The United States alone produces an average volume of commercial low-level radioactive waste of about 500,000 cubic feet each year. That is a lot of waste! This comes from a variety of places. Mainly though, it is produced by nuclear power plants. This waste brings up a problem though. It is difficult to dispose of radioactive materials for two reasons. One, some radioactive materials last for thousands of years. Two, most radioactive materials are hazardous and can't be stored with conventional means. Currently, there are a few proposals that have been made to combat this problem. These include near-surface facilities, mined cavities, and geological repositories.
In the past, some countries dumped radioactive waste into the sea. This is extremely hazardous to the environment. Recently though, more practical ideas have been made to bury the waste. Before the material is even considered for storage or disposal, it must be properly packaged. This includes packing it into steel drums or concrete containers. These containers are expected to provide physical containment for at least a thousand years. If the waste is in a liquid state, it must be placed on a special abosrbitent type of material and then placed into the containers. The next step would be to transport the containers to the burial site.
There are several different types of diposal facilities proposed. One is a near-surface facility. This facility is located within a few tens of meters from the surface. These facilities include trenches, and engineered vaults. Another proposal is mined cavities. These facilities are constructed inside mines and caverns. They are either man-made or natural. The last proposal is called a geological repository. These sites are located more than several hundred meters below the surface in a stable geological formation(away from major fault lines and other problem spots). After the site is located there are other steps in the disposal process.
It is proposed that the drums will be placed in groups of four. Around these groups of four a frame will be built. The frames then will be placed inside hard rock holes or caverns. This will then be covered with a special backfill material that prevents the movement of groundwater.A fter all of this is done, the site will be monitored for up to 100 years to detect any leakage of radioactive material or any outside influences such as flooding.
There have been problems with past proposals though. These problems were caused mainly by the acceptance of liquid waste. The liquid waste leaked out of it's containers much easier than the solid waste. This waste then contaminated the ground water. In other past proposals, some sites were "lost" and accidentally discovered when construction began in the region. This was due to human error and not structural problems. One other problem also experienced by landfills is the availability of space. There aren't too many places to store radioactive material safely and away from the general population. Also, the sites where it is safe for storage are filling up.
At this point in time, the most adequate and logical type of radioactive waste management seems to be burying the material. Although right now it is difficult to see if this method the best available. Only future generations can tell. With further development of the space shuttle program perhaps the method of burying waste will become obsolete.