Correlation for steam–graphite reaction

•New correlation for graphite oxidation.•Improved accuracy of predicting steam–graphite reaction.•Analytical prediction of water ingress in HTR.

A review of available correlations for graphite oxidation by steam, relevant in case of water ingress accidents in HTR, was performed. Accuracy of the available correlation for the primary reaction was investigated by performing comparison with available data. A new correlation was proposed. The new correlation is an extension of the existing correlation of Kubaschewski–Heinrich, obtained by introducing a pressure dependent and burn-off dependent multiplier for best estimate as well as conservative calculations. The best estimate correlation shows significant improvement of accuracy when compared with the same data. The maximum error and applicability range of the best estimate correlation are provided.The maximum deviation of the new correlation results and experimental data is –27% and +15%, compared to the maximum deviations of –72% and +76%, found for the original correlation. The range of application of the correlation is: 1000 K÷1300 K, 105 Pa÷55 × 105 Pa total pressure and 14÷105 Pa steam partial pressure. The work presented in this paper was done within the ARCHER project.