Concerns, Control & Remediation
REMEDIATION - example
Thorium poses a challenge since it is radioactive and when it decays, produces Radon gas (also historically
called Thoron). This gas presents an airborne cancer threat to those exposed.
The Nuclear Regulatory Commission (NRC) addresses the problem in
10CFR 40.13. NRC
regulations mandate that people are exempt from the regulations only when quantities of
Thorium in lantern gas mantles, vacuum tubes, welding rods, electric lamps, germicidal or
sun lamps contain less than 2 grams or less than 0.25 percent by weight Thorium.
For more, see:
Perma-Fix was called on to assist for the Defense Logistics Agency, the logistics arm
of the Federal government. A quantity of Thorium, in the form of Thorium Nitrate,
ThNO3, was being held by the Agency for potential use as reactor breeder fuel,
using the Thorium
Because of its corrosive and hygroscopic nature, the Agency wanted to convert Thorium
Nitrate into a more stable and less corrosive form. Using a jacketed Plowshare
Reactor, Perma-Fix changed the Nitrate compound into the innocuous Thorium Hydroxide,
Th(OH), which also resulted in a significant volume reduction of material as an added
Not only was the form changed from a solid to a safer, more dense powder, Perma-Fix repackaged the
Thorium Hydroxide more efficiently, resulting in fewer drums of material to be stored.