10CFR20 and Radiation Protection Flashcards
Define Stochastic effects
Randomly occurring health effects for which the probability of the effect occurring varies linearly with dose and has no threshold.
Ex: cancer, unpredictable.
10CFR20 limit that helps reduce probability Stochastic effects
5 rem (0.05 Sv) uniform whole body dose.
Define Non-Stochastic Effects
Health effects in which the severity of the effect varies with dose and for which a threshold is believed to exist.
Example of 10CFR20 annual dose limit (thresholds)
Lens of the eye-15 rem. (Cataracts)
What is an ALI?
Annual Limit on Intake
Limit for the amount of radioactive material taken into the body of an adult worker by inhalation or ingestion in a year.
ALI units are in Curies.
5000mRem/1 ALI
Relationship between DAC and ALI
Derived Air Concentration.
Concentration of a given radionuclide that if inhaled for a working year (2000 hours) during light work results in an intake of 1 ALI
2000 DAC-hrs= 1 ALI.
5000 mrem=1 ALI=2000 DAC-hrs
Therefore:
1 DAC-hr=2.5 mrem.
10CFR20 dose limits
Annual TEDE: 5 R/yr
Annual Eye Dose Equivalent [H(eye)]: 15 R/yr
Annual Skin/Extremities dose equivalent [H(s)]: 50 R/yr
Declared Pregnant Worker: 500 mrem over gestation, 50 mrem per month
Admin Dose Limits
TEDE: 2 R/yr
Annual Eye dose equivalent: 12 R/yr
Annual Skin/Extremities: 40 R/yr
Declared Pregnant Worker: 450 mrem for gestation, 50 mrem per month
How to calculate TEDE
TEDE=DDE+CEDE
DDE=Dose x Quality factor
CEDE=Summation of CDE x Wt
Wt is weight factor for particular organ
CDE would also be for a particular organ
Allowable Dose to protect Valuable Equipment
10 rem per incident.
Allowable dose to protect Large Population
</=25 rem whole body per lifetime, as long as the collective dose avoided by the emergency ops is significantly larger than what the worker gets.
>25 rem, same explanation, provided:
1: voluntary
2: must have full awareness of the risk
3: must sign the dose extension form
Allowable dose for Life Saving Actions
Same limits for life saving activities as for large populations.
Define Radiation Area
Accessible area where dose rate could result in dose equivalent of 5 mrem in 1 hour at 30 cm (considered general area).
Define High Radiation Area
100 mrem in 1 hour at 30 cm
Define Locked High Radiation Area
1000 mrem in 1 hour at 30 cm
Define Very High Radiation Area (GRAVE DANGER)
Area where you could get 500 rads in 1 hour at 1 meter.
Define Contamination Area
Area where loose surface contamination may exceed 1000 dpm/100 cm^2 (beta-gamma), or 20 dpm/100 cm^2 (alpha)
Define High Contamination Area
> =100,000 dpm/100 cm^2
Major concerns of plant ALARA program
All work requiring RWPs is reviewed before a job to try to minimize dose (including Design Change Packages).
Work is reviewed during and after a job to document lessons learned to improve dose received in the future.
When to report immediately to the NRC?
When:
Lost, stolen or missing licensed material >1000 times App C quantities that could result in exposure in unrestricted areas.
> 5 x federal annual dose for any parameter.
When to report to NRC within 24 hours
Exceeding federal dose limits
Define Airborne Radioactivity Area
Area in excess of DAC in APP B.
Exceed in 1 week .6% of ALI or 12 DAC-hours (.3 DAC)
