New observations in radon emanation and migration

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5081388

Baugues, C M; Chyi, L L ^[1]

---

1. Univ. of Akron, OH (United States). Dept. of Geology

An apparatus is built to observe radon emanation and migration under laboratory controlled conditions. The setup has a soil column as radon source, a chamber for continuous radon monitoring, and a closed loop with forced air circulation. Within this setup, radon levels are not affected by environmental factors. Radon only disappears through natural decay. Alpha recoil is the most important factor affecting the release of radon from mineral grains. Only those radon atoms produced near the surface of the grain, and recoil toward the surface have the chance of entering the pore space and migrating into the surrounding environment. Therefore, emanation power is related to particle surface area available for this release. A soil sample is collected and sieved to various sizes for radon emanation testing. Under this recoil-release model, one should expect that the radon level in the setup will increase as the particle size decreases. However, the authors discovered that the emanation power decreases with decreasing grain size. A new term, radon retention power, is proposed on the assumption that the negatively charged radon atom, due to alpha decay, could be retained on the surface of the same or another particle. This depends on the nature of the static charge of that particle. Radon levels in the setup are found to increase if the column is allowed to tilt down towards the monitor. As radon gas is approximately 7.5 times heavier than air, concentration of radon due to gravity is possible. This may explain the downward radon flux phenomenon in soil profiles observed by some investigators.

• OSTI ID: 5081388
• Report Number(s): CONF-9303210--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:3
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540130 -- Environment
Atmospheric-- Radioactive Materials Monitoring & Transport-- (1990-)
540230* -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
CHEMICAL COMPOSITION
ECOLOGICAL CONCENTRATION
ELEMENTS
ENVIRONMENTAL TRANSPORT
FLUIDS
GASES
MASS TRANSFER
NATURAL RADIOACTIVITY
NONMETALS
RADIOACTIVITY
RADIOECOLOGICAL CONCENTRATION
RADIONUCLIDE MIGRATION
RADON
RARE GASES
SOILS