Working level

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Working level (WL) is a historical unit of concentration of radioactive decay products of radon, applied to uranium mining environment. [1] One working level refers to the concentration of short-lived decay products of radon in equilibrium with 3,700 Bq/m3 (100 pCi/L) in air. These decay products would emit 1.3 × 105 MeV in complete decay. [2] The Nuclear Regulatory Commission uses this definition. [3]

Working level month (WLM) is a closely related quantity, referring to exposure to one working level for 170 hours per month. This comes from assuming a 40-hour work week.

In 2002, the NRC regulations limited exposure in mines to 0.3 WL, which was comparable with the standards of International Commission on Radiological Protection at the time. [2]

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Nuclear fallout is residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and the shock wave has passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes. The amount and spread of fallout is a product of the size of the weapon and the altitude at which it is detonated. Fallout may get entrained with the products of a pyrocumulus cloud and when combined with precipitation falls as black rain, which occurred within 30–40 minutes of the atomic bombings of Hiroshima and Nagasaki. This radioactive dust, usually consisting of fission products mixed with bystanding atoms that are neutron-activated by exposure, is a form of radioactive contamination.

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Effective dose is a dose quantity in the International Commission on Radiological Protection (ICRP) system of radiological protection.

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Hydraulic fracturing is the propagation of fractures in a rock layer by pressurized fluid. Induced hydraulic fracturing or hydrofracking, commonly known as fracking, is a technique used to release petroleum, natural gas, or other substances for extraction, particularly from unconventional reservoirs. Radionuclides are associated with fracking in two main ways. Injection of man-made radioactive tracers, along with the other substances in hydraulic-fracturing fluid, is often used to determine the injection profile and location of fractures created by fracking. In addition, fracking releases naturally occurring heavy metals and radioactive materials from shale deposits, and these substances return to the surface with flowback, also referred to as wastewater.

References

  1. Vaillant, Ludovic; Bataille, Céline (September 2012). "Management of radon: a review of ICRP recommendations" (PDF). Journal of Radiological Protection. 32 (3): R3. Bibcode:2012JRP....32R...1V. doi:10.1088/0952-4746/32/3/R1. PMID   22809956. S2CID   2423305 . Retrieved 16 September 2016.
  2. 1 2 Shapiro, Jacob (June 2002). Radiation Protection: A Guide for Scientists, Regulators, and Physicians (4th ed.). Harvard University Press. p. 444. ISBN   9780674007406 . Retrieved September 16, 2016.
  3. "NRC Regulations Title 10, Code of Federal Regulations Part 20.1003". United States Nuclear Regulatory Commission. Retrieved 16 September 2016.