Radiation Control Supplement
Chapter 5 – Radiological Health
Currently, Jefferson Lab uses dosimeters that are sensitive to beta, gamma and neutron radiation. The personnel dosimeters provide “dose of record” measurements for gamma rays, neutrons, x-rays and charged particle exposures.
511-01) Personnel dosimeters are provided and processed by an outside lab and are normally changed semiannually. Personnel dosimeters are available through the Radiation Control Department (RCD). Personnel external dosimetry programs shall be adequate to demonstrate compliance with the occupational exposure limits and monitoring requirements in 10 CFR 835. The program shall include routine dosimeter calibration and conformance with the requirements of the Department of Energy (DOE) Laboratory Accreditation Program (DOELAP) for Personnel Dosimetry (or shall be determined by the Secretarial Officer responsible for environmental, safety, and health matters to have substantially equivalent performance). Jefferson Lab maintains a DOELAP-accredited external dosimetry program [§835.402(b)].
511-02) The digital self-reading dosimeter (SRD) is a supplemental device used for real-time dose tracking in conjunction with RWPs, and for issuance to visitors needing access to RCAs for short periods. The SRD can be programmed with dose and dose-rate alarm levels to alert the wearer when predetermined limits are being approached. This type of dosimeter is available through the RCD. The digital dosimeter should not be worn in areas where pulsed radiation fields are known or expected to occur.
511-03) Individual exposures are tracked during each monitoring period via SRD results, and OSL-badge doses are reviewed after each dosimeter exchange. In keeping with the Jefferson Lab design goal alert notification system, individuals who receive more than 120 mrem during a semiannual monitoring period (based on either SRD or OSL badge) are notified in writing (along with their supervisor) and are placed on a more frequent dosimeter processing cycle – normally monthly. The Radiation Control Manager (RCM) may designate individuals for monthly processing at his/her discretion based on dose history, nature and location of work, and expected exposure levels for upcoming periods.
512-01) Personnel dosimeters are issued on a permanent basis to Jefferson Lab Radiological Workers who routinely enter and work in Radiologically Controlled Areas.
512-02) Personnel dosimeters shall be provided to and worn by Radiological Workers who, under typical conditions are likely to receive one or more of the following:
a) An effective dose of 100 mrem in one year;
b) An equivalent dose to the skin or to any extremity of 5 rem or more in a year;
c) An equivalent dose to the lens of the eye of 1.5 rem or more in a year [§835.402(a)(1)].
512-03) Personnel dosimeters shall be provided to and used by:
a) Declared pregnant workers who are like to receive in excess of 10% of the applicable limit in 10 CFR 835.206(a);
b) Occupationally exposed minors who are like to receive in excess of 50% of the applicable limits in 10 CFR 835.207;
c) Members of the public entering a controlled area who are like to receive in excess of 50% of the limit in 10 CFR 835.208 in a year from external sources; and
d) Individuals entering a High or Very High Radiation Area [§835.402(a)(2), (3), (4), (5)].
512-04) Supplemental dosimeters shall be worn for entry into a posted High Radiation or Very High Radiation Area, when there is a potential for whole-body exposure to a radiation field of 100 mrem/h or greater, or as required by any work permit or technical work procedure.
512-05) Dosimeters shall be worn between the neck and waist unless otherwise specified by the RCD. When an SRD is worn with a personnel dosimeter, the dosimeters should be placed next to each other. The dosimeter should be worn consistently at the same location on the body unless otherwise instructed by the RCD. It should be worn on the outside of all clothing.
512-06) Dosimeters shall be returned to their appropriate storage location at the end of the work day. Personnel dosimeters shall be stored in the designated rack, and SRDs shall be logged in by RCD staff members and stored for reuse.
512-07) The RCD determines the need for special configuration dosimetry. Special configuration dosimeters (rings, bracelets, etc.) are available from the RCD. A lead time of approximately 72 hours should be anticipated if a special configuration is required.
512-08) Personnel whose duties make them radiological workers are provided permanent dosimetry. The worker shall complete the Jefferson Lab Personnel Dosimeter Request and an Ionizing Radiation Record Transfer Request (if applicable). A Line Management representative shall sign the form to indicate that the person needs a personnel dosimeter. The form(s) shall then be forwarded to the RCD for dosimeter issuance. These steps may be conducted through an electronic system having secure access and electronic signature capability. The RCD will review the dosimeter application and if applicable, establish a special control level in accordance with Article 217 of this Manual. The radiological worker and his/her supervisor are responsible for ensuring that the worker does not exceed this limit.
512-09) 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.
512-010) Part of the success of an organization’s efforts to reduce total exposure is ensuring that as few people as necessary are authorized to receive radiation exposure. Periodically, a review should be performed to confirm that all persons so authorized actually have a need to be so authorized. The RCM shall make recommendations through the JRRP or other Line Management mechanisms for adjustments to policies and procedures that may cause significant unnecessary assignments of dosimetry or designation of individuals as radiological workers.
512-011) Personnel shall return dosimeters for processing as scheduled or upon request.
512-012) A person, whose dosimeter is lost, damaged, or contaminated while working should place work in a safe condition, immediately exit the area, and report the occurrence to the RCD.
513 Circumstances Requiring an Exposure Investigation
An exposure investigation is required in the following circumstances:
513-01) Missing exposure record (i.e., personnel dosimeter is lost or damaged).
513-02) Suspected inaccuracy in the exposure record. If there is a serious discrepancy between the personnel dosimetry report and the person’s expected exposure, the dosimetry records shall be reviewed and adjusted if necessary. Other circumstances of suspected inaccuracies requiring exposure investigations include discrepancies between multiple badges (when they are worn at the same time), exposures occurring when the person was not wearing a badge, and in accidental exposure situations.
513-03) Unusual exposures or a large increase in reported exposure for a personnel dosimeter reading period as compared to previous exposures.
513-04) Any personnel dosimeter result exceeding the Alert Level (250 mrem), when not anticipated based on supplemental dosimeter results during the period.
514 Self-Reading Dosimeters
Self-reading dosimeters are supplemental dosimeters that provide real-time indication of exposure to radiation and assist in maintaining personnel doses less than Administrative Control Levels. The digital dosimeter should not be worn in areas where there is the likelihood of encountering pulsed radiation fields, high magnetic fields, or radio frequency radiation.
514-01) Supplemental dosimeters should be read periodically while in use.
514-02) Routine work on a Radiological Work Permit shall be stopped when supplemental dosimeter readings indicate total exposure or a rate of exposure substantially greater than planned. The RCD shall be consulted prior to continuation of work.
514-03) Routine comparisons and evaluations should be made of individual and collective exposures from RWP-related supplemental dosimeter readings and dose-of-record monitoring results. These comparisons are useful in evaluating radiological performance and ALARA efforts.
514-04) The energy and pulse rate dependence of supplemental dosimeters should be considered in determining their applicability.
515 Area Monitoring Dosimeters
Establishment and maintenance of a comprehensive area monitoring program minimizes the number of areas requiring the issuance of personnel dosimeters and demonstrates that doses inside Controlled 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.
Area monitoring dosimeters should be used to record and document radiation levels in routinely occupied areas adjacent to areas where radiation or operations with radiation exist.
521 Individual Monitoring
521-01) For the purpose of monitoring individual exposures to internal radiation, internal dosimetry programs (including routine bioassay programs) shall be conducted for:
a) Radiological workers who, under typical conditions, are likely to receive a committed effective equivalent dose of 100 mrem or more from all occupational radionuclide intakes in a year;
c) Occupationally exposed minors who are likely to receive a dose in excess of 50% of the applicable limit stated in 10 CFR 835.207 from all radionuclide intakes in a year; or
d) Members of the public entering a controlled area who likely to receive a dose in excess of 50% of the limit stated in 10 CFR 835.208 from all radionuclide intakes in a year [§835.402(c)].
521-02) Internal dose monitoring programs implemented to demonstrate compliance with Article 521-01 shall be adequate to demonstrate compliance with the dose limits established in Tables 2-1A and 2-1B and (if applicable) shall be:
a) Accredited, or excepted from accreditation, in accordance with the Department of Energy (DOE) Laboratory Accreditation Program for Radiobioassay; or
b) Determined by the Secretarial Officer responsible for environment, safety and health matters to have performance substantially equivalent to that of programs accredited under the DOE Laboratory Accreditation Program for Radiobioassay [§835.402(d)].
Respiratory protection equipment includes National Institute for Occupational Safety and Health (NIOSH) - approved respirators with particulate or gas-filtering cartridges, supplied air respirators, self-contained breathing apparatus, and airline supplied-air suits and hoods.
531-02) Respirators shall be issued only to personnel who are trained, fitted, and medically qualified to wear the specific type of respirator. Training and qualification testing shall be performed as specified in ES&H Manual Chapter 6630 Respiratory Protection.
531-03) The use of respiratory protection for radiological controls shall be in accordance with the Jefferson Lab respiratory protection program, and should be tailored for consistency with applicable guidance specific to radiological respiratory protection, such as NRC Regulatory Guide 8.15, “Acceptable Programs for Respiratory Protection”.
541-01) When personnel detect skin contamination, they shall notify the RCD.
541-02) The extent of skin contamination should be determined prior to initiating decontamination procedures.
541-03) Skin decontamination methods should be non-invasive. Skin abrasion should be avoided during the decontamination process. Any decontamination with the possibility of causing injury shall be performed under the auspices of Jefferson Lab Occupational Medicine personnel. See National Council on Radiation Protection and Measurements Report Number 65. Medical treatment of injuries takes precedence over radiological considerations.
541-04) Personnel with skin contamination that may cause a dose greater than the alert level in Tables 2-1A and 2-1B shall be assessed and should be informed of their initial dose estimate as soon as practicable. An assessment of skin exposure requires time to conduct a detailed evaluation. Final dose assessments should be explained to the persons affected as soon as practicable.
541-05) The treatment of contaminated injuries should be coordinated with Jefferson Lab Occupational Medicine or other appropriate medical personnel.
Monitoring of radiation is performed using fixed (area) or portable radiation instruments, or a combination thereof. Both the fixed and portable instruments must be readily available and capable of measuring ambient radiation dose rates for the purpose of controlling radiation exposures. Prior to starting any operation that could produce radiation, all stationary instruments should be checked to ensure their proper operation. A review of the central computer data logging system for area monitor malfunction is adequate to verify proper operation. Periodic surveys outside of the operating area are typically performed according to a schedule. Portable instruments should be source checked prior to and after a survey if possible. All portable instruments shall undergo a periodic source check performed by a qualified Radiological Control Technologist (RCT) or Assigned Radiation Monitor (ARM). This source check shall be documented on the portable instrument.
551-01) Monitoring of individuals and areas shall be routinely performed, as necessary, to identify and control potential sources of personnel exposure to radiation and/or radioactive material. Monitoring of individuals and areas shall be performed to:
a) Demonstrate compliance with 10 CFR 835
b) Document radiological conditions;
c) Detect changes in radiological conditions;
d) Detect the gradual buildup of radioactive material;
e) Verify the effectiveness of engineered and process controls in containing radioactive material and reducing radiation exposure; and
f) Identify and control potential sources of individual exposure to radiation and/or radioactive material [§835.401(a)].
551-02) Instruments and equipment used for monitoring shall be:
a) Periodically maintained and calibrated on an established frequency;
b) Appropriate for the type(s), levels, and energies of the radiation(s) encountered;
c) Appropriate for existing environmental conditions; and
d) Routinely tested for operability [§835.401(b)].
551-03) Only trained and qualified personnel shall perform monitoring.
551-04) The cognizant radiological supervisor shall review monitoring results. The review should ensure that all required surveys have been performed and that the documentation is accurate and complete.
551-05) Results of current surveys or survey maps should be conspicuously posted to inform personnel of the radiological conditions.
551-06) Monitoring results should be made available to line management and used in support of pre- and post-job evaluations, as low as reasonably achievable (ALARA) preplanning, contamination control and management of radiological control operations.
Fixed instruments are used to provide an indication of area radiation levels, provide a record of area dosimetry for ALARA program purposes, and for protective trip functions (where they prevent situations that could cause persons to exceed certain dose limits). Only RCD staff may direct the movement or placement of CARM probes. The calibration, use, and functional certification of these instruments in safety related systems are the responsibility of the RCD.
552-01) The need and placement of area radiation monitors shall be documented and assessed when changes to facilities, systems, or equipment occur.
552-02) Area radiation monitors shall be tested at least semi-annually to verify audible alarm system operability and audibility under ambient working conditions and operability of visual alarms when so equipped. Interlock function shall be tested at least annually.
552-03) 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.
Appropriate controls shall be maintained and verified to prevent the inadvertent transfer of removable contamination to locations outside of radiological areas under normal operating conditions. Any area in which contamination levels exceed the values specified in 10 CFR 835 Appendix D shall be controlled in a manner commensurate with the physical and chemical characteristics of the contaminant, the radionuclides present, and the fixed and removable contamination levels.
553-01) In addition to the requirements of Article 551, routine contamination surveys should be conducted as follows:
b) Daily, at contamination area control points, change areas, or step-off pads when in use, or per shift in high use situations
c) Weekly, or upon entry if entries are less frequent, where contamination boundaries or postings are located
d) 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
e) After a leak or spill of radioactive materials.
553-02) Items with inaccessible surfaces which were located in known or suspected contamination areas and have the potential to become contaminated at levels likely to exceed 10 CFR 835 Appendix D values should 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.
553-03) Appropriate methods shall be used for assessing representative samples of bulk material, such as sand, sweeping compounds, or plate steel, that are not suitable for normal loose and fixed contamination-level assessment techniques.
553-04) 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.
553-05) Large area wipes should be used to supplement standard swipe techniques in areas generally assumed not to be contaminated. If an evaluation indicates that an area wiped is contaminated, a thorough contamination swipe survey should be performed.
554 Airborne Radioactivity Monitoring
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. Samples are taken as necessary to detect and evaluate the level or concentration of airborne radioactive material at work locations.
554-01) Monitoring of airborne radioactivity shall be performed:
a) Where an individual is likely to receive an exposure of 40 or more derived air concentration (DAC)-hours in a year; or
b) As necessary to characterize the airborne radioactivity hazard where respiratory protective devices for protection against airborne radionuclides have been prescribed [§835.403(a)].
554-02) Real-time air monitoring shall be performed as necessary to detect and provide warning of airborne radioactivity concentrations that warrant immediate action to terminate inhalation of airborne radioactive material [§835.403(b)].
554-03) 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 will be initiated.
554-04) 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).
554-05) For the airborne radioactive material that could be encountered, real-time air monitors shall have alarm capability and sufficient sensitivity to alert exposed or potentially exposed individuals that immediate action is necessary in order to terminate or minimize inhalation exposures.
554-06) The proper operation of continuous air monitoring equipment should be periodically verified by observing relevant computer records of continuously logged operational parameters. Operational checks should include positive air-flow indication, non-zero response to background activity, and internal check sources.
The RCD is responsible for the maintenance, calibration, and operability of radiation detection equipment used for personnel radiation protection. Instruments used for monitoring and contamination control shall be:
· Maintained and periodically calibrated on an established frequency of at least once per year;
· Appropriate for the type(s), levels, and energies of the radiation(s) expected;
· Appropriate for existing environmental conditions; and
· Routinely tested for operability.
For fixed instrumentation, when appropriate, the annual calibration frequency may be extended, if determined through documented analysis that periods longer than one year can be used without degradation in equipment reliability and accuracy. Such evaluations should be conducted in accordance with National Conference of Standards Laboratories Recommended Practice RP-1,
“Establishment and Adjustment of Calibration Intervals”.
562 Use of Radiation Monitoring Instruments
562-01) Prior to using an instrument, checks should be made by the Radiological Control Technologist (RCT) or Assigned Radiation Monitor (ARM):
a) Visual check – Check for physical integrity of the instrument. Discrepancies include loose or broken knobs and switches, broken probe cords, broken probes, and cracked meters.
b) Check instrument calibration due date. Do not use an instrument that is overdue for calibration.
c) Battery check – All battery powered instruments with a “battery check” switch position shall be checked prior to use. A meter reading in the indicated range is the indication of a successful battery check.
d) Function check – Where provided, follow posted instructions and perform a source check on the instrument. Sources are installed in a test rig and a list of acceptable responses is provided.
562-02) If any discrepancies are noted during the performance of the above checks, a “Faulty Instrument” tag should be filled out and attached to the instrument. The instrument should be returned to the RCD and a replacement obtained. UNDER NO CIRCUMSTANCES SHALL A FAULTY INSTRUMENT BE USED.
562-03) When choosing an instrument, care should be taken to select one with a range high enough for the expected conditions. Not only will having the incorrect instrument waste time, but it will also unnecessarily increase radiation exposure.
562-04) The correct instrument for use on any given survey shall be determined by the RCD.
562-05) When entering an area where the level of the radiation field is unknown, the instrument should be set to operate on the highest range until it is seen that the meter reads less than one quarter of the full scale. The operating switch should then be moved to successively lower ranges until the indicated reading is between one quarter and three quarters of the full scale or the lowest range is reached. Note that auto-ranging instruments will select the correct range for the user.
562-06) After use, the instrument should be returned to its appropriate storage location. Ensure that the instrument is turned off prior to storage. Instruments that appear damaged, that failed response checks, or that may otherwise be unfit for future use shall be tagged and returned to the RCD and a replacement obtained.
563 Inspection, Calibration, and Performance Tests
563-01) Radiological instruments shall be used only to measure the radiation for which their calibrations are valid. Records of calibration and repair will be kept for each instrument. National Institute of Standards Technology (NIST) traceable sources shall be used for calibrations.
563-02) Calibration procedures shall be maintained for each instrument type, and include frequency of calibration, recalibration requirements, primary calibration requirements, periodic performance test requirements, calibration record requirements and maintenance requirements.
563-03) Radiation instrumentation response to interfering ionizing and non-ionizing radiation and environmental conditions should be known prior to use.
563-04) Functional tests shall be used to assess instrumentation designs that include alarms or that involve a process control. A functional test shall be performed to test all components involved in an alarm or trip function and should be performed at least annually.
563-05) In unusual and limited situations, it may be necessary to use an instrument in an application other than that envisioned by the manufacturer. The instrument shall be adjusted, calibrated and/or labeled as appropriate to identify the special conditions and used only under the special conditions for which it was calibrated.
563-06) Instruments shall bear a label or tag with the date of calibration and date calibration is due.
563-07) Instruments whose “as found” readings indicate that the instrument may have been used while out of calibration shall be reported to the RCD. The RCD should review surveys performed with the instrument while it was out of calibration and determine if additional surveys are needed.
564-01) A program for preventive and corrective maintenance of all radiological instrumentation shall be maintained and documented.
564-02) Preventive and corrective maintenance should be performed using components and procedures at least as stringent as those specified by the manufacturer of the instrument.
564-03) Radiological instruments shall undergo calibration prior to use following any preventive or corrective maintenance or any adjustment that voids the previous calibration. A battery change is not normally considered maintenance.
565 Calibration Facilities
565-01) Calibration facilities should perform inspections, calibrations, performance tests, calibration equipment selection and quality assurance in accordance with the recommendations of ANSI N323A and take the following actions:
a) Locate activities in a manner to minimize radiation exposure to operating personnel and to personnel in adjacent areas.
b) Minimize sources of interference, such as backscatter and non-ionizing radiation, during the calibration of instrumentation and correct for interferences as necessary.
c) Operate in accordance with the referenced standards.
d) Generate records of calibration, functional tests and maintenance in accordance with the referenced standards.
565-02) For calibrations that cannot be performed by Jefferson Lab, contracted calibration services should be performed in accordance with Jefferson Lab approved procedures.
566 Radiation Safety Interlocks
Safe operations require that a number of electrical and mechanical conditions be satisfied before radiation production can begin. As described in ES&H Manual Chapter 6311 Prompt Radiation Control, interlock systems are designed to ensure that these conditions are satisfied. Interlocks are designed to be “fail safe” and to have considerable redundancy in the system.
Interlock systems shall be described in the work control document approved for the operation. Periodic testing of the interlock systems shall be used to verify system integrity.