Multi-head attention network for prediction of irradiation embrittlement in reactor pressure vessel steels
摘要
The accurate prediction of irradiation embrittlement in reactor pressure vessel (RPV) steel remains challenging. Here, we develop a multi-head attention network (MHANet) and target the service-relevant shift in ductile-brittle transition temperature (ΔDBTT) co-varying with temperature, flux, and fluence. MHANet treats each input column as a token, learns feature dependencies via attention, and yields accurate predictions with transparent attribution. Trained/validated on 1266 IVAR+NUREG samples, MHANet achieves MAE of 5.63 ∘C(IVAR) and 16.21 ∘C (NUREG), and outperforms a baseline multilayer perceptron model. The learned dependencies are found to be physically consistent with the coupled effects by which ΔDBTT is governed, including point defects, solute-defect interactions (particularly involving Cu, Ni, and P), and irradiation-induced precipitation. (i) a higher temperature mitigates embrittlement; (ii) at a fixed fluence, the reduction in ΔDBTT with increasing flux is attributed to the competition between steady-state defect concentrations and the available evolution time; (iii) threshold-like synergies emerge-ΔDBTT increases sharply when Ni ≈ 0.9–1.1 wt.% and Cu (≥0.10 wt.%) or P is elevated. These results provide a coherent path from data-driven prediction to mechanism-aware interpretation and actionable criteria for RPV life assessment and alloy design.