WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- Anyone who’s navigated over land in the military has probably used a lensatic compass.
Lensatic compasses contain a glow-in-the-dark chemical called tritium, a self-powered lighting source that requires no recharging. The tritium illuminates the compass face so it can be seen in low-light conditions. To keep the user safe from exposure, a thin plastic cover blocks the tritium’s beta radiation from escaping while allowing the benefit of illumination.
Unfortunately, tritium only has a shelf life of 10 years. Because it is radioactive, precautions must be taken when the compasses can no longer be used.
Enter the Air Force Radioactive Recycling and Disposal team at Wright-Patterson Air Force Base. In 1994, the team figured out tritium could be recycled and the compasses reused rather than disposed of.
AFRRAD receives compass shipments from every military branch and all over the United States on a regular basis. Once about a thousand compasses are collected, the team packs and sends them to the original manufacturer.
The manufacturer removes the radioactive microspheres and ships them to a contractor, who crushes and renews the tritium. The tritium is sold back to the manufacturer, who puts it back in the compass housing.
“You end up with a brand-new compass. Essentially, it’s a recycled compass but you can’t tell,” said Chris Anthony, AFRRAD program director. “We’ve gone through that for four generations (of compasses).”
Anthony estimates AFRRAD has recycled 30,000 compasses in 25 years. The base program also saves the Air Force about $58,000 annually.
Due to its chemical properties and weak radioactive emissions, tritium is considered one of the least-harmful radionuclides. However, tritium can leach into the soil and groundwater, especially if it is not disposed of properly. By recycling or reusing, there is less chance for contamination.
Tritium does not have chemically toxic effects and its hazard potential to human health is solely because it emits ionizing radiation. The beta particle emitted by tritium is generally only considered to be hazardous if a large quantity is taken into the body by inhalation, skin absorption or ingestion.
Tritium exists throughout the environment, so the general public’s protection falls largely on the companies and entities that produce or possess it and government regulating agencies such as the Nuclear Regulatory Commission, Department of Energy and Environmental Protection Agency.
Prior to AFRRAD’s recycling program, the compasses would have been thrown out and the tritium disposed of as radioactive waste, Anthony said. Radioactive-waste disposal is costly.
The recycling program comes with a fee but it is less expensive than disposal. The cost of recycling a single compass is about $8, while disposal would be about $50. Since its inception, the program has saved the Air Force over $1 million in disposal fees.
Economically and environmentally, compass recycling makes sense, he added.