## 5 Conclusions  
In the frame of the European DEMO BB research activities, a study was carried out with the aim of investigating the thermomechanical performances of the DEMO WCLL COB under NO, UVDE and OP steady state loading scenarios, ensuring the fulfilment of the thermal and structural design requirements, the latter represented by the RCC-MRx structural design criteria. Once the cooling scheme from the thermal point of view was optimized, structural analyses were performed. All the assessed scenarios showed a similar displacements field, with an evident radial displacement in the equatorial region, suggesting a revision of the attachment system to limit the displacement in this direction of the structure. Concerning the fulfillment of the criteria of RCC-MRx design code, not all the criteria were fulfilled in the paths taken into consideration and, especially, the criterion considering the secondary stresses, namely, the Immediate Plastic Flow Localization, probably due to the resistance exerted by the SPs against the thermal expansion. Moreover, as the SB channels were not modelled due to the modelling assumption, no path was investigated within the highly stressed FW-SW region. The present study concludes that the optimized WCLL COB segment geometric layout is also promising from the structural point of view, even though further analyses are necessary in order to study in detail the structural behaviour of the FW-SW region at \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**UVDE (t = 11.585 s)**} \\ \hline  & **Tave [\({}^{\circ}\)C]** & **Pm/Sm** & \begin{tabular}{c} **(Pm +** \\ Pb)/(Keff-Sm)** \\ \end{tabular} & \
\begin{tabular}{c} **(Pm +** \\ Qm)/Sem** \\ \end{tabular} &
\begin{tabular}{c} **(Pm + Pb +** \\ Q + F)/Set** \\ \end{tabular} \\ \hline SPv1,mid & 346.0 & 0.273 & 0.182 & 0.553 & 0.1326 \\ SPv2,mid & 519.3 & 0.337 & 0.237 & 1.739 & 0.246 \\ SPh1,mid & 435.6 & 0.155 & 0.104 & 0.489 & 0.088 \\ SPh2,mid & 473.0 & 0.155 & 0.146 & 0.615 & 0.104 \\ SPv1,top & 325.4 & 0.291 & 0.195 & 0.263 & 0.063 \\ SPv2,top & 462.6 & 0.402 & 0.273 & 1.063 & 0.179 \\ SPh1,top & 400.6 & 0.076 & 0.060 & 0.865 & 0.182 \\ SPh2,top & 458.8 & 0.187 & 0.149 & 0.653 & 0.108 \\ SPv1,bot & 339.2 & 0.088 & 0.059 & 0.177 & 0.042 \\ SPv2,bot & 503.7 & 0.105 & 0.070 & 1.185 & 0.175 \\ SPh1,bot & 430.0 & 0.092 & 0.082 & 0.674 & 0.138 \\ SPh2,bot & 478.1 & 0.080 & 0.057 & 0.750 & 0.126 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Verification of RCC-MRx criteria under UVDE (t = 11.52 s) loading scenario. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**UVDE (t = 11.585 s)**} \\ \hline  & **Tave [\({}^{\circ}\)C]** & **Pm/Sm** & \begin{tabular}{c} **(Pm +** \\ Pb)/(Keff-Sm)** \\ \end{tabular} & \
\begin{tabular}{c} **(Pm +** \\ Qm)/Sem** \\ \end{tabular} &
\begin{tabular}{c} **(Pm + Pb +** \\ Q + F)/Set** \\ \end{tabular} \\ \hline SPv1,mid & 346.0 & 0.292 & 0.199 & 0.542 & 0.130 \\ SPv2,mid & 519.3 & 0.411 & 0.318 & 1.706 & 0.245 \\ SPh1,mid & 435.6 & 0.136 & 0.097 & 0.480 & 0.087 \\ SPh2,mid & 473.0 & 0.146 & 0.218 & 0.612 & 0.111 \\ SPv1,top & 325.4 & 0.322 & 0.217 & 0.281 & 0.068 \\ SPv2,top & 462.6 & 0.511 & 0.356 & 1.094 & 0.184 \\ SPh1,top & 400.6 & 0.085 & 0.064 & 0.865 & 0.182 \\ SPh2,top & 458.8 & 0.165 & 0.151 & 0.666 & 0.111 \\ SPv1,bot & 339.2 & 0.044 & 0.030 & 0.199 & 0.048 \\ SPv2,bot & 503.7 & 0.051 & 0.035 & 1.250 & 0.185 \\ SPh1,bot & 430.0 & 0.129 & 0.114 & 0.668 & 0.139 \\ SPh2,bot & 478.1 & 0.045 & 0.059 & 0.704 & 0.120 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Verification of RCC-MRx criteria under UVDE (t = 11.585 s) loading scenario. different poloidal height of the COB segment, possibly adopting an updated version of the attachment system. Conceptualization, I.C., G.B. and P.A.D.M. ; methodology, I.C., G.B. and P.A.D.M. ; formal analysis, I.C., G.B. and P.A.D.M. ; investigation, I.C. and G.B. ; resources, I.C., G.B. and P.A.D.M. ; data curation, I.C. and G.B. ; writing--original draft preparation, I.C. and G.B.