Radiation Safety Manual - Chapter 02: Radiation Source Authorization and Radiation Worker Registration

Title

Radiation Safety Manual - Chapter 02: Radiation Source Authorization and Radiation Worker Registration

Table of Contents

  1. Procedure for Obtaining Authorization to Use Radiation Sources
    1. Characteristics of Commonly Used Radionuclides
  2. Facilities Evaluation
  3. Radiation Worker Registration
  4. Posting Requirements
  5. Ventilation Hoods

Procedure for Obtaining Authorization to Use Radiation Sources

To obtain authorization to procure and use radiation sources, a prospective Authorized User must complete and submit applicable Schedules of the Laboratory Safety Plan. For help in completing the radioactive materials portion of the Laboratory Safety Plan, please reference “Characteristics of Commonly Used Radionuclides”. The Radiation Safety Officer will review the plan and schedule an interview with the prospective user to evaluate the facilities available, the training and experience of the applicant and staff for the proposed use, and the details of the work to be performed.

The procedures described in the application, as modified by the Radiation Safety Officer and/or the Radiation Safety Committee, become the conditions under which the researcher and his/her personnel are authorized to use radiation sources. Any subsequent change in procedure regarding the use, storage or disposal of sources must be reviewed by the Radiation Safety Officer prior to instituting the change.

Characteristics of Commonly Used Radionuclides
Radionuclide Radiation(s) emitted and energy Radiological Half-Life Biological Half-life Effective Half-life Critical Organ Maximum Permissible Body Burden Shielding Required Special Considerations
H-3 Beta particle: Emax - 18.6 keV
Emean - 5.7 keV
12.3 years 12 days 12 days whole body 1 mCi whole body None None
C-14 Beta particle: Emax - 156 keV
Emean - 49 keV
5730 years 10 days 10 days whole body
fat
.4 mCi whole body
.3 mCi fat
None Do not generate carbon dioxide which can be inhaled.
P-32 Beta particle: Emax - 1709 keV
Emean - 690 keV
14.3 days 1155 days 14.1 days bone .006 mCi bone
.030 mCi whole body
1 cm Plexiglass P-32 is highest energy radionuclide used in research labs. Avoid bremstrahlung x-ray production by shielding with plexiglass and not lead.
P-33 Beta particle: Emax - 246 keV 24.4 days 1155 days 23.9 days bone .032 mCi whole body 1 cm Plexiglass None
S-35 Beta particle: Emax - 167 keV
Emean - 49 keV
87.4 days 623 days 76 days whole body
testes
.4 mCi whole body
.090 mCi testes
None Open vials in ventilated enclosures to prevent inhalation
Ca-45 Beta particle: Emax - 257 keV
Emean - 86 keV
165 days 49.3 days 162 days bone .030 mCi whole body 1 cm Plexiglass
.01 inch Al foil
None
Cr-51 Gamma photon: 320 keV
X-ray: 5 keV
28 days 616 days 27 days lower large intestines .800 mCi whole body 3.2 mm lead None
Co-57 Gamma photons: 122 keV (85.5%)
136 keV (10.8%)
14 keV (9.5%)
692 keV (.16%)
270.9 days 276 days 9.2 days lower large intestines .200mCi whole body 3.2 mm lead None
I-125 Gamma photon: 35 keV (7%)
X-ray: 27-32 keV
60 days 138 days 41.8 days thyroid .00115 mCi thyroid
.006 mCi whole body
.25 mm lead May be volatile when opening vial; therefore open vials in ventilated enclosures such as certified hoods. Do not make I-125 solutions acidic or do not store frozen; both lead to formation of volatile elemental iodine
I-131 Beta particle: Emax - 806 keV
Emean - 180 keV
Gamma photons: 364 keV (81.8%)
637 keV (7.2%)
284 keV (5.9%)
80 keV (2.4%)
723 keV (1.8%)
8.04 days 138 days 7.6 days thyroid .00014 mCi thyroid
.050 mCi whole body
12.7 mm lead Same as 1-125. Additional requirements for gamma radiation shielding

Facilities Evaluation

The review of radiation source use applications will include a review of the adequacy of the proposed facilities. Depending on the quantity of material involved, the type of source and the complexity of the proposed procedures, the following will be considered:

  1. Isolation from general laboratories and public areas.
  2. Availability of radiation detection instrumentation.
  3. Adequacy of ventilation and fume hoods.
  4. Readily cleanable work surfaces and floors.
  5. Provisions for shielding and secure storage of sources

Radiation Worker Registration

To provide the University with a record of the training and experience of persons working with radiation sources, Worker Registration Form is to be completed and submitted to EHS. The Radiation Safety Office will review the registration form and schedule necessary training sessions. EHS is to be informed of all changes in personnel working with radiation sources. An updated Worker Registration Form must be provided when personnel transfers, additions, or deletions occur.

A copy of the approved registration form reviewed by Radiation Safety should be printed from the online application by the Authorized User. This copy must be maintained in the Authorized User's radiation safety records. The original form is kept at the EHS office. Radiation Worker Registration forms must be maintained by the Authorized User and EHS as long as the individual's employment actively involves the use of radiation sources. Upon termination or transfer, the form may be archived or removed from the records after a three year time period has elapsed. Inactive forms should be maintained in a separate section in the radiation safety records.

Posting Requirements

All rooms authorized for radioactive materials use, storage or disposal must be posted with copies of pages 11 and 20 of this Manual and the Radiation Safety Security Procedures. Page 11 presents the radiation safety rules to be followed when using radioactive materials. Page 20 presents the radiation emergency procedures for responding to incidents. The Radiation Safety Security Procedures (see attached document below) provides information on the proper security of radiation sources/radioactive waste and the steps to follow in case of suspected loss of radioactive materials to municipal waste streams. This form includes a section for listing the Housekeeping supervisor for an Authorized User’s building. In case of a radiation source loss, the building supervisor must be informed as soon as possible to stop any waste removal from the building.

A copy of the North Carolina Radiation Protection Section’s Form, “Notice To Employee” (see attached document below) must be posted in each authorized room. This posting provides required information on the employer / employee’s rights and responsibilities as radiation workers.

Ventilation Hoods

The use of volatile materials and other conditions requires the use of a properly designed and operating ventilation hood. The exhaust airflow provided by a hood creates a margin of safety from the accidental inhalation of chemical and radioactive fumes and gases. A minimum hood face velocity air flow of 100 linear feet per minute with an 18 inch sash opening is required for radioactive materials use hoods.

EHS measures the face velocity of all hoods annually. Any deficiencies are noted and referred to the UNC Facility Services for correction. Hoods should not be used for storage. Items in a hood will impede and disturb the exhaust airflow and potentially reduce or eliminate the safety factor. Exceptions may be granted for volatile wastes or certain other approved circumstances.

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Article ID: 132053
Created
Thu 4/8/21 9:22 PM
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Tue 9/7/21 1:48 PM
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Environment, Health and Safety