Radiation Safety Training for User

1
Radiation Safety Training for Users
Elayna Mellas Radiation Safety Officer Environment
al Health Safety Manager Clarkson
University Downtown Snell 155 Tel
315-268-6640 emellas_at_clarkson.edu
This training course has been partially
adapted from slides provided by Steve Backurz,
Radiation Safety Officer of The University of New
Hampshire
2
Table of Contents
Subject Slides
Nuclear Physics 3-30
Biological Effects 31-43
Radiation Exposure and Dose 44-60
Uses of Radioactive Material 61-66
Radiation Hazards 67-80
Radiation Detection 81-87
Lab Procedures at Clarkson 88-115
3
Introduction

• Radiation and radioactive materials are valuable
  tools used in research at Clarkson
• Radio-labeling of biological materials
• Sealed sources in chemistry/engineering
• X-ray diffraction analysis of samples for
  chemistry and engineering research
• Radioactive materials and X-ray machines are very
  safe if used properly and simple precautions are
  followed

4

• Review of Atomic Structure

• Nucleus
• Contains protons and neutrons
• Small Size
• Relatively large mass
• Extremely large density
• Large amount of stored energy
• Orbiting Electrons
• Large size
• Low density
• Orbit nucleus near speed of light
• Small amount of energy relative to nucleus
• Responsible for chemical bonds

5

• Nomenclature for Elements

"X" Element Symbol "Z" Protons Each
element has a unique "Z "N
Neutrons Atomic Mass "A" "A" Z N
Protons Neutrons Isotope same Z, different
N, thus different A
A
X
Z
6

• Phosphorous-32 Atom

7

• Radioactivity ("Activity")

• Definition A collection of unstable atoms that
  undergo spontaneous transformation that result in
  new elements.
• An atom with an unstable nucleus will decay
  until it becomes a stable atom, emitting
  radiation as it decays
• Sometimes a substance undergoes several
  radioactive decays before it reaches a stable
  state
• The amount of radioactivity (called activity)
  is given by the number of nuclear decays that
  occur per unit time (decays per minute).

8

• The Curie

• A unit of activity defined by the number of
  radioactive decays from a gram of radium
• 1Curie (Ci) 2.22 E12 disintegrations/minute
  (dpm)
• Sub-multiples of the Curie
• millicurie 1 mCi 2.22 E9 dpm
• microcurie 1 uCi 2.22 E6 dpm
• nanocurie 1 nCi 2,220 dpm
• picocurie 1 pCi 2.2 dpm
• Typical activities at Clarkson are in the ?Ci to
  mCi range

9

• Other Units of Measure

• Disintegrations per minute (dpm)
• Disintegrations per second (dps)
• The SI unit for activity is the becquerel (Bq)
• 1 Bq 1 disintegration/second
• 1 Curie (Ci) 3.7 E10 Bq or 37 GBq
• 1 millicurie 37 MBq
• 1 microcurie 37 kBq

10

• Ion

• Any atom or molecule with an imbalance in
  electrical charge is called an ion
• In an electrically neutral atom or molecule, the
  number of electrons equals the number of protons
• Ions are very chemically unstable, and will seek
  electrical neutrality by reacting with other
  atoms or molecules

11

• Radiation

• Definition Energy in the form of particles or
  waves
• Types of Radiation
• Ionizing removes electrons from atoms
• Particulate (alphas and betas)
• Waves (gamma and X-rays)
• Non-ionizing (electromagnetic) can't remove
  electrons from atoms
• infrared, visible, microwaves, radar, radio
  waves, lasers

12

• The Electromagnetic Spectrum

13

• Alpha Particles

• Alpha particles
• High mass (4 amu) 2 protons 2 neutrons
• High charge (2)
• High linear energy transfer (cause great
  biological damage)
• Travel a few centimeters in air
• Stopped by a sheet of paper or protective layer
  of skin
• Not an external hazard
• Concern would be for ingestion or inhalation

14

• Beta Particles

• Low mass (0.0005 amu)
• Low charge - can be positively or negatively
  charged (/- 1)
• Travel 10 - 20 feet in air
• Stopped by a book
• Shield betas with low density materials such as
  lucite or plexiglass
• Shielding high energy betas like P-32 with lead
  can generate more radiation than it shields due
  to Bremsstrahlung X-rays

15

• Gamma Radiation

• Wave type of radiation - non-particulate
• Photons that originate from the nucleus of
  unstable atoms
• No mass and no charge
• Travel many feet in air
• Lead or steel used as shielding

16

• Review of Nuclear Decay

17

• Examples of Nuclear Decay

32
32
Beta Minus Decay (neutron-excess nuclides)
-
?
S
P

16
15
0
22
22
?

Beta Plus Decay (neutron-deficient nuclides)
Na

Ne
0
11
10
206
4
?
210
Alpha Decay (Heavy nuclides above atomic number
82)
Pb

Po
2
84
82
18

• Decay Scheme

• A decay scheme is a graphical representation of
  radioactive decay
• Depicts the parent/daughter relationship
• Branching fractions and energy levels are shown

19

• Decay Law Half-Life

• Half life The time required to reduce the amount
  of a particular type of radioactive material by
  one-half
• Example 120 Ci of P-32 (t 1/2 14 days)

20

• X-Rays

• Wave type of radiation - non-particulate
• Photons originating from the electron cloud
• Same properties as gamma rays relative to mass,
  charge, distance traveled, and shielding
• Characteristic X-rays are generated when
  electrons fall from higher to lower energy
  electron shells
• Discrete energy depending on the shell energy
  level of the atom
• Bremsstrahlung X-rays are created when electrons
  or beta particles slow down in the vicinity of a
  nucleus
• Produced in a broad spectrum of energies
• Reason you shield betas with low density material

21

• Bremsstrahlung Radiation

Energy is lost by the incoming charged particle
through a radiative mechanism
Beta Particle
Bremsstrahlung Photon
-


Nucleus
22

• X-Ray Machine Components

23

• X-Ray Machine Basics

• kVp - how penetrating the X-rays are
• Mammography - 20 - 30 kVp
• Dental - 70 - 90 kVp
• Chest - 110 - 120 kVp
• mA - how much radiation is produced
• Time - how long the machine is on
• Combination of the above determines exposure

24

• Types of Radiation

Mass (amu)
Charge
Travel Distance in Air
4.0000
Alpha
2
few centimeters
Beta Plus
0.0005
1
few meters
few meters
Beta Minus
0.0005
-1
Gamma
0.0000
0
many meters
0.0000
X-Rays
0
many meters
Neutron
1.0000
0
many meters
25

• Radiation, Radioactive Material,
• and Contamination

• Radiation Energy in the form of particles and
  waves
• Radioactive Material Material that is unstable
  and emits radiation
• Contamination Radioactive material where it is
  not wanted
• Campfire example burning logs (radioactive
  material), heat (radiation), burning embers that
  escape the controlled area (contamination)

26

• Interaction of Radiation
• with Matter

• Radiation deposits small amounts of energy, or
  "heat" in matter
• alters atoms
• changes molecules
• damage cells DNA
• similar effects may occur from chemicals
• Much of the resulting damage is from the
  production of ion pairs

27
Ionization

• The process by which a neutral atom acquires a
  positive or negative charge

28

• Ionization

Ionization by a Beta particle
-
ejected electron
Beta Particle
-
-
-
Colliding Coulombic Fields
The neutral absorber atom acquires a positive
charge
-
29

• Gamma Interactions

• Gamma interactions differ from charged particle
  Interactions
• Interactions called "cataclysmic" - infrequent
  but when they occur lot of energy transferred
• Three possibilities
• May pass through - no interaction
• May interact, lose energy change direction
  (Compton effect)
• May transfer all its energy disappear
  (photoelectric effect)

30

• Compton Effect

An incident photon interacts with an orbital
electron to produce a recoil electron and a
scattered photon of energy less than the incident
photon
Before interaction
After interaction
Scattered Photon
-
-
-
-
-
-
-
-
Electron is ejected from atom
Incoming photon Collides with electron
31

• Biological Effects of Radiation

32

• Acute Exposure

• Large Doses Received in a Short Time Period
• Accidents
• Nuclear War
• Cancer Therapy
• Short Term Effects (Acute Radiation Syndrome 150
  to 350 rad Whole Body)
• Anorexia Nausea Erythema
• Fatigue Vomiting Hemorrhage
  Epilation Diarrhea Mortality

33

• Effects of Acute Whole Body Exposure on Man

34

• Chronic Exposure

• Doses Received over Long Periods
• Background Radiation Exposure
• Occupational Radiation Exposure
• 50 rem acute vs 50 rem chronic
• acute no time for cell repair
• chronic time for cell repair
• Average US will receive 20 - 30 rem lifetime
• Long Term Effects
• Increased Risk of Cancer
• 0.07 per rem lifetime exposure
• Normal Risk 30 (cancer incidence)

35
Cellular Effects

• Ionization within body tissues similar to water
• Ionization causes many derivatives to be formed
• Peroxides
• Free Radicals
• Oxides
• These compounds are unstable and are damaging to
  the chemical balance of the cell. Various
  effects on cell enzymes and and structures occur.
• Radiation is not the only insult responsible
• Pollutants
• Vitamin imbalance (poor diet)
• Sickness and Disease

36

• Cellular Effects (con't)

• Cells often recover from damage
• Repeated Insults may cause damage to be permanent
• Cell Death
• Cell Dysfunction - tumors, cancer, cataracts,
  blood disorders
• Mitosis (Cell Division) Delayed or Stopped
• Chromosomal breaks
• Organ Dysfunction at High Acute Doses

37

• Variations in Sensitivity

• Wide variation in the radiosensitivity of various
  species
• Plants/microrganisms vs. mammals
• Wide variation among cell types
• Cells which divide are more sensitive
• Non-differentiated cells are more sensitive
• Highly differentiated cells (like nerve cells)
  are less sensitive

38

• Effects on the Fetus

• The fetus consists of rapidly dividing cells
• Dividing cells are more sensitive to radiation
  effects than nondividing cells
• Effects of low level radiation are difficult to
  measure
• A lower dose limit is used for the fetus

39

• Genetic Effects

• It is possible to damage the hereditary material
  in a cell nucleus by external influences like
  Ionizing radiation, chemicals, etc.
• Effects that occur as a result of exposure to a
  hazard while in-utero are called teratogenic
  effects
• Teratogenic effects are thought to be more severe
  during weeks 8-17 of pregnancy - the period of
  formation of the bodys organs
• A higher incidence of mental retardation was
  found among children irradiated in-utero during
  the bombings of Hiroshima and Nagasaki

40

• Maternal Factors Pregnancy

Statistically, a radiation exposure of 1 rem
poses much lower risks for a woman than smoking
tobacco or drinking alcohol during pregnancy
41

• Dose Response Curves

42

• Rate of Absorption

• Most important factor in determining when effects
  will occur
• Recovery is less likely with higher dose rates
  than lower dose rates for an equivalent amount of
  dose more permanent damage
• More recovery occurs between intermittent
  exposures less permanent damage

43

• Area Exposed

• The larger the portion - the more damage (if all
  other factors are the same)
• Blood forming organs are more sensitive
• A whole body dose causes more damage than a
  localized dose (such as in medical therapy).
• Dose limits take this into consideration

44

• Radiation Exposure Dose

45

• Background Exposure

• Your exposure to radiation can never be zero
  because background radiation is always present
• Natural Sources - Radon
• Cosmic
• Terrestrial
• Technologically Enhanced Sources (Man-Made)
• Healing Arts Diagnostic X-rays,
  Radiopharmaceuticals
• Nuclear Weapons Tests fallout
• Industrial Activities
• Research
• Consumer Products
• Miscellaneous Air Travel, Transportation of
  Radioactive Material

46

• Annual Dose from
• Background Radiation

47

• Cosmic Radiation

• 2 x 10 particles (mostly protons) per second are
  incident on the atmosphere
• Energy greater than one BILLION ELECTRON VOLTS
• Interact with atoms in the atmosphere and produce
  secondary particles
• muons, electrons, photons, and neutrons
• responsible for cosmic dose

18
48

• Terrestrial

• Major sources
• Potassium - a few grams per 100 grams of ground
  material
• Thorium and Uranium - a few grams per 1,000,000
  grams of ground material
• Dose due mainly to photons originating near the
  surface of the ground

49

• Radon

• Naturally occurring radioactive gas
• Second leading cause of lung cancer
• Estimated 14,000 deaths per year
• Easy to test for
• short and long term tests available
• EPA guideline is 4 pCi/L
• Fixable
• Radon in water from drilled wells can also be an
  entry method

50

• Exposure, X

• A measure of the ionization produced by
• X or Gamma Radiation in air
• Unit of exposure is the Roentgen

51

• Absorbed Dose, D

• Absorbed Dose (or Radiation Dose) is equivalent
  to the energy absorbed from any type of radiation
  per unit mass of the absorber
• Unit of Absorbed Dose is the rad
• 1 rad 100 ergs/g 0.01 joules/Kg
• In SI notation, 1 gray 100 rads

52

• Dose Equivalent, H

• One unit of dose equivalent is that amount of any
  type of radiation which, when absorbed in a
  biological system, results in the same biological
  effect as one unit of low LET radiation
• The product of the absorbed dose, D, and the
  Quality Factor, Q

H D Q
53

• Units of Dose Equivalent

• Human dose measured in rem or millirem
• 1000 mrem 1 rem
• 1 rem poses equal risk for any ionizing radiation
• internal or external
• alpha, beta, gamma, x-ray, or neutron
• In SI units 1 sievert (Sv) 100 rem
• External radiation exposure measured by dosimetry
  
• Internal radiation exposure measured using
  bioassay sample analysis

54

• Quality Factors for Different Radiations

Quality Factor
X and Gamma Rays
1
Electrons and Muons
1
Neutrons lt 10 kev
5
gt10kev to 100 Kev
10
gt 100 kev to 2 Mev
20
gt2 Mev
10
Protons gt 30 Mev
10
Alpha Particles
20
55

• External Dose

• 2 Standard reference points
• Shallow Dose Live skin tissue at an average
  depth of .007 cm.
• Deep Dose Internal organs close to the body
  surface, 1 cm.
• Shallow Dose Equivalent, SDE
• Alpha radiation not a hazard
• consider beta and gamma radiation.
• Deep Dose Equivalent, DDE
• Alpha and Beta radiation not a hazard.
• For gamma, SDE DDE (typically)

56

• Internal Dose

• All radiation types present a hazard
• 2 Dose quantities
• Committed Dose Equivalent, CDE (specific to a
  particular organ)
• Committed Effective Dose Equivalent, CEDE (sum of
  all organs x weighting factor for importance or
  each specific organ)

57

• Total Effective Dose
• Equivalent, (TEDE)

• Used to combine internal and external doses
• Puts all dose on the same risk base comparison,
  whether from external or internal sources.
• TEDE CEDE DDE
• All units are in rems or Sieverts (Sv)
• All regulatory dose limits are based on
  controlling the TEDE

58
Standards for Rad Protection

• Radiation Protection Program Required
• Occupational Limits
• 5 rem per year TEDE
• 50 rem per year CDE (any single organ)
• 15 rem per year lens of the eye
• 50 rem per year skin dose
• Members of Public
• 100 mrem per year
• No more than 2 mrem in any one hour in
  unrestricted areas from external sources
• Declared Pregnant Females (Occupational)
• 500 mrem/term (evenly distributed)

59

• Declared Pregnant Woman

• Voluntarily informs her employer in writing of
  pregnancy
• Estimated date of conception
• Dose limit is 10 of occupational limit (500
  mrem)
• Avoid substantial variation in dose
• Form for declaring pregnancy is on web site

60

• Clarkson Anticipated
• Worker Radiation Exposure

• Anticipated Exposures Less than the minimum
  detectable dose for film badges (10 mrem/month) -
  essentially zero
• Average annual background exposure for U.S.
  population 360 mrem/year
• State and Federal Exposure Limits 5000 mrem/year

61

• Uses of Radioactive Material

62
Consumer Products

• Building materials
• Tobacco (Po-210)
• Smoke detectors (Am-241)
• Welding rods (Th-222)
• Television (low levels of X-rays)
• watches other luminescent products (tritium or
  radium)
• Gas lantern mantles
• Fiesta ware (Ur-235)
• Jewelry

63
Smoke Detectors

• Alpha particles from americium-241 (red lines)
  ionize the air molecules (pink and blue spheres).
  The ions carry a small current between two
  electrodes. Smoke particles (brown spheres)
  attach to ions reducing current and initiate
  alarm.

64
Research at Clarkson Using Radiation Sources

• Radioactive Materials (both open and sealed
  sources such as S-35, P-32, C-14, H-3, Xe-133,
  Ra-226, Am-241)
• Gas Chromatographs (sealed sources)
• Liquid Scintillation Counters (sealed sources for
  internal standards)
• X-ray Diffraction equipment
• Electron microscopes

65

• Medical

• Diagnostic
• X-rays
• Nuclear Medicine (Tc-99m, Tl-201, I-123)
• Positron Emission Tomography (PET)
• Therapeutic
• X-rays (Linear Accelerators)
• Radioisotopes
• Brachytherapy (Cs-137, Ir-192, Ra-226)
• Teletherapy (Co-60)
• Radiopharmaceuticals (I-131, Sr-89, Sm-153)

66
Industrial Radiography
67

• Radiological Hazards

68
Radiation Protection Basics

• Time minimize the time that you are in contact
  with radioactive material to reduce exposure
• Distance keep your distance. If you double the
  distance the exposure rate drops by factor of 4
• Shielding
• Lead, water, or concrete for gamma X-ray
• Thick plastic (lucite) for betas
• Protective clothing protects against
  contamination only - keeps radioactive material
  off skin and clothes

69

• External Radiation
• Inverse Square Law

70

• Gamma Ray Constant

• Gamma Ray Constant to determine exposure rate
• ??(mSv/hr)/MBq at 1 meter
• Hint multiply (mSv/hr)/MBq by 3.7
• to get (mrem/hr)/uCi
• Exposure Rate Calculation, X (mrem/hr) at one
  meter

X ??????? Where, A Activity (?Ci)
? ??Gamma Ray Constant(mSv/hr)/Mbq
3.7 is the conversion factor
71
Sample Calculation

• 5 Curie Cs-137 Source
• Calculate Exposure Rate at 1 meter
• ? 1.032 E-4 mSv/hr/MBq _at_ 1 meter
• X 1.032 E-4 3.7 5 Ci 1000 mCi/Ci 1000
  uCi/mCi
• X 1909 mrem/hour
• X 1.91 rem/hour

72

• Gamma Ray Shielding

• Effectiveness increases with thickness, d (cm)
• Variation with material, (1/cm)
• attenuation coefficients µ
• High Z material more effective
• Water - Iron - Lead
• good - better - best

73

• Shielding Beta Emitters

• Low energy betas (H-3, C-14, S-35) need no
  shielding for typical quantities at Clarkson
• Higher energy beta emitters (P-32) should be
  shielded
• Beta shielding must be low Z material (Lucite,
  Plexiglas, etc.)
• High Z materials, like lead, can actually
  generate radiation in the form of Bremsstrahlung
  X-rays
• Bremsstrahlung from 1 Ci of P-32 solution in
  glass bottle is 1 mR/hr at 1 meter

74

• Contamination and
• Internal Hazards

• Units of Measure
• activity/area (dpm/100 square cm)
• Fixed vs Removable
• Internal Hazards and Entry Routes
• Ingestion
• Inhalation - Re-suspension
• Skin absorption
• Wound Entry

75

• Protective Clothing

• Can be a very effective means of preventing skin,
  eyes, clothing from becoming contaminated
• Gloves (may want double layer)
• Lab Coat
• Eyewear to prevent splashes and provide shielding
  for high energy beta emitters
• Closed toe footwear
• It is much easier to remove contaminated clothing
  than to decontaminate your skin!

76

• Contamination Control

• Watch out where you put your hot hands during
  an experiment
• Monitor yourself and your work area frequently
  for radioactivity (gloves, hands, feet, etc.)
• Use most sensitive scale on meter (X0.1 or X1)
• Have meter out and handy
• Make sure to wash your hands frequently and after
  finishing an experiment
• Dont bring radioactive material to lunch or to
  your home!
• Monitor your work area before and after an
  experiment

77

• Avoid Ingesting
• Radioactive Material

• Dont bring hands or objects near your mouth
  during an experiment
• Eating, drinking, smoking, applying cosmetics are
  strictly prohibited in radioisotope use areas
• Never mouth pipette
• Never store personal food items in refrigerators
  or freezers used for radioactive material or
  other hazardous material storage

78

• Avoid Inhaling
• Radioactive Material

• Make sure you have proper ventilation for your
  experiments
• When using volatile materials such as Iodine-125
  and some Sulfur-35 compounds, be sure to use a
  fume hood that has been inspected and certified
  for proper airflow

79

• DAC's ALI's

• DAC Derived Air Concentration, an airborne
  concentration of of radioactive material which if
  inhaled for 2000 hrs per year will result in 5
  rem CEDE or 50 rem CDE.
• Units are uCi/cc
• Each DAC-hour gives 2.5 mrem of dose.
• ALI Annual Limit on Intake, A quantity of
  radioactive material, which if inhaled or
  ingested, would result in the applicable annual
  dose limit.
• 1 ALI 5 rem (CEDE) or 50 rem (CDE)
• ALI and DAC Values listed for each nuclide in
  NHRCR (He-P 4090)

80

• External vs Internal Dose

• TEDE Total Effective Dose Equivalent
• TEDE DDE CEDE
• Total Dose External Dose Internal Dose
• 1 rem internal (CEDE) same as 1 rem external
  (DDE)
• Internal dose is protracted over several years
  but calculated over 50 years and assigned in the
  year of intake

81

• Radiation Detection

82
Radiation Detector Types

• Solid State Detectors
• Germanium Lithium High Purity
• Silicone Lithium
• Silicone Diode
• Cadmium Telluride

• Gas Filled Detectors
• Geiger Mueller (GM)
• Gas Flow Proportional Counters
• Ionization
• Scintillation Detectors
• Sodium Iodide (NaI)
• Zinc Sulfide (ZnS)
• Anthracene
• Plastic Scintillators

83

• Gas Filled Detectors

• Ionization detectors
• High Cost
• Survey meters
• Reference class calibration chambers
• Proportional counters
• High cost
• Gross laboratory measurements
• Contamination monitors
• Geiger Mueller (GM) detectors
• Low cost
• Survey meters
• Contamination monitors

84

• Scintillation Detectors

• One of the Oldest Detection Methods, Still Widely
  Used Today
• Transducer Converts Radiation Energy to Visible
  Light
• Visible Light Signals Amplified With
  Photomultiplier Tube
• Output PM Tube Signal Processed
• High Efficiency For Photon Detection Compared To
  Gas-Filled Detectors

85

• Applications of
• Scintillation Counting

• Laboratory
• Liquid Scintillation Counters
• gross counting
• spectroscopy
• Quenching
• Field
• Low Level Radiation Survey Instruments
• Thyroid monitoring for Iodine uptakes

86

• Use of Survey Instruments

• Check Physical Condition
• Cables, Connections, Damage
• Check for Current Calibration (License
  Requirement)
• Battery Check
• Zero Check
• Response check prior to use
• Select Proper Scale
• Response Time (Fast or Slow?)
• Audio (On or Off)

87

• CPM DPM

• A radiation detector will not detect every
  disintegration from a source (i.e., they are not
  100 efficient)
• Counts per minute (cpm) is the number of
  disintegrations that a detector sees
• The efficiency of a detector is determined by the
  following
• Efficiency net cpm / dpm
• gross cpm background cpm / dpm

88
Regulatory Agencies

• U. S. Nuclear Regulatory Commission
• Regulates the nuclear industry pursuant to the
  Atomic Energy Act
• Regulatory guides published to describe methods
  for complying with regulations
• Agreement States
• Some states have entered into an agreement with
  the NRC to regulate by-product material (and
  small quantities of source and special nuclear
  material)
• Currently, 30 states are agreement states
  including New York

89
Radioactive Material at Clarkson

• Activities are licensed by the State of New York
• Radiation Safety Committee has responsibility to
  review, approve, and oversee activities
• Radiation Safety Officer (RSO) runs program
• Clarkson is required to
• Train individuals that use sources of radiation
• Train non-radiation workers that work in the
  vicinity of radiation sources
• Monitor and control radiation exposures
• Maintain signs, labels, postings
• Manage and properly dispose of radioactive waste

90
Ordering Receiptof Radioactive Materials

• Only RSO is authorized to order radioactive
  material
• Use the Radionuclide Purchase Request Form
• Complete form and fax to RSO at 268-7118
• Be sure to state any special ordering
  instructions (preferred delivery date, fresh
  batch, etc.)
• Packages are received by RSO, checked for
  contamination, logged in, and delivered to the
  lab on the same day as receipt

91

• Specific Radioactive Materials

• Tritium (Hydrogen-3)
• 12.3 year half life
• Very low energy beta (0.0186 MeV max)
• No shielding needed
• Surveys by wipe method counted on LSC
• Carbon-14
• 5730 year half life
• Low energy beta (0.156 MeV max)
• Shielding not needed
• Spot checks with GM are possible but
  contamination surveys using wipes are necessary

92

• Specific Radioactive Materials

• Phosporous-32
• 14.3 day half life
• High energy beta (1.710 MeV max)
• Shield with low Z material such as plastics
• Do not use lead shielding
• Wear safety glasses to shield eyes
• Ring badges are required for handling millicurie
  quantities
• GM survey meter required
• Avoid handling containers for extended periods

93

• Specific Radioactive Materials

• Sulfur-35
• 87.4 day half life
• Low energy beta (0.167 MeV max)
• Same general precautions as for C-14
• Should be handled in a fume hood
• Nickel-63
• 100.1 year half life
• Low energy beta (0.066 MeV max)
• Gas chromatographs with electron capture detector
  cells
• No shielding needed

94
Posting Labeling Notices

• Posting
• New York Notice to Employees form
• Caution Radioactive Materials or X-Rays

• Labels
• All containers (unless exempt) must be labeled
• With Caution Radioactive Material
• Should include radionuclide, quantity, date,
• initials, radiation levels, etc.

95

• Employee Rights
• and Responsibilities

• Right to report any radiation protection problem
  to state without repercussions
• Responsibility to comply with the Radiation
  Protection Program and the RSO's instructions
  pertaining to radiation protection
• Right to request inspection
• in writing
• grounds for notice
• signed
• Responsibility to cooperate with NY State
  inspectors during inspections and RSO during
  internal lab audits

96

• Access Restriction

• Required by License and NY Regulations
• Security and Control of Radioactive Material

97

• Security

• Licensed RAM must be secured against unauthorized
  removal at all times
• Must maintain constant surveillance for any
  radioactive material outside a restricted area
• Lock labs containing radioactive material if last
  one out - even if its just for a minute
• Challenge all unknown individuals with May I
  help you?
• OK to ask for ID
• Report to supervisor if suspicious

98

• ALARA

• The goal of radiation protection is to keep
  radiation doses As Low As Reasonably Achievable
• Clarkson is committed to keeping radiation
  exposures to all personnel ALARA
• What is reasonable?
• Includes -State and cost of technology
• -Cost vs. benefit
• -Societal socioeconomic
  considerations

99
Safe Use of Sealed Sources

• Source sign out/in logs
• Physical inventories
• Leak Tests
• Alpha sources every 3 months
• Others every 6 months
• Lost, stolen, or damaged sources must be reported
  to RSO
• May require notification of the State

100
Surveys and Monitoring

• Clarkson Radiation Protection Program specifies
• Monitor all work areas at least once a week
• Instrument surveys and/or wipe surveys should be
  done after each experiment or more often if
  needed
• Isotope storage area must be surveyed at least
  once per month if no work is in progress
• Must keep records of all required surveys for
  inspection by RSO and state inspectors
• Survey equipment calibration intervals (12 months)

101
General Survey Information

• Randomly survey selected areas outside of normal
  radioisotope use areas at least once a month to
  ensure there is no spread of contamination
• Using a form with map of your lab on it is
  strongly recommended to make documenting surveys
  easier
• Check wherever human hands and feet can go.
• A good rule of thumb for determining if
  contamination is present is to look for 2X
  background
• Common contamination sites include soap/towel
  dispensers, phones, chairs, desk tops, drawer and
  door handles, refrigerator handles, pens and log
  books, and the survey meter itself

102
Contamination Surveys

• Direct monitoring with a Gieger Mueller detector
  can be performed when using P-32 and other high
  energy beta or gamma emitters
• Wipe surveys for removable contamination must be
  used for low energy beta emitters (H-3, C-14,
  S-35)
• Wipes are counted in a liquid scintillation
  counter
• Direct monitoring for low energy gamma emitters
  should be done with a low energy gamma
  scintillation probe (NaI crystal)

103
Wipe Test Surveys

• Wear gloves
• Although a moistened swab or filter paper is more
  efficient, a dry filter or soft absorbent paper
  be used
• Use uniform moderate pressure and wipe an area of
  at least 100 cm2 (about 4 X 4 or standard S
  swipe)
• Keep each wipe separate to avoid cross
  contamination
• Keep a record of the area wiped so that you know
  where the contamination is located if the wipe
  comes up hot
• Place the wipe into a liquid scintillation vial,
  add cocktail, and count according to
  manufacturers procedure or your lab specific
  procedure
• Results should be in dpm/100 cm2

104
Documenting Surveys

• Contamination surveys must be documented
• Record the following
• Date performed
• Areas surveyed (map is best)
• Results in dpm/100 cm2 or mR/hour as applicable
• Initials or name of surveyor
• Instrument used and date of calibration
• Action taken if contamination is found
• Be sure to document all post-spill clean up
  surveys very well!

105
Decay-In-Storage of Wastes

• Only for isotopes with half-lives less than 100 d
• Keep all isotopes separate
• Must keep an inventory with amount of activity
• Remove or obliterate all radioactive labels prior
  to disposal
• Store in labeled receptacle with clear plastic
  liner
• Hold for 10 half-lives
• Survey with appropriate detector and confirm
  indistinguishable from background
• Dispose of without regard to radioactivity

106
Liquid Scintillation Waste

• Use environmentally friendly cocktail (water
  soluble)
• If tolulene/xylene based media must be used, keep
  separate
• Must keep an inventory with amount of activity
• Keep LSC separate from other liquid wastes
• Store vials in flats, and check with RSO
  regarding method of disposal
• Do not mix these with cocktails containing other
  radioactive materials

107
Liquid Waste Disposal

• Readily soluble or readily dispersable biological
  materials in water may go down the drain if
• No other hazard is present
• The concentration does not exceed the allowable
  monthly average concentration
• The total amount of radioactivity does not exceed
  50 ?Ci/day
• The sink has been approved by the RSO and is
  appropriately designated and labeled
• Must keep an inventory with amount of activity

108
General Spill Procedure

• When cleaning up a spill, place absorbent
  material around the edges of the spill and clean
  from the outside edges toward the center to avoid
  spreading
• Place materials used to clean the spill into
  appropriate radioactive waste containers
• Notify others in the lab of the spill to prevent
  inadvertent spread of contamination
• After clean-up, monitor all work areas using
  survey meter or wipe surveys, as applicable
• Survey your hands, feet, clothing and all other
  materials that may have come in contact with the
  spilled material

109
Minor Spills

• A minor spill is one that involves small
  quantities, low activities, low energy, or low
  hazard radioactive materials that are confined to
  a relatively small area
• Most spills that could occur in the lab would be
  minor and should be cleaned up by lab personnel
  ASAP
• Use the general spill clean-up procedure and
  common sense
• You do not need to notify the RSO in the event of
  a minor spill

110
Intermediate Spills

• An intermediate spill is one that involves larger
  quantities of radioactive material spread over a
  larger area
• Intermediate spills could also involve small
  amounts of more hazardous radioactive materials
  such as higher energy emitters or volatile
  compounds
• A spill outside a restricted area may also be
  considered intermediate since controlling the
  area may be difficult
• Use the general spill clean-up procedure and
  common sense

111
Intermediate Spills (contd)

• Wear gloves, lab coats, dosimetry, and other
  protective clothing
• Confine the contamination
• Prevent the spread of contamination
• Use a survey instrument to check yourself for
  contamination before leaving the area
• Pay special attention to hands and feet
• Restrict access to the spill area
• Inform others in the immediate area and post
  notice if necessary
• Contact the RSO (x6640) to report the situation

112
Emergency Response

• Fire in radioactive areas
• Notify Fire Department and RSO, clear the area of
  people. Remove any seriously wounded persons.
  Keep your distance
• Theft of radioactive materials
• Notify RSO (info is posted on lab door)
• State notification required
• Notify RSO if you suspect
• Inhalation, ingestion or other intake of
  radioactive material
• Accidental release of radioactive material into
  the environment

113
Inspections

• Inspections
• NY shall be afforded opportunity to inspect at
  all reasonable times
• Records shall be made available
• Inspector may consult with workers privately
• Worker may bring matters to inspector privately
• Workers can request inspection
• Must be in writing
• Name is not revealed

114
Internal Audits

• Internal audits by Clarkson RSO are performed in
  all labs on campus
• Looking for same things as state inspector
• Security of radioactive materials - including
  waste
• Surveys for loose contamination
• Proper procedures in use
• Postings, container labeling, use of protective
  clothing, dosimetry, survey meters, calibrations,
  records of surveys, sink disposal logs, solid
  waste container logs, etc.

115

• Your Role
• in Radiation Protection

• Report anything that looks out of the ordinary or
  if you are uncertain about what to do, where to
  go, requirements, exposures
• Call the people on the emergency list
• Ask the Radiation Safety Officer (RSO)
• Elayna Mellas
• 268-6640
• emellas_at_clarkson.edu

116
Acknowledgements
This training course has been adapted from
slides provided by Steve Backurz, Radiation
Safety Officer of The University of New
Hampshire