Transport flasks

There are several advantages to the use of pass-throughs for the transport of materials into and out of the isolator. These benefits include the fact that the size of the pass-through can be built to meet one s needs. It is easier to transport flasks and other loosely sealed liquid containers in and out of the isolator with fewer concerns about spills. The wash-downs are typically easy to perform and are not technique dependent. 

The fuel is transported from the reactor pools to Sellafield in MEBs contained within heavily shielded, high integrity, transport flasks. The MEBs are cylindrical stainless steel vessels containing stainless steel clad "Boral" or boronated stainless steel dividers between the fuel assemblies to prevent criticality. "Boral" consists of boron carbide particles in an aluminimn matrix clad with pure aluminimn and is widely used as a neutron absorber. MEB s are used to contain mobile contamination from crud or spalling smface layers of the fuel pins. 

The storage capacity of reactor pools is normally several years production but can be increased by adding neutron absorbers to the storage racks. Eventually the fuel assemblies must be transferred in special transport flasks to (interim) storage sites, sent for reprocessing or to final disposal. 

Fuel Receipt. In heavily shielded transport flasks via a rail link to UK stations/European stations (or the BNFL marine terminal at Barrow for sea transport from continental Europe and, for example, Japan) ... 

Use the entire contents of the transport flask for the extraction. In the case of volumes larger than 1 litre, evaporate to 1 litre. Transfer the water sample prepared in this way, including the solution of the sediment, to a 1.3-litre shaking funnel, set the pH to about 3 by adding hydrochloric acid or ammonium hydroxide solution dropwise (test by spotting onto indicator paper), treat with 2 ml of DDTC solution, shake for 10 seconds, then... 

Fig. 7. Diagram indicating the method of loading the source frame on the Slough plant of Johnson s Ethical Plastics Ltd. The transport flask is bolted to the outer face of the cell so that the active rods can be pushed straight from the magazine in the flask through the loading tube into the source frame.

The fuel building Is a rectangular, reinforced concrete structure containing a reinforced concrete, stainless steel lined fuel storage pond for underwater storage of new and Irradiated fuel. Separate stainless steel lined compartments are provided for underwater transfer of new and Irradiated fuel and to allow loading of Irradiated fuel Into the transport flasks. The... 

Transport and storage of LWR irradiated fuel have been carried out safely using a variety of transport flasks and holding inserts. In particular, the Excellox Flask utilized for PWR fuel transport with an insert also utilized for pond storage, originally designed for 7 fuel elements. 

The rate at which fuel could be removed from the site was not controlled by how quickly the fuel could be removed from the reactors but by the rate at which fuel transport flasks could be prepared for dispatch. One of the limiting factors in the transport safely case, and hence the number of fuel elements that can be put into a fuel flask, is the residual heat load of the elements. During the defiielling period the beat load reduces sufficiently to allow an increased loading within the flasks by up about 20%. Revised transport safety cases were therefore prepared for irradiated fuel from defueiling which assisted in reducing the overall duration. 

The coatings of fuel storage ponds and fuel handling ponds, as well as the equipment used in these areas, will become contaminated. When the water level in such ponds is lowered, surfaces may dry out, and this may cause a hazard due to airborne radioactive material. Systems should be provided for decontaminating such surfaces before they dry out. Systems should also be provided for decontaminating, before they dry out, fuel transport flasks and components that may have to be removed from the ponds for repair. 

Spent fuel handling areas (i.e. fuelling machines, the dry fuel store, the fuel dismantling cell, the fuel storage pond and the loading bay for fuel transport flasks) ... 

The pure plutonium nitrate product from the solvent extraction process was concentrated in a titanium evaporator and conditioned with respect to nitric acid concentration and the plutonium IV valency state to reduce radiolytic off-gas production before loading to the transport flask for shipment to BNFL Sellaiield. 

The system resembles that In a gas cooled reactor where new fuel Is put Into the refuelling machine which has previously contained defective or old fuel. When defective fuel Is withdrawn from the core It is Immediately put Into a tube which Is sealed. The tube Is then handled In the same manner as an old fuel element which Is not defective. Old fuel leaves the pond In the fuel transport flask, and while this has slight contamination from pond water, American experience shows that this Is not likely to present any difficulty In local site handling. 

A significant advance was made in this field by Watarai and Freiser [58], who developed a high-speed automatic system for solvent extraction kinetic studies. The extraction vessel was a 200 mL Morton flask fitted with a high speed stirrer (0-20,000 rpm) and a teflon phase separator. The mass transport rates generated with this approach were considered to be sufficiently high to effectively outrun the kinetics of the chemical processes of interest. With the aid of the separator, the bulk organic phase was cleanly separated from a fine dispersion of the two phases in the flask, circulated through a spectrophotometric flow cell, and returned to the reaction vessel. 

Transport Rates. The amount of halogenated compounds in the hexane layer increased linearly with time for up to 12 h for all compounds transported. For many compounds the relationship remained linear for at least 24 h and then it started to level off. This increase, expressed as a transport rate in ug/h was a linear function of the amount added to the flask (Table I). 

The coefficient a is related to the water solubility of the compound. A low transport rate can be expected when the flask loading is less than the amount of the compound that would dissolve in the volume of water in the flask. The transport rate... 

When sparingly soluble compounds have to be reduced they may be transported into the reaction flask for reduction by extraction in a Soxhlet apparatus surmounting the flask [[Pg.21]

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