NRC 10 CFR Part 20: Standards for Protection Against Radiation
- Radiation Area: an area, accessible to individuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 0.005 rem (0.05 mSv) in 1 hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.
- High Radiation Area: an area, accessible to individuals, in which radiation levels from radiation sources external to the body could result in an individual receiving a dose equivalent in excess of 0.1 rem (1 mSv) in 1 hour at 30 centimeters from the radiation source or 30 centimeters from any surface that the radiation penetrates.
- Very High Radiation Area: an area, accessible to individuals, in which radiation levels from radiation sources external to the body could result in an individual receiving an absorbed dose in excess of 500 rads (5 grays) in 1 hour at 1 meter from a radiation source or 1 meter from any surface that the radiation penetrates.
Radiation protection program requirements
- Implement a radiation protection program commensurate with the scope of licensee activities
- Use procedures and engineering controls to achieve occupational and public doses which are As Low As is Reasonably Achievable (ALARA)
- At least annually review radiation protection policies
- Report events which exceed dose limits
- Restrict access to High and Very High Radiation Areas
- Manage individual respiratory protection equipment
- Secure stored materials
- Post caution and danger signs in radiation areas of all levels
- Label radiation sources and containers
- Inspect and survey packages containing radiation sources upon receipt
- Proper disposal of radiation materials
- Maintain records of radiation protection program
- Individual monitored doses both workers and public
- Planned exposures
- Received radiation sources
- Waste disposal
- Reporting of events which exceed dose limits
|Type||Annual Occupational Limit (Adults)||Annual Occupational Limit (Minors)
10% of Adult Limit
For “declared” pregnant woman during entire pregnancy
|Members of Public|
|Total Effective Dose||5 rem (50 mSv)||0.5 rem (5 mSv)||0.5 rem (5 mSv)||0.1 rem (1 mSv); Per Year
0.002 rem (0.02 mSv); dose per hour in unrestricted areas
0.5 rem (5 mSv); Pear Year (visitors/infrequent)
|Individual Organ Excluding Lens||50 rem (500 mSv)||5 rem (50 mSv)|
|Lens||15 rem (150 mSv)||1.5 rem (15 mSv)|
|Skin||50 rem (500 mSv)||5 rem (50 mSv)|
Planned Special Exposures
A licensee may authorize an adult worker to receive doses in addition to the annual dose limits provided that a number of conditions are met.
Surveys and Monitoring
NRC 10 CFR Part 20 requires that sites survey areas which may have non-background radiation present. Additionally, personnel meeting the following criteria must be monitored:
- Adults likely to receive more than 10% of their annual exposure limits
- Minors likely to receive more than 0.1 rem (1mSv) deep dose, 0.15 rem (1.5 mSv) lens dose, or 0.5 rem (5 mSv) dose to skin or extremities
- Declared pregnant women likely to receive more than 0.1 rem (1 mSv)
- Any individual entering a high or very high radiation area
NRC 10 CFR Part 35: Medical Use of Byproduct Materials
Any State with which have entered into agreements with NRC that give them [the states] the authority to license and inspect byproduct, source, or special nuclear materials used or possessed within their borders.
A physician, dentist, or podiatrist meeting certain educational criteria who is authorized to permit the medical use of byproduct material.
Radiation Safety Officer (RSO)
An RSO is responsible for implementing the radiation protection program.
Radiation Safety Committee
The radiation safety committee oversees the use of byproduct material. It must include the RSO, and authorized user, a nurse, and a representative of management.
The licensee must develop, implement, and maintain written procedures for medical uses that require a written directive. These procedures must include:
- Identifying with high confidence the patient’s identify prior to each administration
- Verifying that each administration is given as per the written directive
- Verifying dose calculations
- Verifying that computer generated dose calculations are correctly transferred to the consoles of therapeutic medical units
A written directive is an authorized user’s written order for the administration of byproduct material or radiation from byproduct material to a specific patient or human research subject. There are exceptions to the requirement of a written directive when it would jeopardize patient’s health. Written directives must contain the following:
|Procedure||Written Directive Requirements|
|Administration of greater than 1.11 MBq (30 μCi) of sodium iodide I-131||
|Administration of a therapeutic dosage of unsealed byproduct material other than sodium iodide I-131||
|Gamma Stereotactic Radiosurgery||
|High Dose Rate Brachytherapy||
|All Other Brachytherapy||
A medical event (formerly called a misadministration or recordable event) is an event not caused by patient intervention meeting any of the following criteria:
- Dose delivered differs from the prescribed dose by more than 50mSv (5 rem) effective dose equivalent, 500 mSv (50 rem) to an organ or tissue, AND one of the following
- total dose differs by more than 20% from prescription
- dose from a single fraction varies by more than 50%
- A dose exceeding 50mSv (5 rem) effective dose equivalent, 500 mSv (50 rem) to an organ or tissue arising from any of the following
- Administration of wrong radioactive drug
- Administration of radioactive drug by wrong route of administration
- Administration of a dose to wrong individual
- Administration of dose by the wrong mode of treatment
- A leaking source
- A dose to the skin or an organ or tissue other than the treatment site which exceeds 500 mSv (50 rem) to an organ or tissue AND differs by 50% or more from expected dose
NRC 10 CFR Part 37: Physical Protection of Category 1 and 2 Quantities of Radioactive Material
The source categorization used in NRC 10 CFR Part 37 originates from the International Atomic Energy Agency (IAEA) Safety Standards Series No RS-G-1.9. The 5 source categories are based on their potential for harm if not properly handled.
Category 1 Source: Personally Extremely Dangerous
The amount of radioactive material, if not safely managed or securely protected would be likely to cause permanent injury to a person who handled it, or wher otherwise in contact with it, for more than a few minutes. It would probably be fatal to be close to this amount of unshielded material for a period of a few minutes to an hour.
Category 2 Source: Personally Very Dangerous
The amount of radioactive material, if not safely managed or securely protected, could cause permanent injury to a person who handled it, or were otherwise in contact with it, for a short time (minutes to hours). It could possibly be fatal to be close to this amount of unshielded radioactive material for a period of hours to days.
Category 3 Source: Personally Dangerous
This amount of radioactive material, if not safely managed or securely protected, could cause permanent injury to a person who handled it, or were otherwise in contact with it, for some hours. It could possibly – although it is unlikely – be fatal to be close to this amount of unshielded radioactive material for a period of days to weeks.
Category 4 Source: Unlikely to be Dangerous
It is very unlikely that anyone would be permanently injured by this amount of radioactive material. However, this amount of unshielded radioactive material, if not safely managed or securely protected, could possibly – although it is unlikely – temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks.
Category 5 Source: Not Dangerous
No one could be permanently injured by this amount of radioactive material.
|Radioactive Material||Category 1||Category 2|
|Americium-241||60 TBq (1,620 Ci)||0.6 TBq (16.2 Ci)|
|Americium-241/Be||60 TBq (1.620 Ci)||06 TBq (16.2 Ci)|
|Californium-252||20 TBq (540 Ci)||0.2 TBq (5.40 Ci)|
|Cobalt-60||30 TBq (810 Ci)||0.2 TBq (8.10 Ci)|
|Curium-244||50 TBq (1,350 Ci)||0.5 TBq (13.5 Ci)|
|Cesium-137||100 TBq (2,700 Ci)||1 TBq (27.0 Ci)|
|Gadolinium-153||1,000 TBq (27,000 Ci)||10TBq (270 Ci)|
|Iridium-192||80 TBq (2,160 Ci)||0.8 TBq (21.6 Ci)|
|Plutonium-238||60 TBq (1,620 Ci)||0.6 TBq (16.2 Ci)|
|Plutonium-239/Be||60 TBq (1,620 Ci)||0.6 TBq (16.2 Ci)|
|Promethium-147||40,000 TBq (1,080,000 Ci)||400 TBq (10,800 Ci)|
|Radium-226||40 TBq (1,080 Ci)||0.4 TBq (10.8 Ci)|
|Selenium-75||200 TBq (5,400 Ci)||2 TBq (54 Ci)|
|Strontium-90||1,000 TBq (27,000 Ci)||10 TBq (270 Ci)|
|Thulium-170||20,000 TBq (540,000 Ci)||200 TBq (5,400 Ci)|
|Ytterbium-169||300 TBq (8,100 Ci)||3 TBq (81.0 Ci)|
Access Authorization Requirements
- Limit access to authorize individuals
- Requires background investigation initially and every 10 years
- Criminal history
- Credit history check
- Work history
- Character and reputation evaluation
- Escorted individuals do not need background investigation
Physical Protection Requirements
- Security plan
- Protection of Information
- Coordination with local law enforcement agency (LLEA)
- Establish security zones
- Annual program review
- Report any threats to material
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