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Missouri University of Science and Technology

Environmental Health and Safety Radiation Safety Training

Materials License

The Missouri University of Science and Technology (Missouri S&T) campus is regulated under a Materials License. The U.S. Nuclear Regulatory Commission grants the Materials License. The Curators of the University of Missouri are specified as the licensee for Missouri S&T. The Missouri S&T Materials License can be viewed at the department of Environmental Health and Safety in 108 Campus Support Facility.

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Radiation Safety OfficerThe Radiation Safety Program is a part of the department of Environmental Health and Safety. The Radiation Safety Program consists of a Radiation Safety Officer (RSO), a Health Physicist and one Health Physics Technician. The current RSO is Ray Bono.

The name of the Radiation Safety Officer is specified in paragraph 11 of the Missouri S&T Materials License. Paragraph 11 states:

11. The Radiation Safety Officer for this license is G. Raymond Bono.

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Sealed Source Leak TestsParagraphs 14 A. and 14 B. of the Missouri S&T Materials License specify the frequency at which sealed sources containing > 100 microcuries beta/gamma emitting material or > 10 microcuries of alpha emitting material must be leak tested. Paragraphs 14 A and 14 B state:

14 A. Sealed sources and detector cells shall be tested for leakage and/or contamination at intervals not to exceed 6 months or at such other intervals as specified by the certificate of registration, referred to in 10 CFR 32.210.

B. Notwithstanding Paragraph A of this condition, sealed sources designed to emit alpha particles shall be tested for leakage and/or contamination at intervals not to exceed 3 months.

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The Missouri S&T Handbook of Radiological Operations is the official guide in all matters relating to radiation protection and the control of radioactive materials at the Missouri University of Science and Technology. The Handbook supports the regulations set forth by the Materials and Reactor licenses. The Handbook was prepared by the Radiation Safety Office, with approval from the Radiation Safety Committee. The Handbook is available online at:

http://ehs.mst.edu/labsafety/radiationsafety/UMR_handbook_rad_operations.html

Missouri S&T Handbook of Radiological Operations

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Tritium BioassaysThe Missouri S&T Handbook of Radiological Operations (Section 2.2.4) contains requirements for tritium bioassays.

When tritium is used in uncontained form, a bioassay of a urine specimen is required for each person involved with handling the material in the following amounts:

1. For tritium in uncontained form, of quantities greater than 10millicurie processed in an open room, a bioassay shall be

performed within one week for a single contact or a bioassay shall be performed weekly for continuous contact. 2. For tritium in uncontained form of quantities greater than 100

millicurie, processed in an approved, operating fume hood, a bioassay shall be performed within one week for a single

contact or a bioassay shall be performed weekly for continuous contact. 3. For tritium when there may have been absorption, ingestion,

injection or other accidental deposition in the body of any activity greater than 250 microcuries, a bioassay shall be performed.

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Code of Federal Regulations

The Missouri S&T Radiation Safety Program predominantly uses two parts of “Title 10, Chapter I Code of Federal Regulations”.Part 19 (10 CFR 19) establishes requirements for notices, instructions, and reports by licensees to individuals participating in licensed activities and options available to these individuals. Part 20 (10 CFR 20) contains regulations establishing standards for protection against ionizing radiation resulting from activities conducted under licenses issued by the NRC.

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Worker’s Training

10 CFR 19.12 requires workers who are working in or frequenting any portion of a restricted area to be instructed of/in storage, transfer, health protection problems/precautions, regulations, and responsibilities in regard to minimizing exposure.

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ALARA Concept

The ALARA concept is based on the assumption that every radiation exposure and release of radioactive materials should be kept to a level As Low As Reasonably Achievable. Time, distance, and shielding are integral in maintaining radiation exposures as low as reasonably achievable.

Time – radiation is directly related to the amount of time exposed. Less exposure time means less dose.

Distance – by maintaining distance between yourself and the source, the dose is reduced significantly. The relationship between radiation exposure (dose) and distance follows the inverse square law. If a dose rate from a source at 1 foot is 1 millirem, the dose rate at 2 feet is reduced to 0.25 millirem (i.e. 1/(22) = 0.25).

Shielding – by utilizing appropriate shielding, the radiation exposure (dose) can be reduced significantly.

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Radiation Exposure for a Minor

For purposes of radiation protection, 10 CFR 20.1003 defines a “Minor” as “an individual less than 18 years of age”.

According to 10 CFR 20.1207, the maximum dose a minor can receive is 10% of the limits specified in 10 CFR 20.1201.

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Radiation Exposure to the Public10 CFR 20.1301 has licensee requirements established to protect individual members of the public from radiation exposure.

20.1301 Dose limits for individual members of the public. (a) Each licensee shall conduct operations so that —(1) The total effective dose equivalent to individual members of the public from the licensed operation does not exceed 0.1 rem (1 mSv) in a year, exclusive of the dose contributions from background radiation, from any administration the individual has received, from exposure to individuals administered radioactive material and released under § 35.75, from voluntary participation in medical research programs, and from the licensee’s disposal of radioactive material into sanitary sewerage in accordance with § 20.2003, and(2) The dose in any unrestricted area from external sources, exclusive of the dose contributions from patients administered radioactive material and released in accordance with § 35.75, does not exceed 0.002 rem (0.02 millisievert) in any one hour.

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Radiation SignsThe standard Radiation symbol and the appropriate colors are found in 10 CFR 20.1901.

20.1901 Caution signs. (a) Standard radiation symbol. Unless otherwise authorized by the Commission, the

symbol prescribed by this part shall use the colors magenta, or purple, or black on yellow background. The symbol prescribed by this part is the three-bladed design:

(1) Cross-hatched area is to be magenta, or purple, or black, and(2) The background is to be yellow.

(b) Exception to color requirements for standard radiation symbol. Notwithstanding the requirements of paragraph (a) of this section, licensees are authorized to label sources, source holders, or device components containing sources of licensed

materials that are subjected to high temperatures, with conspicuously etched or stamped radiation caution symbols and without a color requirement.

(c) Additional information on signs and labels. In addition to the contents of signs and labels prescribed in this part, the licensee may provide, on or near the required signs and labels, additional information, as appropriate, to make individuals aware of potential radiation exposures and to minimize the exposures.

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Determination of Prior Accumulated Dose

10 CFR 20.2104 has requirements for determining a worker’s prior accumulated dose. Specifically, 10 CFR 20.2104(e) states: (e) If the licensee is unable to obtain a complete record of an individual's current and previously accumulated occupational dose, the licensee shall assume--

(1) In establishing administrative controls under § 20.1201(f) for the current year, that the allowable dose limit for the individual is reduced by 1.25 rems (12.5 mSv) for each quarter for which records were unavailable and the individual was engaged in activities that could have resulted in occupational radiation exposure; and

(2) That the individual is not available for planned special exposures.

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Posting RequirementsSigns should be posted in accordance with 10 CFR 20.1902. A “Caution, High Radiation Area” should be posted in a high radiation area, a “Caution, Radiation Area” should be posted in a radiation area, etc. Some examples of area definitions, as defined in 10 CFR 20.1003, are:

High radiation area means an area, accessible to individuals, in which radiation levels from radiation sources external to the body could result in an individual receiving a dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour at 30 centimeters from the radiation source or 30 centimeters from any surface that the radiation penetrates.Radiation area means an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.005 rem (0.05 mSv) in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.

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Posting Requirements

According to 10 CFR 20.1902, a “Danger, Radioactive Materials” or “Caution, Radioactive Materials” sign should be posted when an area or room uses or stores an amount of licensed material exceeding 10 times the quantity specified in Appendix C to part 20.

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Waste Disposal

Environmental Health and Safety (EHS) disposes of all waste (radioactive and chemical) at Missouri S&T. Radioactive waste and sources are specifically turned over to Radiation Safety/Health Physics in the department of EHS.

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Contamination

Significant contamination at Missouri S&T is defined as 100 picocuries (pCi) per 100 square centimeters. More information on Health Physics levels of action can be found on the EHS website at:http://ehs.mst.edu/labsafety/radiationsafety/radiological_information_health.html

1 pCi = 2.22 disintegrations per minute (dpm)

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Minor Spills

The procedure for cleaning up minor radioactive spills is located on the EHS website at:http://ehs.mst.edu/labsafety/radiationsafety/radiological_information_health.html#Spills

This policy applies to spills that are microcurie activities and the contamination is only in a single room. If more than microcurie activities are involved in a spill or if the contamination extends beyond a single room, Health Physics must be contacted immediately to supervise the decontamination effort.

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Radionuclide Inventory ControlOne of the records to be maintained by the campus Radiation Safety Office is the quantity of radioactive material currently authorized. The Radiation Safety Officer maintains a listing of the quantities of each radionuclide which has been authorized by the Radiation Safety Committee for use by individual investigators. What the individual investigator must do is keep a record of the receipt, use, storage, and disposal of radioactive materials so that at any time, the amount on hand can be calculated. More information on radionuclide inventory control can be found at:

http://ehs.mst.edu/labsafety/radiationsafety/UMR_handbook_rad_operations.html#maintained

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Occupational Dose LimitsOccupational Dose Limits for adults can be found in 10 CFR 20.1201.

20.1201 Occupational dose limits for adults.(a) The licensee shall control the occupational dose to individual adults, except for planned special exposures under § 20.1206, to the following dose limits.(1) An annual limit, which is the more limiting of--

(i) The total effective dose equivalent being equal to 5 rems (0.05 Sv); or(ii) The sum of the deep-dose equivalent and the

committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50 rems (0.5 Sv).(2) The annual limits to the lens of the eye, to the skin of the

whole body, and to the skin of the extremities, which are:(i) A lens dose equivalent of 15 rems (0.15 Sv), and(ii) A shallow-dose equivalent of 50 rem (0.5 Sv) to the skin of the whole body or to the skin of any extremity.

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Average Radiation Exposure

A member of the public receives an average radiation exposure of 0.2 rem/year or 200 millirem/year. Some sources of radiation exposure include medical x-rays, cosmic radiation, and radon gas.

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Radiation Monitoring DevicesA Luxel dosimeter is used to measure an individual's radiation dose. It can detect x- and gamma radiation above 1 mrem and high-energy beta radiation above 10 mrem. It can not detect radiation emitted from low-energy beta emitters such as H-3, C-14, or S-35. A Luxel dosimeter is required if you routinely handle high-energy beta emitters. For those individuals who require a neutron exposure monitor, a special type of Luxel dosimeter is issued.

A ring dosimeter is used to measure an individual’s extremity dose. It can detect x- and gamma radiation above 30 mrem and high energy beta radiation above 40 mrem. A ring dosimeter is required if you routinely handle high energy beta emitters.

Pocket dosimeters are used primarily at the UMR Reactor. Pocket dosimeters are often used for temporary, short monitoring times (i.e. minutes, hours).

Dosimeters are available at Radiation Safety/Health Physics in the department of Environmental Health and Safety. A Request for Dosimeter Service form is located on the Forms page of the EHS website.

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Radiation EffectsThe scientific community generally assumes that any exposure to ionizing radiation can cause biological effects that may be harmful to the exposed person and that the magnitude or probability of these effects is directly proportional to the dose. These effects may be classified into three categories:

Somatic Effects: Physical effects occurring in the exposed person. These may be “prompt effects” which are observable after a large or acute dose (e.g., 100 rems (1 Sv) or more to the whole body in a few hours); or they may be “delayed effects” such as cancer that may occur years after exposure to radiation.

Genetic Effects: Abnormalities that may occur in the future children of exposed individuals and in subsequent generations.

Teratongenic Effects: Effects such as cancer or congenital malformation that may be observed in children who were exposed during the fetal and embryonic stages of development.

NRC Regulatory Guide 8.29 “Instruction Concerning Risks From Occupational Radiation Exposure” contains more information on the risks of occupational radiation exposure.

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Prenatal Radiation ExposureNRC Regulatory Guide 8.13 “Instruction Concerning Prenatal Radiation Exposure” contains instructions for employers and employees dealing with an employee’s pregnancy.

It is the employee’s responsibility and choice to declare a pregnancy. The employee is responsible for taking all action required to declare a pregnancy. NRC Regulatory Guide 8.13 explains how to declare a pregnancy, and describes the responsibilities of the employee and employer. As stated in NRC Regulatory Guide 8.13, once the employee declares a pregnancy, the employer must ensure that the dose to the embryo/fetus during the entire pregnancy, due to occupational exposure, does not exceed 0.5 rem (5 mSv).

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Questions?

If you have any questions or concerns, please contact the Radiation Safety Officer.

Ray Bono, Radiation Safety OfficerEnvironmental Health and Safety108 Campus Support Facility341-4305