# Activation Analyses of Disposal Options for Irradiated Be\({}_{12}\)Ti
## 4 Results of Activation Calculations  
### Activity of the Be\({}_{12}\)Ti in the HCPB Blankets  
The activation calculations for the Be\({}_{12}\)Ti blocks were performed in the IB and OB blanket modules of the HCPB DEMO to assess total activity and decay heat making use of the different Be\({}_{12}\)Ti material definitions, Table 4. The DEMO tokamak is made up of 16 toroidal segments including 2 IB, 2 OBL and 1 OBC blankets. The total mass of the Be\({}_{12}\)Ti in the HCPB DEMO, \(\sim\)600 tons, was calculated making use of the MCNP geometry model and the results for different blankets are listed in Table 5. This corresponds to \(\sim\)270 m\({}^{3}\) of Be\({}_{12}\)Ti in the HCPB DEMO tokamak. During the first phase of the DEMO operation (5.2 CY), the total activity of the Be\({}_{12}\)Ti accumulated in the HCPB OB blanket can achieve \(\sim\)5.52\(\cdot\)10\({}^{17}\) Bq in the central outboard blanket (Be\({}_{12}\)Ti max) right after the reactor shutdown, Figure 5. The spread of the results for the different material compositions, specified in Table 4, does not exceed \(\sim\)1% for cooling times up to 1 year. The activity of the Be\({}_{12}\)Ti drops down by a factor of \(\sim\)50 one day and by the factor of \(\sim\)500 one year after the shutdown of the reactor relative to the results right after the reactor shutdown. The difference of the results for the Be\({}_{12}\)Ti (max) and (min) is about the factor of 6 and 2 at the moments of 10 and 100 years after the reactor shutdown, respectively. The results do not include tritium activity assuming its full detritian after the shutdown. The uncertainty of the FISPACT inventory results was assessed only for the cooling phase and it amounts to 3% at the short cooling times (less than 1 year) and it is up to \(\sim\)10% for the cooling times exceeding 1 year. The representative results of the Be\({}_{12}\)Ti activity in the central outboard blanket (OBC) averaged over the Be\({}_{12}\)Ti volume for the cooling times from the shutdown to 100 years after are given in Table 6. The results discussed below in the text refer to the OBC blanket because the data for the lateral blanket are very close and the activity of the Be\({}_{12}\)Ti in the IB blanket is \(\sim\)1.8 times less compared to the results for the OB blankets. Figure 4: The DEMO operation scenario (1 st phase). \begin{table}
\begin{tabular}{c c c c} \hline
**IB Blanket** & **Central OB Blanket** & **Lateral OB Blanket** & **Total Reactor** \\ \hline
6.8 & 8.3 & 7.9 & **603.2** \\ \hline \end{tabular}
\end{table} 
Table 5: Total mass of Be\({}_{12}\)Ti in the HCPB DEMO blankets (tons). The tritium production in Be\({}_{12}\)Ti through \({}^{9}\)Be(n,r)\({}^{8}\)Li reaction represents a potential danger in the handling procedure of any irradiated material including pure beryllium. Due to zero retention at high-operation temperatures [18], tritium is assumed to be removed from the Be\({}_{12}\)Ti blocks with the He purge gas in the HCPB blanket [3] and therefore tritium activity is not accounted for in the present results (the results are nevertheless available). The tritium generation due to the fusion neutron irradiation of Ti is negligible and does not noticeably affect the activation of the Be\({}_{12}\)Ti. The tritium retention in the Be\({}_{12}\)Ti tends to be zero at temperatures above 600 \({}^{\circ}\)C and it goes up at lower temperatures [18]. The current HCPB blanket layout assumes that the Be\({}_{12}\)Ti block is warmed up to \(\sim\)800 \({}^{\circ}\)C in the regions close to the first wall and up to \(\sim\)530 \({}^{\circ}\)C in the rear part of the breeder zone [3]. Due to an uncertainty of the experimental data [18], it is likely that some parts of the Be\({}_{12}\)Ti assembly with not high enough temperatures could theoretically retain some tritium amount. This option is not considered in the current work.