IFMIF Research Articles

New developments of hydrogen impurity online-monitoring in liquid lithium of IFMIF-DONES

On the way to future nuclear fusion power plants, the International Fusion Materials Irradiation Facility (IFMIF) – DEMO Oriented Neutron Source (DONES), is an important key element between ITER and DEMO to study before the influence of DEMO-neutron irradiation on foreseen fusion materials. The core of DONES, currently under construction near Granada, Spain, is based on a circuit containing liquid lithium at elevated temperatures acting as a functional material for the (d,n)-Li reaction in a materials test cell. In addition to this actual function of DONES, there are important aspects of maintenance in which hydrogen isotopes are generated under operating conditions and dissolved in this aggressive and very reactive alkali metal. This implies strong unfavourable effects on the applied structural materials, e.g. hydrogen embrittlement and others.To counteract these unfavourable effects, endangering the safe operation, an Impurity Control System (ICS) is an integral part of the DONES instrumentation. As part of the tasks of the European Neutron Source (ENS) to develop redundant systems for monitoring impurities, a special sub-task was defined for the development of an electrochemical H-sensor for concentrations in liquid lithium, ECHSLL. It is determined by detecting the electrical potentials of the lithium melts compared to a standard Li-based chemical reference system. This allows an inherent material property to be directly correlated (i.e. through appropriate electrochemical instrumentation) with chemical concentration values. This article presents important advancements in the applied ECHSLL technique, such as improving laboratory measurements from stagnant conditions to dynamic and realistic flow conditions of the liquid lithium material, as well as appropriate approaches to overcome the challenges in distinguishing the hydrogen isotopes by ECHSLL system (protium and deuterium among given laboratory conditions).

High beam current operation with beam diagnostics at LIPAc

The Linear International Fusion Materials Irradiation Facility Prototype Accelerator (LIPAc) is under commissioning in Rokkasho Fusion Institute in Japan and aims to accelerate 125 mA D+ at 9 MeV in Continuous Wave mode for validating the IFMIF accelerator design. To ensure a fine characterization and tuning of the machine many beam diagnostics are installed spanning from injector to the beam dump. The beam operations in 1.0 ms pulsed D+ at 5 MeV were successfully completed with a low power beam dump in 2019. Despite the challenges posed by the pandemic, the crucial transition to a new LINAC configuration was also finalized to enable operation in 1.0 ms — CW D+ at 5 MeV with the high-power beam dump. The 1st beam operation of the configuration was carried out in 2021. The experiences and challenges encountered during these beam campaigns are described in this paper.

Achievement of high-current continuous-wave deuteron injector for linear IFMIF prototype accelerator (LIPAc)

The Linear IFMIF (International Fusion Materials Irradiation Facility) Prototype Accelerator (LIPAc) is aiming at demonstrating the low-energy section of a 40 MeV/125 mA IFMIF deuteron accelerator up to 9 MeV with a full beam current in continuous-wave operation. For such a high-power beam, the LIPAc injector is required to produce a beam current of 140 mA and 100 keV D+ beams. The injector commissioning to reach high beam current has been progressing at high duty cycle operation, then stable operation for many hours at a beam condition of 150 mA total extracted current. This result demonstrates that the LIPAc injector can meet the required performance for nominal 125 mA long pulse deuteron beam acceleration.

Thermal and structural analysis of the DONES target system under steady state and transient loading conditions

One of the crucial steps in the European Roadmap to the realisation of fusion energy is the design and construction of the Demo-orientated NEutron Source (DONES) facility. DONES is a fusion-like neutron source, based on the International Fusion Materials Irradiation Facility (IFMIF) concept, aimed at qualifying and testing the materials to be used in fusion reactors. The Target System (TSY) is a crucial system as it is the component where the interactions between deuterons and a liquid lithium target, flowing on a solid surface (i.e. the Back Plate), take place to produce neutrons for irradiating the testing materials. In this regard, an investigation campaign has been performed to evaluate the thermo-mechanical behaviour of the DONES TSY under selected steady state and transient loading conditions, in light of the most recent design updates (new bellows and connection systems). The first part of the assessment concerned the analysis of the TSY under the normal operation steady state loading scenario. A detailed 3D FEM model has been set up, considering the newest updates of the TSY geometry and of the operational parameters, and a thermo-mechanical analysis has been launched. Results have been mainly checked in terms of TSY global deformation, focusing on the Back Plate and on the connecting bellows displacements, in order to exclude overlapping with the High Flux Test Module and misalignments with the beam footprint. Afterwards, since the lithium inlet temperature has been increased from 250 °C to 300 °C, a transient thermo-mechanical analysis of the TSY under the start-up loading conditions has been performed to check if it is able to withstand the hotter lithium flow according to the RCC-MRx criteria. Therefore, the reference pre-heating strategy has been adopted, assessing the thermal and mechanical behaviour of the TSY, focusing on the Back Plate. The obtained results are presented and critically discussed, suggesting important recommendations for the follow-up of the design.

Study of the production of radioisotopes at IFMIF-DONES: 177Lu with deuterons

The production of radioisotopes for nuclear medicine is boosted by different international agencies. The International Fusion Materials Irradiation Facility - Demo Oriented NEutron Source (IFMIF-DONES) will be a infrastructure for testing under high neutron flux the materials to be used in future DEMO fusion reactor. IFMIF-DONES will generate neutrons by means of the impact of a high-power deuteron beam onto a lithium-jet target. There is an important effort to take advantage of the outstanding characteristics of the facility in terms of neutrons and deuterons. Thus, a complementary program is being developed, where the production of radioisotopes for medicine is one of the main applications. Here, we discuss the production of 177Lu with deuterons at IFMIF-DONES.

Interactive simulations as a tool for logistics and maintenance of IFMIF-DONES

Pre-configured virtual reality (VR) simulations of the logistics and maintenance processes have proven to be useful for identifying potential design issues as well as planning operations during an early design phase of facility. But VR simulations can also be used to deeply explore the feasibility of these procedures in a more interactive manner, so that we can identify potential risks and difficulty levels from early stages and study different maintenance strategies to assist the maintenance worker during these procedures. This article presents a framework to design and validate logistics and maintenance procedures in complex facilities, such as the International Fusion Materials Irradiation Facility DEMO Oriented Neutron Source (IFMIF-DONES). Our framework begins with a preparatory phase where essential information about the procedures and Computer-Aided Design (CAD) models is compiled into a comprehensive Virtualization Task Document (VTD). Differently from previous work, this VTD allows representation of parallel tasks. We implement the interactive version of the virtual environment, where the different maintenance and logistics equipment, as well as a virtual maintenance worker is controlled by the user (the person executing the interactive simulation). We have validated this interactive framework with two simulations for the installation process of the Superconducting Radio Frequency Linear accelerator (SRF Linac) modules in IFMIF-DONES. In one simulation (the automatic one), the procedures are reproduced as they are planned, while in the second simulation (the interactive one) the user freely controls the movements of the moving parts of the crane, grab and release plant equipment, move platforms, etc. Based on our simulations, the interactive version allows easier detection of potential points of collisions as well as more precise assessment of the difficulty of the tasks to be performed.

Engineering design status of IFMIF-DONES High Energy Beam Transport line and Beam Dump system inside the TIR and RIZ

IFMIF-DONES (International Fusion Materials Irradiation Facility – DEMO Oriented Neutron Source) is a fusion materials testing facility that is currently being designed under the framework of a work package of the EUROfusion Consortium. It will use a 125mA at 40MeV deuteron beam to generate a high neutron flux through Li(d,xn) stripping nuclear reactions in a liquid lithium target. The High Energy Beam Transport line (HEBT), the most upstream system of the IFMIF-DONES accelerator, is responsible for the guidance and shaping of the beam towards the target. Additionally, during commissioning periods, the HEBT is also responsible for diverting the beam, through the Beam Dump Transport Line, to the Beam Dump for testing purposes. The HEBT is spread along different rooms and zones: the Accelerator Vault, the Radiation Interface Zone (RIZ), and Target Interface Room (TIR). The engineering design of the HEBT components situated within the TIR and RIZ has been updated to satisfy new requirements, with a focus on ensuring the protecting of the Fast Isolation Valve (FIV) from the backscattered radiation from the target. These modifications include relocating the FIV from the TIR to the RIZ, adjusting the building layout to accommodate the new FIV module, configuring an enclosure cabinet for the RIZ, and adding local shielding to extend the lifetime of the FIV seal actuators. This work describes the current status of these TIR and RIZ engineering design, including radioprotection, commissioning and maintenance plan, beam diagnostics devices, beam dynamics and new remote handling approaches, as well as the layout and integration of the required components along the beamline. The TIR and RIZ are critical areas for IFMIF-DONES, and their design and operation must be compliant with functional, reliability and safety requirements. The updated design addresses potential issues and enhances the facility’s overall functionality.

DONES EVO: Risk mitigation for the IFMIF-DONES facility

The International Fusion Materials Irradiation Facility- DEMO Oriented Neutron Source (IFMIF-DONES) is a scientific infrastructure aimed to provide an intense neutron source for the qualification of materials to be used in future fusion power reactors. Its implementation is critical for the construction of the fusion DEMOnstration Power Plant (DEMO).IFMIF-DONES is a unique facility requiring a broad set of technologies. Although most of the necessary technologies have already been validated, there are still some aspects that introduce risks in the evolution of the project.In order to mitigate these risks, a consortium of companies, with the support of research centres and the funding of the CDTI (Centre for the Development of Industrial Technology and Innovation), has launched the DONES EVO Programme, which comprises six lines of research:•Improvement of signal transmission and integrity (planning and integration risks)•Optimisation of RF conditioning processes (planning and reliability risks)•Development of a reliable beam extraction device (reliability risks)•Development of technologies for the production of medical isotopes (reliability risks)•Improvement of critical parts of the lithium purification system (safety and reliability risks)•Validation of the manufacture of critical components with special materials (reliability risk).DONES EVO will focus on developing the appropriate response to the risks identified in the IFMIF-DONES project through research and prototyping around the associated technologies.This contribution will present a discussion of the risks, the proposed response to them and the evolution of the technologies involved, following selected experiments carried out throughout the project.

IFMIF/EVEDA achievements overview

In a fusion reactor, the plasma based on a deuterium-tritium reaction generates high energy neutron flux interacting with the materials of the plasma facing components. In order to study the irradiated behavior of these materials, the International Fusion Materials Irradiation Facility (IFMIF) was conceived to generate these fusion relevant neutrons through d-Li stripping source. IFMIF is presently in its Engineering Validation and Engineering Design Activities (EVEDA) phase under the Broader Approach agreement signed between EURATOM and Japanese Government in 2007. This agreement mandates the IFMIF/EVEDA project to validate the design of the different systems of IFMIF and to produce an integrated engineering design of IFMIF, together with the data necessary for future decisions on its construction and operation. While the Engineering Validation Activity (EVA) of the Lithium Target Facility and the Test Facility was completed by constructing prototypes, the EVA of the Accelerator Facility with the Linear IFMIF Prototype Accelerator (LIPAc) is still on-going at the Rokkasho Fusion Institute, Japan. This paper overviews the achievements in the previous phase ended on 31 March 2020 and the progress in the current phase to complete the commissioning of the LIPAc.

The LiFIRE experimental facility: Final design, construction and experimental campaign

Recently, nuclear fusion-related experiments and dedicated facilities worldwide relying on the usage of liquid metals are experiencing a renewed interest.This is the case of the International Fusion Materials Irradiation Facility – DEMO-Oriented Neutron Source (IFMIF-DONES), a radioactive facility which will use several cubic meters of pure liquid lithium as a target for deuterons to produce high neutron fluxes having an energy spectrum as effective as the expected fusion reactors. The primary mission of IFMIF-DONES will be to irradiate selected candidate structural materials for building a comprehensive database on fusion material properties.Generally, alkali metals, such as lithium, exhibit safety issues related to their chemical reactive nature and material compatibility. Due to the wide uncertainty regarding the lithium behavior confirmed by an extensive literature review, a dedicated experimental facility has been conceived to primarily study lithium ignition conditions in support of the licensing process of IFMIF-DONES. The ultimate purpose of the LiFIRE facility will be to demonstrate by means of experimental evidences the set of requirements on lithium fire protection to be applied to the final engineering design of IFMIF-DONES.This work describes the final design, construction and experimental campaign of the LiFIRE facility currently under development at CIEMAT's premises.

Updates of the removable biological shielding blocks inside of the test cell, part of the test systems of IFMIF-DONES

The International Fusion Materials Irradiation Facility - DEMO Oriented Neutron Source (IFMIF-DONES) is a facility which is designed under the framework of the EU fusion roadmap. It is going to be an essential irradiation facility for testing and qualifying candidate materials under severe irradiation conditions of a neutron field having an neutron irradiation effect on materials like the one expected in a commercial fusion power reactor. The material specimens are irradiated in a containment structure named Test Cell (TC), which is part of the Test Systems (TS).The first protecting „barrier” against irradiation affecting the surrounding of the TC, are the Removable Biological Shielding Blocks (RBSBs). These ∼9 m height, ∼80 tons elements, which are formed by stainless steel liners filled with heavy concrete, need to be remotely handled as after the first experiments they will get dose rates above the hands-on limit. Irradiation will also result in a large nuclear heat power deposited in the shielding blocks, therefore needs to be actively water cooled by a system of embedded pipes to control the temperature.In this paper the updated design of the RBSBs is described, including the latest achievements and proposals for feasible manufacturing, lifting and positioning possibilities of the blocks inside of the TC respecting the given tolerances.

Abstract A041: FHD-286, a potent and selective inhibitor of BRG1 and BRM, shifts metastatic uveal melanoma tumor towards a less immunosuppressive state in patient samples

Abstract BRG1/BRM are key components of the SWI/SNF complex that are critical in regulation of transcriptional programs that control cell fate and identity. Tumor cells aberrantly hijack and upregulated BRG1 levels, hijacking “stemness features”. Furthermore, BRG1 has been shown to impact immune cell polarization, driving programs associated with T cell exhaustion and an immunosuppressive cell state. Our group previously demonstrate that the combination of FHD-286 and anti-PD-1 antibody is synergistic in syngeneic mouse models from various lineages, and substantially shifted with tumor microenvironment (TME) towards a more tumor killing state (Ichikawa, K. 2022, SITC). FHD-286 was evaluated in a phase 1 dose escalation (FHD-286-001, NCT04879017), in metastatic uveal melanoma (mUM) a tumor with low response rate to standard immune checkpoint therapy as well as high levels of immunosuppressive cell infiltration. Thus, we endeavored to determine if there was evidence of biological changes in peripheral blood and TME shifts in samples taken from our phase 1 dose escalation in patients with metastatic uveal melanoma. Subjects were on a daily dosing regimen ranging from 2.5 to 10 mg or an intermittent regimen of 1-week on/1-week-off ranging from 10 to 22.5 mg in 73 patients. RNA sequencing was performed in 46 patient blood samples collected in Paxgene tubes during dose escalation (2.5 mg- 15mg, C1D1, C1D15, C3D1 and other intermediate timepoints) and analyzed for transcriptional changes associated with shifts in immune polarization and activation. Tumor biopsies were collected at screening and either Cycle 3 or end of treatment. Biomarker changes in the tumor were quantified using multiplex IF (mIF) panel (Neogenomics) to assess co-localization and spatial orientation of 20 different immune related markers in 16 patients, 13 of which had samples from screening and on-treatment. Further changes were assessed using RNA sequencing of paired biopsies in 9 patients. Analysis of peripheral blood identified changes in expression of genes associated with a reduction in immunosuppressive signatures, particularly a dose dependent reduction of FOXP3 from baseline, as well as an increase in transcripts associated with activation of neutrophils. The mIF panel highlighted a reduction in immunosuppressive cells of multiple lineages including in on treatment samples, with 12/13 patients showing a reduction of one or more of the following: FOXP3+ Tregs (8/13), PD-L1+ Macrophages (8/13), an increase in the M2 Mf to tumor cells distance (8/13), markers of T cell exhaustion (PD1) on both CD4 (7/13) and CD8 T cells (8/13), or an increase in CD8/Treg ratio (5/13). Taken together these results suggest FHD-286 may reduce the immunosuppressive “blockade”, priming mUM patients to response in combination with an immune checkpoint inhibitor. Citation Format: Liv H Johannessen, Jessica Wan, Kim Horrigan, Mike Collins, GiNell Elliott, Kana Ichikawa, Ammar Adam, Sam Agresta, Jessica Piel, Martin Hentemann. FHD-286, a potent and selective inhibitor of BRG1 and BRM, shifts metastatic uveal melanoma tumor towards a less immunosuppressive state in patient samples [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A041.

3D beam-envelope approach for an asymmetric beam in a high intensity linac with a solenoid channel

Presented here is a theory model based on the beam-envelope approach to determine the global behavior of a charged beam propagating through a high intensity linac with a solenoid channel, namely, the orbital evolution of the root-mean-square beam size in the transverse and longitudinal direction. The model is applied to the Gaussian particle distribution, where the motion of an individual particle is governed by linear focusing/defocusing forces in the solenoid channel and RF fields, except for space-charge forces. In this model, highly nonlinear effects that originated from space-charge forces disappear by averaging over the harmonic motions such as the betatron motion and phase motion in the moving direction and the Gaussian distribution. All particles making up a 3D Gaussian bunch obey the same linear equations of motion where all information of nonlinearity in the space-charge forces and the particle distribution are carried in. The theory is validated using Gaussian macro-particle simulation and one of the widely used photonic integrated circuit codes, TraceWin. As an example, the model is applied to the case of an international fusion materials irradiation facility superconducting linac with solenoid guiding and half wave RF acceleration. The results are compared with results obtained by this model and other two approaches.

High power experiments of the Prototype Solid State RF System for IFMIF-DONES

The current trend in the radiofrequency (RF) power systems of many large scientific facilities is the use of solid-state power amplifiers (SSPAs). When it is feasible, for mid-range power levels at frequencies below 1 or 2 GHz, replacing vacuum technology for solid-state (SS) entails significant advantages. Consequently, SS technology has been also selected for the RF Power System of IFMIF-DONES (International Fusion Materials Irradiation Facility – DEMO (DEMOnstration power plant) Oriented Neutron Source). IFMIF-DONES is one of the central facilities of the European roadmap towards fusion electricity, necessary for the validation and qualification of the materials capable to withstand the harsh conditions inside future fusion reactors. Nevertheless, reaching the high power levels of vacuum technology with SSPAs entails the combination of many SS devices. Hence the search for efficient RF power combination techniques is critical in the development of SSPAs.Resonant cavity combination is an innovative technique that provides a high-power and high-efficient combination in a single step. This minimizes the overall combination losses and reduces the size compared with conventional corporate combination schemes. Two prototype cavity combiners at 175 MHz have been designed and manufactured. The first prototype was validated up to 24 kW in continuous wave (CW) and 100 kW in pulsed mode (duty cycle DC=4 %). The conclusions obtained from those experiments revealed the need for temperature control and/or detuning compensation in the cavity combiner to maintain high efficiency at high-power levels in CW. The second prototype is a water-cooled 160-input cavity combiner capable to combine up to 240 kW in CW. It has been validated at 100 kW in CW, using a witty variant in the experimental test bench that simplifies the experiment. This paper presents the design and small-signal characterization of this 160-input cavity combiner, as well as the results of the high-power validation experiments.

Conjugated heat transfer analysis of the Start-Up Monitoring Module (STUMM) for IFMIF-DONES including heat generation mapping

The Start-Up Monitoring Module (STUMM) is designed for the commissioning phase of the IFMIF-DONES (International Fusion Materials Irradiation Facility – Demo Oriented NEutron Source). The main aim is the detailed characterization of the irradiation field in space for the validation of the nuclear models. The thermo-hydraulic analysis of the STUMM was carried-out in the Ansys FLUENT software predicting the steady-state temperature distribution in the full range of the allowable inlet temperatures (15–60 °C), inlet pressures (3–3.5 bar), and the maximum allowable helium flow rate of 0.18 kg/s. The heat generation maps obtained from MCNP analyses were mapped on the CFD mesh via the in-build FLUENT functionality of “profiles”. To ensure the conservation of the global heat generation a correction coefficient αcorr was introduced to modify the MCNP profiles before the import to CFD: qCFD(x,y,z)=αcorr qMCNP(x,y,z). A dedicated test case of a cylinder subjected to a point irradiation source was studied, confirming the convergence of the global heat with a refinement of the MCNP and CFD discretization, where the MCNP model was discretized with cuboid cells and the CFD with a polyhedral. The global STUMM model was solved with 5 MCNP profiles with cell sizes from 5 mm to 1 mm (0.2–23.3 mln data points). Even though the smallest feature of the global CFD model was 0.5 mm (thickness of a detector wall) the MCNP profile with ∼4 mm cuboid cells gave almost identical results to the finest 1 mm profile, confirming the precision of the method and no need of solving very finely discretized MCNP models. With the direct transfer of results between MCNP and CFD model with the in-build FLUENT functionality of “profiles”, the simulation set-up was fast. A negligible impact of the internal radiation heat transfer on the temperatures was found (with the Discrete Ordinates (DO) model). Two possible flow directions of the helium were analysed for the worst-case scenarios. With the maximum pressure drop of 4.12 kPa, the maximum helium outlet temperature of 71.6 °C, and the max temperature of the detectors of 157.5 °C all the design requirements were satisfied, as values were far from the limits of 60–80 kPa, 150 °C and 250 °C respectively.

Status of the engineering design of the IFMIF-DONES high energy beam transport line and beam dump system

IFMIF-DONES plant [1] (International Fusion Materials Irradiation Facility – DEMO Oriented Neutron Source) is currently being developed under the framework of a work package of the EUROfusion Consortium. It will be a facility located at the south of Spain in Granada. Its objective and main goal is the testing and qualification of fusion materials by the generation of a neutron flux with a broad energy distribution covering the typical neutron spectrum of a (D-T) fusion reactor. This is achieved by the Li (d,xn) nuclear reactions occurring in a liquid lithium target where a 40 MeV at 125 mA deuteron beam with a variable beam footprint between 200 mm × 50 mm and 100 mm × 50mm collides. The Accelerator Systems is in charge of providing such high energy deuterons to produce the required neutron flux. The High Energy Beam Transport line (HEBT) is the last subsystem of the IFMIF-DONES accelerator, and its main functions are to guide the deuteron beam towards the liquid lithium target and to shape it with the required rectangular reference beam footprints. The HEBT system includes a Beam Dump devoted to stop the beam during commissioning and start-up phases. The present work details the present status of the HEBT engineering design, including beam dynamics, vacuum configuration, radioprotection, beam diagnostics devices and remote handling analyses performed detailing the layout and integration of required components through-out the beamline.

Shielding analyses supporting the Lithium loop design and safety assessments in IFMIF-DONES

The assessment of radiation fields in the lithium loop pipes and dump tank during the operation were performed for International Fusion Materials Irradiation Facility – DEMO-Oriented NEutron Source (IFMIF-DONES) in order to obtain the radiation dose-rate maps in the component surroundings. Variance reduction techniques such as weight window mesh (produced with the ADVANTG code) were applied to bring the statistical uncertainty down to a reasonable level. The biological dose was given in the study, and potential shielding optimization is suggested and more thoroughly evaluated. The MCNP Monte Carlo was used to simulate a gamma particle transport for radiation shielding purposes for the current Li Systems’ design. In addition, the shielding efficiency was identified for the Impurity Control System components and the dump tank. The analysis reported in this paper takes into account the radiation decay source from and activated corrosion products (ACPs), which is created by d-Li interaction. As a consequence, the radiation (resulting from ACPs and Be-7) shielding calculations have been carried out for safety considerations.

Evaluation of the impact of experimental fusion-aimed installations on their area of influence: the price of sustainable energy

The need of clean, stable, safe and free of uncertainty energy sources has been increased after the current geopolitical tension. In this framework, nuclear energy is receiving renewed attention which finally led the European Commission to consider it as Green Energy. In spite of the expected "golden age" of nuclear energy, the fission still has some problems that must be solved. For this reason, the research on nuclear fusion is now and more than ever a real must. The path towards the control of fusion is plenty of technical difficulties, mainly related to the extreme temperatures and pressures needed and also to the neutronic radiation. The International Fusion Materials Irradiation Facility – Demo Oriented NEutron Source (IFMIF-DONES) is an experimental facility whose target s the testing of materials with fusion-like neutrons in order to evaluate the damages and decide which material is the most convenient to build the future reactors. The impact of IFMIF-DONES on the people living in the area where it is going to be located (Escúzar, Province of Granada, Spain) has been evaluated through a survey among its inhabitants. The results are presented and discussed in this work.

Design and manufacturing of the combined quadrupole and corrector magnets for the LIPAc accelerator high energy beam transport line

The International Fusion Materials Irradiation Facility (IFMIF) is a project aiming to investigate candidate materials to be used in the most exposed zones of future fusion reactors. The linear IFMIF prototype accelerator (LIPAc), presently under commissioning in Rokkasho, Japan, is a prototype of the frontend section of one of the IFMIF accelerators. Eight quadrupole magnets, six pairs of corrector magnets and one dipole are responsible for generating the magnetic fields needed for a proper beam handling along the 10 m long LIPAc high energy beam transport line, which connects the end of the superconducting radio frequency Linac with the beam dump. A novel design of combined magnets with the correctors integrated in the quadrupole poles is chosen for compactness reasons. The different stages of the production of the combined magnets, from the magnetic and mechanical design to their manufacturing and testing, including exhaustive characterization of the magnetic performance are described in this work. The results from the tests revealed the quality of the magnetic field produced. The materials selection was done carefully, to withstand the high levels of ionizing radiation expected at the magnet locations. This paper focuses on the activities performed in Europe, before sending the magnets to Japan for their installation and commissioning at the Rokkasho site.

Electrochemical hydrogen detection in DONES loop materials

• Design of an electrochemical sensor adequate to RAMI conditions of IFMIF-DONES. • Determination of hydrogen in liquid lithium. • Online electrochemical muliplex monitoring. • Modular design for different extended approaches (impurities, electrochemical procedures, sizes). The radiation-induced degradation of materials in fusion systems is planned to be investigated in IFMIF-DONES ( International Fusion Materials Irradiation Facility - DEMO Oriented NEutron Source ), where fast neutrons are produced by a reaction of deuteron-beams with a liquid lithium target. A by-product as critical impurity is hydrogen, which might affect the reliable and safe operation of the IFMIF-DONES loops. Therefore, an important issue is the measurement and control of the hydrogen impurity concentrations in liquid lithium. Initially, a practically applicable direct measurement of hydrogen concentrations in lithium facilities did not exist. However, one promising approach to manage this issue is based on the electrochemistry of the DONES materials The developed Electro-Chemical Hydrogen Sensor for Liquid Lithium (ECHSLL) allows the measurement of the electromotive Force (EMF) between a reference materials system and the loop lithium melt, and thus the monitoring of the hydrogen impurity concentrations. This article will show backgrounds of non-metallic impurities in liquid metal materials and the specific material stabilities within DONES. Liquid lithium is a very reactive material. Therefore critical issuesareviable materials compatibilities, the interactions with hydrogen and the transport behaviour of H-ions in electrolytes at the applied temperatures. Further issues are also the syntheses of the electrochemical materials, as hydrogen conducting electrolytes, reference electrode systems and the different procedures (heat treatments and conditioning steps). The tests showed the functionality of the developed H-sensor. Beyond that, the used material combinations exhibited reliable behaviour in melts under harsh conditions. Hence, the most critical aspect (stability of the sensor materials in the Li-melt) has been resolved by using niobium sensor heads. The observed experimental EMF potentials are in good accordance compared with calculated models, also in long-time experiments.