Assessing the durability of nuclear plant elements under high‑frequency broadband loading

Due to the current standards providing failing to account for the entire spectrum of loading amplitudes under broadband vibration exposure, durability can be significantly overestimated. The consideration of several harmonics in isolation is insufficient to evaluate actual maximum values and loading amplitudes, which are determined by integrating the spectral density depending on the interval width ∆f. Based on the damageability equivalence principle, a method for reducing broadband exposure to a harmonic equivalent is proposed taking into account the slope of the fatigue curve in the area with the number of cycles exceeding 10⁷. A comparison of equivalent loading parameters obtained using the proposed approach with a shadow-method schematization demonstrated satisfactory results.