The radial distribution of plutonium in high burnup UO2 fuels

Abstract. Microbeam analysis is widely used in the nuclear power industry. It is used to characterise the as-fabricated fuel, for routine post-irradiated examination and for research into the mechanisms of phenomena that limit the energy production of the fuel. The techniques most commonly used are wavelength-dispersive electron probe microanalysis, scanning electron microscopy and secondary ion mass spectrometry. Other microbeam analysis techniques that have been successfully applied to irradiated nuclear fuel are transmission and replica electron microscopy, X-ray fluorescence and micro X.-ray diffraction. Specific examples illustrating the past and present use of microbeam analysis in nuclear research establishments are presented with emphasis on the unique results they provide. As an aid to understanding, some basic facts about nuclear fuel rods and their irradiation are first given. This is followed by a description of features that set apart the microbeam analysis of high radioactive materials from standard practice.

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“…The correction procedure adopted is described in ref. [17] and can be employed for other interferences.…”

Section: Plutonium and The Minor Actinides Americium And Curiummentioning

confidence: 99%

Microbeam analysis of irradiated nuclear fuel

Walker¹,

Stephan²,

Pöml³

et al. 2012

IOP Conf. Ser.: Mater. Sci. Eng.

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“…The changes to the FRAPCON-3 code to install and use the TUBRNP subcode provided by the Institute for Transuranium Elements, Karlsrulhe, Germany (Lassmann et al 1994), are extensive. They involve, first of all, changing the fuel and cladding temperature calculator from the method of weighted residuals to a finite-difference scheme defined in Berna et al 1997.…”

Section: Changes To Frapcon-3 To Include and Accommodate The Tubrnp Smentioning

confidence: 99%

“…In addition, users of the FRAPCON-3 code must reference the Lassmann et al 1994 citation in published calculational results in which the TUBRNP model is employed.…”

Section: Range Of Application and Uncertaintymentioning

confidence: 99%

“…Lassmann et al (1994) from the Institute for Transuranium Elements, Karlsruhe, Germany, wrote the TUBRNP code, which improves upon RADAR by modifying the parameters for the plutoniumdistribution function and accounting for the plutonium isotopes explicitly. The result is a somewhat more edge-peaked distribution function at nominal to high fuel burnups, which is supported by comparison to detailed neutronics calculations and to detailed electron microprobe data on the distribution of both plutonium and stable fission products (Lassmann et al 1994;Lassmann et al 1995). Lassmann's model has demonstrated good comparisons to detailed data on burnup distribution while retaining more generality than the specific-case interpolations by Matsamura or Shann; it is therefore chosen for application in FRAPCON-3.…”

Section: Introductionmentioning

confidence: 99%

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FRAPCON-3: Modifications to fuel rod material properties and performance models for high-burnup application

Lanning¹,

Beyer²,

Painter³

1997

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“…To characterize the rim formation more realistically, the threshold burnup was analyzed on the basis of the Rest's model(7)(s). The model suggests the rim formation as the microstructure change by recrystallization, which occurs in the fuel periphery above the threshold burnup given by (1) tion of thermal conductivity in the fuel periphery due to the formation of rim structure. Figure 1 shows the threshold burnup for recrystallization as a function of temperature.…”

Section: Threshold Burnupmentioning

confidence: 98%

Rim Characteristics and Their Effects on the Thermal Conductivity in High Burnup UO₂Fuel

Lee

Koo

Sohn

2001

Journal of Nuclear Science and Technology

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Characteristics of high burnup U02 fuel such as threshold burnup for the formation of high burnup microstructure (rim), rim average burnup and rim width were estimated and then the thermal conductivity degradation due to the porous rim region was investigated.The threshold burnup for rim formation was estimated as a function of temperature and fission rate using Rest's model. The calculated threshold burnup, which shows a particular dependence on temperature, ranges from 40 to 50MWd/kgU at typical fuel periphery temperatures of 400 to 600°C. In addition, the rim average burnup and the rim width were obtained by statistical analysis of the data available in open literature.To consider the additional degradation of thermal conductivity in. the rim region, a formula for rim porosity was presented with the assumption that rim pores are overpressurized and that all the produced fission gases are retained in the rim pores.To estimate the thermal conductivity in the porous rim using the general correction method applicable to two-phase structure, it was assumed that the rim region consists of pores and fully dense materials composed of U02 matrix and solid fission products. Then by combining the general model for two-phase with the rim porosity developed in the present paper and HALDEN's thermal conductivity model, a thermal conductivity model for the porous rim region was developed.The predicted thermal conductivity shows an additional reduction of ~20% due to the porous rim structure which would cause to increase the fuel temperature of high burnup fuel during steady-state operation and transient irradiation.

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The radial distribution of plutonium in high burnup UO2 fuels

Cited by 107 publications

References 6 publications

Microbeam analysis of irradiated nuclear fuel

Microbeam analysis of irradiated nuclear fuel

FRAPCON-3: Modifications to fuel rod material properties and performance models for high-burnup application

Rim Characteristics and Their Effects on the Thermal Conductivity in High Burnup UO₂Fuel

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The radial distribution of plutonium in high burnup UO2 fuels

Cited by 107 publications

References 6 publications

Microbeam analysis of irradiated nuclear fuel

Microbeam analysis of irradiated nuclear fuel

FRAPCON-3: Modifications to fuel rod material properties and performance models for high-burnup application

Rim Characteristics and Their Effects on the Thermal Conductivity in High Burnup UO2Fuel

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Rim Characteristics and Their Effects on the Thermal Conductivity in High Burnup UO₂Fuel