Department of Energy (DOE) Radiological Control Manual

Chapter 5. - Radiological Health Support Operations

Part 5 - Radiological Monitoring and Surveys

Table of Contents (Articles 55x)

• 551 Requirements
• 552 Radiation Exposure Surveys
• 553 Area Radiation Monitors
• 554 Contamination Surveys
• 555 Airborne Radioactivity Monitoring

Article 551 - Requirements

1. Radiological monitoring of radiation exposure levels, contamination and airborne radioactivity shall be conducted to characterize workplace conditions, to verify the effectiveness of physical design features and engineering and administrative controls, and to identify areas requiring postings.

2. Monitoring shall be performed only by trained and qualified personnel using instruments that are properly calibrated and routinely tested for operability.

3. Surveys for radiation, contamination and airborne radioactive materials shall be performed as specified in Technical Work Documents and Radiological Work Permits.

4. The Radiological Control Organization shall perform and document a review of the adequacy of sampling and monitoring systems as part of any facility or operational changes affecting radiological control. In the absence of such changes, a review should be conducted annually.

5. Instruments used to perform radiation surveys shall be readily available and response-checked daily or prior to operation. When response checks are not within ~ 20 percent of the expected value, the instrument should be taken out of service. When response checks are not feasible, such as with instruments used to measure neutrons or tritium, compensatory actions should be established to ensure proper instrument performance.

6. Assessment of radiological conditions should include a sufficient number of survey points to characterize the radiation present and to verify boundaries.

7. Surveys should be performed before, during and at the completion of work that has the potential for causing changes in levels of radiation and radioactivity.

8. Survey frequencies should be established based on potential radiological conditions, probability of change in conditions and area occupancy factors.

9. Monitoring results should be reviewed by the cognizant radiological supervisor. The review should ensure that all required surveys have been performed and that the documentation is accurate and complete.

10. Results of current surveys or survey maps should be conspicuously posted to inform personnel of the radiological conditions.

11. Monitoring results should be made available to line management and used in support of pre- and post-job evaluations, ALARA preplanning, contamination control and management of radiological control operations.

12. Monitoring data in each building or area should be compiled and reviewed at least quarterly. Changes or trends should be noted and corrective actions assigned.

Article 552 - Radiation Exposure Surveys

1. In addition to the requirements of Article 551, routine radiation surveys should be performed in accordance with the following minimum frequencies:

2. Daily, in office space located in Radiological Buffer Areas where the potential exists for external radiation exposure
3. Weekly, in routinely occupied Radiological Buffer Areas and Radiation Areas
4. Upon initial entry, weekly during continuing operations, and when levels are expected to change in High Radiation Areas
5. Weekly, for operating HEPA-filtered ventilation units
6. Weekly, for temporary Radiation Area boundaries to ensure that radiation areas do not extend beyond posted boundaries
7. Monthly, or upon entry, if entries are less frequent than monthly for Radioactive Material Areas
8. Monthly, for potentially contaminated ducts, piping and hoses in use outside radiological facilities.

• Performance of radiation surveys should include dose rate measurements of the general area, dose rates at a distance of 30 centimeters from a source or surface of interest to evaluate potential whole body exposures, and dose rates on contact with potential sources of radiation where there is a potential for hands-on work.

• Surveys should be conducted whenever operations are being performed that might result in personnel being exposed to small intense beams of radiation, such as those generated by shielded x-ray devices or due to removal or alteration of shielding.

• Radiation monitoring instruments shall be capable of measuring ambient radiation dose rates for the purpose of controlling radiation exposures. Return to Chapter 5, Part 5 Table of Contents

Article 553 - Area Radiation Monitors

1. In addition to the requirements of Article 551, area radiation monitors (not to include area monitoring dosimeters discussed in Article 514) should be installed in frequently occupied locations with the potential for unexpected increases in dose rates and in remote locations where there is a need for local indication of dose rates prior to personnel entering remote locations.

2. Area radiation monitors should not be substituted for radiation exposure surveys in characterizing a workplace.

3. The need and placement of area radiation monitors should be documented and assessed when changes to facilities, systems or equipment occur.

4. In addition to the requirements of Article 562, area radiation monitors should be tested at least quarterly to verify audible alarm system operability and audibility under ambient working conditions and operability of visual alarms when so equipped.

5. If installed instrumentation is removed from service for maintenance or calibration, a radiation monitoring program providing at least equal detection capability should be maintained, consistent with the potential for unexpected increases in radiation dose rates.

6. Where an area radiation monitor is incorporated into a safety interlock system the circuitry shall be such that a failure of the monitor shall either prevent entry into the area or prevent operation of the radiation producing device.

Article 554 - Contamination Surveys

1. In addition to the requirements of Article 551, routine contamination surveys should be conducted in Radiological Buffer Areas established for the control of contamination and other areas with the potential for spread of contamination as follows:

2. Prior to transfer of equipment and material from one Radiological Buffer Area to another
3. Prior to transfer of equipment and material from highly contaminated areas within Radiological Buffer Areas unless precautions such as bagging or wrapping are taken prior to transfer
4. Daily, at contamination area control points, change areas, or step-off pads when in use, or per shift in high use situations
5. Daily, in office space located in Radiological Buffer Areas
6. Daily, in lunch rooms or eating areas near Radiological Buffer Areas
7. Weekly, in routinely occupied Radiological Buffer Areas
8. Weekly, or upon entry if entries are less frequent, in areas where radioactive materials are handled or stored
9. Weekly, or upon entry if entries are less frequent, where contamination boundaries or postings are located
10. During initial entry into a known or suspected contamination area, periodically during work, at completion of job, or as specified in a Radiological Work Permit
11. After a leak or spill of radioactive materials.

• Surveys for the release of materials shall be conducted in accordance with Articles 421 and 422.

• Contamination surveys should incorporate techniques to detect both removable and fixed contamination.

• Items with inaccessible surfaces which were located in known or suspected contamination areas and had the potential to become contaminated at levels likely to exceed Table 2-2 values shall be treated as potentially contaminated and subject to administrative controls unless the items are dismantled and monitored or special survey techniques are used to survey all surfaces.

• The requirements for assessing representative samples of bulk material, such as sand, sweeping compounds or plate steel, which are not suitable for normal loose and fixed contamination-level assessment techniques, are specified in DOE 5400.5.

• Swipe surveys for removable contamination shall be reported in units of disintegrations per minute per 100 cm2 (dpm/100 cm2). For swipe surveys of small items covering less than 100 cm2, the results shall be reported in units of dpm per area swiped.

• Large area wipes are encouraged and should be used to supplement standard swipe techniques in areas generally assumed not to be contaminated, such as entrances to Radiological Buffer Areas. If an evaluation indicates that an area wiped is contaminated, a thorough contamination swipe survey should be performed.

• Areas identified as either contaminated with, or having the potential for being contaminated with, highly radioactive particles ("hot particles") should be surveyed weekly. These areas should be surveyed at least daily during periods of work that may result in the generation of hot particles. Special swipe techniques to collect hot particles, such as tape and large area wipes, should be used. Return to Chapter 5, Part 5 Table of Contents

Article 555 - Airborne Radioactivity Monitoring

1. In addition to the requirements of Article 551, air monitoring equipment should be used in situations where airborne radioactivity levels can fluctuate and early detection of airborne radioactivity could prevent or minimize inhalation of radioactivity by personnel. Selection of air monitoring equipment should be based on the specific job being monitored. Air monitoring equipment includes portable and fixed air sampling equipment and continuous air monitors.

2. Air sampling equipment shall be used in occupied areas where, under normal operating conditions, a person is likely to receive an annual intake of 2 percent or more of the specified Annual Limit of Intake (ALI) values (40 Derived Air Concentration (DAC) hours). An annual intake of 2 percent of a specified ALI generally represents a committed effective dose equivalent to a person of approximately 100 mrem.

3. Continuous air monitoring equipment shall be installed in occupied areas where a person without respiratory protection is likely to be exposed to a concentration of radioactivity in air exceeding 1 DAC or where there is a need to alert potentially exposed workers to unexpected increases in the airborne radioactivity levels. A person exposed continuously to a concentration of radioactivity in air of 1 DAC for 1 work week would generally receives a committed effective dose equivalent of approximately 100 mrem.

4. Air sampling equipment should be positioned to measure air concentrations to which persons are exposed. If this cannot be achieved, a program of personal breathing-zone air sampling should be initiated.

5. Air monitoring equipment shall be routinely calibrated and maintained at a frequency of at least once per year. Continuous air monitors should be capable of measuring 1 DAC when averaged over 8 hours (8 DAC-hours) under laboratory conditions.

6. Continuous air monitoring equipment required by Article 555.3 shall have alarm capability and sufficient sensitivity to alert personnel that immediate action is necessary in order to minimize or terminate inhalation exposures.

7. The proper operation of continuous air monitoring equipment should be verified daily by performing an operational check. Operational checks should include positive air-flow indication, non-zero response to background activity, and internal check sources or 60 Hz electronic checks when available. Continuous air monitoring equipment should be verified weekly by checking for instrument response with a check source or with ambient levels of radon and thoron daughters.

8. Preliminary assessments of air samples utilizing field survey techniques should be performed promptly upon removal. In situations where background levels of radon and thoron daughters interfere with evaluation of alpha air samples, prompt field assessments may not be possible.

9. Air sample results should be evaluated as quickly as practicable for evaluation of the need for respiratory protection, area evacuation (if necessary), worker intake and worker relief from respirator use.