The Seismic Engineering Subgroup of the NEA Working Group on Integrity and Ageing of Components and Structures (WGIAGE) will organise the Workshop to share the current state of practice in Seismic Input Motion Development (SIMD), raise awareness of the need for power spectral density (PSD) checks in the varying SIMD practices, discuss perspectives and recommendations on integrating Response Spectra(RS)-matching with PSD checks, and explore future activities to complement RS with PSD or other best practices in all aspects of seismic engineering. Through a series of presentations and panel discussions, participants will gain valuable insights into the technical rationale on PSD checks and important intensity measures, and how they affect various types of seismic analyses and seismic risk assessments. The workshop will promote international uniformity and efficiency, particularly in supporting advanced reactor designs for which licenses may be pursued in multiple countries. Many of these designs involve innovative systems such as seismic isolators, graphite fuel pebbles, and water pools and other fluid systems that behave in the nonlinear regime during strong earthquakes.