The aging of natural gas plants and processing infrastructure, including those associated with propane and propylene production, is leading to ever-increasing decommissioning-related efforts and other intrusive work, such as enhanced operational maintenance and equipment upgrading. During these efforts lead-210-related Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) may be encountered. This contact, especially when unpredicted and unexpected, can result in adverse worker radiological exposures. Whereas radiological health and safety plans may include provisions to optimize "Distance-Time-Shielding"-oriented measures to provide protectiveness to workers, these may largely or exclusively emphasize threats posed by alpha, beta, and gamma forms of ionizing radiation. However, due to the rather unique form of interaction of high energy alpha particles emanating from decaying polonium-210, a daughter product of lead-210, with lithium-7-bearing material, problematic activities of neutron radiation; an "unexpected" form of ionizing radiation may result. Further, neutron radiation is not typically measured during field survey exacerbating the issue as to the possible presence of this form of radiation. Consequently, a comprehensive radiological worker safety program must consider this additional form of radiation to proactively detect its presence and level of activity, to provide optimal safety protocols and provide for permissible disposal and recycling options for impacted materials. This paper will discuss how the radioactive decay of naturally occurring radon-222 present in just-produced natural gas can lead to deposition of its radiogenic daughter, lead-210, and the subsequent radiogenic progeny within natural gas handling and onward processing facilities. It will be shown that these radionuclides can accumulate to potentially problematic activities that upon interaction with lubricating grease, which may have an elevated lithium content, can pose an additional worker safety issue and disposal challenge. The 22.3-year half-life of lead-210 will also allow for a multi-decade period of accumulation to occur and to persist after plant operations have ceased. The far shorter half-lives of its radiogenic progeny, especially that of polonium-210 (138 days), causes secular equilibrium to be quickly approached during operations and being achieved soon after plant operations have halted. The consequences of the highly efficient and unintended concentration of radon-222 and resultant enhanced lead-210 accumulation in cryogenic propane and propylene plants will be examined. A particular focus will be on the consequences of lithium present within grease that can preferentially concentrate radon-222 and lead-210 and its subsequent progeny in terms of neutron generation potential and consequences for adverse worker exposure. Specifically, the interaction between high energy alpha emissions produced during polonium-210 decay and lithium-7 (Po/Li) will be scrutinized with the ensuing neutron fluence generation estimated and the associated radiological risk. Experience has shown that it is not strictly the presence of TENORM that is problematic but rather its "unexpected" presence discovered during intrusive work that was not incorporated into facility deconstruction design and associated radiological health and safety plans. Conversely, when implementing a program that proactively considers the potential for lead-210, then this form of TENORM simply becomes another "special waste" that can be safely, efficiently, and effectively addressed without associated adverse worker exposures, project cost over-runs, and schedule delays. Additionally, it is vital to comprehensively and systematically consider and address all forms of ionizing radiation that may be present, including neutron fluence, to incorporate optimal safety protocols.
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