Environmental Health & Safety

University of Colorado Boulder

Resources

Radiation Safety Handbook Appendix A – The University of Colorado’s ALARA Program

This Environmental Health & Safety guideline documentation is intended for researchers working with radiation.

Revised as of October 1, 2010

General Description

The University of Colorado maintains a Radioactive Materials license through the Colorado Department of Public Health and Environment (CDPHE). The ALARA philosophy, or As Low As Reasonably Achievable, is a regulatory requirement for all radiation protection programs.

The University of Colorado maintains a Radioactive Materials license through the Colorado Department of Public Health and Environment (CDPHE). The ALARA philosophy, or As Low As Reasonably Achievable, is a regulatory requirement for all radiation protection programs. The University actively works to reduce dose and exposure due to radiation in our radiation safety program. This reduction in dose and exposure should be accomplished in accordance with ALARA with an emphasis on protecting individuals at the University, including members of the general public.

ALARA Levels

Dosimetry – External Monitoring

The ALARA levels used for monthly and/or quarterly monitoring are as follows:

Dose Level I Level II Level III
Whole Body Dose 0.5 mSv (50 mrem) 3 mSv (300 mrem) 5 mSv (500 mrem)
Skin Dose 0.5 mSv (50 mrem) 5 mSv (500 mrem) 50 mSv (5000 mrem)
Lens of the Eye Dose 0.5 mSv (50 mrem) 5 mSv (500 mrem) 15 mSv (1500 mrem)
Extremity Dose 0.5 mSv (50 mrem) 5 mSv (500 mrem) 50 mSv (5000 mrem)
Individual Organ Dose 0.5 mSv (50 mrem) 5 mSv (500 mrem) 50 mSv (5000 mrem)

Actions taken:

  1. Dose/Exposure less than Level I – No action unless deemed necessary by RSO.
  2. Dose/Exposure equal to or greater than Level I – Notification of employee and the RSC.
    A copy of this notification is maintained in the individual’s dosimetry file.
  3. Dose/Exposure equal to or greater than Level II – Notification of employee and the RSC.
    A copy of this notification is maintained in the individual’s dosimetry file. The employee is encouraged to investigate and evaluate techniques for reducing future exposure in their work. Assistance may be provided by Health Physics.
  4. Dose/Exposure equal to or greater than Level III (10% of Annual Limit) – Notification of employee and the RSC.
    A copy of this notification is maintained in the individual’s dosimetry file. An investigation will be performed by the employee and Health Physics. A written report explaining the exposure will be provided for their dosimetry file and the RSC.

Bioassay – Internal Monitoring

The ALARA levels (modified in 1999 to match the University’s Radioactive Materials License Conditions) used to monitor internal contamination are as follows:

Level I Level II Level III
Thyroid (Iodine-125) 2.22 kBq (60 nCi) 4.44 kBq (120 nCi) 18.5 kBq (500 nCi)
Thyroid (Iodine-131) 0.74 kBq (20 nCi) 1.48 kBq (40 nCi) 5.18 kBq (140 nCi)
Urinalysis (Tritium) 370 kBq (10 μCi)/Liter 1.04 MBq (28 μCi)/L 1.85 MBq (50 μCi)/L

Actions taken:

  1. Exposure less than Level I – No action unless deemed necessary by RSO. A copy of the test report is given to the employee and placed in his/her dosimetry file.
  2. Exposure equal to or greater than Level I – Notification of employee and the RSC. A copy of this notification is maintained in the individual’s dosimetry file. The employee is encouraged to discuss experimental protocols with Health Physics to seek ways of reducing future exposures.
  3. Exposure equal to or greater than Level II – Notification of employee and the RSC. A copy of this notification is maintained in the individual’s dosimetry file. In addition,
    For Tritium –
    If this level is exceeded in the course of a calendar quarter, a written report shall be sent to the Director of CDPHE within 30 days of the end of the quarter. This report will contain the results of all urinalyses for the individual during the calendar quarter, the cause of the excessive concentrations, and the corrective steps taken or planned to prevent recurrence.For Radioiodines –

    1. An investigation by Health Physics personnel will examine operations involved, potentially including ventilation surveys, to determine the causes of exposures and to evaluate the potential for further exposures.
    2. If this investigation indicates that further work in the area might result in exposure of the employee to concentrations that are excessive, the employee will be restricted from further exposure until the source of exposure is discovered and corrected.
    3. Following the investigation, corrective actions that will eliminate or lower the potential for further exposures will be implemented and documented.
    4. A repeat bioassay will be performed within one week of the previous measurement to confirm the effectiveness of the corrective action and/or to verify internal radioiodines present.
  4. Exposure equal to or greater than Level III – Notification of employee and the RSC. A copy of this notification is maintained in the individual’s dosimetry file. In addition,
    For Tritium –
    If this level is exceeded in a single bioassay, a written report shall be sent to the Director of CDPHE within 7 days of the receipt of the bioassay results.For Radioiodines –

    1. The employee will be prevented from any further handling of radioiodine until the thyroid burden is below this limit.
    2. All investigative steps listed in item 3 above, will be carried out.
      The employee will be sent to an appropriate medical facility for evaluation of therapeutic methods to accelerate removal of the radioiodine from the body.
    3. Repeat bioassays shall be conducted at one-week intervals until the thyroid burden is below 0.12 μCi of I-125 or 0.04 μCi of I-131.
  5. If any bioassay shows dose levels exceeding the limits listed in RH 4.52 of the Colorado Rules and Regulations Pertaining to Radiation Control, all notifications will occur as required, with follow-up written reports to CDPHE within 30 days.

    Total Effective Dose Equivalent –
    IMMEDIATE NOTIFICATION OF CDPHE: 2.5 Sv (25 rem)
    24-HOUR NOTIFICATION OF CDPHE: 0.5 Sv (5 rem)

    Total Organ Dose Equivalent –
    IMMEDIATE NOTIFICATION OF CDPHE: 2.5 Gy (250 rad)
    24-HOUR NOTIFICATION OF CDPHE: 0.5 Sv (50 rem)

Sealed Sources

The ALARA levels used with leaking sealed sources are as follows:

Level I Level II
Tier I source/wipe 37 Bq (0.001 μCi) 185 Bq (0.005) μCi)

Actions taken:

  1. Contamination less than Level I – No action taken unless deemed necessary by RSO.
  2. Contamination equal to or greater than Level I – Notification of user and the RSC. It is recommended that the source be monitored more frequently and possibly removed from circulation, repaired, or disposed of as radioactive waste.
  3. Contamination equal to or greater than Level II – Notification of user, the RSC, and CDPHE (RH 4.58). The source is removed from use for repair or disposal by Health Physics personnel.

Radiation Surveys

The ALARA levels currently used for Contamination Surveys are as follows:

Level I Level II
dpm/100 cm2 100 1,000

Actions taken:

  1. Contamination less than Level I – No action taken unless deemed necessary by RSO.
  2. Contamination equal to or greater than Level I – Notification of the licensee/lab and RSC. Immediate clean-up of the area is recommended. Documentation is maintained by the laboratory involved.
  3. Contamination equal to or greater than Level II – Notification of the licensee/lab and RSC. Immediate clean-up is required and the area is re-surveyed by Health Physics staff. Documentation is maintained by the laboratory involved and Health Physics.

The ALARA levels currently used for Freezer Frost Contamination are as follows:

Level I Level II Level III
dpm/100 cm2 or per ml 100 1,000 10,000

Actions taken:

  1. Contamination less than Level I – No action taken unless deemed necessary by RSO.
  2. Contamination equal to or greater than Level I – Notification of the licensee/lab and RSO.
  3. Contamination equal to or greater than Level II – Notification of the licensee/lab and RSO. Defrosting or clean-up of the freezer is recommended.
  4. Contamination equal to or greater than Level III – Notification of the licensee/lab and RSC. Defrosting or clean-up of the freezer is required and the freezer is re-surveyed by Health Physics personnel.

Radioactive Material Receipt and Inventory

The following ALARA levels are in effect for packages received:

Level I Level II
dpm/100 cm2 on outside of vial 1,000 10,000
dpm/100 cm2 on outside of box 100
mR/hr on outside of box 200

Actions taken:

  1. Contamination/Exposure rate less than Level I on vial or box – No action taken unless deemed necessary by RSO. Package is delivered to laboratory.
  2. Contamination equal to or greater than Level I on vial – Notification of laboratory and the RSC. The laboratory is reminded of safe handling practices and has the right to refuse the package. Contamination equal to or greater than Level I on box – An alternate box with appropriate certification and labeling may be used to transport the package, provided the vial is not contaminated. The contaminated box is disposed of as radioactive waste.
  3. Contamination equal to or greater than Level II on vial – Notification of laboratory and the RSC. The package is not delivered to the laboratory but is instead disposed of at Health Physics as radioactive waste. Arrangements for replacement are the responsibility of the laboratory involved.
    Exposure rate equal to or greater than Level II on box – CDPHE is contacted for further instruction before the box is opened by Health Physics staff.