Corrigendum to “REGAL International Program: Analysis of experimental data for depletion code validation” [Ann. Nucl. Energy 172 (2022) 109057](S0306454922000925)(10.1016/j.anucene.2022.109057)

In the original submission of this paper, comparison between the calculated and experimental nuclide inventory of UO₂ and (U, Gd)O₂ fuel rod samples was presented [1]. The experimental analysis of the Gd inventory was recently found to be biased on the two isotopes of interest, ¹⁵⁵Gd and ¹⁵⁷Gd, which were both close to full depletion in the (U, Gd)O₂ sample discussed in the paper. The analysis of the Gd isotopic inventory was performed by Isotope Dilution Thermal Ionization Mass Spectrometry (ID-TIMS) after column separation of fission generated lanthanides which could isobarically interfere with the isotopes of interest. Gadolinium was analysed using its monoxide ion signals (GdO⁺), while TIMS analyses of the other elements were performed on the metal ion signals (M⁺). The reason for this relates back to the original TIMS method development at SCK CEN and has been applied as such for decades: measurements on the direct Gd metal ion signals were often unstable, hence the choice to measure Gd at its monoxide GdO⁺ ion masses. The gadolinium vector (Gd-152 to Gd-160) was thus measured on masses 168 to 176. The data processing, however, did not originally include corrections for the isotopes of oxygen ([¹⁶O] = 0.99757(16), [¹⁷O] = 0.00038(1), [¹⁸O] = 0.00205(14)) [2]. When deep burnout is reached on isotopes ¹⁵⁵Gd and ¹⁵⁷Gd, interference of the ¹⁵⁵Gd¹⁶O monoxide signal at mass 171 due to ¹⁵⁴Gd¹⁷O and of the ¹⁵⁷Gd¹⁶O signal at mass 173 due to ¹⁵⁶Gd¹⁷O become significant. The interference on mass 173 due to ¹⁵⁵Gd¹⁸O remains negligible since ¹⁵⁵Gd is present in low concentrations only. As the effect of the minor oxygen isotopes was not taken into account in the experimental analysis, the isotopic abundances of both ¹⁵⁵Gd and ¹⁵⁷Gd were overestimated. For ¹⁵⁵Gd, the overestimation was 5.6%, and for ¹⁵⁷Gd, the overestimation was 60%. Concentrations of other nuclides remained unaffected as they were analysed on the metal ion (M⁺) signal. In the original paper, comparison between calculated and experimental nuclide concentrations were reported for several codes and code-library combinations [1]. For the ¹⁵⁵Gd and ¹⁵⁷Gd isotopes, the C/E – 1 values showed a systematic bias with of 6.4% and 60%, respectively. When performing the same assessment using the ¹⁵⁵Gd and ¹⁵⁷Gd concentrations properly corrected for the oxygen isotope effect, the systematic bias disappears. For ¹⁵⁵Gd, deviations are of the same order of magnitude as the experimental uncertainty (3.4% at 2 sigma) for all codes. The experimental uncertainty of ¹⁵⁷Gd is larger (8.4% at 2 sigma), and most codes calculate the measured ¹⁵⁷Gd concentration reasonably well. Only the WIMS code, in combination with the ENDF/B VII.1 library, has a significant deviation for ¹⁵⁷Gd. Table 4 and Figure 7 of the original publication are revised. For completeness, the entire Table 4 and complete Figure 4 are reproduced, but only the experimental values for the two gadolinium nuclides, ¹⁵⁵Gd and ¹⁵⁷Gd have changed. A paper on the experimental methodology is under preparation. Table 4. Comparison of code predictions to experimental measurements for the E14 sample, expressed in percentage as C/E–1 with C the calculated value (per code) and E the experimental value in g/g_fuel. The nuclide ‘‘Fissile” is the sum of U-235, Pu-239, and Pu-241. [Table presented][Formula presented] Fig. 1 Comparison of code predictions to experimental measurements for the E14 sample, expressed in percentage as C/E–1 with C the calculated value (per code) and E the experimental value in g/g_fuel. Due to the large discrepancy, the C/E–1 value for the WIMS code for Gd-157 is outside of the scale shown. The error bars represent the uncertainty (2 sigma) of the experimental data. References [1] J. Eysermans, M. Verwerft, K. Govers, R. Ichou, G. Ilas, U. Meryturek, N. Messaoudi, P. Romojaro, N. Slosse, REGAL International Program: Analysis of experimental data for depletion code validation, Annals of Nuclear Energy 2022, 172. [2] J.S. Coursey, D.J. Schwab, J.J. Tsai, R.A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1). [Online] Available: http://physics.nist.gov/Comp 2015. (Accessed 2023-05-31 2023). The authors would like to apologise for any inconvenience caused.