Fuel removal

Fuel Removal (Foam sealing, isolation, pump-out, etc.) 

If the fuel is removed or consumed by the subject combustion process, no more fuel supplies will be available for the combustion process to continue and it will cease. In some cases, a fuel is not literally removed from a fire, but is separated from the oxidization agent. Foam suppression methods are good examples where the a barrier is introduced to remove the fuel from the air (i.e., oxidizer). Storage tanks and pipeline fires can use pump-out methods and inventory isolation, respectively, as methods of fuel removal. 

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Not all of the Pu-239 will fission during the fuel cycle in a nuclear reactor. Some of the plutonium will not experience neutron bombardment sufficient to cause fission. Other plutonium atoms will absorb one or more neutrons and become higher numbered isotopes of plutonium, such as Pu-240, Pu-241, etc. Plutonium comprises just over 1 percent of nuclear reactor spent fuel—the fuel removed from the... 

Severe hydroprocessing required to produce ultra-low sulfur fuel removes most of the polar organic compounds from the fuel. The resulting product is virtually unable to effectively dissipate static charge as it builds in moving fuel. Instead, electrical discharge into pockets of gas within a pipeline or into air and vapors as fuel is being dispensed can occur. An explosion may result. Low levels of a fuel-soluble electrical conductivity improver to ultra-low sulfur fuel can help restore fuel electrical conductivity to safe levels. 

Jet fuels -removal by air stripping [WASTE TREATMENT, ITAZARDOUS WASTE] (Vol 25)... 

Therefore, three major means exist for reducing fire damage -- removing the fuel, removing the air, and lowering the temperature. For each means, there are several approaches. The success of each approach is influenced by the type and nature of the fire. 

Reactor-grade plutonium in spent fuel. Most of the plutonium that has been produced in the world so far remains in the spent fuel removed from civil nuclear power plants. Plutonium in this form can be used for nuclear explosives only after separation from the spent fuel and purification, through an operation known as reprocessing. 

Spent fuel is generally regarded as proliferation-resistant due to the high level of radioactivity and the low concentration of fissile material in the fuel removed from a reactor. High levels of radioactivity promote proliferation resistance because special, easily monitored facilities are required to process the fuel and the high level of radioactivity makes removal of fuel without detection extremely difficult. Spent fuel is also proliferation-resistant because the concentration of fissile material is below that required to achieve a nuclear detonation. 

When the time comes to replace fuel in a reactor, either because of loss of reactivity or because of changes in its physical properties, the reactor operator is faced with a number of alternative choices. The operator must decide whether to remove all or part of the fuel in the reactor, and whether to move some of the fuel remaining in the reactor from one location to another, and he or she must choose the composition of new fuel to replace the fuel removed. 

The state of the installation at the end of the draining operations (fuel removed from the reactor building, primary circuit sodium and secondary loops sodium eliminated), and the presence of small quantities of residual sodium, means that the work will be carried out on the basis of a single containment barrier. However, the principle of precaution will require the installation of an additional temporary containment such as formed by the reactor building enclosure. 

The largest potential for fuel discharge under accident conditions offers the diluent S/A system of the core. TTie CAPRA core contains 52 diluent S/As where 22 of them are partly filled with B4C as moderator to improve void and Doppler values. Usually six fuel S/As are grouped around one diluent. The diluents can become activated for fuel removal after local fuel pool formation and melt-through of the S/A walls in the early transition phase. The empty steel pins can be eroded after fuel enters the bundle and the large hydraulic diameter of the bundle becomes available for the fuel flow. These diluents might be optimises for a maximum potential of fuel release. 

Schwarz-Selinger T, von Toussaint U, Hopf Ch, Jacob W (2009b) Fuel removal from tile gaps with oxygen discharges reactivity of neutrals. Phys Scr T138(014009) 8... 

Pebble Bed Reactor Core A pebble bed reactor core arrangement, would be similar to the Siemens/KWU HTR concept, consisting of a bed of graphite pebbles, some of which contain fuel particles, surrounded by graphite reflector. In the case of UEADIR-PS however, the fuel pebbles float in the coolant, and new and recycled fuel pebbles are added to the bottom of the reactor, and irradiated fuel removed from the top (opposite to the THTR-3(X)) during semi-continuous or batch refuelling. 

Fuel removal procedures follow normal refuelling operations as carried out throughout the station lifetime. 

The ISIS fuel handling and storage systems are conventional. Spent fuel removed from the reactor vessel is temporarily stored underwater. The spent fuel racks are located inside the Spent Fuel Storage Pool (SFP) under sufficient water to provide radiological shielding. It can store up to 3 reactor cores. 

In order to ensure the safety of the SaR operations, as well as to support the fuel removal activities, one of the main issues was relevant to analysis of the stability of the stranded ship on the seafloor. Therefore, a monitoring network was installed to measure potential movements... 

B9 Biodegradation of diesel fuel- Removal of diesel fuel Biomass supported on lava rock Wastewater treatment [24]... 

Fuel Removal. Fuel removal can be accomplished in a variety of ways. One of the most common examples is the practice of building a firebreak across the path of an advancing forest fire. 

Interruption of Chemical Reaction. Extinguishment by cooling, by oxygen dilution, and by fuel removal, is applicable to all classes of flaming and glowing fires. Extinguishment by chemical flame inhibition applies to the flaming mode only. 

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