Evaluation of the breeding material activation and radionuclide inventory analysis for EU DEMO.

• MCNP and FISAPCT-II tools were used. • WCLL activity densities at the 1st second of shutdown reach 5.02e16 Bq/m3 and, after 1000 years, decrease to 2.53e10 Bq/m3. • HCPB activity densities at the 1st second of shutdown reached 2.80e16 Bq/m3 and, after 1000 years, decreased to 5.60e9 Bq/m3. • Decay heat values for HCPB and WCLL decreased from 20.6 kW/m3 to 0.0352 µW/m3 and 11.9 kW/m3 to 0.622 µW/m3. • The primary radionuclides contributing to the dose rate values are 16N and 207mPb at the beginning, while at the end of the observation period - 26Al and 205Pb. The Breeding Blanket (BB) is a crucial component in the EU DEMO Fusion Reactor. It has three main important functions: ensuring the thermal power deposition and consequent efficient extraction to achieve a positive net electrical power generation, guaranteeing adequate radiation shielding for personnel and sensible devices working in the Plant, and self-production of enough Tritium to fulfill the reactor self-sufficiency. In past studies, four blanket concepts have been investigated to support achieving these goals. Breeding blanket designs primarily revolve around lithium-containing ceramics, focusing on lithium-orthosilicate and lithium-lead. During the pre-conceptual phase, two blanket options were selected as driven concepts: HCPB (Helium-Cooled Pebble Bed) and WCLL (Water-Cooled Lithium Lead). The HCPB concept employs lithium orthosilicate ceramic pebble beds with lithium titanium oxide as the breeding material. Hexagonal blocks with Be12Ti are positioned around the breeding material tubes and act as the neutron multiplier. In the case of the WCLL concept, LiPb is used as both the breeding material and the neutron multiplier. Safety is a top priority in the EU DEMO project, and the approach to evaluating potential activities and doses to workers and the environment reflects this commitment. This study presents neutron flux and specific activity calculations for the EU DEMO breeding materials. The MCNP6 (Monte Carlo N-Particles) was harnessed to estimate neutron spectra in the blanket's breeding material, while the FISPACT-II code was meticulously employed for activation calculations. The nuclear data libraries FENDL 3.2 and TENDL - 2017 were used for transport and activation calculations, respectively, ensuring the highest level of accuracy and reliability in our findings. [ABSTRACT FROM AUTHOR]