ES&H Manual

Radiation Control Supplement




Chapter 2 – Radiological Standards





Part 1 Administrative Control Level and Dose Limits



Exposure to ionizing radiation, however small the amount, is presumed to involve some risk.  To minimize radiation dose to personnel, engineered and administrative controls are employed at Jefferson Lab.  Physical design features are the primary means by which unnecessary radiation exposures are prevented.  Although all facilities have been designed and constructed to minimize exposure, administrative controls are used as supplemental measures to control radiation exposure.   For these controls to be effective, individual workers must understand and exercise their responsibilities in the radiation protection program.


211        Administrative Control Level


The following administrative limits have been established at Jefferson Lab for exposure to ionizing radiation:

211-01)         The Jefferson Lab Administrative Control Level (Action Level) is 1 rem per calendar year (whole body).  No person shall be allowed to go above the Action Level without the prior approval of the Jefferson Lab Director.  If an exposure exceeding the Action Level occurs in the absence of prior planning and approval, the Notable Event process will be employed to investigate the cause of the condition and implement any needed corrective actions.

211-02)         An Administrative Control Level of 20 percent of the relevant limit in 10 CFR 835 is established for dose to individual organs or tissues.  The approval and event investigation requirements above apply to these limits also.

211-03)         Approval by the Program Secretarial Official or designee should be obtained prior to allowing a radiological worker to exceed 2 rem (whole body).

211-04)         To maintain positive control of radiological worker exposure, an exposure alert system is in effect at Jefferson Lab.  When a radiological worker’s annual radiation dose approaches or exceeds 250 mrem (Jefferson Lab Alert Level), the worker and his/her supervisor shall be notified that his/her exposure is at or has exceeded the Jefferson Lab design goal.  The worker should then consult with his/her supervisor and with the Radiation Control Department (RCD) to ensure that supervisor and worker are doing as much as possible to minimize exposure to radiation and adhere to the As Low as Reasonably Achievable (ALARA) process.

211-05)         The Alert Level for members of the general public, including employees who are not radiological workers, is 10 mrem.  This dose may be determined by either estimation or measurement.  Exposures shall be kept below the limits in Table 2-1A and maintained as low as reasonably achievable [§835.1003(a)].


Table 2-1A Occupational Limits and Administrative Control Levels (total effective dose)a, b


Radiological Workers

General Employees (total)

Annual Limit

5 rem (50 mSv)

100 mrem (1 mSv)

Action Level

1 rem (10 mSv)

50 mrem (0.50 mSv)

Jefferson Lab Design Goals (Alert Level)

250 mrem (2.5 mSv)

10 mrem (0.1 mSv)

a   Except for planned special exposure conducted consistent with 10 CFR 835.204 and emergency exposures authorized in accordance with 10 CFR 835.1302, the occupational dose received by employees shall be controlled such that the limits in the table are not exceeded in a year.

b  See 10 CFR 835.2 for definitions of dosimetric terms not defined in this manual.


211-06)         All occupational doses received during the current year, except doses resulting from planned special exposures conducted in compliance with 10 CFR 835.204 and emergency exposures authorized in accordance with 10 CFR 835.1302, shall be included when demonstrating compliance with 10 CFR 835.202(a) and 835.207 [§835.202(b)].  Annual organ/extremity equivalent dose limits are presented in Table 2-1B.

211-07)         Doses from background, therapeutic, and diagnostic medical radiation and participation as a subject in medical research programs shall not be included in dose records or in the assessment of compliance with the occupational dose limits [§835.202(c)].

211-08)         For the purpose of monitoring individual exposures to internal radiation, internal dose evaluation programs (including routine bioassay programs) shall be conducted for radiological workers who, under typical conditions, are likely to receive 100 mrem (0.001 sievert) or more committed effective dose, and/or 5 rem (0.05 sievert) or more committed equivalent dose to any organ or tissue, from all occupational radionuclide intakes in a year.

211-09)         The total effective dose during a year is determined by summing the effective dose from external exposures and the committed effective dose from intakes during the year [§835.203(a)].

211-010)      Equivalent dose to the whole body may be used as effective dose in evaluating external exposures.  Determination of the effective dose shall be made using the radiation and tissue weighting factor values provided in 10 CFR 835.2 . [§835.203(b)] For the case of uniform external irradiation of the whole body, a tissue weighting factor equal to 1 may be used in determination of the effective dose.

211-011)      Any method used for internal and external monitoring shall be adequate to demonstrate compliance with limits for radiological workers, declared pregnant radiological workers, minors, and members of the general public.


Table 2-1B Annual Organ/Extremity Equivalent Dose Limits & Levels

Type of Exposurea







Equivalent dose to lens of eye

15 rem

3 rem

1 rem

The sum of the equivalent dose to the skin or any extremity (hands and arms below the elbows; feet and legs below the knees) for external exposures and the committed equivalent dose to the skin or to any extremity.

50 rem

10 rem

2.5 rem

The sum of the equivalent dose to the whole body for external exposures and the committed equivalent dose to any organ or tissue other than the skin or the lens of eye,

50 rem

10 rem

2.5 rem

a  See 10 CFR 835.202 for definitions; see 10 CFR 835.205 for determination of non-uniform dose to the skin.


212        Radiological Worker Dose Limits for Routine Occupational Exposure


A radiological worker is any individual whose job assignment involves operation of radiation producing devices or working with radioactive materials, or who is likely to be routinely occupationally exposed above 0.1 rem (100 mrem) per year total effective dose.  The following limits have been established at Jefferson Lab for occupational exposure to ionizing radiation:


212-01)         The annual exposure limits for radiological workers are found in Tables 2-1A and 2-1B.  Occupational radiation exposure of Jefferson Lab radiological workers resulting from DOE activities (other than planned special exposures and emergency exposure situations indicated below), shall be controlled so the annual limits listed in Tables 2-1A and 2-1B are not exceeded [§835.202(a), §835.1003(a)]].

212-02)         Occupational doses received as a result of the following activities (which are excluded from the regulation) and radioactive material transportation shall be included to the extent practicable in determining compliance with occupational dose limits:

a)               Activities conducted under the authority of the Deputy Directors for Naval Reactors as described in Pub. L. 98-525 and 106-65;

b)               Activities that are regulated through a license by the Nuclear Regulatory Commission or a State under an Agreement with the Nuclear Regulatory Commission, including activities certified by the Nuclear Regulatory Commission under section 1701 of the Atomic Energy Act;

c)               Activities conducted under the Nuclear Explosives and Weapons Surety Program relating to the prevention of accidental or unauthorized nuclear detonations;

d)               DOE activities conducted outside the U.S. on territory under the jurisdiction of a foreign government to the extent governed by occupational radiation protection requirements agreed to between the U.S. and the cognizant government; and

e)               Radioactive material transportation not performed by DOE or a DOE contractor.

212-03)         A radiological worker whose occupational exposure has exceeded the numerical value of the applicable limits specified in Tables 2-1A and 2-1B (as a result of an authorized emergency exposure) may be permitted to return to work in radiological areas during the current year, provided that all of the following conditions are met [§835.1301(a)]:

a)               Approval is first obtained from the contractor management and the Head of the responsible DOE field organization;

b)               The individual receives counseling from radiological protection and medical personnel regarding the consequences of receiving additional occupational exposure during the year;

c)               The doses exceeding the limits specified in Tables 2-1A and 2-1B have been recorded in the individual’s occupational dose record [§835.1301(b)]; and

d)               The affected employee agrees to return to radiological work.


The table in Appendix 2A contains Guidelines for Control of Emergency Exposures.


212-04)         When the conditions under which a dose was received in excess of limits specified in Tables 2-1A and 2-1B (except those doses received in accordance with provisions for planned special exposures) have been eliminated, Jefferson Lab management will notify the Jefferson Lab DOE Site Office Manager or designee [§835.1301(c)].

212-05)         Operations at Jefferson Lab that use or produce ionizing radiation or radioactive material, and which have been suspended after an emergency or accidental exposure in excess of the limits specified in Tables 2-1A and 2-1B, will be resumed only with the approval of the appropriate DOE authority, as indicated in the DOE-approved Jefferson Lab Occurrence Reporting and Processing System (as described in Chapter 5300 Occurrence Reporting to Department of Energy (DOE) of the ES&H Manual) [§835.1301(d)].

212-06)         Jefferson Lab does not anticipate rescue or recovery actions resulting in exposures in excess of applicable regulations.  However, Jefferson Lab will minimize the risk of injury to those individuals involved in rescue and recovery operations [§835.1302(a)].  Jefferson Lab management will weigh actual and potential risks to rescue and recovery individuals against the benefits to be gained [§835.1302(b)].  Volunteers will perform any rescue actions at Jefferson Lab that might involve substantial personal risk [§835.1302(c)].  Any individual authorized to perform emergency actions likely to result in occupational doses exceeding the limits for radiological workers in Table 2-1A or 2-1B shall be trained in accordance with §835.901(b) and be briefed beforehand of the known or anticipated hazards to which the individual will be subjected [§835.1302(d)].


213        Planned Special Exposures for Radiological Workers


213-01)         A planned special exposure may be authorized for a radiological worker to receive doses (in addition to and accounted for separately from the doses received under the limits specified in Tables 2-1A and 2-1B), provided that the following conditions are satisfied:

a) The planned special exposure is considered only in an exceptional situation when alternatives that might prevent a radiological worker from exceeding the limits in Tables 2-1A and 2-1B are unavailable or impractical [§835.204(a)(1)].

b) The Jefferson Lab RCM and Laboratory Director (and employer, if the employer is not Jefferson Lab) specifically request the planned special exposure and submit the request in writing for approval by the DOE [§835.204(a)(2)].

c) Joint written approval from the appropriate DOE Headquarters program office and the Secretarial Officer responsible for Environment, Safety and Health is received [[§835.204(a)(3)].

213-02)         Prior to requesting an individual to participate in an authorized planned special exposure, the individual’s dose from all previous planned special exposures and all doses in excess of occupational dose limits shall be determined [§835.204(b)].

213-03)         An individual shall not receive a planned special exposure that, in addition to the doses determined in 213-02, would result in a dose exceeding the following:

a) In a year, the numerical values of the applicable dose limits established in Table 2-1A and 2-1B [§835.204(c)(1)] or

b) Over the individual's lifetime, five times the numerical values of the dose limits established in Table 2-1A and 2-1B [§835.204(c)(2)].

213-04)         Prior to a planned special exposure, written consent shall be obtained from each individual involved [§835.204(d)].  Each such written consent shall include:

a) The estimated doses and associated potential risks and specific radiological conditions and other hazards which might be involved in performing the task [§835.204(d)(2)],

b) The purpose of the planned operations and procedures to be used [§835.204(d)(1)], and

c) Instructions on the measures to be taken to keep the dose ALARA considering other risks that may be present [§835.204(d)(3)].

213-05)         Records of the conduct of a planned special exposure shall be maintained and a written report submitted within 30 days after the planned special exposure to the approving organizations identified in 213-01 [§835.204(e)].

213-06)         The dose from planned special exposures is not to be considered in controlling future occupational dose of the individual under Tables 2-1A and 2-1B, but is to be included in records and reports required by 10 CFR 835 [§835.204(f)].


214        Dose Limits to Minors


No individual under the age of 18 shall be allowed into a Radiologically Controlled Area (RCA) without the permission of his/her parent or guardian, the Jefferson Lab Director, and the RCM.  The annual dose limit to any minor occupationally exposed to radiation and/or radioactive materials from Jefferson Lab activities is 100 mrem (1mSv) total effective dose, and 10% of the occupational dose limits specified in Table 2-1B [§835.207].  The administrative control levels for non-radiological workers in Table 2-1A shall be applied to occupationally exposed minors.  Monitoring requirements for occupationally exposed minors are specified in Chapter 5 of this manual. 


215        Dose Limit for Visitors and Members of the General Population


215-01)         The total effective dose limit for members of the public exposed to radiation and/or radioactive material during access to a controlled area is 100 mrem (1 mSv) in a year [§835.208].  The administrative control levels for non-radiological workers in Table 2-1A are applicable to members of the public; however, specific actions triggered by approaching or exceeding the values listed are to be tailored appropriately, considering the context of the exposure scenario.  For instance, if a member of the public were to receive an effective dose of 10 mrem, the individual and their escort/sponsor would be informed that the dose had reached the design goal, and every reasonable effort would be made to prevent further exposure.    Monitoring requirements for members of the public entering a controlled area are specified in Chapter 5 of this manual.

215-02)         The total effective dose limit for members of the public offsite, from all routine DOE activities, is 100 mrem in a year.  The ALARA process shall be used to reduce doses to the public as far below this limit as is reasonably achievable.  Jefferson Lab’s Environmental Radiological Protection Program, including activities related to DOE environmental protection Orders, is described in the Environmental Radiological Protection Program Plan.

215-03)         In keeping with the limits and reporting requirements for exposures to members of the public in DOE Order458.1, Jefferson Lab has established an Action Level for total effective dose where, under plausible exposure conditions, a person at the site boundary could receive 10 mrem in a year.  Further, the design goal for such exposures is very conservatively established at 10 mrem in a year, under conditions of continuous exposure (8760 hours). 


216        Embryo/Fetus Dose Limits


A Declared pregnant worker is a woman who has voluntarily declared to her employer, in writing, her pregnancy for the purpose of being subject to the occupational dose limits to the embryo/fetus as provided below.  This declaration may be revoked, in writing, at any time by the declared pregnant worker.


216-01)         The declaration of pregnancy shall include an estimated date of conception, and may be completed prior to conception by a woman who is planning a pregnancy.  After a female radiological worker declares pregnancy, she should receive counseling concerning prenatal radiation exposure by the Radiation Control Manager (or designee) and Occupational Medicine.

216-02)         Declared pregnant workers who are Jefferson Lab employees will be provided the option of a mutually agreeable assignment of work tasks, without loss of pay or promotional opportunity, such that further occupational radiation exposure to the declared pregnant worker is unlikely.  Radiological workers not employed by Jefferson Lab should also be provided this option.

216-03)         The equivalent dose limit for the embryo/fetus from the period of conception to birth, as a result of occupational exposure of a declared pregnant worker, is 0.5 rem (5 mSv) [§835.206(a)].  Substantial variation above a uniform exposure rate that would satisfy the 0.5 rem limit shall be avoided [§835.206(b)].

216-04)         The dose to the embryo/fetus from radiation external to the mother is taken as the equivalent dose to the whole body to the mother’s abdomen or torso.

216-05)         An internal dose evaluation program, including a routine bioassay program, shall be conducted for declared pregnant workers likely to receive an intake resulting in an equivalent dose to the embryo/fetus in excess of 10% of the limit stated above.

216-06)         If the dose to the embryo/fetus is determined to have already exceeded 0.5 rem (5 mSv) when a worker declares her pregnancy, the declared pregnant worker shall not be assigned to tasks where additional occupational radiation exposure is likely during the remainder of the gestation period [§835.206(c)].


217        Special Control Levels


Certain situations require lower individualized exposure control levels.  In addition to considering recommendations from the RCM and medical officials, the Jefferson Lab Director should obtain advice from professionals in other disciplines, such as human resources and legal counsel, in establishing Special Control Levels.  The Jefferson Lab Director may wish to establish these Special Control Levels with the advice of the RCM, the Occupational Medicine Physician, and the Jefferson Lab Radiation Review Panel.  Planned Special Exposures carry additional legal notification requirements as indicated in Article 213.


217-01)         A Special Control Level for annual occupational exposure shall be established for each person with a lifetime occupational dose exceeding N rem, where N is the age of the person in years.  The Special Control Level will not exceed 1 rem and should allow the person’s lifetime occupational dose to approach N rem as additional occupational exposure is received.

217-02)         Although background, therapeutic and diagnostic medical exposures are not included in either personnel radiation dose records or assessment of dose against the limits of Tables 2-1A and 2-1B, Special Control Levels taking these exposures into account may be established as agreed upon by management and the individual.

217-03)         Notification to the RCD should be made if any Radiological Worker has been medically administered a long-lived radionuclide.  The RCD shall make a determination if any Special Control Levels should be applied.

217-04)         A Special Control Level shall be established for any individual for whom formal records of previous exposure during the year have not been obtained.  This Special Control Level is normally 0.1 rem.

217-05)         A Special Control Level shall be established for any radiological worker whose previous recorded or estimated exposure for the year is greater than 1 rem.  Establishment and approval of this Special Control Level shall be consistent with the ALARA principle and Article 211.



Part 2 Contamination Control and Control Levels



Jefferson Lab maintains appropriate methods of control thatprevent the inadvertent transfer of removable contamination to locations outside of radiological areas under normal operating conditions.  These methods ensure that contamination is controlled in a manner commensurate with the physical and chemical characteristics of the contaminant, the radionuclides present, and the fixed and removable contamination levels.  Control of radioactive contamination is achieved by using engineered and administrative controls to contain contamination at the source, reducing existing areas of contamination, and to the extent feasible, promptly decontaminating areas that become contaminated.


221        Personnel Contamination Control


221-01)         Personnel exiting Contamination Areas, High Contamination Areas, or Airborne Radioactivity Areas shall be monitored, as appropriate, for contamination as required by Article 338.  Personnel monitoring is normally not required when exiting areas posted for airborne radioactivity when the posting is based solely on the presence of gaseous activation products, but is appropriate when posting is required due to airborne particulates.

221-02)         Monitoring for contamination should be performed using monitoring equipment that is sensitive enough to detect total contamination to the levels specified in Appendix 2B Contamination Control Limits.

221-03)         Personnel found with contamination on their skin or personal clothing, other than gases or natural background radioactivity, should be promptly decontaminated as described in Article 541.


222        Contamination Control Levels


222-01)         A surface shall be considered contaminated if either the removable or total surface radioactivity is detected above the levels in Appendix 2B.  If an area cannot be decontaminated promptly, then it shall be posted as specified in Article 234.

222-02)         In this document, a potentially contaminated item/area is defined as an item that has been used or stored in a radiological area that is known or suspected to contain unconfined radioactive material; or as an item or area suspected to be contaminated, based on experience or process knowledge.

222-03)         Surfaces exceeding the values of Appendix 2B for total contamination may be covered with a fixative coating to prevent the spread of contamination.  However, reasonable efforts should be made to decontaminate an area before a coating is applied.  A fixative coating, other than that used for a temporary work condition, shall not be applied without the approval of the RadCon Manager.

222-04)         Volume-activated materials that are not contaminated on the surface are not subject to contamination controls.

222-05)         In accordance with the exemption granted June 8, 1998, Jefferson Lab uses a special limit of 30,000 dpm/100 cm2 for Be-7 in lieu of the 10 CFR 835 Appendix D limits for beta-gamma emitters (see Appendix 2B of this manual).  Be-7 is produced in air and water exposed to high energy beams and can build up on surfaces and in systems in beam enclosures.  The Jefferson Lab exemption involves the following conditions:

a)               The exemption applies to posting and controls used in controlled areas only.  Release of materials from controlled areas must comply with other applicable requirements.  In general, this involves meeting the release criteria in O458.1.  For nuclides of concern at Jefferson Lab, the limits for unrestricted release are the same as those in 10 CFR 835, Appendix D.  Therefore, with the exception of Be-7, the contamination control values used to identify contamination areas are the same as those for unrestricted release.  Technical basis documents and written procedures provide specific requirements and protocols for release surveys that are consistent with the exemption requirements.

b)               The exemption requires that areas historically known to contain Be-7 above the Appendix D values be identified, and posted, marked or labeled to warn workers not to enter without appropriate authorization.  The processes that result in production and buildup of Be-7 on/in components and systems are well understood.  Historically, locations that have been affected are electrical rack spaces and electronic components, air handling equipment, and various cooling water systems within beam enclosures.  Typically, levels only exceed Appendix D values where there is significant beam loss, such as in experimental halls A and C.  However, the potential for buildup of Be-7 exists to some degree in any beam enclosure, and the equipment for which there is significant potential for such buildup is marked accordingly.  In addition, administrative procedures, such as the General Access Radiation Work Permit identify this condition and reinforce the required work authorizations.  Written procedures address survey and posting requirements consistent with the exemption.


223        Airborne Radioactivity Control Levels


223-01)         Personnel should not be exposed unnecessarily to airborne radioactivity.  Use of engineered and administrative controls to reduce the potential for internal exposure should be evaluated before allowing personnel, with or without respiratory protection, to enter areas with airborne radioactivity.

223-02)         The Derived Air Concentration (DAC) values given in Appendices A and C of 10 CFR 835 shall be used to control occupational exposures to airborne radioactive material [§835.209(a)].  Occupied areas with airborne concentrations of radioactivity that are greater than, or potentially greater than 1 DAC, or where an individual without respiratory protection could exceed 12 DAC-hours per week, shall be posted as specified in Article 234.  For most radionuclides, air containing a DAC results in a committed effective dose of approximately 100 mrem if inhaled for 40 hours in one work week. 

223-03)         The estimation of internal dose shall be based on bioassay data rather than air concentration values unless bioassay data are:

a)               unavailable,

b)               inadequate, or

c)               internal dose estimates based on representative air concentration values are demonstrated to be as or more accurate than bioassay data [§835.209(b)].



Part 3 Posting



231        Posting Requirements


231-01)         Radiological posting shall be used to alert personnel to the presence of radiation and radioactive materials and to aid them in minimizing exposures and preventing the spread of contamination.  Signs required by 10 CFR 835 shall be clearly and conspicuously posted and may include radiological protection instructions [§835.601(b)].  Signs shall contain the standard radiation symbol (trefoil) in magenta or black on a yellow background [§835.601(a)].  Lettering shall be magenta or black.  Standardized signs, as described in written procedures, should be used where practicable.

231-02)         Radiological postings should be displayed only to signify actual or potential radiological conditions.  Signs used for training should be clearly marked, such as “For Training Purposes Only.”

231-03)         Posted areas should be as small as practicable for efficiency.  Postings should be maintained in a legible condition and updated based upon the results of the most recent surveys.  If more than one radiological condition (such as contamination and high radiation) exists in the same area, each condition shall be identified.

231-04)         In areas of ongoing work activities, the dose rate or range of dose rates should be available at the work area.  Entrance points to areas of ongoing radiological work should state basic entry requirements.

231-05)         Rope, tape, chain, and similar barriers used to designate the boundaries of posted areas should be yellow and magenta in color.  Radiological barriers should be employed in a manner commensurate with the radiological hazards in the area.  Barriers should be clearly visible from all directions and at various elevations.  Radiological boundaries may be defined by natural physical boundaries such as the walls of a room or container.  Barriers should clearly denote the scope and extent of the area, and not contain gaps that would allow inadvertent entry.  These barriers shall be set up such that they do not impede the intended use of emergency exits or evacuation routes.  Where appropriate for access/egress considerations, boundaries may be established by use of designations such as prominent painted lines or use of a series of posted stanchions that are visible from all directions of approach.

231-06)         Posting of doors should be such that the postings remain visible whether doors are open or closed.  A radiological posting that signifies the presence of an intermittent radiological condition should include a statement specifying when the radiation is present, such as “CAUTION: RADIATION AREA WHEN MAGENTA BEACON IS ON.”

231-07)         The posting and labeling requirements in 10 CFR 835 may be modified to reflect the special considerations of DOE activities conducted at private residences or businesses.  Modifications (to posting requirements) made by Jefferson Lab will provide the same level of protection to individuals as the existing provisions [§835.601(c)].


232        Posting Controlled Areas


A Controlled Area is any area to which access is managed to protect individuals from exposure to radiation and/or radioactive material.  Individuals who enter only Controlled Areas without entering Radiological Areas or Radioactive Material Areas are not expected to receive a total effective equivalent dose of more than 100 mrem (1mSv) in a year [§835.602(a)].  Each access point to a Controlled Area shall be posted, identifying it as a Controlled Area, whenever Radiological Areas or Radioactive Material Areas are present [§835.602(a)], and should be posted wherever there is a source of radiation that produces a Radiologically Controlled Area (defined below).  Signs used for Controlled Areas only may be selected by Jefferson Lab to avoid conflict with local security requirements [§835.602(b)].  For access controls and training requirements, see Article 331.


233        Posting Radiologically Controlled Areas (RCAs)


233-01)         Jefferson Lab has defined RCAs such that any person who works in such an area for one year might receive a whole body dose in excess of 100 mrem annual exposure from all pathways (excluding natural background and medical exposures).  RCAs are typically posted based on the dose rate 30 cm from a surface emitting radiation (“whole body” dose rate).  When this dose rate exceeds 0.05 mrem/h, the condition above is assumed to be met.  RCAs shall be posted following standard signage formatting used at Jefferson Lab; the posting may contain additional information concerning entry requirements and/or the radiological conditions within.  Within RCAs, occupational exposure is controlled by establishing regulated Radiological Areas: Radiation Areas, High Radiation Areas, etc.  This graded approach increases access requirements on the basis of the increasing potential for radiation exposure.

233-02)         RCAs shall be designated on the basis of estimated or measured radiation dose rate or on account of levels of surface or airborne contamination above specified limits.  As a general practice, RCAs should be posted whenever a radiological area exists to act as a “buffer zone” around radiological areas, as described above.  RCA postings may be contiguous with radiological area boundaries, but only when it is impractical to create an RCA boundary at some point beyond the extent of the radiological area.  Subject to the level of supervision and approval by the RCM, relaxation of radiologically controlled area definition in terms of dose rates may be permitted on grounds of infrequent or brief occupancy or transient radiation conditions.

233-03)         Persons who are not Radiation Workers needing access to RCAs must be escorted by staff having Radiation Worker I training.


234        Posting Radiological Areas


Each access point to radiological areas shall be posted with conspicuous signs bearing the wording provided in this section.  The requirement for an RWP should be included either on or in conjunction with each posting, as applicable.


234-01)         Radiation Area

The words “CAUTION, RADIATION AREA” shall be posted at each radiation area [§835.603(a)] defined as follows: Any area, accessible to individuals, in which radiation levels could result in an individual receiving an equivalent dose to the whole body in excess of 0.005 rem (0.05 mSv) in 1 hour at 30 centimeters from the source or from any surface that the radiation penetrates.

234-02)         High Radiation Area

The words “CAUTION, HIGH RADIATION AREA” or “DANGER, HIGH RADIATION AREA” shall be posted at each high radiation area [§835.603(b)] defined as: Any area accessible to individuals, in which radiation levels could result in an individual receiving an equivalent dose to the whole body in excess of 0.1 rem (0.001 Sv) in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.


234-03)         Very High Radiation Area

The words “GRAVE DANGER, VERY HIGH RADIATION AREA” shall be posted at each very high radiation area [§835.603(c)] defined as: Any area, accessible to individuals, in which radiation levels could result in an individual receiving an absorbed dose in excess of 500 rads (5 grays) in one hour at 1 meter from a radiation source or from any surface that the radiation penetrates.


234-04)         Posting Contamination, High Contamination and Airborne Radioactivity Areas

a)               The words “CAUTION, CONTAMINATION AREA”, “CAUTION, HIGH CONTAMINATION AREA” or “DANGER, HIGH CONTAMINATION AREA”, respectively, shall be posted at any area accessible to individuals where removable surface contamination values exceed or are likely to exceed the applicable removable surface contamination values in Appendix 2B [§835.603(e),(f)].  Areas accessible to individuals shall be posted to alert personnel to contamination in accordance with Article 231.

b)               The words “CAUTION, AIRBORNE RADIOACTIVITY AREA” or “DANGER, AIRBORNE RADIOACTIVITY AREA” shall be posted at any accessible area in which the concentration of airborne radioactivity above natural background, exceeds or is likely to exceed the DAC value listed in 10 CFR 835, Appendices A or C; or an individual present in the area without respiratory protection could receive an intake exceeding 12 DAC-hours in a week [§835.603(d)].


235        Posting Radioactive Material Areas


235-01)         Accessible areas in which items or containers of radioactive materials exist and the total activity of radioactive material exceeds the applicable values in 10 CFR 835, Appendix E shall be posted “CAUTION, RADIOACTIVE MATERIAL(S)” [§835.603(g)].  The posting shall meet the requirements in Article 231.

235-02)         Radioactive Material Areas shall be located within Controlled Areas.

235-03)         The definition of radioactive material and the requirements for labeling radioactive material are contained in Chapter 4.


236        Posting Hot Spots


Contact readings should be used to determine the presence of hot spots.  Hot spots are defined as spots where the dose rate on contact is greater than 100 mrem/hr and at least five times the dose rate at 30 cm.  Posting of hot spots is not required in areas requiring a job-specific Radiological Work Permit (RWP) or radiological briefing for entry. 


237        Exceptions to Posting Radiological Areas and Radioactive Material Areas


237-01)         Radiological Areas and Radioactive Material Areas may be excepted from the posting requirements of Articles 234 and 235 for periods of less than 8 continuous hours when placed under continuous observation and control of an individual knowledgeable of, and empowered to implement, required access and exposure control measures [§835.604(a)].

237-02)         Areas may be excepted from the radioactive material area posting requirements of Article 235 when:

a)               Posted in accordance with Article 234-01 through -04; or

b)               Each item or container of radioactive material is labeled in accordance with Article 412, such that individuals entering the area are made aware of the hazard; or

c)               The radioactive material of concern consists solely of structures or installed components that have been activated (i.e., such as by being exposed to neutron radiation or particles produced in an accelerator) [§835.604(b)].

237-03)         Areas containing only packages that have been received from radioactive material transportation labeled and in non-degraded condition need not be posted in accordance with Article 234 or 235 until the packages are monitored in accordance with Article 432-04 [§835.604(c)].


Table 2-3 Criteria for Posting Radiological Areas


Posting Criteria


Radiation Area

> 5 mrem in one hour (at 30 cm)


High Radiation Area

> 100 mrem in one hour (at 30 cm)


Very High Radiation Area

> 500 rad in one hour (at 1 m)



Contamination Area

Levels (dpm/100 cm2) > 1 time but < 100 times Appendix 2B values


High Contamination Area

Levels (dpm/100 cm2) > 100 times Appendix 2B values


Airborne Radioactivity Area

Concentrations (µCi/ml) > DAC value listed in 10 CFR 835 Appendices A or C, or an area in which a person without respiratory protection could receive an intake exceeding 12 DAC-hrs in a week



a  Appropriate access requirements should be included on the posting.


238    Posting Exclusion Areas


Exclusion Areas are locations that are locked and interlocked to prevent personnel access while an accelerator is operating.  A fully enclosed and interlocked area is not considered to be accessible [DOE G 420.2-1].  Beam enclosure areas that are configured with a certified Personnel Safety System (PSS) are Exclusion Areas when the beam or high power RF is operable [§835.502(c)].  Signs and/or clearly labeled lights reflecting current interlock or beam status shall be provided at all accelerator enclosure entry doors.  Beam enclosures, test facilities, shielded caves, etc., that are not fully enclosed, or not protected by a certified PSS are not Exclusion Areas, and shall be posted in accordance with the requirements for posting Radiological Areas.











RadCon Dept

Keith Welch





This document is controlled as an on line file.  It may be printed but the print copy is not a controlled document.  It is the user’s responsibility to ensure that the document is the same revision as the current on line file.  This copy was printed on 2/27/2014.