Sampling mine atmospheres for potential alpha energy due to the presence of radon-220 (thoron) daughters
Although thorium minerals are not commonly found with uranium minerals mined in the United States, the mineral combination has been observed in a few deposits. The possibility also exists that thorium minerals might be associated with nonuranium ores or that thorium may be a constituent of the rocks surrounding nonradioactive ore deposits. Thorium-232, like uranium-238, is the parent of a decay series which includes a dense radioactive gas. In the thorium series this gas (radon-220) is commonly called thoron. Thoron decays through a series of short-lived daughters, some of which are alpha-particle emitters, and can pose the same health hazard (lung cancer) as has been attributed to excessive exposure to radon daughters. This paper describes the decay characteristics of thoron and its daughters, and gives a simple field method for testing for the presence of thoron daughters. Where such a test proves positive, the procedure for determining potential alpha energy (working levels) from thoron daughters is given. The occurrence of thoron (radon-220) and radon (radon-222) daughters together complicates the problem of computing the working level attributable to each decay series. A system is given for determining if a mixture of thoron and radon daughters is present, and the method for computing the total potential alpha energy for such mixtures is described.
- Research Organization:
- Mining Enforcement and Safety Administration, Denver, CO (USA). Denver Technical Support Center
- OSTI ID:
- 5975906
- Report Number(s):
- MESA-IR-1015; ON: DE83902960
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
RADON 220
AEROSOL MONITORING
ALPHA DETECTION
DECAY
URANIUM MINES
AIR
AIR SAMPLERS
MEASURING METHODS
MINES
RADIATION HAZARDS
RADIATION MONITORING
RADON 222
SAMPLING
THORIUM 232
UNDERGROUND MINING
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
CHARGED PARTICLE DETECTION
DAYS LIVING RADIOISOTOPES
DETECTION
EQUIPMENT
EVEN-EVEN NUCLEI
FLUIDS
GASES
HAZARDS
HEALTH HAZARDS
HEAVY NUCLEI
ISOTOPES
MINING
MONITORING
NUCLEI
RADIATION DETECTION
RADIOISOTOPES
RADON ISOTOPES
SAMPLERS
SECONDS LIVING RADIOISOTOPES
THORIUM ISOTOPES
UNDERGROUND FACILITIES
YEARS LIVING RADIOISOTOPES
054000* - Nuclear Fuels- Health & Safety
500300 - Environment
Atmospheric- Radioactive Materials Monitoring & Transport- (-1989)
050300 - Nuclear Fuels- Mining- (-1987)
653005 - Nuclear Theory- Radioactive Decay