## 3 Nuclear Analyses
### Summary of the Nuclear Load's Spatial Distributions Analyses

Table 8: Maximum and minimum values and related position (in terms of row (R) and column (C) of the array) of nuclear heating density (W/cm\({}^{3}\)), nuclear damage (dpa/FPY), He-production (appm/FPY) on the PFCs of the HCPB inner target. \begin{table}
\begin{tabular}{c c c c c c} \hline  & \multicolumn{5}{c}{**HCPB–Outer Target**} \\ \hline Nuclear heating & \multicolumn{2}{c}{W monoblocks} & \multicolumn{2}{c}{Cu/CuCrZr components} & \multicolumn{2}{c}{Eurofer PFC-CB supports} \\ \cline{2-5} (W/cm\({}^{3}\)) & Value & R \(\times\) C & Value & R \(\times\) C & Value & R \(\times\) C \\ \hline Max. & 19.00 & \(\begin{array}{c}47\times 1\\ 47\times 43\end{array}\) & 7.66 & \(\begin{array}{c}52\times 1\\ 52\times 43\end{array}\) & 6.12 & \(\begin{array}{c}11\times 1\\ 11\times 43\end{array}\) \\ \hline Min. & 7.84 & \(4\times 22\) & 2.48 & \(1\times 22\) & 1.62 & \(2\times 22\) \\ \hline Nuclear damage & \multicolumn{2}{c}{W-Monoblocks} & \multicolumn{2}{c}{Cu/CuCrZr components} & \multicolumn{2}{c}{Eurofer—PFC-CB supports} \\ \cline{2-5} (dpa/FPY) & \multicolumn{2}{c}{W-Monoblocks} & \multicolumn{2}{c}{Cu/CuCrZr components} & \multicolumn{2}{c}{Eurofer—PFC-CB supports} \\ \hline Max. & 1.84 & \(\begin{array}{c}53\times 1\\ 53\times 43\end{array}\) & 7.22 & \(\begin{array}{c}53\times 1\\ 53\times 43\end{array}\) & 4.41 & \(\begin{array}{c}11\times 1\\ 11\times 43\end{array}\) \\ \hline Min. & 0.39 & \(1\times 22\) & 1.28 & \(1\times 22\) & 0.68 & \(1\times 22\) \\ \hline He-production & \multicolumn{2}{c}{W-Monoblocks} & \multicolumn{2}{c}{Cu/CuCrZr components} & \multicolumn{2}{c}{Eurofer—PFC-CB supports} \\ \cline{2-5} (appm/FPY) & \multicolumn{2}{c}{W-Monoblocks} & \multicolumn{2}{c}{Cu/CuCrZr components} & \multicolumn{2}{c}{Eurofer—PFC-CB supports} \\ \hline Max. & 1.90 & \(\begin{array}{c}53\times 1\\ 53\times 43\end{array}\) & 56.28 & \(\begin{array}{c}54\times 1\\ 54\times 43\end{array}\) & 55.81 & \(\begin{array}{c}11\times 1\\ 11\times 43\end{array}\) \\ \hline Min. & 0.37 & \(1\times 22\) & 8.14 & \(1\times 22\) & 8.50 & \(1\times 22\) \\ \hline \end{tabular}
\end{table} 
Table 9: Maximum and minimum values and related position (in terms of row (R) and column (C) of the array) of nuclear heating density (W/cm\({}^{3}\)), nuclear damage (dpa/FPY), He-production (appm/FPY) on the PFCs of the HCPB outer target. * The thermal load achieves its peak values (10-20 MW/m\({}^{2}\) as stationary heat load and during slow transient events [2; 6; 7; 10; 11; 12]) in the lower part of the straight leg of the vertical target (strike zone) as shown in Figure 30; on the contrary, as outlined in this study, the neutron irradiation is maximum on the top part of the target (baffle region). This represents an important aspect for the engineering and technological design of the DEMO divertor targets, being the peak values of the two main and demanding loads (thermal and nuclear) not superimposed. Although, during the divertor project phase, a conservative approach can be chosen (overlapping the two peaks), during the operation phase, it is expected that the most loaded PFCs in terms of thermal power do not correspond to those with the highest irradiation dose. * As specified in the introduction, nuclear damage represents one of the main and most critical primary irradiation effects, which can seriously affect the secondary material's responses in terms of physical, chemical and thermo-mechanical properties, thus leading as a last step, to a significant impact on the PFCs structural integrity, if neutron irradiation is considered. In this regard, the limit values for the damage in Eurofer used in the shielding block, as well as in the structural components of the divertor CB and CuCrZr in PFCs, are under evaluation and the following values can be currently considered as reference: 6 dpa for Eurofer and 10-20 dpa for CuCrZr, both at the End-Of-Life (EOL), which is expected to be 1.5 FPY as foreseen design value and at least included in the acceptable range of 0.8-2 FPY [6; 7; 10; 11; 12].