I have recently been posting about the undetermined release of radioactive materials from the Waste Isolation Pilot Project near Carlsbad, New Mexico. In February, there was an event that released plutonium and americium into the atmosphere. Despite months of investigation, the ultimate cause of the radiation release still has not been determined. The WIPP is the only repository for low level waste, tools, clothing, etc. generated by the production of nuclear weapons for the U.S. arsenal. It is located in an old salt mine. Since the radiation release, the WIPP has been closed and there are estimations that it may remain closed for up to three years.
A new theory has been proposed to explain the radiation release. The waste shipped to the WIPP is contained in sealed drums. WIPP will not accept any liquid waste so some substance has to be added to any drum containing liquid to soak it up. In the past, the substance added was an inorganic clay-based absorbent similar to commercial cat litter. Such absorbents have been used to soak up chemical spill for many years. In the nuclear industry, these clay absorbents were routinely used to soak up liquids that were used to clean laboratories. The silicate minerals in the clay bound to and stabilized ammonia nitrates in the waste water.
Recently, a change was made to an organic absorbent made from wheat which is also used in commercial cat litter. It has been suggested that the new organic absorbent may have caused a chemical reaction that allowed nitrate salts to dry out instead of being bound and stabilized. These unstable nitrate salts could have caused a “mild” explosion that broke open some of the drums and released the radioactive isotopes. There is some evidence of melted seals on some drums of waste which suggests that something in or near the drums generated heat.
Inspectors of the sealed drums would not have seen anything that would have alerted them to the problem. The testing that is done for the buildup of gases above the materials in the drums before they are stored would also have given no indication of the problem.
There are drums that contain the new absorbent in the WIPP and more are piling up at temporary locations until the cause of the February radiation release has been determined. Environmental experts demand that those drums which are outside of the WIPP be moved inside and that drums in temporary storage be shipped to the WIPP. If the room is properly sealed as soon as the drums are stored, that should prevent a future radiation release. If the drums in temporary storage are not moved to the WIPP and sealed in then there may be more explosions in less secure places, releasing much more radiation into the environment.
The experts think that the absorbent explanation is the most likely cause of the radiation release but are not completely sure. In any case, this situation is illustrative of how complex nuclear technology can be. Apparently no one really investigated what organic absorbent could do before putting it into the drums. How many other bad decisions based on incomplete information will result in dangerous accidents?
Drums of low-level waste diverted from the WIPP to temporary storage in Texas:
