## 5 Results of the Inventory Calculations  
A spatial accumulation of the radioactive isotopes in the rods along the radial direction was assessed for each radioactive isotope specified in Section 2.2, making use of the computational technique and irradiation scenarios discussed above. The maximum isotope production rate is expected in the radial segment of the rods adjacent or close to the plasma-faced supporting grid. The accumulated activity of the isotopes in the different locations in the rod depends on the radial coordinate of the segment or capsule. The efficiency of the isotope production in the irradiation port of the DEMO can be assessed by the comparison of the activity produced in the rods with the reference data discussed above (see Section 2.3). These reference data refer to the actual isotope production efficiency of the available commercial reactors; therefore, they represent the typical average isotope activity that is consumed on the world market. The spread of the specific activities over the reference value that can be utilized in the industry is significant. To keep a very conservative approach, the minimum value of the specific activity that could find an application and consumption in the medicine and industry is assumed to be \(\sim\)10% from the reference value. Activity levels above the reference value have a very high potential for the practical applications because it allows the use of very compact radioactive sources. This approach is used for the assessment of the commercial yield of the radioactive isotopes in the DEMO irradiation unit. Nevertheless, the total isotope yields in the rods were calculated as well. No optimization of the isotopes production, that is, a variation of the geometry layouts and the irradiation duration, was implemented because the scope of the work was to demonstrate the principal capability of the radioactive isotopes production in the DEMO. Shown in Figure 6 are the results for the production of \({}^{99}\)Mo and \({}^{192}\)Ir isotopes: the peak production in the front 5 cm part of the rod and the radial distribution of the isotope accumulation in the rods. The reference values of the typical isotope production are also given for the assessment of the commercial radioactive isotope yields. In both cases, the irradiation campaign amounts to 10 days (240 h) of the DEMO pulse irradiation, and the total number of the feasible campaigns is 11 per calendar year, assuming 30% of the total facility availability. The commercial yield is an integral of the production within 0-35 cm and 0-90 cm of the radial depth in the rods in the case of the \({}^{99}\)Mo and \({}^{192}\)Ir isotopes production, respectively. In these locations, the specific activity is higher than or equal to 10% of the reference activity level. The maximum specific activity of the \({}^{99}\)Mo achieved at the end of one irradiation campaign within the first 5 cm of the irradiation rods can reach 1.2 \(\times\) 10\({}^{10}\) Bq/g, which corresponds the maximum yield of 3.32 \(\times\) 10\({}^{2}\) TBq in all rods and cassettes. A so-called _six-day activity_ (the activity after 6 days of the decay) often applied for the \({}^{99}\)Mo production is 4.40 \(\times\) 10\({}^{1}\) TBq (\(\sim\)1200 Ci) and the commercial yield is 1.40 \(\times\) 10\({}^{2}\) TBq (\(\sim\)3800 Ci) per one irradiation campaign of 10 days. The maximum production rate per 10-day irradiation period is \(\sim\)60% of production in the Opal one (\(\sim\)2200 six-days Ci, see Section 2.2) having 15% of the world's market. The maximum specific activity of the \({}^{192}\)Ir that can be reached in the port is 6.0 \(\times\) 10\({}^{11}\) Bq/g  
Figure 5: Irradiation scenarios considered in the assessment of the production of short-lived isotopes (**a**), and long-lived isotope \({}^{60}\)Co (**b**). and the maximum yield is 3.00 \(\times\) 10\({}^{1}\) TBq. The commercial yield in this case amounts to 1.92 \(\times\) 10\({}^{2}\) TBq.