The ITER tritium systems Glugla, M.; Antipenkov, A.; Beloglazov, S. ...
Fusion engineering and design,
10/2007, Volume:
82, Issue:
5
Journal Article, Conference Proceeding
Peer reviewed
ITER is the first fusion machine fully designed for operation with equimolar deuterium–tritium mixtures. The tokamak vessel will be fuelled through gas puffing and pellet injection, and the Neutral ...Beam heating system will introduce deuterium into the machine. Employing deuterium and tritium as fusion fuel will cause alpha heating of the plasma and will eventually provide energy. Due to the small burn-up fraction in the vacuum vessel a closed deuterium–tritium loop is required, along with all the auxiliary systems necessary for the safe handling of tritium.
The ITER inner fuel cycle systems are designed to process considerable and unprecedented deuterium–tritium flow rates with high flexibility and reliability. High decontamination factors for effluent and release streams and low tritium inventories in all systems are needed to minimize chronic and accidental emissions. A multiple barrier concept assures the confinement of tritium within its respective processing components; atmosphere and vent detritiation systems are essential elements in this concept.
Not only the interfaces between the primary fuel cycle systems – being procured through different Participant Teams – but also those to confinement systems such as Atmosphere Detritiation or those to fuelling and pumping – again procured through different Participant Teams – and interfaces to buildings are calling for definition and for detailed analysis to assure proper design integration. Considering the complexity of the ITER Tritium Plant configuration management and interface control will be a challenging task.
The scope of the EUFOfusion Work Package Breeding Blanket is to develop a blanket concept for the EU DEMO reactor; this includes the blanket segments inside the Vacuum Vessel and the related Tritium ...Extraction/Removal Systems. In the Pre-Concept Design (PCD) Phase, two concepts have been selected as candidates; a solid and a liquid breeder blanket cooled with helium and water, respectively. The design of these two blanket systems has been adapted to the DEMO plant design developed in the PCD Phase and performances assessed. A large R&D programme has been implemented with the scope to evaluate different technologies for these blankets; including the development of breeders, tritium extraction and cooling technologies, and the manufacturing of the blanket system. A major milestone in the subsequent Concept Design Phase is the final selection of the blanket concept for DEMO.
•18 cm blocks of hydrates like ZrH1.6 or TiH2 can potentially lead to less dpa accumulation in the VV compared to the WCLL blanket.•16 N and 17 N produced by coolant activation: cumulated doses after ...7 fpy in the UPC due to the γ 16 N decay have been calculated referring to the current end of life dose of 2 MGy of valves used in PHTS.•Two dedicated experimental rigs at TLK aim at quantifying co-permeation of Q2 species in He/He or He/water set-ups.•R&D efforts aim at characterizing the two anti-permeation coatings, PLD and ALD, in terms of fabrication and performances under relevant operational conditions.•A combination of anti-permeation coatings and CPS would allow to rely on existing technology for the water detritiation.
In the frame of the EUROfusion consortium activities the Helium Cooled Pebble Bed (HCPB) and the Water Cooled Lithium Lead (WCLL) concepts are being developed as possible candidates to become driver Breeding Blanket (BB) for the EU DEMO, which aims at the tritium self-sufficiency and net electricity production. The two BB design options encompass water or helium as coolants and solid ceramic with beryllium/beryllides or PbLi as tritium breeder and neutron multipliers. The BB segments have evolved towards a more stable conceptual design taking into account multiple feasibility aspects and requirements imposed by interfacing systems. Possible solutions to improve shielding capabilities of Helium cooled BB are investigated and the impact of water coolant activation is assessed by studying the spatial distribution of 16N and 17N isotopes dose rates, in particular in proximity of isolation valves. The reference and back-up technologies for the Tritium Extraction and Removal (TER) from the helium purge gas and the PbLi are developed addressing key feasibility aspects and implications on the tokamak layout and with considerable R&D efforts. As the BB internals offer an ideal environment (high temperatures, thin structural material) to promote the tritium permeation, studies are devoted to establish a tritium balance in the different systems during operation, with special care to the permeation rate and inventory in the coolant. Those are the key parameters for the feasibility assessment and technology selection for the Coolant Purification Systems (CPS).
ITER fuel cycle R&D: Consequences for the design Glugla, M.; Murdoch, D.K.; Antipenkov, A. ...
Fusion engineering and design,
02/2006, Volume:
81, Issue:
1
Journal Article, Conference Proceeding
Peer reviewed
The ITER fuel cycle is designed to handle considerable flow rates of tritium with high flexibility and reliability; experimental work is ongoing to validate these designs. Cryo-pumping systems for ...torus exhaust and neutral beam injectors have been tested to confirm fast regeneration scenarios and to reduce the accumulation of semi-permanent inventories of tritiated impurities. A 1:1 prototype of the torus exhaust cryo-pump is going to be manufactured and extensively tested. Tritium compatible mechanical pumps are being developed, in which leak rates to the exterior and contact between tritiated gases and lubricating oil have been minimized. Comprehensive integrated tests with the three-step process for torus exhaust processing were carried out. An ITER scale prototype fast delivery, self-assay storage bed has been developed; this component is designed to maximize the ratio of delivery rate to stored inventory and is undergoing testing. An integrated concept for the isotope separation (ISS) and water detritiation (WDS) systems has been developed and is being tested on relevant scale; this will provide an additional decontamination step for the potentially tritiated protium reject from the ISS. Extensive use of computer modeling to study the dynamic behavior of these and other fuel cycle systems is made.
State of art imaging techniques might be a useful tool to early detect the retinal vessels lesions in diabetes.
This analytical observational study investigates the retinal microcirculation changes ...in type I and II diabetic patients without retinopathy using adaptive optics ophthalmoscopy (AOO) and optical coherence ophthalmoscopy angiography (OCTA).
Fifty-five subjects were included in this study and were divided in three groups: type I diabetic group (n=16), type II diabetic group (n=19) and control group (n=20). An adaptive optics retinal camera was used to assess the parameters of the temporal superior retinal arterioles. Moreover, vessel density of the superficial capillary plexus across the parafoveal area was measured with OCT-A. All cases were investigated once, in a cross-sectional design.
Diabetic patients from both groups had a higher wall-to-lumen-ratio compared to the controls (p=0.01 and 0.01, respectively). Interestingly, no significant differences were found between the two diabetic groups (p=0.69). Moreover, the vessel density was smaller in the type I diabetic group than in the control group (p=0.001).
AOO might be a useful tool to detect early retinal vascular changes in diabetes before any clinical signs and together with OCTA it might bring important information on the prognostic and pathophysiology of the disease.
Currently, for the EU DEMO, two Breeding Blankets (BBs) have been selected as potential candidates for the integration in the reactor. They are the Water Cooled Lithium Lead and the Helium Cooled ...Pebble Bed BB concepts. The two BB variants together with the associated ancillary systems drive the design of the overall plant. Therefore, a holistic investigation of integration issues derived by the BB and the installation of its ancillary systems has been performed. The issues related to the water activation due to the 16N and 17N isotopes and the impact on the primary heat transfer systems have been investigated providing guidelines and dedicated solution for the integration of safety devices as isolation valves. The tritium retention and the permeation rates through the blanket and its ancillary systems have been also assessed taking into account different operating points both for the BB and ancillaries and comparing, when possible, the releases with the operating and safety limits. Moreover, the issues related to the tritium start-up inventory as well as the uncertainties on the Tritium Breeding Ratio (TBR) due to the integration of the auxiliary systems within the Vacuum Vessel have been also studied. Finally, the impact of the BB concepts on the safety systems like the Vacuum Vessel Pressure Suppression System is described with a particular focus on the different measures that should be implemented according to the considered concept. All these aspects are then taken into account to drive future developments during the Concept Design Phase.
Alimentary supplements may have beneficial effects on retinal microvasculature in diabetic patients.
State-of-the-art imaging techniques were used to assess retinal microcirculation in diabetic ...patients in an observational study before and after 3 months treatment with a multinutrient complex including resveratrol, vitamins D3, C, E, essential fatty acids, trace elements (zinc and copper) and macular pigments (lutein and zeaxanthin)-Resvega.
Fifteen subjects were included in this study. Adaptive optics ophthalmoscopy was used to measure the parameters of temporal retinal arterioles. Optical coherence tomography angiography was employed to assess foveal avascular zone and vessel densities of the superficial capillary plexus, deep capillary plexus and choricapillary plexus.
After 3 months of treatment, there was a statistically significant median decrease in wall-to-lumen ratio (p=0.0001). The same tendencies were noticed for wall thickness values (p=0.008) and wall cross sectional area values (p=0.001). On the other side, no significant changes were noticed concerning the OCTA parameters.
Resvega seems to have a beneficial effect on the retinal arterioles in diabetic patients.
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