Riso AN8

Overview

The Riso AN8 experiment was conducted at the Riso DR3 water-cooled HP1 rig and utilized an unopened rod from the Biblis A pressurized water reactor (PWR). The original fuel rod, named CB10, was irradiated over four reactor cycles up to about 44 GWd t $var element = document.getElementById("moose-equation-68220e6b-c807-41a9-95ba-9428963a093e");katex.render("^{-1}", element, {displayMode:false,throwOnError:false});$ , then underwent ramp testing in unopened conditions, hence this rod did not experience any re-fabrication process.

note:Current BISON Results

BISON time domain results on this page have not been updated to reflect the latest modeling and simulation formulations.

Test Description

Rod Design Specifications

The CB10 rod geometry is tabulated in Table 1, in which details regarding fuel characteristics are also reported.

Table 1: Riso AN8 Test Rod Specifications

Fuel Rod	Measurement	Unit
Overall length	0.5418	m
Fuel stack height	0.514	m
Nominal plenum height	61.0	mm
Fill gas composition	He
Fill gas pressure	2.31	MPa
Fuel	Measurement	Unit
Material	UO $var element = document.getElementById("moose-equation-689a37d6-5d4b-4096-8fab-0f2ab01e2a27");katex.render("_2", element, {displayMode:false,throwOnError:false});$
Enrichment	2.95	$var element = document.getElementById("moose-equation-d9eb4517-1163-4edf-8786-ee850b85fba5");katex.render("\\%", element, {displayMode:false,throwOnError:false});$
Density	93.74	$var element = document.getElementById("moose-equation-941567e5-b423-4ca0-b298-fc4ef339be5a");katex.render("\\%", element, {displayMode:false,throwOnError:false});$
Outer diameter	9.053	mm
Grain diameter	6.0	$var element = document.getElementById("moose-equation-4dd79140-86ed-424c-b7ff-0bca52bb71c9");katex.render("\\mu", element, {displayMode:false,throwOnError:false});$ m
Cladding	Measurement	Unit
Material	Zr-4
Outer diameter	10.81	mm
Inner diameter	9.261	mm
Wall thickness	0.772	mm

Operating Conditions and Irradiation History

The power history for the base irradiation carried out at the Biblis A PWR is shown in Figure 1. The experiment power history carried out at the Riso DR3 facility is shown in Figure 2. The rod axial power profile, clad surface temperature, coolant pressure and fast flux during experiments have been prescribed coherently with the data available in the International Fuel Performance Experiments database (Sartori et al., ) and in the Bump Test AN8 final report (R, 1990). Details on reactor operation parameters are tabulated in Table 2.

Table 2: Operational input parameters.

Base Irradiation
Coolant inlet temperature	$var element = document.getElementById("moose-equation-7c6b1a85-9ea4-4909-8911-d6ce61a31a32");katex.render("^{\\circ}", element, {displayMode:false,throwOnError:false});$ C	284.7
Coolant pressure	MPa	15.52
Fast neutron flux	n cm $var element = document.getElementById("moose-equation-9b89a311-7987-429f-8725-e60cf8413eac");katex.render("^{-2}", element, {displayMode:false,throwOnError:false});$ s $var element = document.getElementById("moose-equation-a43f8bc4-dc91-4c6b-9a52-a8f516ec170c");katex.render("^{-1}", element, {displayMode:false,throwOnError:false});$ per (kW m $var element = document.getElementById("moose-equation-b62c724e-2434-453e-84ed-d062c291b770");katex.render("^{-1}", element, {displayMode:false,throwOnError:false});$ )	3.4 $var element = document.getElementById("moose-equation-cc8ad424-240f-4bb9-a3c6-422f0fdcaf90");katex.render("\\times 10^{12}", element, {displayMode:false,throwOnError:false});$
Power Ramps
Coolant pressure	MPa	15.3
Fast neutron flux	n cm $var element = document.getElementById("moose-equation-24d07fda-9b4d-40cd-9e67-4b863f557d72");katex.render("^{-2}", element, {displayMode:false,throwOnError:false});$ s $var element = document.getElementById("moose-equation-2f085d42-36ee-4a18-8693-1d8a58be38c8");katex.render("^{-1}", element, {displayMode:false,throwOnError:false});$ per (kW m $var element = document.getElementById("moose-equation-8e8ec90b-8ffe-40e5-bc90-75cafbb89d85");katex.render("^{-1}", element, {displayMode:false,throwOnError:false});$ )	4.0 $var element = document.getElementById("moose-equation-fdad34a2-c354-4a75-954e-5923d4a30a42");katex.render("\\times 10^{11}", element, {displayMode:false,throwOnError:false});$

Figure 1: Base irradiation history for fuel segment CB10, carried out at Biblis A PWR.

Figure 2: Riso DR3 irradiation period for test AN8 (CB10).

Model Description

Geometry and Mesh

The fuel rod geometry was modeled for the entire simulation with a smeared column of flat ended pellets.

A 2-dimensional axisymmetric quadratic (Quad8 elements) mesh was used to model the geometry of the rod used in the AN8 experiment. The mesh script files used to generate the mesh of the considered rod are included in the rod analysis subfolder.

Input files

The BISON input and all supporting files (power histories, axial power profile, fast neutron flux history, etc.) for this case are provided with the code distribution at bison/assessment/LWR/validation/ and bison/assessment/LWR/validation/Riso_AN8/analysis.

To avoid code duplication, the input files are structured in this format: A first base input file contains characteristics common to all the Riso cases: Riso_Base.i. A second base input file contains characteristics common to all the Riso case that do not use the action: Riso_Base_sub.i. Input files containing information specific to the fuel rod and the type of problem solving use the !include function to build a complete input file with the base files.

To run a specific assessment, such as the Riso AN8, run: Riso_AN8.i.

Material and Behavioral Models

The following material and behavioral models for UO $var element = document.getElementById("moose-equation-ea0a3d8d-cabe-4c8d-bda9-28b4e7623d2c");katex.render("_2", element, {displayMode:false,throwOnError:false});$ fuel were used:

UO2Thermal - NFIR: NFIR model for temperature and burnup dependent thermal properties
ComputeFiniteStrainElasticStress and UO2ElasticityTensor: elastic mechanical behavior
UO2RelocationEigenstrain: relocation strains, relocation activation threshold power set to 5 kW/m
ComputeThermalExpansionEigenstrain: thermal expansion with a constant instantaneous thermal expansion coefficient
UO2VolumetricSwellingEigenstrain : volumetric expansion due to solid and gaseous swelling
UO2Sifgrs: fission gas release model used with the gaseous swelling model UO2VolumetricSwellingEigenstrain (Pastore et al., 2015)

For the cladding material, a constant thermal conductivity of 16 W/m-K was used and both thermal and irradiation creep were considered using the Limback model (Limbäck and Andersson, 1996). The following material and thermal behavior models were used for the Zircaloy-4 cladding:

HeatConductionMaterial: Thermophysical material properties
ZryCreepLimbackHoppeUpdate and ComputeIsotropicElasticityTensor: mechanical creep and elastic deformation behavior for Zircaloy-4, with a Young's modulus of 1.0 $var element = document.getElementById("moose-equation-8366a0d9-9c0e-4db5-aa54-3116b4a7ad71");katex.render("\\times", element, {displayMode:false,throwOnError:false});$ 10 $var element = document.getElementById("moose-equation-e994a655-50e7-456a-8e64-50d798ecb2aa");katex.render("^{11}", element, {displayMode:false,throwOnError:false});$ and a Poisson's ratio value of 0.3
ZryIrradiationGrowthEigenstrain: ESCORE model for volumetric swelling due to irradiation exposure
ZryThermalExpansionMATPROEigenstrain: thermal expansion with an instantaneous thermal expansion coefficient that varies according to the MATPRO cthexp model
ZryOxidation: cladding oxidation thickness growth model for metal-water reactions

Details and references for all of these models listed above can be found on the linked BISON documentation pages.

Boundary and Operating Conditions

The power history considered comprehends the base irradiation, shown in Figure 1, and the subsequent ramp test, reported in Figure 2. The temperature boundary conditions as a function of time was prescribed according to the files available in the IFPE database (Sartori et al., ).

Results Comparison

The Riso AN8 experiment is used to assess the code's capability to predict integral fission gas release (FGR) at EOL, as well as to predict cladding deformation after the ramp test.

Figure 3: BISON total fission gas release comparison to Riso experimental data.

Figure 4: BISON cladding diameter results compared to measured data.

Fission Gas Release

The calculated integral fuel rod FGR is compared to the final, measured data in Figure 3. BISON results show a good agreement with the experimental data, in line with the intrinsic modeling uncertainties (Pastore et al., 2015).

EOL Cladding Diameter

The BISON results of cladding outer diameter at the end of irradiation as a function of axial position are presented in Figure 4 and compared to the experimental measurements. The figure shows an acceptable agreement between simulated and measured cladding diameter at EOL. The deviation of BISON calculations appear to be in line with state-of-the-art fuel performance codes accuracy (IAEA, 2008-2012). The systematic over-estimation of the cladding diameter may be reduced if fuel creep is considered in the simulations. This issue will be further investigated in future work.

References

IAEA. Improvement of Computer Codes Used for Fuel Behaviour Simulation (FUMEX-III): Report of a Coordinated Research Project 2008-2012. Technical Report IAEA-TECDOC-1697, International Atomic Energy Agency, 2008-2012.

@TECHREPORT{fumexIII-Report,
    author = "IAEA",
    title = "{Improvement of Computer Codes Used for Fuel Behaviour Simulation (FUMEX-III): Report of a Coordinated Research Project 2008-2012}",
    institution = "International Atomic Energy Agency",
    year = "2008-2012",
    number = "IAEA-TECDOC-1697"
}

M. Limbäck and T. Andersson. A model for analysis of the effect of final annealing on the in- and out-of-reactor creep behavior of zircaloy cladding. In Zirconium in the Nuclear Industry: Eleventh International Symposium, ASTM STP 1295, 448–468. 1996.

@INPROCEEDINGS{Limback1996,
    author = {Limb{\"a}ck, M. and Andersson, T.},
    title = "A Model for Analysis of the Effect of Final Annealing on the In- and Out-of-Reactor Creep Behavior of Zircaloy Cladding",
    booktitle = "Zirconium in the Nuclear Industry: Eleventh International Symposium",
    year = "1996",
    series = "ASTM STP 1295",
    pages = "448-468"
}

G. Pastore, L.P. Swiler, J.D. Hales, S.R. Novascone, D.M. Perez, B.W. Spencer, L. Luzzi, P. Van Uffelen, and R.L. Williamson. Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling. Journal of Nuclear Materials, 465:398–408, 2015.

@ARTICLE{pastore_et_al_2015,
    author = "Pastore, G. and Swiler, L.P. and Hales, J.D. and Novascone, S.R. and Perez, D.M. and Spencer, B.W. and Luzzi, L. and Uffelen, P. Van and Williamson, R.L.",
    title = "Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling",
    journal = "Journal of Nuclear Materials",
    year = "2015",
    volume = "465",
    pages = "398-408"
}

Giovanni Pastore, L.P. Swiler, J.D. Hales, S.R. Novascone, D.M. Perez, B.W. Spencer, L. Luzzi, P. Van Uffelen, and R.L. Williamson. Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling. Journal of Nuclear Materials, 456:398–408, 2015. doi:10.1016/j.jnucmat.2014.09.077.

@article{PASTORE2015398,
    author = "Pastore, Giovanni and Swiler, L.P. and Hales, J.D. and Novascone, S.R. and Perez, D.M. and Spencer, B.W. and Luzzi, L. and {Van Uffelen}, P. and Williamson, R.L.",
    title = "Uncertainty and sensitivity analysis of fission gas behavior in engineering-scale fuel modeling",
    journal = "Journal of Nuclear Materials",
    volume = "456",
    pages = "398-408",
    year = "2015",
    issn = "0022-3115",
    doi = "10.1016/j.jnucmat.2014.09.077"
}

R. The Third RisøFission Gas Project: Bump Test AN8 (CB10). Technical Report Risø-FGP3-AN8, Risø, september 1990.

@techreport{riso3_an8,
    author = "R",
    title = "{The Third Ris\o Fission Gas Project: Bump Test AN8 (CB10)}",
    institution = "Ris\o",
    year = "1990",
    month = "september",
    number = "Ris\o-FGP3-AN8"
}

E. Sartori, J. Killeen, and J. A. Turnbull. International Fuel Performance Experiments (IFPE) Database. OECD-NEA, 2010, available at http://www.oecd-nea.org/science/fuel/ifpelst.html.

@misc{ifpe_database,
    author = "Sartori, E. and Killeen, J. and Turnbull, J. A.",
    title = "International {F}uel {P}erformance {E}xperiments ({IFPE}) {D}atabase",
    year = "",
    note = "{OECD-NEA}, 2010, available at http://www.oecd-nea.org/science/fuel/ifpelst.html"
}

Results Comparison
References
Overview
Test Description
Model Description
Input files