Radiation%20in%20Your%20Environment

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Radiation in Your Environment
2
Radiation Around You

• Nature
• Cosmic (direct and cosmic-produced
  radioactivity
• Terrestrial (including radon)
• Medical
• Consumer Products
• Transportation
• Nuclear Power
• Nuclear Weapons Fallout

3
Naturally Occurring Radioactive Material

• Primordial radionuclides- left over from when the
  earth was created.
• Cosmogenic radioactivity - Radionuclides produced
  when cosmic radiation interacts with the upper
  atmosphere

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Cosmic Radiation

• The primary source of cosmic radiation is outside
  this solar system sun and stars
• The atmosphere and the earths magnetic field act
  as a shield against radiation, reducing the
  radiation that reaches the earths surface.
• Higher doses at higher altitudes.

5
Terrestrial Radiation

• Primordial radionuclides in rock and soil
• Primarily long lived nuclides
• K-40 (also in food)
• Body contains about 0.1 µCi which produces 0.2
  mSv(20 mrem) per year
• U-238 series
• Source of radon in buildings
• Th-232 series

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Environmental Monitoring
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Primary Objective of a Nuclear Facility

• Keep radioactive effluents at a minimum
• Particulate filters to remove particles from air
  effluents
• Charcoal filters to remove iodine
• Hold-up tanks or charcoal traps to allow
  radioactive noble gasses to decay
• Filter liquid effluents

8
Environmental Monitoring

• Purpose
• To detect any radioactivity released by a nuclear
  facility
• To look for high activities of natural
  radioactivity
• Verify and validate radioactive effluent
  monitoring program

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Reasons for Environmental Monitoring

• External regulators
• Nuclear Regulatory Commission
• Environmental Protection Agency
• Internal motivation
• Environmental stewardship
• Insurance (American Nuclear Insurers)
• Concern for ourselves, families, and neighbors

10
Nuclear Facilities

• Program for nuclear facilities
• Radioactive Environmental Monitoring Program
  (REMP)
• Sampling for a period of three years prior to
  operation
• Assess natural radioactivity
• Continual sampling during operation
• Look for radionuclides from the plant

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Nuclear Facilities REMP

• Measure
• Radioactivity
• Air
• Water
• Food
• Radiation dose
• At site boundary
• Public exposures

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REMP Objectives

• Protection of environment and people from
  releases
• Documentation of existing and continuing
  radiological conditions
• Compliance with regulations
• Documentation of unanticipated environmental
  effects
• Protection from legal liabilities
• Research verification of models

13
REMP Design

• Facility information
• Radioactivity produced
• Physical form
• Particulates
• Gasses
• Chemical
• Effluent controls
• Pathway information

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REMP What to Measure

• Direct gamma radiation
• Thermoluminescent dosimeters
• Ionization meters (real time)
• Air pathways (inhalation/ingestion)
• Air (particulates/iodine)
• Crops
• Grass-cow-milk pathway

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REMP How to Measure

• Continuous measurements of effluents
• Stack monitors to measure airborne effluents
• Radiation monitors in liquid streams
• Periodic grab samples from environment
• Food products (milk, fish, vegetables, etc.)
• Plants (pasture grass, broad leaf vegetation)

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REMP MeasurementsDirect Radiation

• Thermo- Luminescent Dosimeters (TLD) measure
  radiation from facility

17
REMP MeasurementsDirect Radiation

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REMP Water Measurements

• Water pathways (ingestion)
• Water
• Fish
• Aquifers
• Invertebrates
• Field/outfall mixing zones

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REMP Air Measurements

• Noble gases
• Not chemically reactive
• Readily dispersed
• Gases of interest
• Xe-133, Xe-135
• Short half-lives (5.2 day, 9.1 hr)
• Kr-85
• Long half-life (10.8 yr)

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REMP Air Measurements

• Tritium (H-3)
• Liquid effluents
• Cannot remove from water
• Iodine and particulates
• I-131, Cs-137, Sr-90,Co-60
• Readily removed from effluent
• Very small releases

21
REMP Air Measurements

• Low volume air sampler measures particulate
  material and iodine

22
Natural Radioactivity

• Cosmic ray produced
• H-3, C-14, Na-22, Be-7
• 4 million Curies of H-3 produced each year
• Terrestrial
• Uranium-238 and Thorium-232 series
• Radium and radon
• Potassium-40, Rubidium-87

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Typical Radioactivity in the Environment

• Air particulates
• Gross beta 0.004 - 0.04 pCi/m3
• Be-7 0.02 - 0.2 pCi/m3
• Air Iodine
• Not detectable
• Soil
• Sr-90 0.02 - 0.2 pCi/g
• Cs-137 0.1 - 1.0 pCi/g
• K-40 5 - 20 pCi/g
• Ra-226 10 - 50 pCi/g

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Typical Radioactivity in the Environment

• Precipitation
• Gross beta 1 - 4 pCi/L
• H-3 75 - 200 pCi/L
• Be-7 40 - 100 pCi/L
• Water
• Gross beta 0.5 - 5.0 pCi/L
• H-3 75 - 200 pCi/L
• I-131 0.25 - 1.0 pCi/L (hospital releases)
• Sediment
• Cs-137 0.1 - 1.0 pCi/g

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Typical Radioactivity in the Environment

• Fish
• Sr-90 0.002 - 0.02 pCi/g
• Cs-137 0.01 - 0.02 pCi/g
• Milk
• I-131 not detectable
• Cs-137 1 - 10 pCi/L
• K-40 1000 - 2300 pCi/L
• Sr-90 0.5 - 5.0 pCi/L
• Food products
• K-40 0.5 - 5.0 pCi/g
• Sr-90 0.002 - 0.02 pCi/g