Upper internal structure

The design of upper internal structure (UIS) and variable arm type in-vessel transfer machine (IVTM). Required are ... 

As already mentioned, Phenix was restarted in June 2003. The reactor was shut down in November 1998 for plant inspection, normal maintenance, and renovation works in view of its lifetime extension. The renovation works comprised buildings seismic reinforcement, sodium fires protection measures, installation of new emergency cooling circuits, and steam generator (SG) repair after the detection of a significant crack on one SG module. Inspection work comprised the ultra-sonic inspection of the welds of the core support conical skirt, and the visual inspection of the hanging structures of the vessel, and of the upper internal structures of the reactor block (above-core structures and subassembly heads). 

Tlie core-internal thermal-hydraulic performance of fuel temperature, core-internal structure, and core-internal coolant distribution were confirmed to be appropriate to their design during the full power operation. Tlie maximum temperature of the core support-plate measured at the upper surface of the centre core support-plate was 450°C that was sufficiently below its limited value of 530°C. Also, it was confirmed that other core-internal structure temperatures were well below their design criteria. From the result tliat no core-internal structure temperature measurement showed an abnormal value, it was confinned tliat there was no abnormal leak flow of coolant such as cross and bypass flows between fuel blocks, replaceable reflector blocks, permanent reflector blocks, etc. The maximum fuel temperature was evaluated to be 1 463°C prior to the high-temperature test operation. It was re-evaluated using the measured temperature data i.e. core-inlet and -outlet coolant temperatures and the calculated value of 1478°C does not exceed the normal operation hmit of 1 495°C. 

Bacterial cells are not the bags of protoplasm they were once envisioned to be. Considering that they have no membrane compartments, their internal structure is surprisingly well organized. Note, for example, the spatial separation of the supercoiled DNA molecule (upper left) from other biomolecules. (Also refer to Figure 2.5.)... 

As early as 1700, Bernardino Ramazzini, one of the founders of occupational medicine, had associated certain physical activities with musculoskeletal disorders (MSD). He postulated that certain violent and irregular motions and unnatural postures of the body impair the internal structure [Snook et al., 1988]. Presently, much effort is directed toward abetter understanding of work-related musculoskeletal disorders involving the back, cervical spine, and upper extremities. The World Health Organization (WHO) has defined occupational diseases as those work-related diseases where the relationship to specific causative factors at work has been fully established [WHO, 1985]. Other work-related diseases may have a weaker or unclear association to working conditions. They maybe aggravated, accelerated, or exacerbated by workplace factors and lead to impairment of workers performance. Hence obtaining the occupational history... 

A schematic ofa pilot plant is shown in Figure 11.5. The pilot plant was 1500 mm wide, 900 mm long and 1500 mm high. Figure 11.6 shows the internal structure of the pilot plant in which 20 microreactors were set up in a constant-temperature bath. The inside of the pilot plant has a lower and upper step structure and it is composed of a flow control system, temperature and reaction control system and monitoring system. The flow control system consisted of non-pulsatile pumps and tanks in the lower step and electromagnetic valves and needle valves in the upper step. The withstand... 

The RPV Internal structures comprise a lower assembly which supports the core and an upper assembly which locates the top of the core and guides the control rods. During operation both the upper and lower Internal assemblies are completely enclosed within the reactor vessel and are supported from the area of the main vessel flange. To refuel the reactor the upper Internal assembly must be removed to expose the fuel assemblies. With all the fuel assemblies removed the lower Internal assembly can also be removed to facilitate Inspection of Itself and the reactor vessel. 

Inside the reactor pressure vessel, the reactor core is fixed in position by the core internal structure consisting of the core shroud and an upper and lower core grid plate (see Fig. 1.3.). In a 1300 MWe plant the reactor core itself consists of 193 fuel assemblies arranged in a geometrical pattern inside the reactor pressure vessel as an example, a core scheme also containing mixed-oxide fuel assemblies is shown in Fig. 1.8. 

When the steel is heated still further, the structural changes continue until a second temperature is reached where the change in the internal structure of the steel is complete. This temperature is known as the upper critical temperature and varies for plain-carbon steel according to the percentage carbon content. Fig. 14.3. 

The metallic internal structures are composed of the core vessel, upper and lower support plates, holddown plates and a positioning plate. They provide support and housing to the ceramic internal structures and also transmit the mechanical loads coming from the fuel pebble bed and the ceramic internals to the reactor pressure vessel. 15CrMoR is selected as the material for most metallic core internal structures. The total weight of the metallic core internals is about 72.5 t. 

Praeangustothyris from the Upper Permian of the Far East is defined by the sulcate shell, absence of visceral foramen, presence of septalium and rudimentary dental plates. Comparison of the internal structures of the adult stage of the type species... 

The containment vessel is a cylindrical welded steel vessel with elliptical upper and lower heads, supported by embedding a lower segment between the containment internal structures concrete and the basemat concrete. The containment internal structure is reinforced concrete with structural modules used for some walls and floors. 

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