Transport of fuel and radioactive materials including wastes

A wide variety of radioactive materials are transported

from nuclear power stations. The main types are samples sent for analysis, radioactive wastes sent for disposal, items of contaminated/irradiated plant re­quiring off-site testing or maintenance. In addition, radioactive sources that are used at both nuclear and conventional stations for measurement and test pur­poses such as radiography and tracer experiments.

Wastes for sea disposal were usually sent by rail to the port of shipment. Otherwise most consignments are sent by road.

Effluent samples are invariably low in activity con­tent and are sent in excepted packages, which might consist of a glass or plastic bottle surrounded by ab­sorbent material within a cardboard box. On the other hand, some samples of reactor structural materials such as steel and graphite are highly radioactive and are transported in specially designed Type A or Type В packages.

Radioactive wastes arise as a result of normal op­erations on nuclear stations and those routinely dis­posed of include used protective clothing, redundant items of equipment, incinerator ash, contaminated oil and general trash. Wastes such as pond sludges and spent ion exchange resins arise from the treatment of effluent or of cooling pond water.

The low level wastes are sent for shallow land burial. Their specific activity or surface contamination levels are such that most meet the specifications for low specific activity material (LSA) or surface contami­nated objects (SCO). They can therefore be sent in ordinary industrial drums, sometimes having a plastic bag with a liner. Some treatment of contaminated items may be required to reduce the readily dispersi­ble component of the contamination. Drums are then loaded into a reinforced freight container to give added integrity. Contaminated items too large to be drummed are also transported in a reinforced freight container. An ordinary road tanker is used to take contaminated oil to oil-fired power stations where it is burnt after being mixed with normal fuel. Oily residues which have a higher activity are absorbed on solids and sent in drums to regional incinerators.

The higher activity spent ion exchange resins are currently stored on stations but if they are to be trans­ported to disposal sites they will have to be processed into solid compact blocks, as were the pond sludges which were sent for sea disposal. These wastes require specially designed packaging that provides shielding as well as containment. As the solid compact block provides some containment, the containment provided by the packaging can be reduced. In order to make the disposal operations more cost effective, the future trends may be to have larger packages incorporating more waste. This will involve using Type В packages and having re-usable rather than disposable shielding.

The packaging required for the miscellany of other contaminated plant cannot be specified in advance as it will depend upon the activity levels and the facilities at the off-site testing establishment. After decontami­nation, the item may be suitable for transport un­packaged or in excepted packaging, i. e., a wooden box. However, packaging having a higher integrity may have to be employed.

Radiography sources mainly require Type A pack­aging, although the higher activity sources may require Type В packaging. In general the source container itself provides the packaging.

Industrial packaging, used for LSA and SCO, and Type A packaging do not require competent authority approval provided they are fissile exempt (see Sec­tion 2.8.3 of this chapter), but approvals are issued by the health and safety department to ensure a uniform standard throughout the CEGB. The approval and supporting documentation, including any test re­ports, are kept centrally and are available for inspec­tion by the competent authority.

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