Current through Register Vol. XLI, No. 44, November 1, 2024
Section 64-23-3 - DefinitionsAs used in this rule, these terms have the definitions set forth below. Additional definitions used only in a certain part will be found in that part.
3.1. A1 - the maximum activity of special form radioactive material permitted in a Type A package.3.2. A2 - the maximum activity of radioactive material, other than special form radioactive material, permitted in a Type A package. These values are either listed in Table 64-23 Ee of this rule, Table 64-23 Ee a, or may be derived in accordance with the procedure prescribed in Table 64-23 Ee of this rule.3.3. Absorbed Dose - the energy imparted by ionizing radiation per unit mass of irradiated material. The units of absorbed dose are the Gray (Gy) and the Rad.3.4. Accelerator - any machine capable of accelerating electrons, protons, deuterons, or other charged particles in a vacuum and of discharging the resultant particulate or other radiation into a medium at energies usually in excess of one (1) MeV. For purposes of this definition, particle accelerator is an equivalent.3.5. Accelerator Produced Material - any material made radioactive by exposing it in a particle accelerator.3.6. Activity - the rate of disintegration or transformation or decay of radioactive material. The units of activity are the Becquerel (Bq) and the Curie (Ci).3.7. Adult - an individual eighteen (18) or more years of age.3.8. Agency - the West Virginia division of health.3.9. Airborne Radioactivity Area - a room, enclosure, or area in which airborne radioactive materials exist in concentrations: 3.9.a. In excess of the derived air concentrations (DACS) specified in Table 64-23 F, Table i of this rule; or3.9.b. To such a degree that an individual present in the area without respiratory protective equipment could exceed, during the hours an individual is present in a week, an intake of six tenths (0.6) percent of the annual limit on intake (ALI) or twelve (12) DAC hours.3.10. Airborne Radioactive Material - any airborne radioactive material dispersed in the air in the form of dusts, fumes, mists, vapors or gases.3.11. As Low As Reasonably Achievable (ALARA) - making every reasonable effort to maintain exposures to radiation as far below the dose limits in this rule as is practical, consistent with the purpose for which the registered activity is undertaken, taking into account the state of technology, the economics of improvements in relation to state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and registered sources of radiation in the public interest.3.12. Background radiation - radiation from cosmic sources; naturally occurring radioactive materials, including radon, except as a decay product of source or special nuclear material, and including global fallout as it exists in the environment from the testing of nuclear explosive devices. Background radiation does not include sources of radiation from radioactive materials regulated by the agency.3.13. Becquerel (Bq) - the SI unit of activity. One (1) Becquerel is equal to one (1) disintegration or transformation per second (DPS or TPS).3.14. Bioassay - the determination of kinds, quantities or concentrations, and, in some cases, the locations of radioactive material in the human body, whether by direct measurement, in vivo counting, or by analysis and evaluation of materials excreted or removed from the human body. For purposes of this rule, "radiobioassay" is an equivalent term.3.15. Brachytherapy - a method of radiation therapy in which sealed sources are utilized to deliver a radiation dose at a distance of up to a few centimeters, by surface, intracavitary, or interstitial application.3.16. Byproduct Material: 3.16.a. Any radioactive material, except special nuclear material, yielded in or made radioactive by exposure to the radiation incident to the process of producing or utilizing special nuclear material; and3.16.b. The tailings or wastes produced by the extraction or concentration of uranium or thorium from ore processed primarily for its source material content, including discrete surface wastes resulting from uranium or thorium solution extraction processes. Underground ore bodies depleted by these solution extraction operations do not constitute "byproduct material" within this definition.3.17. Calibration - the determination of (a) the response or reading of an instrument relative to a series of known radiation values over the range of the instrument, or (b) the strength of a source of radiation relative to a standard.3.18. Collective Dose - the sum of the individual doses received in a given period of time by a specified population from exposure to a specified source of radiation.3.19. Committed Dose Equivalent (HT,50) - the dose equivalent to organs or tissues of reference (T) that will be received from an intake of radioactive material by an individual during the fifty- (50) -year period following the intake.3.20. Committed Effective Dose Equivalent (HE, 50) - the sum of the products of the weighting factors (wT) applicable to each of the body organs or tissues that are irradiated and the committed dose equivalent to each of these organs or tissues (HE,50 = E wT HT,50).3.21. Calendar Quarter - not less that twelve (12) consecutive weeks nor more than fourteen (14) consecutive weeks. The first calendar quarter of each year shall begin in January and subsequent calendar quarters shall be so arranged such that no day is included in more than one calendar quarter and no day in any one year is omitted from inclusion within a calendar quarter. No registrant shall change the method observed by him of determining calendar quarters for the purpose of this rule except at the beginning of the calendar year.3.22. Curie - a unit of quantity of activity. One (1) Curie (Ci) is that quantity of radioactive material which decays at the rate of 3.7E+10 disintegrations or transformations per second (dps or tps).3.23. Deep Dose Equivalent (Hd), which applies to external whole body exposure, is the dose equivalent at a tissue depth of one (1) centimeter (one thousand [1000] mg/cm2).3.24. Depleted Uranium - the source material uranium in which the isotope uranium-235 is less than seven hundred eleven one thousandths (0.711) weight percent of the total uranium present. Depleted uranium does not include special nuclear material.3.25. Dose - as used in this rule shall mean absorbed dose or dose equivalent as appropriate. 3.25.a. Absorbed Dose - is the energy imparted to matter by ionizing radiation per unit mass of irradiated material at the place of interest. The specific unit of absorbed dose is the rad.3.25.b. Dose Equivalent - the product of the absorbed dose in tissue, quality factor, and all other necessary modifying factors at the location of interest. The units of dose equivalent are the sievert (Sv) and Rem.3.26. Dose Limits - the permissible upper bounds of radiation doses established in accordance with this rule. For purposes of this rule, "limits" is an equivalent term.3.27. Effective Dose Equivalent (HE) - the sum of the products of the dose equivalent to each organ or tissue (HT) and the weighting factor (wT) applicable to each of the body organs or tissues that are irradiated (HE = E wTHT).3.28. Embryo or Fetus - the developing human organism from conception until the time of birth.3.29. Entrance or Access Point - any opening through which an individual or extremity of an individual could gain access to radiation areas or to registered radioactive materials. This includes entry or exit portals of sufficient size to permit human entry, irrespective of their intended use.3.30. Explosive Material - any chemical compound, mixture, or device which produces a substantial instantaneous release of gas and heat spontaneously or by contact with sparks or flame.3.31. Exposure - the quotient of the dQ by dm where "dQ" is the absolute value of the total charge of the ions of one sign produced in air when all the electrons (negatrons and positrons) liberated by photons in a volume element of air having mass "dm" are completely stopped in air. The SI unit of exposure is the Coulomb per kilogram (C/kg). (The special unit of exposure is the Roentgen [R].)3.32. Exposure Rate - the exposure per unit of time, such as R/min., mR/hr., etc.3.33. Extremity - hand, elbow, arm below the elbow, foot, knee, and leg below the knee.3.34. Eye Dose Equivalent - the external dose equivalent to the lens of the eye at a tissue depth of three tenths (0.3) centimeter (three hundred [300] mg/cm2).3.35. Former Atomic Energy Commission or Nuclear Regulatory Commission Licensed Facilities - nuclear reactors, nuclear fuel reprocessing plants, uranium enrichment plants, or critical mass experimental facilities where Atomic Energy Commission or Nuclear Regulatory commission licenses have been terminated.3.36. Generally Applicable Environmental Radiation Standards - standards issued by the Environmental Protection Agency under the authority of the Atomic Energy act of 1954, as amended, that impose limits on radiation exposures or levels, or concentrations or quantities of radioactive material, in the general environment outside the boundaries of locations under the control of persons possessing or using radioactive material.3.37. Gray (Gy) - the SI unit of absorbed dose. One (1) Gray is equal to an absorbed dose of one (1) joule per kilogram (one hundred [100] Rad).3.38. Half Life - the amount of time required for the activity of a specific radioactive material to reach one-half of its original activity.3.39. Healing Arts - diagnostic or healing treatment of human and animal maladies including but not limited to the following which are duly registered by the State of West Virginia for the lawful practice of: medicine and its associated specialties, dentistry, veterinary medicine, osteopathy, chiropractic, and podiatry.3.40. High Radiation Area - any area, accessible to individuals in which radiation levels could result in an individual receiving a dose equivalent in excess of one (1) mSv (one-tenth [0.1] Rem) in one (1) hour at thirty (30) centimeters from any source of radiation or from any surface that the radiation penetrates.3.41. Human Use - the internal or external administration of radiation or radioactive materials to human beings.3.42. Individual - any human being.3.43. Individual Monitoring - the assessment of:3.43.a. Dose equivalent (a) by the use of individual monitoring devices or (b) by the use of survey data; or3.43.b. Committed effective dose equivalent (a) by bioassay or (b) by determination of the time-weighted air concentrations to which an individual has been exposed, that is, DAC-hours.3.44. Individual Monitoring Devices - devices designed to be worn by a single individual for the assessment of dose equivalent. For purposes of this rule, "personnel dosimeter" and "dosimeter" are equivalent terms. Examples of individual monitoring devices are film badges, thermoluminescent dosimeters (TLDS), pocket ionization chambers, and personal air sampling devices.3.45. Inspection - an official examination or observation including but not limited to tests, surveys, and monitoring to determine compliance with rules, regulations, orders, requirements and conditions of the agency.3.46. Installation - the location where one or more sources of ionizing radiation are used, operated or stored.3.47. Instrument Traceability (for ionizing radiation measurements) - the ability to show that an instrument has been calibrated at specified time intervals using a national standard or a transfer standard. If a transfer standard is used, the calibration must be at a laboratory accredited by a program which requires continuing participation in measurement quality assurance with the national institute of standards and technology or other equivalent national or international program.3.48. Interlock - a device arranged or connected such that the occurrence of an event or condition is required before a second event or condition can occur or continue to occur.3.49. Internal Dose - that portion of the dose equivalent received from radioactive material taken into the body.3.50. Licensing State - any state with regulations equivalent to the suggested state regulations for control of radiation relating to, and an effective program for, the regulatory control of narm and which has been granted final designation by the Conference of Radiation Control Program Directors, Inc.3.51. Limits - the permissible upper bounds of radiation doses established in accordance with this rule.3.52. Lost or Missing Source of Radiation - registered source of radiation whose location is unknown. This definition includes, but is not limited to, radioactive material that has been shipped but has not reached its planned destination and whose location cannot be readily traced in the transportation system.3.53. Major Processor - a user processing, handling, or manufacturing radioactive material exceeding Type A quantities as unsealed sources or material, or exceeding four (4) times Type B quantities as sealed sources, but does not include nuclear medicine programs, universities, industrial radiographers, or small industrial programs. Type A and B quantities are defined in Subsection 13.2. of this rule.3.54. Member of the Public - an individual except when that individual is receiving an occupational dose.3.55. Monitoring - the measurement of radiation, radioactive material concentrations, surface area activities or quantities of radioactive material and the use of the results of these measurements to evaluate potential exposures and doses. For purposes of this rule, "radiation monitoring" and "radiation protection monitoring" are equivalent terms.3.56. NARM - any naturally occurring or accelerator-produced radioactive material. It does not include byproduct, source, or special nuclear material.3.57. Natural Radioactivity - the radioactivity of naturally occurring nuclides.3.58. Nuclear Regulatory Commission - the Nuclear Regulatory Commission or its duly authorized representatives.3.59. Occupational Dose - the exposure of an individual to radiation (a) in a restricted area; or (b) in the course of employment in which the individual's duties involve exposure to radiation, provided, that occupational dose shall not be deemed to include any exposure of an individual to radiation for the purpose of diagnosis or therapy of such individual.3.60. Package - the packaging together with its radioactive contents as presented for transport.3.61. Particle Accelerator - any machine capable of accelerating electrons, protons, deuterons, or other charged particles in a vacuum and of discharging the resultant particulate or other radiation into a medium at energies usually in excess of 1 MeV. For purposes of this definition, particle accelerator is an equivalent.3.62. Person - any individual, corporation, partnership, firm, association, trust, estate, public or private institution, group, agency, political Subdivision of West Virginia, any other state or political Subdivision or agency thereof, and any legal successor, representative, agent or agency of the foregoing, other than the United States Nuclear Regulatory Commission, or any successor thereto, or other federal government agencies.3.63. Personnel Monitoring Equipment - devices designed to be worn by a single individual for the assessment of dose equivalent. For purposes of this rule, "personnel dosimeter" and "dosimeter" are equivalent terms. Examples of individual monitoring devices are film badges, thermoluminescent dosimeters (TLDS), pocket ionization chambers, and personal air sampling devices.3.64. Protective Apron - an apron made of radiation-attenuating materials used to reduce exposure to radiation.3.65. Public Dose - the dose received by a member of the public from sources of radiation from registered operations. Public dose does not include occupational dose, or dose received from background radiation, or dose received as a patient from medical practices, or dose received from voluntary participation in medical research programs.3.66. Pyrophoric Material - any liquid that ignites spontaneously in dry or moist air at or below 130 EF (54.4 EC) or any solid material, other than one classed as an explosive, which under normal conditions is liable to cause fires through friction, retained heat from manufacturing or processing, or which can be ignited readily and, when ignited, burns so vigorously and persistently as to create a serious transportation, handling, or disposal hazard. Included are spontaneously combustible and water-reactive materials.3.67. Qualified Expert - an individual having the knowledge and training to measure ionizing radiation, to evaluate safety techniques, and to advise regarding radiation protection needs, for example, individuals certified in the appropriate field by the American Board of Radiology, or the American Board of Health Physics, or the American Board of Medical Physics, or those having equivalent qualifications. With reference to the calibration of radiation therapy equipment, an individual having, in addition to the above qualifications, training and experience in the clinical applications of radiation physics to radiation therapy, for example, individuals certified in Therapeutic Radiological Physics or X-ray and Radium Physics by the American Board of Radiology, or those having equivalent qualifications.]3.68. Quality Factor (Q) - the modifying factor, listed in Tables 64-23 A and B, that is used to derive dose equivalent from absorbed dose.3.69. Rad - the special unit of absorbed dose. One (1) rad is equal to an absorbed dose of one hundred (100) ergs per gram or one-one hundredth (0.01) joule per kilogram (0.01 Gy).3.70. Radiation - ionizing radiation, i.e., gamma rays and x-rays, alpha and beta particles, high speed electrons, neutrons, and other nuclear particles capable of producing ion pairs. For purposes of this rule, ionizing radiation is an equivalent term. Radiation, as used in this rule, does not include nonionizing radiation, such as microwaves, radiowaves, visible, infrared, or ultraviolet light.3.71. Radiation Area - any area, accessible to individuals, in which there exists radiation at such levels that a major portion of the body could receive in any one hour a dose in excess of five (5) milliRems, or in any five (5) consecutive days a dose of one hundred (100) milliRems.3.72. Radiation Machine - any device capable of producing radiation except those which produce radiation only from radioactive material.3.73. Radiation Safety Officer - one who has the knowledge and responsibility to apply appropriate radiation protection rules.3.74. Radioactive Material - any material (solid, liquid, or gas) which emits ionizing radiation spontaneously.3.75. Radioactivity - the disintegration of unstable atomic nuclei by the emission of radiation.3.76. Radiobioassay - the determination of kinds, quantities or concentrations, and, in some cases, the locations of radioactive material in the human body, whether by direct measurement, in vivo counting, or by analysis and evaluation of materials excreted or removed from the human body.3.77. Registered Material - radioactive material received, possessed, used, transferred or disposed of under a registration issued by the agency.3.78. Registrant - any person who is registered with the agency and is legally obligated to register with the agency pursuant to this rule.3.79. Registration - the filling with the agency by a registrant of all registrable items in accordance with this rule.3.80. Rem - the special unit of any of the quantities expressed as dose equivalent. The dose equivalent in rem is equal to the absorbed dose in rad multiplied by the quality factor (one [1] Rem = one one-hundredth [0.01] Sv).3.81. Research and Development - (a) theoretical analysis, exploration, or experimentation; or (b) the extension of investigative findings and theories of a scientific or technical nature into practical application for experimental and demonstration purposes, including the experimental production and testing of models, devices, equipment, materials, and processes. Research and development does not include the internal or external administration of radiation or radioactive material to human beings.3.82. Restricted Area (controlled area) - any area access to which is controlled by the registrant for purposes of protection of individuals from exposure to radiation and radioactive material. Restricted areas shall not include any areas used for residential quarters, although a separate room or rooms in a residential building may be set apart as a restricted area.3.83. Roentgen (R) - the special unit of exposure. One Roentgen equals 2.58 E 10G4 Coulombs/kilogram of air.3.84. Sealed Source - radioactive material that is permanently bonded or fixed in a capsule or matrix designed to prevent release and dispersal of the radioactive material under the most severe conditions which are likely to be encountered in normal use and handling.3.85. Shallow Dose Equivalent (Hs) - which applies to the external exposure of the skin or an extremity, means the dose equivalent at a tissue depth of seven one-thousandth (0.007) centimeter (seven [7] mg/cm2) averaged over an area of one (1) square centimeter.3.86. SI - the abbreviation for the international system of units.3.87. Sievert - the SI unit of any of the quantities expressed as dose equivalent. The dose equivalent in Sievert is equal to the absorbed dose in gray multiplied by the quality factor (one [1] Sv = one hundred [100] Rem).3.88. Source Material - (a) uranium or thorium, or any combination thereof, in any physical or chemical form, or (b) ores which contain by weight one-twentieth (1/20) of one (1) percent (five one-hundredths [0.05] percent) or more of (i) uranium, (ii) thorium, or (iii) any combination thereof. Source material does not include special nuclear material.3.89. Source Material Milling - any activity that results in the production of byproduct material as defined by definition (b) of byproduct material.3.90. Source of Radiation - any radioactive material, or any device or equipment emitting or capable of producing radiation.3.91. Source Traceability - the ability to show that a radioactive source has been calibrated either by the national standards laboratory of the national institute of standards and technology, or by a laboratory which participates in a continuing measurement quality assurance program with national institute of standards and technology or other equivalent national or international program.3.92. Special Form Radioactive Material - radioactive material that satisfies the following conditions:3.92.a. It is either a single solid piece or is contained in a sealed capsule that can be opened only by destroying the capsule;3.92.b. The piece or capsule has at least one dimension not less than five (5) millimeters (two tenths (0.2) inch); and3.92.c. It satisfies the test requirements specified by the Nuclear Regulatory Commission. A special form encapsulation designed in accordance with the Nuclear Regulatory Commission requirements in effect on June 30, 1983, and constructed prior to July 1, 1985, may continue to be used. A special form encapsulation either designed or constructed after June 30, 1985, must meet requirements of this definition applicable at the time of its design or construction.3.93. Special Nuclear Materials: 3.93.a. Plutonium, Uranium-233, Uranium enriched in the isotope 233 or in the isotope 235, and any other material that the Nuclear Regulatory Commission, pursuant to the provisions of Section 51 of the atomic energy act of 1954, as amended, determines to be special nuclear material, but does not include source material; or3.93.b. Any material artificially enriched by any of the foregoing but does not include source material.3.94. Special Nuclear Material in Quantities not Sufficient to Form a Critical Mass - uranium enriched in the isotope U-235 in quantities not exceeding three hundred fifty (350) grams of contained U-235; Uranium-233 in quantities not exceeding two hundred (200) grams; plutonium in quantities not exceeding two hundred (200) grams; or any combination of them in accordance with the following formula: For each kind of special nuclear material, determine the ratio between the quantity of that special nuclear material and the quantity specified above for the same kind of special nuclear material. The sum of such ratios for all of the kinds of special nuclear material in combination shall not exceed one (1). For example, the following quantities in combination would not exceed the limitation and are within the formula: Click Here To View Image
3.95. Survey - the evaluation of the radiological conditions and potential hazards incident to the production, use, transfer, release, disposal, or presence of sources of radiation. When appropriate, such evaluation includes, but is not limited to, tests, physical examinations, and measurements of levels of radiation or concentrations of radioactive material present. 3.96. Test - the process of verifying compliance with an applicable regulation.3.97. This rule - Sections 1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12., 13., 14., 15. and 16. of the Radiological Health Rules and any subsequent changes or additions thereto.3.98. Total Effective Dose Equivalent (TEDE) - the sum of the deep dose equivalent for external exposures and the committed effective dose equivalent for internal exposures.3.99. Total Organ Dose Equivalent (TODE) - the sum of the deep dose equivalent and the committed dose equivalent to the organ receiving the highest dose as described in Paragraph 6.46.a.6. of this rule.3.100. Traceable to a National Standard - the ability to show that an instrument or radioactive source has been calibrated by a laboratory which participates in a continuing measurement quality assurance program with National Institute of Standards or other equivalent national or international program.3.101. Units of Exposure and Dose.3.101.a. As used in this rule, the unit of exposure is the Coulomb per kilogram (C/kg) of air. One Roentgen is equal to 2.58E-4 Coulomb per kilogram of air.3.101.b. As used in this rule, the units of dose are:3.101.b.1. Gray (Gy) is the SI unit of absorbed dose. One Gray is equal to an absorbed dose of one (1) joule per kilogram (one hundred [100] rad).3.101.b.2. Rad is the special unit of absorbed dose. One Rad is equal to an absorbed dose of one hundred (100) erg per gram or one one-hundredth (0.01) joule per kilogram (one one-hundredth [0.01] Gy).3.101.b.3. Rem is the special unit of any of the quantities expressed as dose equivalent. The dose equivalent in Rem is equal to the absorbed dose in rad multiplied by the quality factor (one [1] Rem = one one-hundredth [0.01[ Sv).3.101.b.4. Sievert is the SI unit of any of the quantities expressed as dose equivalent. The dose equivalent in Sievert is equal to the absorbed dose in gray multiplied by the quality factor (one [1] Sv = one hundred [100] Rem).3.101.c. As used in this rule, the quality factors for converting absorbed dose to dose equivalent are shown in Table 64-23 A.3.101.d. If it is more convenient to measure the neutron fluence rate than to determine the neutron dose equivalent rate in sievert per hour or rem per hour, as provided in Section 3.102.c., one one-hundredth (0.01) Sv (one [1] Rem) of neutron radiation of unknown energies may, for purposes of this rule, be assumed to result from a total fluence of twenty-five (25) million neutrons per square centimeter incident upon the body. If sufficient information exists to estimate the approximate energy distribution of the neutrons, the registrant may use the fluence rate per unit dose equivalent or the appropriate Q value from Table 64-23 B to convert a measured tissue dose in Gray or Rad to dose equivalent in Sievert or Rem.3.102. Units of Activity. For purposes of this rule, activity is expressed in the SI unit of Becquerel (Bq) or in the special unit of Curie (Ci), or their multiples, or disintegrations or transformations per unit of time.3.102.a. One (1) Becquerel (Bq) = one (1) disintegration or transformation per second (DPS or TPS).3.102.b. One (1) Curie (Ci) = 3.7E+10 disintegrations or transformations per second (DPS or TPS) = 3.7E+10 Becquerel (Bq) = 2.22E+12 disintegrations or transformations per minute (DPM or TPM).3.103. Unrefined and Unprocessed Ore - ore in its natural form prior to any processing, such as grinding, roasting, beneficiating, or refining.3.104. Unrestricted Area - any area access to which is not controlled by the registrant for purposes of protection of individuals from exposure to radiation and radioactive material, and any area used for residential quarters.3.105. Unrefined and Unprocessed Ore - ore in its natural form prior to any processing, such as grinding, roasting, beneficiating, or refining.3.106. Waste - those low-level radioactive wastes that are acceptable for disposal in a land disposal facility. For the purposes of this definition, low-level waste has the same meaning as in the Low-Level Radioactive Waste Policy Act, P.L. 96-573, as amended by P.L. 99-240, effective January 15, 1986; that is, radioactive waste (a) not classified as high-level radioactive waste, spent nuclear fuel, or byproduct material as defined in Section 11e.(2). of the Atomic Energy Act (uranium or thorium tailings and waste) and (b) classified as low-level radioactive waste consistent with existing law and in accordance with (c) by the Nuclear Regulatory Commission.3.107. Waste Handling Registrant - persons registered to receive and store radioactive wastes prior to disposal and persons registered to dispose of radioactive waste.3.108. Week - seven (7) consecutive days starting on Sunday.3.109. Whole Body - the whole body, for purposes of external exposure, head, trunk including male gonads, arms above the elbow, or legs above the knee.3.110. Worker - an individual engaged in work under a registration issued by the agency and controlled by a registrant, but does not include the registrant.3.111. Working Level (WL) - any combination of short-lived radon daughters in one (1) liter of air that will result in the ultimate emission of 1.3E+5 MeV of potential alpha particle energy. The short-lived radon daughters of Radon-222 are Polonium-218, Lead-214, Bismuth-214, and Polonium-214; and those of Radon-220 are Polonium-216, Lead-212, Bismuth-212, and Polonium-212.3.112. Working Level Month (WLM) - an exposure to one (1) working level for one hundred seventy (170) hours -- two thousand (2,000) working hours per year divided by twelve (12) months per year is approximately equal to one hundred seventy (170) hours per month.3.113. Year - the period of time beginning in January used to determine compliance with the provisions of this rule. The registrant may change the starting date of the year used to determine compliance by the registrant provided that the change is made at the beginning of the year and that no day is omitted or duplicated in consecutive years. NOTE: Other terms not herein specifically defined shall be used in accordance with the definitions in the recommendations of the national council on radiation protection and measurements, or any successor thereto, as published in handbooks of the national bureau of standards or reports of the NCRP.