Radiation in Your Environment

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

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

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

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

Environmental Monitoring

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

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

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

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

Nuclear Facilities REMP  Measure:  Radioactivity  Air  Water  Food  Radiation dose  At site boundary  Public exposures

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

REMP: Design  Facility information  Radioactivity produced  Physical form Particulates Gasses Chemical  Effluent controls  Pathway information

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

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)

REMP: Measurements Direct Radiation Thermo- Luminescent Dosimeters (TLD) measure radiation from facility

REMP: Measurements Direct Radiation

REMP: Water Measurements  Water pathways (ingestion)  Water  Fish  Aquifers  Invertebrates  Field/outfall mixing zones

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)

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

REMP: Air Measurements Low volume air sampler measures particulate material and iodine

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

Typical Radioactivity in the Environment  Air particulates  Gross beta: pCi/m 3  Be-7: pCi/m 3  Air Iodine  Not detectable  Soil  Sr-90: pCi/g  Cs-137: pCi/g  K-40: pCi/g  Ra-226: pCi/g

Typical Radioactivity in the Environment  Precipitation  Gross beta: pCi/L  H-3: pCi/L  Be-7: pCi/L  Water  Gross beta: pCi/L  H-3: pCi/:L  I-131: pCi/L (hospital releases)  Sediment  Cs-137: pCi/g

Typical Radioactivity in the Environment  Fish  Sr-90: pCi/g  Cs-137: pCi/g  Milk  I-131: not detectable  Cs-137: pCi/L  K-40: pCi/L  Sr-90: pCi/L  Food products  K-40: pCi/g  Sr-90: pCi/g