Host phases for actinides in simulated metallic waste forms

Janney, Dawn E.

doi:10.1016/j.jnucmat.2003.08.032

Cited by 25 publications

(17 citation statements)

References 24 publications

(77 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…EDX data from the pH 4 coupon are almost entirely from corrosion products above the sample surface, and consist primarily of Cr and Fe in varying proportions. Although the highest concentration of U is ~17% (comparable to the maximum reported in uncorroded waste forms with 11% U [1,2]), correlations between it and other elements are less clear than in the pH 3 coupon. The single spectrum collected from material below the sample surface is from the central part of Fig.…”

Section: Ph 4 Couponmentioning

confidence: 61%

“…Proportions of elements in all of the corrosion products do not in general match those in the bulk waste form (which has 16 at% Cr, 1% Mn, 60% Fe, 9% Ni, 11% Zr, 1% Mo, and 3% U), in steels, or in intermetallics. The maximum concentration of U in corrosion products (~25 at%) is slightly higher than the highest reported concentration of U in a waste form with 11% U (~ 17-19%) [1,2], and high-U corrosion products are also high in Cr.…”

Section: Ph 3 Couponmentioning

confidence: 66%

“…Scanning electron microscope (SEM) observations of metallic waste forms show eutectic intergrowths consisting of ~50 volume% actinide-free iron solid solutions (commonly referred to as "steels") and ~50 volume% of actinide-bearing Fe-Zr-Cr-Ni intermetallic phases (e.g. References [1] and [2]). Mo is present in low concentrations in both steels and intermetallics [3].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dissolution Testing of a Metallic Waste Form in Chloride Brine

Janney

2006

MRS Proc.

View full text Add to dashboard Cite

Argonne National Laboratory has developed an electrometallurgical process for conditioning spent sodium-bonded metallic reactor fuel from the Experimental Breeder Reactor II (EBR-II). One waste stream from this process consists of a metal waste form (MWF) whose baseline composition is stainless steel alloyed with 15 wt% Zr (SS-15Zr) and whose microstructure is a eutectic intergrowth of iron solid solutions and Fe-Zr-Cr-Ni intermetallics. This paper reports scanning electron microscope (SEM) observations of corrosion products formed during static immersion tests in which coupons of surrogate MWF containing 10 wt% U (SS-15Zr-10U) were immersed in solutions with nominal pH values of 3 and 4 and 1000 ppm added chloride for 70 days at 50 °C. Although the majority of the surface areas of the coupons appear unchanged, linear areas with localized corrosion products apparently consisting of porous materials overlying corrosion-product-filled channels formed on both coupons, cross-cutting phase boundaries in the original eutectic microstructures. Many of the linear areas intersected the sample edge at notches present before the tests or followed linear flaws visible in pre-test images. Compositions of corrosion products differed significantly from the bulk composition, and the maximum observed concentration of U in corrosion products (~25 at%) slightly exceeded the highest reported values in actinide-bearing phases in uncorroded surrogate MWF samples with comparable concentrations of U (~17-19 at%). INTRODUCTIONArgonne National Laboratory has developed an electrometallurgical process for conditioning spent sodium-bonded metallic reactor fuel from the Experimental Breeder Reactor II (EBR-II) prior to disposal at the planned federal high-level radioactive waste repository to be constructed at Yucca Mountain, Nevada. In this process, chopped spent fuel is electrolytically partially dissolved in molten LiCl-KCl eutectic salt. Undissolved material (primarily fuel cladding hulls but also including zirconium, metallic fission products, and a low concentration of actinide elements) will be immobilized in a metal waste form (MWF) whose baseline composition is stainless steel alloyed with 15 wt% Zr (SS-15Zr). Scanning electron microscope (SEM) observations of metallic waste forms show eutectic intergrowths consisting of ~50 volume% actinide-free iron solid solutions (commonly referred to as "steels") and ~50 volume% of actinide-bearing Fe-Zr-Cr-Ni intermetallic phases (e.g. References [1] and [2]). Mo is present in low concentrations in both steels and intermetallics [3].An extensive series of static leach tests was conducted by immersing surrogate MWF ingots with 10 wt% U (SS-15Zr-10U) for 70 days at temperatures of 50, 70, and 90 °C in solutions with pH values from 3 to 12 and 0 to 10,000 ppm added Cl. The test results support the use of the HLW glass degradation model to represent MWF degradation for purposes of performance assessment for the proposed repository [4]. Studies of apparently uncorroded surfaces of surrogate...

show abstract

Section: Ph 4 Couponmentioning

confidence: 61%

Section: Ph 3 Couponmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dissolution Testing of a Metallic Waste Form in Chloride Brine

Janney

2006

MRS Proc.

View full text Add to dashboard Cite

show abstract

“…[4][5][6] Intermetallics with the Fe 23 Zr 6 structure were observed in alloy 5U and alloy 11U. They can be recognized in SEM images by their characteristic polygonal appearance and intermediate brightness in backscattered electron images.…”

Section: Structure-composition Relationshipsmentioning

confidence: 99%

Actinides in metallic waste from electrometallurgical treatment of spent nuclear fuel

Janney

Keiser

2003

JOM

View full text Add to dashboard Cite

Actinides OverviewArgonne National Laboratory has developed a pyroprocessing-based technique for conditioning spent sodiumbonded nuclear-reactor fuel in preparation for long-term disposal. The technique produces a metallic waste form whose nominal composition is stainless steel with 15 wt.% Zr (SS-15Zr), up to ~11 wt.% actinide elements (primarily uranium), and a few percent metallic fi ssion products. Actual and simulated waste forms show similar eutectic microstructures with approximately equal proportions of iron solid solution phases and Fe-Zr intermetallics. This article reports on an analysis of simulated waste forms containing uranium, neptunium, and plutonium.

show abstract

“…Development of the metal waste form has progressed from the initial surrogate test program [8,9] to production-scale irradiated operations and includes compositional and microstructural evaluations for phase stability, [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] corrosion testing, [26][27][28][29][30][31][32][33] mechanical as well as thermophysical property testing, and process qualification. [34,35] As a result of the extensive developmental test program, the following conclusions can be stated: (1) the intermetallic ZrFe 2 phase incorporates the noble metals and actinides exclusively, with the exception of technetium which may also be present in the iron solid solution, (2) the metal waste alloy is as corrosion resistant as borosilicate glass based on a variety of durability tests including immersion, electrochemical, galvanic, hydration, and toxicity, and (3) the alloy is a viable high-level waste form for geological disposal despite the recent delay in repository licensing.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

Westphal

Frank

McCartin

et al. 2013

Metall Mater Trans A

View full text Add to dashboard Cite

As part of the pyrometallurgical treatment of used Experimental Breeder Reactor-II fuel, a metal waste stream is generated consisting primarily of cladding hulls laden with fission products noble to the electrorefining process. Consolidation by melting at high temperature [1873 K (1600°C)] has been developed to sequester the noble metal fission products (Zr, Mo, Tc, Ru, Rh, Te, and Pd) which remain in the iron-based cladding hulls. Zirconium from the uranium fuel alloy (U-10Zr) is also deposited on the hulls and forms Fe-Zr intermetallics which incorporate the noble metals as well as residual actinides during processing. Hence, Zr has been chosen as the primary indicator for consistency of the metal waste. Recently, the first production-scale metal waste ingot was generated and sampled to monitor Zr content for Fe-Zr intermetallic phase formation and validation of processing conditions. Chemical assay of the metal waste ingot revealed a homogeneous distribution of the noble metal fission products as well as the primary fuel constituents U and Zr. Microstructural characterization of the ingot confirmed the immobilization of the noble metals in the Fe-Zr intermetallic phase.

show abstract

Host phases for actinides in simulated metallic waste forms

Cited by 25 publications

References 24 publications

Dissolution Testing of a Metallic Waste Form in Chloride Brine

Dissolution Testing of a Metallic Waste Form in Chloride Brine

Actinides in metallic waste from electrometallurgical treatment of spent nuclear fuel

Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

Contact Info

Product

Resources

About