3/31/2012 NSEN 619 by G. Beitel 32 Effects of reduction

    33. 3/31/2012 NSEN 619 by G. Beitel 33 Effects of reduced state

    34. 3/31/2012 NSEN 619 by G. Beitel 34 Radiation effects

    35. 3/31/2012 NSEN 619 by G. Beitel 35 Effects of phase separation

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