DONES LIthium DIAgnostics (DONES-LIDIA)
Development of critical diagnostics for the operation of the IFMIF-DONES Lithium target
IFMIF-DONES is an accelerator-based neutron source that will generate a neutron flux with a broad energy distribution, covering the typical neutron spectrum of a Deuterium-Tritium fusion reactor. This is achieved through the deuterium–lithium (Li) nuclear reactions in a liquid Li target when it is bombarded by a deuteron beam, with a maximum footprint of 200 mm × 50 mm. The energy of the deuterons (40 MeV) and the current of the beam (125 mA) is tuned to maximize the neutrons flux up to ~ 1015 n/(cm2·s), emulating the damage on the first wall of future fusion reactors like DEMO. Fig. 1 represents a schematic of the IFMIF-DONES facility. IFMIF-DONES is being developed in the frame of the EUROfusion Work Package Early Neutron Source (WPENS) and it is currently under construction in Granada, Spain.
Fig. 1 Schematic of the IFMIF-DONES facility.
The IFMIF-DONES lithium target is one of the most critical parts of the facility, where a high power (5 MW) deuteron beam will impinge on a Li jet flowing at 15 m/s with a temperature of 300 ºC. The interaction between deuteron beam and Li will produce a large amount of neutrons (and gamma radiation) with a fusion-like spectrum, which will irradiate the materials under study. The beam power absorption can be performed in a safe way whenever the Li thickness is kept constant during operation in 25 ± 1 mm. This prevents the beam power from impacting the back plate, which would entail irreparable damage and the facility shutdown.
The lithium target behavior was studied during the IFMIF-EVEDA phase in 2015 by means of the Li circuit prototype at Orai (Japan). However, the environmental conditions in this experiment were far from DONES ones, as there was no radiation and the diagnostics (based on a fast visible camera and laser) were placed in the same position as the beam accelerators in DONES. Therefore, the diagnostics used in this prototype would not be feasible for DONES. Since 2015 and under Eurofusion WPENS Project, different research institutes have studied how to adapt the diagnostics used in the IFMIF-EVEDA phase to the real operation conditions of DONES: laser diagnostic, contact probes, or visible cameras. Due to the extreme environment conditions in the Li target area, at this moment there is not a planned Li target diagnostic with the robustness and fast response time required for the safe operation of DONES, being a high risk for the facility. The use of metallic millimeter wave antennas may entail a compact and resistant solution for the harsh environmental conditions. The objective of this project is to define and design a novel and essential diagnostic instrumentation for the DONES Li target based on radiofrequency (RF) with the following functionalities:
Lithium thickness diagnostic: monitoring of the Li thickness variation in the beam impact area, in communication with the DONES facility Machine Protection System (MPS) for fast emergency stop.
Surface scanning of the beam impact area for instabilities detection and study of homogeneity and perturbations in the liquid Li flow.
With this purpose, several studies and calculations will be performed to define the compatibility of the equipment under DONES radiation and working conditions: nuclear calculations and radiation-induced accuracy degradation, thermomechanical analysis, and studies of remote handling studies and safety. Finally, a demonstrator will be designed and developed in order to validate the technology and its viability in IFMIF-DONES and extrapolate the results to future fusion reactors.
Reference: PID2021-125334OB-I00
Funded by MCIN/AEI/ 10.13039/501100011033, Proyectos de Generación de Conocimiento 2021.
Area/subarea: Energía y Transporte/Energía
Principal Investigators: David Jiménez-Rey [1]; Cristina de la Morena [2]
Start-end dates: 01/09/2022 - 31/08/2026
Financing granted (direct costs): 126.000 €
