“A Sea of Radiation”
As Dr. Dade W. Moeller used to say: “We live in a sea of radiation.” The sources of this radiation include cosmic rays from outer space, terrestrial radiation from naturally occurring radioactive materials (NORM) found in the rocks and minerals around us, and man-made radiation from sources including global fallout or nuclear medicine. A significant component of terrestrial sources of radiation is radon gas.
What Is Radon?
Radon is an inert radioactive gas produced by the decay of uranium or thorium. As radon undergoes radioactive decay, several radioactive decay products are produced. Most of these products have relatively short half-lives (the time it takes for half of the radioactive atoms present to undergo transformation through radioactive decay), with the exception of Lead-210 and Polonium-210, which have half-lives of 22.6 and 138 days, respectively.
Radon in Natural Gas
Radon can be of concern in natural gas production because it will flow with the natural gas and potentially expose both workers in gas production facilities, and individuals in homes that use natural gas for heating and cooking.
Radon on Processing and Storage Equipment
After radon undergoes radioactive decay, the radon decay products attach to airborne particles and ultimately can form thin radioactive films on the inner surfaces of natural gas processing and storage equipment. Radon is constantly entering with the feed natural gas, allowing the buildup of radon decay products inside the equipment over time.
Radon in “Pigging” Waste
As a routine maintenance activity, gas pipelines undergo a process known as “pigging,” where a device is sent through the pipeline to physically scrape materials from the inner surfaces of the pipe that may restrict the flow of gas. When these devices are extracted from the pipeline, waste is collected, which can contain elevated concentrations of radon decay products. This waste can potentially be a hazard to workers involved in the pigging process, as well as those that package and dispose of the waste.
Radon in Homes that Use Natural Gas
Homes that use natural gas for heating and cooking can experience an incremental increase of indoor radon over the concentrations established from the migration of radon into the home from the surrounding rocks and soil. Numerous studies have attempted to quantify indoor radon from the use of natural gas, but as can be expected, such concentrations are dependent on several factors, including:
- the amount of radon in the recovered natural gas,
- the time elapsed between gas recovery and use (allowing for radioactive decay), and
- household ventilation.
While there are various national and international regulations and guidance on radiation protection, these are not typically specific to the oil and gas industry.
NCRP Scientific Committee 5-2
The National Council on Radiation Protection and Measurements (NCRP) is the organization chartered by Congress in 1964 to provide radiation protection guidance to the United States. As part of its mission, the NCRP established Scientific Committee 5-2 to provide recommendations for technologically enhanced NORM (“TENORM”) waste management.
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