Insight into the structural integrity assessment of the European DEMO fusion reactor divertor (Part II: Application examples)

• The European DEMO divertor, its development and its structural integrity assessment. • P type and S Type checks, Insights into the RCC MRx code of standards. • Structural integrity code rules interpretation. The DEMO fusion reactor Divertor design group within the EUROfusion consortium use RCC-MRx as the main analysis code for the Divertor's structural integrity assessment. Analysis has been carried out within the same group using an in-house developed Finite Element Analysis post processing script which follows the Design by Elastic Analysis rules of RCC MRx. A number of stress classification lines (SCLs) were placed in the Divertor component regions which are susceptible to Type P and Type S damage. This paper focuses on two of these stress classification lines. One is located in the region of a stress singularity while the other is in a region of high stress where the temperature is above the creep threshold along part of the SCL. Design by Analysis was performed using a spreadsheet application. The purpose was to highlight difficulties encountered in using the RCC-MRx elastic design methodology applied to the DEMO divertor. Issues mainly arose because of stress singularities in the geometry, because of the inherent non-axisymmetric geometry and loading of the divertor and because of limited material data for Eurofer97 steel which is the main material used for the DEMO Divertor. This paper is Part II of a companion paper and compliments it by considering the two SCLs as application examples and case studies. In the companion paper (Part I), general discussions on the difficulties and issues encountered are presented including some theoretical background on the phenomenon of elastic follow up and on Neuber's hyperbola rule that addresses plasticity and stress relaxation. An additional outcome of this work emphasises the need to further develop the in-house Finite Element Analysis post processing script and to incorporate within it best practice in implementing the RCC-MRx Design by Elastic Analysis rules for the Divertor components. The post processing tool development would improve the assessment reliability and productivity in order to suggest timely Divertor design modifications.