Department of Energy (DOE) Radiological Control Manual

Chapter 5. - Radiological Health Support Operations

Part 1 - External Dosimetry

Table of Contents (Articles 51x)

• 511 Requirements
• 512 Technical Requirements for External Dosimetry
• 513 Pocket and Electronic Dosimeters
• 514 Area Monitoring Dosimeters
• 515 Nuclear Accident Dosimeters

Article 511 - Requirements

1. Personnel dosimetry shall be required for the following:

2. Personnel who are expected to receive an annual external whole body dose greater than 100 mrem or an annual dose to the extremities, or organs and other tissues (including lens of the eye and skin) greater than 10 percent of the corresponding limits specified in Table 2-1
3. Declared pregnant workers who are expected to receive from external sources a dose equivalent of 50 mrem or more to the embryo/fetus during the gestation period
4. Minors and students, visitors and public expected to receive an annual external whole body dose equivalent of 50 mrem or more in a year.

• Neutron dosimetry shall be provided when a person is likely to exceed 100 mrem annually from neutrons.

• Dosimeters shall be issued only to personnel formally instructed in their use and shall be worn only by those to whom the dosimeters were issued.

• To minimize the number of personnel in the dosimetry program, the issuance of dosimeters is discouraged to other than personnel entering Radiation Areas, High Radiation Areas or Radiological Buffer Areas where there is a potential for external exposure. Although issuing dosimeters to personnel who are not occupationally exposed to radiation can appear as a conservative practice, it creates the impression that the wearers are occupationally exposed to radiation.

• Personnel shall return dosimeters for processing as scheduled or upon request, and should be restricted by line management from continued radiological work until dosimeters are returned.

• Personnel shall wear their primary dosimeters on the chest area, on or between the waist and the neck, in the manner prescribed by dosimetry personnel.

• Film dosimeters shall not be worn or taken off-site unless specifically authorized by the Radiological Control Manager.

• The practice at some facilities of taking thermoluminescent dosimeters (TLDs) off-site is discouraged and shall not be implemented where not in place.

• Personnel shall not wear dosimeters issued by their resident facilities while being monitored by a dosimeter at another facility unless authorized by the Radiological Control Manager. Personnel shall not expose their dosimeters to security x-ray devices, excessive heat, or medical sources of radiation.

• A person whose dosimeter is lost, damaged, or contaminated should place work in a safe condition, immediately exit the area and report the occurrence to the Radiological Control Organization. Reentry of the person into Radiological Buffer Areas should not be made until a review has been conducted and management has approved reentry. Return to Chapter 5, Part 1 Table of Contents

Article 512 - Technical Requirements for External Dosimetry

1. DOE 5480.15 specifies the requirements for accreditation of personnel external dosimetry monitoring programs by the DOE Laboratory Accreditation Program (DOELAP). A technical basis document shall be developed and maintained for the external dosimetry program. Personnel external dosimeters include but are not limited to TLDs, track etch dosimeters and neutron sensitive film.

2. The technical basis document shall also address dosimeters monitoring radiation outside the scope of DOELAP, such as dosimetry associated with high-energy accelerators and extremity dosimeters.

3. Facilities should participate in intercomparison studies for external dosimetry programs.

4. Personnel exposures to the skin, lens of the eye and extremities shall be reported separately when monitored.

5. Multiple dosimeters should be issued to personnel to assess whole body exposure in non-uniform radiation fields or as required on Radiological Work Permits. Non-uniform radiation fields exist when the dose to a portion of the whole body will exceed the dose to the primary dosimeter by more than 50 percent and the anticipated whole body dose is greater than 100 mrem. The technical basis document should describe the methodology used in determining the dose of record when multiple dosimeters are used.

6. A dose assessment shall be performed for each instance of a lost, damaged or contaminated personnel dosimeter.

Article 513 - Pocket and Electronic Dosimeters

Pocket and electronic dosimeters are supplemental dosimeters that provide real-time indication of exposure to radiation and assist in maintaining personnel doses less than Administrative Control Levels.

1. Supplemental dosimeters shall be issued to personnel prior to entry into a High Radiation or Very High Radiation Area (see Article 334 for entry requirements); when a person could exceed 10 percent of an Administrative Control Level from external radiation in 1 work day; or when required by a Radiological Work Permit. Pocket dosimeters should be selected with the lowest range applicable (typically 0-200 mR) for anticipated personnel exposures.

2. Supplemental dosimeters shall be worn simultaneously with the primary dosimeter and located in accordance with Article 511.6.

3. Supplemental dosimeters shall be read periodically while in use and should not be allowed to exceed 75 percent of full scale.

4. Work authorized by a Radiological Work Permit shall be stopped when supplemental dosimeter readings indicate total exposure or rate of exposure substantially greater than planned. The Radiological Control Organization shall be consulted prior to continuation of work.

5. The energy dependence of supplemental dosimeters, particularly to low-energy beta radiation, should be considered in determining their applicability.

6. Use of electronic dosimeters is encouraged for entry into High Radiation Areas or when planned doses greater than 100 mrem in 1 work day are expected. An electronic dosimeter provides an early warning of elevated exposure through the use of alarm set points at specified dose rates or integrated doses.

7. When the dose results from the pocket or electronic dosimeters differ by more than 50 percent from the primary dosimeter result and the primary dosimeter result is greater than 100 mrem, an investigation should be initiated to explain the difference.

Article 514 - Area Monitoring Dosimeters

Establishment and maintenance of a comprehensive area monitoring program minimize the number of areas requiring the issuance of personnel dosimeters and demonstrate that doses outside Radiological Buffer Areas are negligible. Minimizing the number of personnel dosimeters issued saves in the costs of operating the dosimetry program and reduces costs associated with maintaining personnel with enhanced training and qualifications.

1. Area monitoring dosimeters shall be used to record and document radiation levels in routinely occupied areas adjacent to areas where radiation or operations with radiation exist. This monitoring requirement does not apply when the radiation arises solely from low-energy beta sources (e.g., Carbon-14 or tritium).

2. Area monitoring dosimeter results should be used to support dosimetry investigations where personnel express concerns about their work environments and exposure to ionizing radiation.

3. Area monitoring dosimeters should be used in Controlled Areas to supplement existing monitoring programs and to provide data in the event of an emergency.

Article 515 - Nuclear Accident Dosimeters

DOE 5480.11 specifies the requirements for a Nuclear Accident Dosimetry Program when sufficient quantities and kinds of fissile material exist to potentially constitute a critical mass as defined in DOE 5480.5 and where exposure of personnel to radiation from a nuclear accident is possible.

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