10CFR20 and Radiation Protection

Question 1

Define Stochastic effects

Answer 1

Randomly occurring health effects for which the probability of the effect occurring varies linearly with dose and has no threshold.
Ex: cancer, unpredictable.

Question 2

10CFR20 limit that helps reduce probability Stochastic effects

Answer 2

5 rem (0.05 Sv) uniform whole body dose.

Question 3

Define Non-Stochastic Effects

Answer 3

Health effects in which the severity of the effect varies with dose and for which a threshold is believed to exist.

Question 4

Example of 10CFR20 annual dose limit (thresholds)

Answer 4

Lens of the eye-15 rem. (Cataracts)

Question 5

What is an ALI?

Answer 5

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

Question 6

Relationship between DAC and ALI

Answer 6

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.

Question 7

10CFR20 dose limits

Answer 7

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

Question 8

Admin Dose Limits

Answer 8

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

Question 9

How to calculate TEDE

Answer 9

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

Question 10

Allowable Dose to protect Valuable Equipment

Answer 10

10 rem per incident.

Question 11

Allowable dose to protect Large Population

Answer 11

</=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

Question 12

Allowable dose for Life Saving Actions

Answer 12

Same limits for life saving activities as for large populations.

Question 13

Define Radiation Area

Answer 13

Accessible area where dose rate could result in dose equivalent of 5 mrem in 1 hour at 30 cm (considered general area).

Question 14

Define High Radiation Area

Answer 14

100 mrem in 1 hour at 30 cm

Question 15

Define Locked High Radiation Area

Answer 15

1000 mrem in 1 hour at 30 cm

Question 16

Define Very High Radiation Area (GRAVE DANGER)

Answer 16

Area where you could get 500 rads in 1 hour at 1 meter.

Question 17

Define Contamination Area

Answer 17

Area where loose surface contamination may exceed 1000 dpm/100 cm^2 (beta-gamma), or 20 dpm/100 cm^2 (alpha)

Question 18

Define High Contamination Area

Answer 18

> =100,000 dpm/100 cm^2

Question 19

Major concerns of plant ALARA program

Answer 19

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.

Question 20

When to report immediately to the NRC?

Answer 20

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.

Question 21

When to report to NRC within 24 hours

Answer 21

Exceeding federal dose limits

Question 22

Define Airborne Radioactivity Area

Answer 22

Area in excess of DAC in APP B.
Exceed in 1 week .6% of ALI or 12 DAC-hours (.3 DAC)