Academia.eduAcademia.edu

Figure 1 – uploaded by Lelio Luzzi

See full PDFdownloadDownload figure
Figure 1: Left: Experimental data for the temperature of maximum burst release rate from Une and Kashibe [13], Baker and Killeen [37] and Small [38] as a function of burnup and best-estimate fitting curve. Right: Micro-cracking parameter, m, and temperature derivative, dm/dT, as a function of temperature. The asymptotic value of 1773 K for the inflection temperature is considered for this plot.

Figure 1 Left: Experimental data for the temperature of maximum burst release rate from Une and Kashibe [13], Baker and Killeen [37] and Small [38] as a function of burnup and best-estimate fitting curve. Right: Micro-cracking parameter, m, and temperature derivative, dm/dT, as a function of temperature. The asymptotic value of 1773 K for the inflection temperature is considered for this plot.

Related Figures (8)

Table 1: Definitions and analytic expressions of the relative sensitivity coefficients defined in this analysis. The analytic expressions can be derived by differentiation from Eqs. 3, 4 and 6. Figure 2: Results of the analytic sensitivity analysis of the transient model. (a) Bar plot reporting the upper, mean and lower value of the relative sensitivity coefficients analysed over the temperature-burnup range of [300, 2300 K] x [0, 80 GWdtu~']. (b) Detailed temperature-burnup 2D map of the relative sensitivity coefficient associated with the inflection temperature. The dashed line represents the inflection temperature as a function of burnup. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.
Table 1: Definitions and analytic expressions of the relative sensitivity coefficients defined in this analysis. The analytic expressions can be derived by differentiation from Eqs. 3, 4 and 6. Figure 2: Results of the analytic sensitivity analysis of the transient model. (a) Bar plot reporting the upper, mean and lower value of the relative sensitivity coefficients analysed over the temperature-burnup range of [300, 2300 K] x [0, 80 GWdtu~']. (b) Detailed temperature-burnup 2D map of the relative sensitivity coefficient associated with the inflection temperature. The dashed line represents the inflection temperature as a function of burnup. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.
Table 2: Summary of the irradiation experiments from the OECD/NEA IFPE database [15] analysed in this work. lated each fuel rod with both the BISON and TRANSU- RANUS codes. Also, each fuel rod is analysed both using the canonical diffusion-based models (Section 2.1) alone and with the transient (burst release) model extension ap- plied. First, in Section 6.1, detailed results for two selected 6. Results and discussion
Table 2: Summary of the irradiation experiments from the OECD/NEA IFPE database [15] analysed in this work. lated each fuel rod with both the BISON and TRANSU- RANUS codes. Also, each fuel rod is analysed both using the canonical diffusion-based models (Section 2.1) alone and with the transient (burst release) model extension ap- plied. First, in Section 6.1, detailed results for two selected 6. Results and discussion
Figure 3: (a) Example of BISON 2D finite-element mesh employed in this work, and (b) representation of TRANSURANUS mesh (not to scale).
Figure 3: (a) Example of BISON 2D finite-element mesh employed in this work, and (b) representation of TRANSURANUS mesh (not to scale).
Figure 4: FGR and fuel central temperature as a function of time for the AN3 fuel rod during the ramp test. Experimental measurements are compared to calculations with BISON (left) and TRANSURANUS (right). FGR results obtained with (w/) and without (w/o) the transient model applied are presented. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article. the retained gas concentration. This affects (reduces) lo- cal fuel gaseous swelling and leads to a corresponding in- crease in FGR. In general, a good agreement is observed between the calculated and the measured xenon concen- tration profiles, although some discrepancies are observed. These may be ascribed to uncertainties inherent in fission gas behaviour modelling [30], as well as uncertainties in the measured concentrations, which are associated with the experimental technique [48]. For both codes, the tran- with the canonical diffusion-based models and with the transient model extension applied, are illustrated in Fig. 6. The plots showcase local gas retention in the fuel, which is coupled to gas release, as reproduced by the fission gas behaviour models in the codes. Direct modelling of the physical mechanisms of fission gas diffusion and bubble evolution underlies calculated concentrations [30,32]. The transient model acts on such physical representation in- troducing a reduction, dependent on local conditions, of
Figure 4: FGR and fuel central temperature as a function of time for the AN3 fuel rod during the ramp test. Experimental measurements are compared to calculations with BISON (left) and TRANSURANUS (right). FGR results obtained with (w/) and without (w/o) the transient model applied are presented. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article. the retained gas concentration. This affects (reduces) lo- cal fuel gaseous swelling and leads to a corresponding in- crease in FGR. In general, a good agreement is observed between the calculated and the measured xenon concen- tration profiles, although some discrepancies are observed. These may be ascribed to uncertainties inherent in fission gas behaviour modelling [30], as well as uncertainties in the measured concentrations, which are associated with the experimental technique [48]. For both codes, the tran- with the canonical diffusion-based models and with the transient model extension applied, are illustrated in Fig. 6. The plots showcase local gas retention in the fuel, which is coupled to gas release, as reproduced by the fission gas behaviour models in the codes. Direct modelling of the physical mechanisms of fission gas diffusion and bubble evolution underlies calculated concentrations [30,32]. The transient model acts on such physical representation in- troducing a reduction, dependent on local conditions, of
Figure 5: FGR and fuel central temperature as a function of time for the AN4 fuel rod during the ramp test. Experimental measurements are compared to calculations with BISON (left) and TRANSURANUS (right). FGR results obtained with (w/) and without (w/o) the transient model applied are presented. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.
Figure 5: FGR and fuel central temperature as a function of time for the AN4 fuel rod during the ramp test. Experimental measurements are compared to calculations with BISON (left) and TRANSURANUS (right). FGR results obtained with (w/) and without (w/o) the transient model applied are presented. For interpretation of the references to colour in this figure legend, the reader is referred to the web version of the article.
Table 3: Summary of integral FGR results obtained with BISON and TRANSURANUS for the fuel rod irradiation experiments analysed in this work. sient model tends to improve the results compared to the canonical model. For the TRANSURANUS calculation with the canonical model, a higher amount of gas is stored in the fuel inner region compared to the BISON calcula- tion. This is consistent with the differences in calculated FGR mentioned above. As discussed, such different be-
Table 3: Summary of integral FGR results obtained with BISON and TRANSURANUS for the fuel rod irradiation experiments analysed in this work. sient model tends to improve the results compared to the canonical model. For the TRANSURANUS calculation with the canonical model, a higher amount of gas is stored in the fuel inner region compared to the BISON calcula- tion. This is consistent with the differences in calculated FGR mentioned above. As discussed, such different be-
Figure 6: Radial profiles of xenon concentration in the CB-2R-5 fuel sample from the AN3 rod. Experimental data are compared tc calculations with BISON (left) and TRANSURANUS (right). Since the experimental data were measured along the fuel diameter but our calculations are axially symmetric, we define a positive and a negative radius in reporting measurements. The origin is assumed in the centre of the pellet. The red region represents the potential HBS formation zone, which is not accounted for ir the simulation and for which the comparison is less meaningful. For interpretation of the references to colour in this figure legend the reader is referred to the web version of the article.
Figure 6: Radial profiles of xenon concentration in the CB-2R-5 fuel sample from the AN3 rod. Experimental data are compared tc calculations with BISON (left) and TRANSURANUS (right). Since the experimental data were measured along the fuel diameter but our calculations are axially symmetric, we define a positive and a negative radius in reporting measurements. The origin is assumed in the centre of the pellet. The red region represents the potential HBS formation zone, which is not accounted for ir the simulation and for which the comparison is less meaningful. For interpretation of the references to colour in this figure legend the reader is referred to the web version of the article.
Figure 7: Simulation results of integral FGR at the end of irradiation from BISON (left) and TRANSURANUS (right) compared to experimental data. Each data point corresponds to one of the 19 irradiation experiments from the OECD/NEA IFPE database analysed in this work. The open symbols represent the results obtained with the canonical models, whereas the full symbols are the results obtained with the transient model applied. The distance from the 45° line is a measure of the accuracy. Dashed lines correspond to deviations of a factor of 2 from measured data [30].
Figure 7: Simulation results of integral FGR at the end of irradiation from BISON (left) and TRANSURANUS (right) compared to experimental data. Each data point corresponds to one of the 19 irradiation experiments from the OECD/NEA IFPE database analysed in this work. The open symbols represent the results obtained with the canonical models, whereas the full symbols are the results obtained with the transient model applied. The distance from the 45° line is a measure of the accuracy. Dashed lines correspond to deviations of a factor of 2 from measured data [30].
Related topics:
Materials EngineeringMaterials ScienceNuclear MaterialsFission Gas ReleaseTRANSURANUS codeFission gasFuel performance codes
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved