Radioactive Waste in Nepal

Thirty countries currently use nuclear power and about the same number are considering, planning or actively working to include it in their energy mix. In Nepal, radioactive sources are mainly used in medicine (Cancer treatment and other medical treatment), Research, mining, education, food and drug administration. Absence of nuclear power plants but surrounded by those plants in neighboring country of Nepal. Different National and International policies like National Nuclear Policy, (2007) guides for use, transportation of radioactive compounds.

Type of Radioactive waste

Radioactive waste includes any material that is either intrinsically radioactive, or has been contaminated by radioactivity, and that is deemed to have no further use. Every radionuclide has a half-life – the time taken for half of its atoms to decay, and thus for it to lose half of its radioactivity. Radionuclides with long half-lives tend to be alpha and beta emitters – making their handling easier – while those with short half-lives tend to emit the more penetrating gamma rays. Eventually all radioactive waste decays into non-radioactive elements. The more radioactive an isotope is, the faster it decays. Radioactive waste is typically classified as either low-level (LLW), intermediate-level (ILW), or high-level (HLW), dependent, primarily, on its level of radioactivity.

The amount of waste generated by nuclear power is very small relative to other thermal electricity generation technologies. Used nuclear fuel may be treated as a resource or simply as a waste. Nuclear waste is neither particularly hazardous nor hard to manage relative to other toxic industrial wastes. Safe methods for the final disposal of high-level radioactive waste are technically proven the international consensus is that geological disposal is the best option.

How is waste managed?

In most of the recent purchases there exists an agreement with Manufacturers/ Suppliers which binds them to take care of the sources after usage. This, however, was found lacking in sources because such sources can just be dumped like any household waste after their activity has been reduced.

The steps employed in radioactive waste management depend on the nature of the radioactive waste being managed. There are a series of basic steps that commonly take place:

Treatment involves operations intended to change waste streams? characteristics to improve safety or economy. Treatment techniques may involve compaction to reduce volume, filtration or ion exchange to remove radionuclide content, or precipitation to induce changes in composition.

Conditioning is undertaken to change waste into a form that is suitable for safe handling, transportation, storage, and disposal. This step typically involves the immobilisation of waste in containers. Liquid LLW and ILW are typically solidified in cement, whilst HLW is calcined/dried then vitrified in a glass matrix. Immobilised waste will be placed in a container suitable for its characteristics.

Storage of waste may take place at any stage during the management process. Storage involves maintaining the waste in a manner such that it is retrievable, whilst ensuring it is isolated from the external environment. Waste may be stored to make the next stage of management easier (for example, by allowing its natural radioactivity to decay). Storage facilities are commonly onsite at the power plant, but may be also be separate from the facility where it was produced.

Disposal of waste takes place when there is no further foreseeable use for it, and in the case of HLW, when radioactivity has decayed to relatively low levels after about 40-50 years.

Summary:

The categorization - high, intermediate, low - helps determine how wastes are treated and where they end up. High-level wastes require shielding and cooling, low-level wastes can be handled easily without shielding.

All radioactive waste facilities are designed with numerous layers of protection to make sure that people remain protected for as long as it takes for radioactivity to reduce to background levels. Low-level and intermediate wastes are buried close to the surface. For low-level wastes disposal is not much different from a normal municipal landfill. High-level wastes can remain highly radioactive for thousands of years. They need to be disposed of deep underground in engineered facilities built in stable geological formations. While no such facilities for high-level wastes currently operate, their feasibility has been demonstrated and there are several countries now in the process of designing and constructing them.

Bibliography

BIBLIOGRAPHY Bhusal, S. (2013). STATUS OF RADIOACTIVE WASTE MANAGEMENT IN NEPAL. MINISTRY OF SCIENCE TECHNOLOGY AND ENVIRONMENT.