University of California, Santa Cruz Radioisotope Laboratory Safety UCSC Conrad Sherman x9-3911 RSO/Health Physicist Marcus Balanky x9-5167 ARSO/ Health

University of California, Santa Cruz

Radioisotope Laboratory SafetyUCSC

Conrad Sherman x9-3911RSO/Health Physicist

Marcus Balanky x9-5167ARSO/ Health Physicist

Vern Ares x9-5167Assistant Health Physicist

Environmental Health & SafetyRadiation Safety

(831) 459-3911 Environmental Health & SafetyRadiation Safety(831) 459-3911


Radiation Safety


Training Requirements*

Academic training :– Principles and practices of radiation protection– Radioactivity measurements, monitoring techniques, and

using instruments– Mathematics and calculations basic using and measuring

radioactivity– Biological effects of radiation.

• Appropriate on-the-job-training:– Observing authorized personnel using survey equipment,

collecting samples, and analyzing samples– Using survey equipment, collecting samples, and analyzing

samples under the supervision and in the physical presence of an individual authorized to perform surveys.

* NUREG 1556 Volume 11 Appendix S


Radiation Safety Fundamentals

New Radiation User

Dependent UserLearns "hands-on" skills from a

more experienced user.

Annual Refresher Training

RadioisotopeLaboratory

Safety

Sealed SourceSafety

X-rayProducingMachineSafety

You are here


A Banana Slug


Required reading


To increase your knowledge to enable you to perform your job safely by adhering to proper radiation protection practices while working with or around x-ray generating devices.

What is the purpose of safety training?



Radiation Units

• Roentgen (R) The roentgen (R) is a unit of radiation exposure in air. – It is defined as the amount of x-ray or radiation that will

generate 2.58E-4 coulombs/kg of air at standard temp and pressure.

• rad RAD stands for Radiation Absorbed Dose and is the amount of radiation that will deposit 0.01 J/kg of material. – A roentgen in air can be approximated by 0.87 rad in air, 0.93

rad in tissue, and 0.97 rad in bone.

• Dose– The SI unit of absorbed dose is the gray (Gy), which has the

units of J/kg. 1 Gy= 100 rad.


Radiation Units

• REM REM stands for Roentgen Equivalent Man. The REM is a unit of absorbed dose and is equal to the rad multiplied by a weighting factor which varies according to the type of radiation. The weighting factor for x-rays is equal to 1.

• For x-rays, one rem is equal to one rad.

• The SI unit used in place of the rem is the sievert (Sv). 1 Sv = 100 rem.


Radiation Sources

• X-ray diffraction is a source of very intense radiation.

• The primary beam can deliver as much as 400,000 R/minute

• Collimated and filtered beams can produce about 5,000 to 50,000 R/minute

• Diffracted beams can be as high as 80 R/hour


Fundamental Radiation Physics

• Radioactivity – spontaneous nuclear transformations– Generally alpha particles and beta particles– Often accompanied by gamma ray emission

• Radiation – alpha particles, beta particles, gamma rays, etc.

• Ionizing Radiation – radiation capable of producing charged particles (ions) in the material through which it passes


Four principal kinds of ionizing radiation

Kind Atomic

Mass

Electrical Charge

Range in Air

Range in Body Tissue

Attenuation Exposure Hazard

Alpha 4 +2 < inch Unable to penetrate skin

Stopped by a sheet of paper or skin

Internal

Beta 1/1840 -1 Several feet

1/3 inch Stopped by a thin sheet of aluminum

Skin, eyes, and internal

Gamma / x-ray

NA None Passes through

Passes through

Thick lead or steel

External and internal

Neutron 1 Neutral Hundreds of feet

About 10% goes through

Several feet of water or plastic

Primarily external


Radiological Fundamentals

Electron

Nucleus

Nucleus

Protons Neutrons

The basic unit of matter is the atom.



X-RAY AND GAMMA ( ) RAY PROPERTIES

Cloud & Charge: None

Mass: None

Velocity: 3 x 108 m/s

Origin:

Rays: Nucleus

X Rays: Electron Bremsstrahlung


General Radiation

• Radiation is energy in transit in the form of high speed particles and electromagnetic waves. We encounter electromagnetic waves every day. They make up our visible light, radio and television waves, ultra violet (UV), and microwaves with a spectrum of energies. These examples of electromagnetic waves do not cause ionization of atoms because they do not carry enough energy to remove electrons from atoms.


General Radiation

• Ionizing radiation is radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from their orbits, causing the atom to become charged or ionized. Ionizing radiation deposits energy at the molecular level, causing chemical changes which lead to biological changes. These include cell death, cell transformation, and damage which cells cannot repair. Effects are not due to heating.



Visible Light


X-rays on EM spectrum


Background Radiation

Radon - 200 mrem

Cosmic - 28 mrem

Diet - 40 mrem

Terrestrial - 28 mrem


Man-made Radiation

Man-made sources of radiation contribute tothe annual radiation dose (mrem/yr).

Fallout < 1

Round trip US by air5 mrem per trip

Medical - 53Cigarette smoking - 1300

Building materials - 3.6Gas range - 0.2Smoke detectors - 0.0001




Dose Limits

• EPA Guidance for dose limits

• NRC Regulations for dose limits

• DOT Regulations for transport

• State Agreement States

• Licensee Institutional Admin Limits


Regulatory Limits

Radiation Worker

• Whole Body

• Extremities

• Skin and other organs

• Lens of the eye

Non-Radiation Worker

• Embryo/fetus

• Visitors and Public

• 5 rem/year• 50 rem/year • 50 rem/year• 15 rem/year• 0.5 rem/year

• 0.5 rem/gestation period• 0.1 rem/year


ALARA Program

• As Low As Reasonably Achievable– Responsibility of all

employees

• Exposures shall be maintained ALARA– Below regulatory limits– No exposure without

commensurate benefit


Responsibilities for ALARAManagement

Safety Organization

Radiation Worker

Ultimately YOU are!

•To establish a program•Meet regulatory limits

•Implementing a program•Run the daily operation

•To follow program


General Methods of Protection

• Time

• Distance

• Shielding



What are x-rays?• X-rays are photons (electromagnetic radiation) which originate in the

energy shells of an atom, as opposed to gamma rays, which are produced in the nucleus of an atom.


X-RAY AND GAMMA ( ) RAY PROPERTIES

Charge: None

Mass: None

Velocity: 3 x 108 m/s

Origin:

Rays: Nucleus

X Rays: Electron Cloud & Bremsstrahlung


Ionizing Radiation


Legal Limits

ANNUAL OCCUPATIONAL DOSE LIMITS

EXTENAL mRemDEEP DOSE 5,000

EYE DOSE 15,000

SKIN DOSE 50,000

EXTREMITY DOSE 50,000

ORGAN DOSE 50,000

INTERNAL uCiH-3 80,000

C-14 2,000

P-32 900

P-33 8,000

S-35 10,000

I-125 60

ALLOWED LIMIT OF INTAKE

(INHALATION-INGESTION)

Note: DOSE = INTAKE5 REMS ALI


Pregnancy Policy


Ordering Procedures for Radioactive Material

Calibrations

Surveys

Inventory

Disposal

Radiation Exposure

Transfer

PART A

PART B


Receipt Record

• Sign for package on Receipt and Use Log form




Receipt and Use Log

•Record–Use (%, volume, or activity)

–Name–Date–Purpose

•Use blank column for other units


Waste Tracking Form



Laboratory and Material Security

Avoids deliberate misconduct 1. Lock and key storage

2. Lock lab

3. Challenge response to unknown intruders


Avoid Ingesting Radioactive Material

NO–Eating–Drinking–Smoking–Applying Cosmetics–Mouth Pipetting


Protective Clothing

• Gloves• Lab coat • Eyewear• Pants• Closed toe

footwear



Instrumentation



Liquid Scintillation Counter

• Excellent choice for Excellent choice for detecting and measuring detecting and measuring low energy betalow energy beta

• Not portable - wipe or Not portable - wipe or smears required for smears required for radiation survey useradiation survey use

• Requires more training to Requires more training to prepare samples and prepare samples and interpret results than other interpret results than other instrumentsinstruments


General Tips LSC Wipe Survey

• Survey discrete areas so that if contamination is found the spot will be easy to identify

• Avoid cross contamination of samples• Artifacts may cause false positives

• Static electricity• Chemoluminescence• Phosphorescence


User Program 10

• EH&S Radiation Safety provides a user program for wipe surveys.

• Please use this program for your routine laboratory wipe surveys.

• We can provide an efficiency for the isotope you are using.


Calibration and Maintenance

• Annual calibration required– Electronic calibration – Calibration in a known radiation field– Efficiency determination

• Routine operational checks

• Be sure to turn off the instrument when done.


D


View Video






Contamination Defined

• What is background?– Background: a representative sample of an

area that is not expected to have been contaminated, for example, the hallway wall, window pane in a lab, or office phone.

– Blank: clean wipe filter paper that has not been swiped.

• What is the 2X Background Rule?– Contamination suspected if counts are 2-3x

background


Pipet use


Radiation vs. Radioactive Contamination

• Radiation is particles or waves of energy emitted from unstable atoms.

• Radioactive Contamination is radioactive material usually in any location you do not want it.


Monitoring for contamination


Removing Your Gloves



Documenting Surveys

• Contamination surveys must be documented• Record the following:

– date performed– area(s) surveyed (a map helps!)– results– identity of surveyor– instrument used– action taken if contamination is found





Decontamination Procedures

• Area and Material Decontamination– Wear protective clothing– Clean in an inward direction

• Personnel Decontamination– Flush with water first– Soap and water only!!!– Report to Occupational Health before

attempting any stringent measures


Radioactive Waste Disposal Procedures

• Guidelines at UCSC

• Minimizing waste production

• Reducing mixed waste

• Decontamination

• “Getting the lead out”


Radioactive Waste

• Research involving radioactive material generates contaminated waste. EHS Radiation Safety supplies containers and removes radioactive waste from campus labs.

• The laboratory staff is responsible for monitoring, labeling, maintaining and preparing their waste for disposal.



Radioactive Waste Disposal Instructions For Segregation

• PACKAGING DRY WASTE

• PACKAGING SCINTILLATION VIALS

• PACKAGING BULK AQUEOUS LIQUIDS

• PACKAGING ABSORBED LIQUIDS


Disposal of Shipping Containers

• Containers should be disposed of as non-radioactive waste.

• Remove or deface any radioactive material labels before disposal.


Storage of Radioactive Waste

Each radioactive waste container must have a “Caution Radioactive Materials” sign/label

Radioactive waste containers must be stored in a controlled area


Dry Solid Radioactive Waste

• No sharps

• No Liquids

• No lead or metals

• No high activity (stock vials)


Liquid Radioactive Waste

• Store in 2.5 gal plastic carboys with secondary-containment.

• pH must be adjusted to between 6 and 9.

• Identify chemical contents including non-hazardous and hazardous components.


Radioactive “Sharps”

• Radioactive sharps are items such as razor blades, scalpels, syringes and hypodermic needles.

• Plastic and glass pipette tips, broken glassware, etc. should not be disposed of as radioactive sharps.

• Contact the Natural Science Stockroom for radioactive sharps containers.


Emergency Procedures


Small (Minor) Spill

• Most spills that occur in the lab are minor, and should be cleaned up by lab personnel ASAP.

• You do not need to inform EH&S Radiation Safety in the event of a minor spill.


Small Spill Procedures

• Confine the spill

• Decontaminate the area

• Notify your supervisor

• Make a record.



Large Spills- What to Do

• Confine contamination do NOT track contamination outside the area.– Restrict access to the spill area

• Notify EH&S Radiation Safety (9-2553), then your supervisor.

You will not be penalized for reporting a spill, but on the other hand...


Other protocols


iodination


We’re there for you.

Environmental Health & Safety x9-2553

– Conrad Sherman x9-3911– RSO/Health Physicist

– Marcus Balanky x9-5167– ARSO/ Health Physicist

– Vern Ares x9-5167– Assistant Health Physicist

• Environmental Health & Safety• Radiation Safety• (831) 459-3911Web site http://www.ehs.ucsc.edu/

http://www.ehs.ucsc.edu/



Quiz

• Question Number 1- Biology– In experiments with certain cells, it is found that survival is

exponential as a function of dose. What dose is the lethal dose to half the cells?

• Question Number 2 – Chemistry– In experiments with P-32, it is found that the number of atoms

remaining is exponential as a function of time. What time is required for half the atoms to disintegrate?

• Question Number 3 – Physics– In experiments with shielding it is found that the Cs-137 gamma

ray photo attenuation is exponential as a function of density. What thickness of lead is required for half the photons to be attenuated?


Quiz Question 1

• In experiments with certain cells, it is found that survival is exponential as a function of dose. The relative number of cells N/No that survive an absorbed dose D is given by N/No = e(-kD), where k is a constant.– If only 1 % of the cells survive a dose of 3850 rad,

what is the numerical value of K?– What dose is the lethal dose to half the cells?– How is k related to the average dose for killing a cell?100%

50%

Relative Abundance

Time


Quiz Question 1 Answer

– If only 1 % of the cells survive a dose of 3850 rad, what is the numerical value of K?

N/No = 0.01 = e-3850k

K = 1.20 x 10-3 rad-1 = 0.00120/rad

– What dose D50 is the lethal dose to half the cells?

N/No = 0.50 e-0.00120D50

D50 = 578 rad

– How is k related to the average dose for killing a cell?K is a quantity with the dimensions of reciprocal dose.

The dose 1/k gives the survival level N/No = e-1 = 0.37 = D37 or the dose that gives 37% survival.

100%

50%

Relative Abundance

Time


Quiz Question # 2

• In experiments with P-32, it is found that the number of atoms remaining is exponential as a function of time.

• The relative (radio)activity A/Ao is given by:– A/Ao = e(-λt), – where λ is a constant called the decay constant.– λ = ln (2) t / t1/2

• What time (t) is required for half the atoms to disintegrate?

• What is the mean lifetime of a P-32 atom?• Hint: Enter the terms you see in this problem in a Google

search, and eventually you will be able to work out the answer.


Quiz Question # 3

• In experiments with shielding it is found that the gamma ray photo attenuation is exponential as a function of density. What thickness of lead is required for half the photons to be attenuated?– I/Io = e(-µx), – where µ is the attenuation coefficient– and x is the thickness of lead.

• Hint: Enter the terms you see in this problem in a Google search, and eventually you will be able to work out the answer.

Documents

University of California, Santa Cruz Radioisotope Laboratory Safety UCSC Conrad Sherman x9-3911 RSO/Health Physicist Marcus Balanky x9-5167 ARSO/ Health