Fuel transfer tube

These two areas are connected by the fuel transfer tube through which an underwater conveyor or fuel transfer system carries the new fuel into the reactor containment and spent fuel into the fuel handling building. 

Head package maintenance facility t+23.771 m O.D. main plant access, +21.028 m O.D. operating floor Pipewc /cable race Upper internals storage Lower internals storage +10.868 m O.D. fuel transfer tube... 

Fired heaters are extensively used in the oil and gas industry to process the raw materials into usable products in a variety of processes. Fuel gas is normally used to fire the units which heat process fluids. Control of the burner system is critical in order to avoid firebox explosions and uncontrolled heater fires due to malfunctions and deterioration of the heat transfer tubes. Microprocessor computers are used to manage and control the burner system. 

Figure 6 Calculation results of transient behaviour of primary coolant pressure, heat transfer tube temperature of PPWC and IHX, RPV temperature and fuel temperature...

A full scale dummy fuel assembly for hydraulic testing has been fabricated at Nuclear Fuel Complex, Hyderabad. This will be tested at IGCAR in the hydraulic test rig which is being installed. The core plan was finalised taking into account number of in-vessel storage locations required and additional shielding that may be required for invessel transfer post. The temperature limits for fuel cladding tube under transients were determined from the data available on transient tests and the limits have been stipulated as 1073 and 1173 K. 

The entrance gate monitor (ENGM) is a passive neutron coincidence collar detector permanently installed at the entrance to the fresh fuel transfer route of a fast breeder reactor (Hashimoto et al. 1994 Iwamoto et al. 1997). The detector head has four groups of He with six tubes each. Fresh fuel assemblies entering the reactor facility must pass through the ENGM so that their Pu content can be verified. Therefore, the ENGM is the system that verifies the amount of fresh fissile fuel in an assembly and serves as the first detector in a sequence of detector systems that follow the movement of fuel assemblies within the reactor facility. 

Helical heat transfer tubes (Shell tube heat exchanger) Core (Driver fuel, Reflector, Shielding)... 

Longer tubes provide a longer co-current heat transfer path in the reformer, and thereby reduce the flue gas exit temperature, which conserves fuel. Longer tubes also reduce the number of tubes. However, the pressure drop is higher. The optimum tube length is typically 40 to 45 feet. 

The primary reformer is essentially a process furnace in which fuel is burned with air to indirectiy provide the heat of reaction to the catalyst contained within tubes. This area of the furnace is usually referred to as the radiant section, so named because this is the primary mechanism for heat transfer at the high (750—850°C) temperatures required by the process. Reforming pressures in the range 3 —4 MPa (30,000—40,000 atm) represent a reasonable compromise between cost and downstream compression requirements. 

In fossil fuel-fired boilers there are two regions defined by the mode of heat transfer. Fuel is burned in the furnace or radiant section of the boiler. The walls of this section of the boiler are constmcted of vertical, or near vertical, tubes in which water is boiled. Heat is transferred radiatively from the fire to the waterwaH of the boiler. When the hot gas leaves the radiant section of the boiler, it goes to the convective section. In the convective section, heat is transferred to tubes in the gas path. Superheating and reheating are in the convective section of the boiler. The economizer, which can be considered as a gas-heated feedwater heater, is the last element in the convective zone of the boiler. 

The inside of the convection tubes rarely foul, but occasionally the Hquid unsaturates in feedstocks tend to polymerize and stick to the walls and thus reduce the heat transfer. This soft coke is normally removed by mechanical means. In limited cases, the coke can also be burnt off with air and steam. Normally, the outside surface of the convection section fouls due to dust and particles in the flue gas. Periodically (6 to 36 months), the outside surface is cleaned by steam lancing. With Hquid fuel firing, the surface may require more frequent cleaning. 

Pressure-tubes allow the separate, low-pressure, heavy-water moderator to act as a backup hesit sink even if there is no water in the fuel channels. Should this fail, the calandria shell ilsdf can contain the debris, with the decay heat being transferred to the water-filled shield tank around the core. Should the severe core damage sequence progress further, the shield tank and the concrete reactor vault significantly delay the challenge to containment. Furthermore, should core melt lead to containment overpressure, the concrete containment wall will leak and reduce the possibility of catastrophic structural failure (Snell, 1990). 

The furnace was fitted with interlocks that should have isolated the fuel supply if the tube wall temperature or the pressure of the heat transfer oil got too high. Neither interlock worked, and neither had been tested or maintained. The set-point of the high tube wall interlock had been raised far above its original set-point, from 433°C to 870°C, a simple way of putting it out of action [15]. Changing the set-point of an interlock is a modification and should be allowed only when the equipment is capable of withstanding the new conditions (see Chapter 2). 

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