Radiation Safety Exam NMTCB
Questions with Complete Solutions
accelerator produced radionuclides - Answer-I-123
Ga-67
Tl-201
In-111
Reactor produced radionuclides - Answer-Mo-99/Tc-99m
I-131
I-125
Xe-133
Cr-51
Sr-89
Sm-153
P-32
Total radiation dose based on length of exposure - Answer-Total dose=(dose rate)(time)
Inverse Square Law - Answer-(Intensity 1)(Distance 1)^2=(Intensity 2)(Distance 2)^2
Half-value layer HVL - Answer-Thickness of material required to reduce radiation
intensity to half its original value.
Equation for exposure after HVL added - Answer-Intensity=intensity(original)e^-(0.693)
(x/HVL)
x = the thickness of the shielding material
NRC Regs are based on - Answer-Risk-informed, performance based approach in
which the NRC will not, for the most part, specify exactly what methods must be used or
how frequently radiation safety procedures must be performed. The licensee must
develop policies and procedures that ensure NRC requirements are met.
Whole-body TEDE - Answer-5rem or 50mSv per year
Lens of eye - Answer-15rem or 150mSv per year
Organ Tissue dose - Answer-50rem or 500mSv per year
General public dose - Answer-0.1rem or 1mSv per year
Embryo/fetal dose - Answer-0.5rem or 5mSv for entire pregnancy
, Unrestricted area - Answer-Anyone in area will receive less than 2mrem or 0.02mSv in
any 1 hour.
Caution: Radiation Area - Answer-Individual receives more than 5mrem (0.05mSv) in 1
hr at 30cm from source.
High Radiation Area - Answer-100mrem (1mSv) in 1hr at 30cm from source
Very High Radiation Area - Answer-An individual could receive an absorbed dose
greater than 500 rads or 500 cGy or 5 Gy in one hour at one meter from the radiation
source.
Receipt of RAM - Answer-All shipments display radioactive label
Wipe tested
Surveyed at 1 meter
Packages monitored within 3 hours of receipt, or if delivered after hours, within 3 hours
of dept reopening
When should NRC and shipment carrier be notified of excessive exposure rate? -
Answer-If rate exceeds 200mR/hr at surface and 10mR/he at 1 meter.
If removable contamination (wipe) exceeds 22 dpm per cm^2
Equation for dpm - Answer-Dpm=net cpm/efficiency of well counter
Radioactive label White I - Answer-0.5mR/hr at surface
No detectable radiation at 1 meter
Radioactive label Yellow II - Answer-50mR/hr at surface
1mR/hr at 1 meter
Radioactive label Yellow III - Answer-200mR/hr at surface
10mR/hr at 1 meter
Decay in storage - Answer-RAM with 1/2life of less than 120days can be retained in
shielded storage area until activity equals background.
Usually 10 half-lives
Package limits for Returned RAM waste - Answer-Xe-133/54.1mCi
Tl-201/27mCi
Tc-99m/21.6mCi
Ga-67/16.2mCi
I-123/16.2mCi
In-111/5.4mCi
I-131/1.4mCi
Sr-89/1.4mCi
Questions with Complete Solutions
accelerator produced radionuclides - Answer-I-123
Ga-67
Tl-201
In-111
Reactor produced radionuclides - Answer-Mo-99/Tc-99m
I-131
I-125
Xe-133
Cr-51
Sr-89
Sm-153
P-32
Total radiation dose based on length of exposure - Answer-Total dose=(dose rate)(time)
Inverse Square Law - Answer-(Intensity 1)(Distance 1)^2=(Intensity 2)(Distance 2)^2
Half-value layer HVL - Answer-Thickness of material required to reduce radiation
intensity to half its original value.
Equation for exposure after HVL added - Answer-Intensity=intensity(original)e^-(0.693)
(x/HVL)
x = the thickness of the shielding material
NRC Regs are based on - Answer-Risk-informed, performance based approach in
which the NRC will not, for the most part, specify exactly what methods must be used or
how frequently radiation safety procedures must be performed. The licensee must
develop policies and procedures that ensure NRC requirements are met.
Whole-body TEDE - Answer-5rem or 50mSv per year
Lens of eye - Answer-15rem or 150mSv per year
Organ Tissue dose - Answer-50rem or 500mSv per year
General public dose - Answer-0.1rem or 1mSv per year
Embryo/fetal dose - Answer-0.5rem or 5mSv for entire pregnancy
, Unrestricted area - Answer-Anyone in area will receive less than 2mrem or 0.02mSv in
any 1 hour.
Caution: Radiation Area - Answer-Individual receives more than 5mrem (0.05mSv) in 1
hr at 30cm from source.
High Radiation Area - Answer-100mrem (1mSv) in 1hr at 30cm from source
Very High Radiation Area - Answer-An individual could receive an absorbed dose
greater than 500 rads or 500 cGy or 5 Gy in one hour at one meter from the radiation
source.
Receipt of RAM - Answer-All shipments display radioactive label
Wipe tested
Surveyed at 1 meter
Packages monitored within 3 hours of receipt, or if delivered after hours, within 3 hours
of dept reopening
When should NRC and shipment carrier be notified of excessive exposure rate? -
Answer-If rate exceeds 200mR/hr at surface and 10mR/he at 1 meter.
If removable contamination (wipe) exceeds 22 dpm per cm^2
Equation for dpm - Answer-Dpm=net cpm/efficiency of well counter
Radioactive label White I - Answer-0.5mR/hr at surface
No detectable radiation at 1 meter
Radioactive label Yellow II - Answer-50mR/hr at surface
1mR/hr at 1 meter
Radioactive label Yellow III - Answer-200mR/hr at surface
10mR/hr at 1 meter
Decay in storage - Answer-RAM with 1/2life of less than 120days can be retained in
shielded storage area until activity equals background.
Usually 10 half-lives
Package limits for Returned RAM waste - Answer-Xe-133/54.1mCi
Tl-201/27mCi
Tc-99m/21.6mCi
Ga-67/16.2mCi
I-123/16.2mCi
In-111/5.4mCi
I-131/1.4mCi
Sr-89/1.4mCi
