BUSINESS
Radioactive Waste Management
Radioactive Waste
Radioactive waste is a waste product containing radioactive decay material. It is usually the product of a nuclear process such as nuclear fission, though industries not directly connected to the nuclear power|nuclear power industry may also produce radioactive waste.
Radioactivity diminishes over time, so in principle the waste needs to be isolated for a period of time until it no longer poses a hazard. This can mean hours to years for some common medical or industrial radioactive wastes, or thousands of years for high-level radioactive waste. High-level wastes from nuclear power plants and nuclear weapons reprocessing.
The majority of radioactive waste is "low-level waste", meaning it has low levels of radioactivity per mass or volume.
The main approaches to managing radioactive waste to date have been segregation and storage for short-lived wastes, near-surface disposal for low and some intermediate level wastes, and deep burial or transmutation for the long-lived, high-level wastes.
Waste Classification Criteria and Treatment Methods
Exempt Waste
· Wastes to be deregulated, exempted and deregulated
· IAEA RS-G.1.7 application : Co-60 (0.1Bq/g)
Very Short Lived Waste
· 100 days of half-life
· Store and in-house disposal until it collapses below the EW level
Very Low Level Waste
· Waste dozens to hundreds of times the EW radiation level
· Simple landfill disposal : surface layer
Low Level Waste
· Requires Isolation and Containment for hundreds of years
· Limit : alpha 400Bq/g, beta/gamma dozens kBq/g
· shallow land disposal : up to 30 m deep from surface
Intermediate Level Waste
· Long-sensitive nuclide
· Requires more isolation and Containment than LLW
· Middle layer disposal : tens to hundreds of meters
High Level Waste
· consideration in which thermal acid is important
· Scope of radioactivity : 104～106TB/㎥
· underground disposal
Radioactive Waste Management
Radioactive waste is extremely varied in terms of physical and chemical form, radioactivity and the half-life of the radioactive elements it contains, as well as volume.
Sorting
This consists in separating waste according to its different properties, in particular the half-lives of the radionuclides it contains. It also involves separating waste that can be compacted, incinerated or melted down to reduce the volume.
Treatment and Conditioning
Different types of waste undergo different types of treatment (incineration, calcination, melting, compacting, cementation, vitrification, etc.). It is then sealed in a container. The result is a radioactive waste package.
Storage and Disposal
Storage facilities are designed to accommodate waste packages for a limited period of time. Disposal is the final stage of the waste management process and implies that the packages have reached their final destination or, at least, that there is no intention of retrieving them. That means, of course, that the steps taken must protect people and the environment both in the short and very long term.
Estimated amount of decommissioning waste for GCR and PWR (IAEA)
Radioactive Materials
GCR (250 MWe)
Activated steel
Graphite
Activated concrete
Contaminated steel
Contaminated steel (slightly)
Contaminated concrete
Contaminated lagging
contaminated technological waste
Total
3,000
2,500
600
6,000
-
150
150
1,000
13,400 ton
PWR (900-1300 MWe)
650
-
300
2,400
1,100
600
150
1,000
6,200 ton
Forecasts of radioactive wastes generated by domestic nuclear