Types of Radioactive Waste Generated in a Nuclear Power Station and Methods Employed for their Disposal
Q. State the types of radioactive waste generated in a nuclear power station. Explain the methods employed for their disposal.
- Low level waste disposal : The low level waste comprises of papers, tools, clothing, filter through a special processing, so it becomes more compact in size. It is suitably buried at a little depth in land. Most of the low level waste do not require shielding during handling and transport.
- Intermediate level waste disposal : Intermediate level waste contains higher amounts of radioactivity and normally required shielding during handing and transport. All Intermediate level waste is treated and conditioned and I then kept in concrete container which is surrounded by a metal container. These containers are then deposited in deep underground facilities.
- High level waste disposal : High level waste is highly radioactive and requires shielding and cooling. It mainly comes from reprocessing of nuclear fuel which has already been used In a reactor. This used fuel contains Uranium (96%) and Plutonium. The Uranium and Plutonium are then separated by a separate process. The left over is extremely radioactive and emits high level of heat. Most of the high level waste is in the liquid form. This high level waste in liquid form is stored in specially built stainless tanks. These tanks are buried deep underground. Another method of disposal of liquid high level waste is deep – well Injection disposal in which the liquid is pumped under pressure and sent to ground at a depth of 3500 to 16000 feet. Also the high level waste in liquid form is somewhat difficult to handle and dispose. So it is converted into solid form for ease of handling. The solid blocks are put in stainless steel container which is then surrounded by reinforced concrete. The tanks are now ready for disposal. There are two ways of disposing this solid waste in tanks.
- It can be kept in trench deep underground.
- It can be suspended in sea beds.