Ponente
Descripción
Neutronics analyses performed in this work continue the task of neutron spectra assessments [1] inside the Complementary Experiments Room (CER) collimated by the Neutron Beam Tube and Shutter (NBT&S) system. The NBT&S system is developed to supply neutrons from the D-Li target of the IFMIF-DONES Test Cell (TC) to the CER (Room R160) for conducting experiments with neutron spectra variated from fast to thermal. The variants of employing one or two D+ ions IFMIF-DONES accelerators of continuous beams with the 125 mA or 250 mA currents correspondingly have been studied. The diameter of the NBT&S collimated continuous neutron beam is 15 cm, the length of collimation inside the Removable Biological Shielding Block (RBSB) and the Bucket is 6.6 m. At the exit of NBT&S to CER, the total neutron flux equals 2.15e+10 n/cm2/s, and 88% of that value (1.90e+10 n/cm2/s) is attributed to a fast flux with energy above 0.5 MeV. To make it thermal, moderator blocks made of Polyethylene (PE) are set along the beam line inside the CER. According [1], open NBT&S results in Red (forbidden) radiation zone with the Dose Rate (DR) above 1e5 microSv/h inside CER, by closing the shutter, the DR drops below 1e3 microSv/h, making CER the Yellow (limited regulated) radiation zone.
For more effective use of neutrons and to test tritium breeding materials at the DEMO blanket conditions in IFMIF-DONES, it is proposed in this work to place the irradiated breeding materials close to the D-Li neutron source, where the materials get the highest neutron loads and, therefore, the space is most valuable for materials irradiation. Such space has been found behind the High Flux Test Module (HFTM), in the region of the Medium Flux Test Module (MFTM) of IFMIF. It is proposed to adapt the detailed engineering design of the Tritium Release Test Module (TRTM) developed at the EVEDA phase to the needs of the IFMIF-DONES. The TRTM design [2] has been used in the creation of the MCNP 3D neutronics model [3]. The TRTM neutronics model has been optimized for the irradiation conditions close to the European HCPB DEMO tritium breeding blanket [3], concerning the nuclear responses such as displacements per atom (dpa), tritium, and helium production. Therefore, the adaptation of the TRTM design [3] to DONES has been used in this work to demonstrate the extended functions for materials irradiation. As the integration of TRTM inside the IFMIF-DONES Test Cell, especially the TRTM’s 30-cm thick graphite reflector and tungsten moderator reduce the level of neutron flux at the entrance to the NBT&S system, the impact of TRTM on neutron spectra in TC and CER R160 has been analyzed. The analyses are performed for both scenarios of the IFMIF-DONES operation, with one and two accelerators generating deuteron currents of 125 mA and 250 mA.
References:
[1] A. Serikov et al., “Neutrons supply to the IFMIF-DONES Complementary Experiments Room through the neutron tube and neutron beam shutter”, First IFMIF-DONES Users Workshop, September 26-27, 2022, https://agenda.ciemat.es/event/3879/contributions/4128/.
[2] A. Abou-Sena, F. Arbeiter, ‘‘Development of the IFMIF Tritium Release Test Module in the EVEDA Phase,’’ Fusion Engineering and Design, 88 (2013), 818-823; http://dx.doi.org/10.1016/j.fusengdes.2013.02.041.
[3] K. Kondo et al., “Neutronic Analysis of the IFMIF Tritium Release Test Module Based on the EVEDA Design”, Fusion Science and Technology, 66:1 (2014), 228-234, https://doi.org/10.13182/FST13-74310.13182/FST13-743
