sign in sign up
<<
Home , Absorbed dose, Becquerel, Beta particle, Gray (unit), Particle radiation, Radiation protection

Fundamental Principles of

Kathryn Gladden Environmental Monitoring Programs Nevada Site Specific Advisory Board (NSSAB) Educational Session November 9, 2016 Fundamentals of

11/9/2016 – Page 2 PageLog 2Title No. 2012Page-248 2 What is an ?

11/9/2016 – Page 3 PageLog 3Title No. 2012Page-248 3 Atoms are the building blocks of ALL

-

+ +

N N

-

A atom is used in this example

11/9/2016 – Page 4 PageLog 4Title No. 2012Page-248 4 Nucleons

Proton

Neutron is about 1 amu

Mass is about 1 amu

1 Unit (amu) = 1.66 x 10-24 Mass is about 0.0005 amu

11/9/2016 – Page 5 PageLog 5Title No. 2012Page-248 5 Atoms

• Nuclear particles form atoms • Similar atoms combine to form elements • Elements combine to form molecules • Molecules combine to form compounds

11/9/2016 – Page 6 PageLog 6Title No. 2012Page-248 6

• The number of defines the ELEMENT • The number of defines the • The isotopes of an element have similar chemical properties but different nuclear properties – Some isotopes are stable – Some isotopes are radioactive

11/9/2016 – Page 7 PageLog 7Title No. 2012Page-248 7 Isotopes Different Isotopes of

“Normal” Hydrogen Deuterium or Protium 1 1 proton 1 proton 1 2 neutrons 0 neutron 1 1 electron 2 3 1 electron 1 H 1 H 1 1 H

- - -

+ + +

N N N

11/9/2016 – Page 8 PageLog 8Title No. 2012Page-248 8 Isotopes and Atomic Notation X = The symbol of the element

A Z = The (# of protons) Z X

A = The atomic mass number (# of protons + neutrons) Different Isotopes of Hydrogen

“Normal” Hydrogen or Protium Deuterium Tritium 1 proton 1 proton 1 proton 0 neutrons 1 neutron 2 neutrons 1 electron 1 electron 1 electron 1 2 3 1 H 1 H 1 H

- - -

+ + + N N N

11/9/2016 – Page 9 PageLog 9Title No. 2012Page-248 9 Ionizing Radiation

11/9/2016 – Page 10 PageLog 10Title No. 2012Page-248 10 Two Types of Radiation

• Non-Ionizing

• Ionizing

11/9/2016 – Page 11 PageLog 11Title No. 2012Page-248 11 Non-Ionizing

Radiation that doesn’t have enough to form :

• Radar Waves

•

• Laser

• Visible

11/9/2016 – Page 12 PageLog 12Title No. 2012Page-248 12 The Electromagnetic Spectrum is a large family of radiation that includes light, , , X-rays, radio waves, and gamma rays

11/9/2016 – Page 13 PageLog 13Title No. 2012Page-248 13 Ionizing Radiation

Excess energy (from unstable atoms) capable of removing orbiting from an atom, producing electrically- charged particles called ions. The “free” electron (- charge) and the remaining atom (+ charge) are the ions.

11/9/2016 – Page 14 PageLog 14Title No. 2012Page-248 14 Stability of Nucleus

Alpha (α)

Beta (β)

Gamma (γ)

11/9/2016 – Page 15 PageLog 15Title No. 2012Page-248 15 Radiation

11/9/2016 – Page 16 PageLog 16Title No. 2012Page-248 16 Alpha (continued)

Alpha • Large, highly positive • Range in air about 1 - 2 inches • Shielding can be a piece of paper, clothing or even the dead outer layer of skin • Biological hazard is inhalation or ingestion

11/9/2016 – Page 17 PageLog 17Title No. 2012Page-248 17 Radiation

11/9/2016 – Page 18 PageLog 18Title No. 2012Page-248 18 Beta Particle Radiation (continued)

Beta • Small, negative charged particle • Range in air is about 10 feet • Shielding can be , glass, metal foil, or safety glasses • Biological hazard is inhalation or ingestion • Externally, the eyes and skin are at risk

11/9/2016 – Page 19 PageLog 19Title No. 2012Page-248 19 Gamma-Ray Radiation

11/9/2016 – Page 20 PageLog 20Title No. 2012Page-248 20 Gamma-Ray Radiation (continued)

Gamma • Electromagnetic waves or that have no charge, similar to X-rays • Range in air is several hundred feet • Shielding is more difficult due to high penetrating power - dense materials (high Z number) such as concrete, , • Biological hazard is whole body

11/9/2016 – Page 21 PageLog 21Title No. 2012Page-248 21

11/9/2016 – Page 22 PageLog 22Title No. 2012Page-248 22 Neutron Radiation (continued)

Neutron • Neutral particle ejected from nucleus • Range in air is several hundred feet • Shielding is better with materials that have high hydrogen content - , plastic, , and even paraffin (low Z number) • Biological hazard is whole body due to high penetrating power

11/9/2016 – Page 23 PageLog 23Title No. 2012Page-248 23 Radioactivity

Radioactivity is a natural and spontaneous process by which unstable radioactive atoms decay to a different state and emit excess energy in the form of radiation Half-life (T½) is the amount of time required for radioactive material to decrease by one half; each radioisotope has a unique Half-life time period

11/9/2016 – Page 24 PageLog 24Title No. 2012Page-248 24 Units of Measure

11/9/2016 – Page 25 PageLog 25Title No. 2012Page-248 25 Units for Radiation Dose and Exposure

Roentgen (R) Unit for measuring exposure Defined only for effect on air Applies only to gamma and X-ray radiation Does not relate biological effects of radiation to the human body

11/9/2016 – Page 26 PageLog 26Title No. 2012Page-248 26 Units for Radiation Dose and Exposure (continued)

Rad (Radiation ) Unit for measuring absorbed dose in any material Defined for any material Applies to all types of radiation Does not take into account the potential effect that different types of radiation have on the body

11/9/2016 – Page 27 PageLog 27Title No. 2012Page-248 27 Units for Radiation Dose and Exposure (continued)

Rem ( Equivalent Man) Unit for measuring effective dose (most commonly used unit) Pertains to human body Applies to all types of radiation Takes into account the energy absorbed (dose) and the biological effect on the body due to the different types of radiation

11/9/2016 – Page 28 PageLog 28Title No. 2012Page-248 28 Units for Radiation Dose and Exposure (continued)

Rad Rem Roentgen (R) (Radiation Absorbed Dose) () Unit for measuring exposure Unit for measuring absorbed Unit for measuring dose dose in any material equivalence (most commonly used unit) Defined only for effect on air Defined for any material Pertains to human body Applies only to gamma and Applies to all types of Applies to all types of X-ray radiation radiation radiation Does not relate biological Does not take into account Takes into account the effects of radiation to the the potential effect that energy absorbed (dose) and human body different types of radiation the biological effect on the have on the body body due to the different types of radiation

Rem = Rad x WF

11/9/2016 – Page 29 PageLog 29Title No. 2012Page-248 29 Not All Radiation is the Same

• Different radiation has different biological effects

• Radiation WEIGHTING FACTORS

Alpha = 20 α Neutron = 5 - 20 η Beta = 1 β Gamma = 1 γ

11/9/2016 – Page 30 PageLog 30Title No. 2012Page-248 30 Prefixes for Units

1 rem = 1,000 mrem (millirem)

1 mrem = 1,000 µrem (microrem)

The same holds true for the new SI units, i.e.,

1 (Sv) = 1,000 mSv (millisieverts)

1 mSv = 1,000 µSv (microsieverts)

11/9/2016 – Page 31 PageLog 31Title No. 2012Page-248 31 Unit Conversions

Source Activity (disintegrations per Exposure Dose unit time) Old Units (Ci) = 37x109 dps Roentgen (R) Rem-roentgen dps = disintegrations per RAD or rad: equivalent man radiation absorbed dose New SI Units (Bq) (Gy) Sievert (Sv) 1 Bq – 1 dps 1 Gy – 100 rad 1 Sv – 100 rem 1 Ci – 37 GBq 1 rad – 1 cGy 1 rem – 10 mSv

For gamma and x-ray radiation, a common “conversion factor” between exposure, absorbed dose, and dose equivalent is: 1 R = 1 rad = 1 rem

11/9/2016 – Page 32 PageLog 32Title No. 2012Page-248 32 Sources of Radiation

11/9/2016 – Page 33 PageLog 33Title No. 2012Page-248 33 Natural Sources of Radiation

• Cosmic radiation • Terrestrial radiation • • Human body

11/9/2016 – Page 34 PageLog 34Title No. 2012Page-248 34 Man-made Sources of Radiation

• Medical radiation • • Consumer products • Industry and Research • Other minor sources

11/9/2016 – Page 35 PageLog 35Title No. 2012Page-248 35 Average Doses from Radiation Sources

• Average person in the U.S. receives about 620 mrem each year – Natural sources = 310 mrem – Medical procedures and consumer products = 310 mrem

Unaltered information taken from the 2015 NNSS Environmental Report

11/9/2016 – Page 36 PageLog 36Title No. 2012Page-248 36 Sources of

Unaltered information taken from the 2015 NNSS Environmental Report

11/9/2016 – Page 37 PageLog 37Title No. 2012Page-248 37 Biological Effects of Radiation Exposure

11/9/2016 – Page 38 PageLog 38Title No. 2012Page-248 38 Exposure to radiation will cause none of these things to happen

You will not get super powers

You will not turn green

Radiation does not cause things to grow larger You will not glow in the dark

11/9/2016 – Page 39 PageLog 39Title No. 2012Page-248 39 Two Categories of Radiation Dose

• Acute

• Chronic

11/9/2016 – Page 40 PageLog 40Title No. 2012Page-248 40 Acute Radiation Doses

• An acute effect is a physical reaction due to massive cell damage • Damage caused by a large amount of radiation in a short period of time

11/9/2016 – Page 41 PageLog 41Title No. 2012Page-248 41 Acute Radiation Dose Effects

Blood changes 25 – 100 Rad Anorexia (loss of appetite) 150 Rad Nausea 200 Rad 220 Rad 280 Rad Epilation 300 Rad Diarrhea 350 Rad Mortality (w/o supportive care) 350 Rad Mortality (with supportive care) 500 Rad

11/9/2016 – Page 42 PageLog 42Title No. 2012Page-248 42 Chronic Radiation Doses

• Chronic radiation dose is typically a small amount of radiation received over a long period of time

• Example: the dose we receive from natural every of our lives

11/9/2016 – Page 43 PageLog 43Title No. 2012Page-248 43 Chronic Radiation Dose Effects

• The principal effect of chronic radiation dose is increased risk of contracting

• No increased risk of cancer has been observed in individuals who receive radiation dose at occupational levels (500 – 5,000 mrem/yr)

• No observable radiation effects in humans below a one-time dose of about 10,000 mrem

11/9/2016 – Page 44 PageLog 44Title No. 2012Page-248 44 Possible Effects of Radiation on Cells

When a cell is exposed to ionizing radiation, several things can happen:

• No damage

• Cells repair the damage and operate normally

• Cells are damaged and operate abnormally

• Cells die as a result of the damage

11/9/2016 – Page 45 PageLog 45Title No. 2012Page-248 45 Factors Affecting Biological Damage from Radiation

• Total dose • Dose rate • Type of radiation • Area of the body receiving the dose • Cell sensitivity • Individual sensitivity

11/9/2016 – Page 46 PageLog 46Title No. 2012Page-248 46 Genetic Effects

There is no direct evidence of radiation-induced genetic effects in humans, even at high doses. Various analyses indicate that the rate of genetic disorders produced in humans is expected to be extremely low, on the order of a few disorders per million live born per rem of parental exposure.

11/9/2016 – Page 47 PageLog 47Title No. 2012Page-248 47 Comparison of Risks

Estimate of Life Health Risk Expectancy Lost Smoking 20 cigarettes a day 6 years Overweight (by 15%) 2 years Alcohol consumption (U.S. average) 1 year Agricultural accidents 320 days Construction accidents 227 days Automobile accidents 207 days Home accidents 74 days 1 rem/yr from age 18 to 65 51 days All natural hazards (earthquake, etc.) 7 days Medical radiation 6 days

11/9/2016 – Page 48 PageLog 48Title No. 2012Page-248 48

11/9/2016 – Page 49 PageLog 49Title No. 2012Page-248 49 ALARA s

ow s

easonably

chievable

11/9/2016 – Page 50 PageLog 50Title No. 2012Page-248 50 ALARA Exposure Practices

There are three basic practices used to maintain exposures to ALARA:

TIME Reduce Exposure Time DISTANCE Increase Distance SHIELDING Use Shielding

11/9/2016 – Page 51 PageLog 51Title No. 2012Page-248 51 Time

DOSE RATE: Energy per unit time

DOSE: Total energy absorbed

Dose = (Dose rate) x Time Example of dose rate: 100 mrem/hr

11/9/2016 – Page 52 PageLog 52Title No. 2012Page-248 52 Time (continued) DOSE RATE: Energy per unit time DOSE: Total energy absorbed Dose = (Dose rate) x Time

Example of dose rate: 100 mrem/hr • If you stayed in this dose rate for an , what would your total dose be? • What would your dose be after 15 ? • If your allowed total dose is 75 mrem, what is your stay time?

11/9/2016 – Page 53 PageLog 53Title No. 2012Page-248 53 Distance

Inverse Square Law Double the distance … ¼ the dose rate Halve the distance … four times the dose rate

11/9/2016 – Page 54 PageLog 54Title No. 2012Page-248 54 Shielding

Shielding: Material between you and the source

Wax Bricks Lead Plastic Paper

Source

11/9/2016 – Page 55 PageLog 55Title No. 2012Page-248 55 Shielding: If you can’t be in the shielded booth...

11/9/2016 – Page 56 PageLog 56Title No. 2012Page-248 56 ...then stand behind the Doctor

11/9/2016 – Page 57 PageLog 57Title No. 2012Page-248 57 Radiation Dose Limits*

Mrem Annual limit for occupational workers 5,000 Annual limit for member of public 100

* Limits for radiation exposure above background radiation (620 mrem/yr U.S. average from all sources)

11/9/2016 – Page 58 PageLog 58Title No. 2012Page-248 58 ALARA

Radiation exposure to the work force and general public shall be controlled such that exposures are well below regulatory limits and that there is:

no radiation exposure without an equal benefit

11/9/2016 – Page 59 PageLog 59Title No. 2012Page-248 59 Radiological Dose Assessment Goals (NNSS Environmental Report Chapter 9) Limits = Limit = 10 Limit = 25 Limit = 100 <0.1 rad/day mrem/year mrem/year mrem/year & <1 rad/day Determine Determine Determine dose to Determine max dose terrestrial max dose max dose to the public to the plants, to the public public from from NNSS aquatic waste from all animals air exposure emissions management and to sites pathways terrestrial combined animals

Demonstrate Compliance with DOE Limits

11/9/2016 – Page 60 PageLogLog 60 No.Title No. 2014 2012Page-210-248 60 Potential Exposure Pathways from NNSS Activities (Past and Present)

11/9/2016 – Page 61 PageLogLog 61 No.Title No. 2013 2012Page-173-248 61 Dose to the Public from Natural Background Sources and from the NNSS • 2015 dose to the public from all pathways is 2.91 mrem/year – Maximum dose from inhalation, ingestion, and direct exposure pathways that is attributable from NNSS operations – Well below DOE dose limit of 100 mrem/year – Indistinguishable from natural background radiation experienced by the public residing in communities near the NNSS

Unaltered information taken from the 2015 NNSS Environmental Report

11/9/2016 – Page 62 PageLog 62Title No. 2012Page-248 62