Experimental and computational synergy for modelling an advanced gas‐cooled reactor core under seismic excitation

Abstract

Summary The advanced gas‐cooled reactors (AGRs) are the backbone of the United Kingdom's nuclear generation fleet, producing approximately 17% of the country's electricity. Their safety cases are supported by thorough inspection and monitoring of their graphite cores and extensive theoretical, analytical, and experimental studies. This paper presents a unique, highly innovative and technically challenging earthquake engineering project that has provided vital evidence to underpin the seismic safety assessments of the AGRs. Two modelling approaches, one experimental (a multilayer array physical model), and one numerical (a SOLFEC nonsmooth contact dynamics computational model) have been developed to investigate the seismic behaviour of an aged graphite core. The synergetic relationship between the two approaches is a product of insightful collaborative learning between the University of Bristol and Atkins, with the experiments providing material parameters and validation data and the computer simulations feeding array design and test schedule recommendations to the physical model. The predictive capabilities of the physical and the numerical models are tested by direct comparison and the good agreement between the results has increased the confidence in both. The model's versatility allows a variety of core scenarios to be tested that can explore in detail the AGR core behaviour in seismic conditions.

A mathematical framework for evaluation of column shape profiles for an advanced gas-cooled reactor core model subject to seismic excitation

“…The MLA is a quartersized AGR-core like structure consisting of 8 layers of 20 bricks arranged to match the octagonal layout of an AGR core (Dihoru, 2017). Significant experimental testing, modelling and analysis has been employed over the past decade on the MLA core model (Dihoru et al, 2020(Dihoru et al, , 2019(Dihoru et al, , 2018. For this testing the MLA model (Figure 1) was mounted onto the shaking table at the University of Bristol and subjected to a range of seismic and harmonic input motions to investigate the response of the array to different seismic events.…”