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Controlled Zones and Limits
Upon completion of this lesson, the participants will demonstrate their knowledge and understanding of the information by obtaining a score greater than or equal to 80% on a written examination. The information presented in this lesson plan may be part of an overall exam or be the only information for which the student is examined.
Terminal Objective
Standards and conditions apply to all enabling objectives. They include under the examination ground rules, without the use of training materials or outside assistance, and utilizing information presented in this lesson plan. Upon completion of this lesson each participant will be able to:
Enabling Objectives
Enabling Objectives
• Define “clean area”.
• Define “ restricted area” and the identificationmechanisms utilized.
• Define Radiological Control Area and the identification mechanisms utilized, and state the requirements for entry.
Enabling Objectives
• Describe the Radioactive Material posting, labeling, marking and use requirements.
• Define Radiation Area, posting requirements and precautions, and determine the posting based upon a dose rate.
Enabling Objectives
• Define High Radiation Area, posting requirements and precautions, and determine the posting based upon a dose rate.
• Define Locked Radiation Area, posting requirements and precautions, and determine the posting based upon a dose rate.
• Define Very High Radiation Area, posting requirements and precautions, and determine the posting based upon a dose rate.
Enabling Objectives• Define “Hot Spot”.
• Define Contamination Area, posting requirements and precautions.
• Describe Fixed contamination in termsof radioactive material label requirements and markings.
• Define Airborne Radioactivity Area and posting requirements.
• List contamination limits for clean area release, personnel, protective clothing.
Restricted Area
RADIOLOGICALLY CONTROLLED AREA
MONITORING DEVICE REQUIRED
NOTIFY RADCON PRIOR TO ENTRY
NO EATING, DRINKING, OR SMOKING
Radiological Control Area
Radiological hazards exist or the potential for radiological hazards exist
Buffer zone between areas with radiological hazards and the “clean area”
Designated by yellow and magenta rope, ribbon, or chain as a boundary and a radiological posting
RADIOLOGICALLY CONTROLLED AREA
MONITORING DEVICE REQUIRED
NOTIFY RADCON PRIOR TO ENTRY
NO EATING, DRINKING, OR SMOKING
Radiological Control AreaEntry Requirements
Personnel must have Radiation Worker training prior to entry.
Entry to and exit from the area shall be via designated access points.
Personnel shall monitor themselves for contamination prior to exit.
RADIOACTIVE MATERIAL
RADIOACTIVEMATERIAL
PRECAUTIONS
RADIOACTIVEMATERIAL
PRECAUTIONS
(SEE OTHER SIDE)
Identification ____________________________________________
Radiation Level
Gamma_____Mrem/hr at contactGamma_____Mrem/hr at______Beta_______Mrem/hr at contactOther______Mrem/hr at_______
CONTAMINATION LEVEL Location____Smearable/Direct____ Location____Smearable/Direct____
__________________________________________________________Survey By:____ Survey NO:_____Time:_________ Date:__________
Radioactive Material
Posting required when radioactive material is stored or used in excess of 10 times the quantity listed in appendix C of 10CFR20.
Radioactive material labeled per 10CFR20.1904 & 10CFR20.1905. Labels require
• Radiation levels• Contamination levels• Kinds of material• Identity of person who
labeled the material
Tools & equipment not labeled will be marked
RADIOACTIVE MATERIAL
RADIOACTIVEMATERIAL
PRECAUTIONS
RADIOACTIVEMATERIAL
PRECAUTIONS
(SEE OTHER SIDE)
Identification ____________________________________________
Radiation Level
Gamma_____Mrem/hr at contactGamma_____Mrem/hr at______Beta_______Mrem/hr at contactOther______Mrem/hr at_______
CONTAMINATION LEVEL Location____Smearable/Direct____ Location____Smearable/Direct____
__________________________________________________________Survey By:____ Survey NO:_____Time:_________ Date:__________
Radioactive Material
Movement/storage a in manner to prevent the spread of contamination and/or excessive exposure & prevent the loss of control in transient.
Removal from RCA requires Radcon approval. Labels require
• Radiation levels• Contamination levels• Kinds of material• Identity of person who
labeled the material
Tools & equipment not labeled will be marked
RADIATION AREA
Radiation Area
Dose rates 5 mrem/hr @ 30 cm
Work is planned and controlled to eliminate excessive exposure.
HIGH RADIATION AREA
High Radiation Area
Dose Rates >100 mrem/hr
Barricaded and conspicuously posted
Entry controlled through the use of Radiation Work Permits (RWP)
Any individual permitted to enter shall be provided with: A radiation monitoring device which continuously indicates
the radiation dose rate in the area A radiation monitoring device which continuously integrates
the radiation dose rate in the area and alarms when preset integrated dose is received
Continuous Radcon coverage
HIGH RADIATION AREA
LOCKED HIGH RADIATION AREA
• Continuous Radcon Coverage is required for entry.
• Strict key control for lock and entry.
Locked High Radiation AreaDose rates in the area exceed 1000 mrem/hr.
• Must follow the requirements set forth in 10CFR20
• Thus the entryways are locked or guarded
GRAVE DANGER
VERY HIGH RADIATION AREA
Very High Radiation Area
Dose rates exceed 500 rad/hr @ 1 meter
In addition to the requirements for a High Radiation Area, the licensee shall institute additional measures to ensure that an individual is not able to gain unauthorized or inadvertent access.
Entry requires approval of the Radcon Superintendent and may require further approval.
ID#__________
HOTSPOT
______mrem/hr
Hot Spot
Hot Spots are normally caused by “crud” buildup
inside the piping.
Information posting to inform worker of an area exist with a significant radiation level in correspondence to the surrounding area.
• Contact dose rate greater than or equal
to 100 mrem/hr
• Contact dose rate 5 X’s higher 30 cm dose rate.
On August 17, 1999 - Performing the monthly survey • Dose rate >100 mem/hr @ 30 cm- outside HRA posted
boundary
• Dose rates - ankle level - RO-2 ion chamber meter -Source of radiation - ankle level
• Event cause -inconsistent techniques employed by technicians -some ankle height to eight-foot elevation - others waist height to the eight-foot -procedures not clear guidance all levels of a boundary
Operating Experience
• No personnel overexposure occurred - potential for exposure existed
• Corrective actions – extend HRA, Validating new boundary, updating radiological area status sheet, briefing technicians to perform surveys to address whole body , verifying other HRA boundaries, rocedures revised to clearly define dose rate measurement techniques
• Event not significant -no overexposure from unposted area
• Event noteworthy - inconsistent survey techniques result unposted HRA
Operating Experience
CONTAMINATION AREA
Contamination Area
Contamination Areas
Conspicuous boundaries - rad-ribbon, rad-rope, rad-tape, and step-off pads
Limitations - radiation tape and/or radiation hazard tags.
Space limitation - floor drains, electrical panels, sample sinks, etc.
Loose contamination in excess of1000 dpm/100cm2 beta/gamma 20 dpm/100cm2 alpha
REMOVE ALL ANTI-C ZONE
CLOTHING BEFORESTEPPING HERE
Levels – minimum- decontamination Protective clothing - required Open cuts, wounds, skin rashes, and
infections - protected
Fixed Contamination
Items with fixed contamination will have to be tagged as Radioactive Material when levels are in accordance with 10CFR20.1904 and 10CFR20.1905.
Levels are less than Rad material but >100 cpm beta/gamma and/or >30 cpm alphaItem is marked to designate RCA use
Fixed contamination - contamination is not transferred or detected by smear survey. Transferable through operations such as grinding, welding, etc.
AIRBORNE RADIOACTIVITY AREA
An airborne radioactivity area is an area, room, or enclosure in which airborne radioactive material composed wholly or partly of licensed material exist in concentrations exceeding 30 percent of the limits in site procedures or 10 CFR 20 Appendix B, Table 1, when isotopic analysis is available.
If the isotopes are unidentified, the limits are:
Alpha – 6 x 10 -13
Beta/gamma – T ½ >2 hr – 3 x 10 -9
T ½ <2 hr – 1 x 10 -6
Airborne Radioactivity Area
Total Radioactivity
(Direct Survey) Removablec
Alphab
Beta-Gammaa
Alphab Beta-gamma
AREA/ITEM (cpm) (cpm) (dpm/100 cm2)
(dpm/100 cm2)
Clean zone surfaces
30 100 20 1000
or material release
Personal clothing 30 100 N/Ae N/Ae
or skin surfaces.
Total Radioactivity
(Direct Survey) Removablec
Alphab
Beta-Gammaa
Alphab Beta-gamma
AREA/ITEM (cpm) (cpm) (dpm/100 cm2)
(dpm/100 cm2)
Respirators or 30 500 20 1000
cartridges.
C-zone clothing 30 4500 20d 1000d
and respiratory
equipment excluding
face mask and cartridge
June 24, 2002, Davis Besse -containment decon tent - mirror insulation – high contamination levels
Decon mirror insulation - workers questioned - boric acid on mirror insulation
Rad tag smearable - 30,000dpm/100cm2
Contacted technician – 5,000,000dpm/100cm2 1.5 rad/hr.
Decon tent - up to 1,000,000 dpm/100cm2
Decon tent prior -20,000 to 50,000 dpm/100cm2
Air sampler - 0.62% DAC
OE 13939
One worker - minor contamination on modesty garments, No intakes
Caused by mislabeling of the bag -wrong tag on bag after initial tagging
Contamination control - upgraded - survey all insulation prior to decon
Event -not significant -no excessive exposure or potential
Event is NOTEWORTHY - work practices resulted in significantly higher than expected smearable contamination levels
OE 13939
