Problem Set VI
Radioisotope Laboratory Techniques
You have completed a radiation contamination swipe survey for a radioactive materials laboratory that is currently using H-3, S-35 and P-32. Using the skills you acquired in Chapter 4 and the LSC Data Sheet below, answer questions 1 through 6.
(NOTE: You will need to fill out the table below in order to complete Test Question 1 on Page 2.)
LSC DATA SHEET
USER: 7ID: CPMPRESET TIME: 1.00 MINUTE MON 20AUG 2010 08:40
WINDOW 1: LL 0, UL 400, BKG SUB: 18.00
WINDOW 2: LL 0, UL 670, BKG SUB: 26.00
WINDOW 3: LL 0, UL 1000, BKG SUB: 40.00
(H-3) (S-35) (P-32)
SAMPLE# / WINDOW 1CPM1 / WINDOW 2 CPM2 / WINDOW 3 CPM3 / TIME
1 / 0 / 2 / 4 / 1.00
2 / 88 / 89 / 91 / 1.00
3 / 32 / 47 / 320 / 1.00
4 / 10 / 21 / 33 / 1.00
5 / 3 / 6 / 10 / 1.00
6 / 19 / 28 / 39 / 1.00
7 / 0 / 1 / 3 / 1.00
8 / 18 / 23 / 42 / 1.00
9 / 532 / 6220 / 6374 / 1.00
10 / 17 / 24 / 56 / 1.00
NOTE: LSC has been set to subtract background automatically
(H-3) (S-35) (P-32)
SAMPLE # / WINDOW 1CPM1 / DPM / WINDOW 2 CPM2 / DPM / WINDOW 3 CPM3 / DPM / TIME
1 / 0 / 2 / 4 / 1.00
2 / 88 / 89 / 91 / 1.00
3 / 32 / 47 / 320 / 1.00
4 / 10 / 21 / 33 / 1.00
5 / 3 / 6 / 10 / 1.00
6 / 19 / 28 / 39 / 1.00
7 / 0 / 1 / 3 / 1.00
8 / 18 / 23 / 42 / 1.00
9 / 532 / 6220 / 6374 / 1.00
10 / 17 / 24 / 56 / 1.00
SAMPLE ANALYSIS REPORT
Principal Investigator: Don Munroe Date: 08/20/10Lab: Room DG-11 Assayed by: J. Weaver
The following swipes were assayed for radioactivity utilizing a BECKMAN model LS-6500 liquid scintillation counter, serial #7067501. Each swipe represents approximately 100 cm2 of surface being surveyed.
Low Energy W1 / Mid Energy W2 / High Energy W3
Efficiency (%) / 30 / 50 / 70
NOTE:These efficiencies are to be used only with Problem Set VI and represent theoretical efficiencies from quench curves for a typical liquid scintillation counter. You must generate your own quench curves for the particular counter you are using to determine what efficiencies apply to your data.
1. (20 pts) Complete the Sample Analysis Report below using the LSC Data Sheet (from previous page.)
DPM = (CPM - Background)
% Efficiency
Sample Number / CPM / DPM1. Absorbent paper in work area
2. Outside of storage freezer
3. Floor at work area
4. Pipette handle
5. Shelf in freezer
6. Bench at work area
7. Centrifuge in hood
8. Floor
9. Dry waste container cover
10. Base of hood
2. (4 pts)Which of the contaminated areas (> than the UF limit) was due to H-3, which was due to S-35, and
which was due to P-32?
H-3 sample # / S-35 sample # / P-32 sample #3. (4 pts)What is the most probable root cause for contamination at sites #2 and #9?
4. (4 pts)What is the most probable root cause for contamination at site # 3?
5. (4 pts)What methods of decontamination would you recommend for these contaminated areas?
6. (4 pts)I use only P-32 in my lab. After each use I use a Geiger counter to survey my entire work area. Am I required to perform a swipe survey using a liquid scintillation counter?
a)yes
b)no
7. (4 pts)What is the University of Florida’s limit for removable radioactive contamination?
Beta/Gamma ______dpm per 100 cm2
Alpha ______dpm per 100 cm2
8. (4 pts)A spill of 50 Ci of P-32 liquid has occurred in your work area. What is the first action you should take to follow Emergency Procedures?
a)decontaminate
b)prevent the spread
c)call for help
d)notify others in the area
e)survey
9. (4 pts)You need to transport samples of liquid P-32 from one lab to another down a busy hallway. The samples contain a total of 500 Ci. What necessary precautions should you take before transport?
a)carry them in an open cardboard box
b)transport them on a cart and in a deep tray to prevent spills
c)use a cafeteria tray to prevent spills
d)carry them in the LSC rack
10. (4 pts)The same sample reads 10 mR/hr on contact using a GM survey meter. As you learned in Chapter 3 and as stated in 10CFR20, the dose to any individual members of the public in any unrestricted area shall not exceed 2 mR/hr. What additional precautions should you take before transporting the samples?
a)travel fast
b)use lead shielding
c)shield with Acrylic or Plexiglas until dose rate is less that 2mR/hr.
d)use paper or cardboard as shielding
11. (4 pts)A spill of 150 Ci of unbound I-125 has occurred in your work area. What should you do first?
a)decontaminate
b)evacuate everyone, keep all personnel together until cleared by Radiation Control
c)shield the source, if possible
d)close the room
e)call for help
f)prevent the spread
12. (4 pts)You have spilled several drops of H-3 liquid waste on your lab coat sleeve and you have discovered that some liquid has dropped onto your arm. Place the following correct actions in proper order.
_____call Radiation Control
_____wash skin area gently over lab sink with warm, soapy water
_____take off coat and place in plastic bag
13. (4 pts)How often are you required to perform AND document a radioactive contamination swipe survey, assuming you are using radioisotopes on a daily basis?
a)every day
b)once per week
c)once per month
d)after every use of radioactive material
14. (4 pts)Preferably, how often should you perform surveys for removable radioactive contamination in your work area?
a)every day
b)after every use of radioactive material
c)once a month
d)once a week
15. (4 pts)You have not used radioactive materials for quite some time but you are storing some in a freezer. How often are you required to perform and document swipe survey to ensure no contamination is present?
a)every day
b)not until used
c)once a month
d)once a week
16. (4 pts)Is a lab required to perform and document a radiation contamination swipe survey if they only have radioactive waste?
a)yes
b)no
17. (4 pts)A radioactive labeled centrifuge needs to be sent out for repair. Can it be sent out after the lab surveys it and removes the radioactive labels?
a)yes
b)no - Radiation Control needs to perform a final survey to verify the results prior to shipping. Radiation Control will document that it is clean and will remove the radiation-warning labels.
18. (4 pts)Dr. X is leaving the University. He has closed out his lab, removed all radioactive materials (including radioactive waste) and he has performed and documented a swipe survey. Dr. X contacted Radiation Control who conducted a final swipe survey. Dr. X waited for the survey results. Is there anything else that he is required to do?
a)yes
b)no
19. (4 pts)With radioactive materials present, you have to leave the lab and no one else is around. You must lock the lab door or secure all radioactive material if you are going to be gone for:
a)a one hour lunch
b)a 30 minute meeting
c)a 15 minute break
d)2 minutes to use the restroom
e)all of the above
20. (4 pts)You see a man in your lab that your do not recognize. Even though you are a new employee, what should you do?
a)ignore him, probably another sales representative
b)confront him
c)acknowledge him with a smile
21. (4 pts)A radioactive spill has occurred in your lab. Even though you need all the help you can get, only trained and authorized radioactive material users should assist you.
a)true
b)false
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Radiation Safety Short CourseProblem Set VI