Radiological Dispersion Devices and Nuclear WeaponsAn Overview Victor E. Anderson, C.H.P. Radiologic Health Branch California Department of Public Health
Use of Radioactive Materials for Terrorist Attack • Few, if any deaths due to radiation. • Possible deaths due to the explosion. ?
Use of Radioactive Materials for Terrorist Attack • Most likely impact will psychological. • The most important impact will be economic.
Radiation Dose Delivery • External Dose • Source • Fragments • Fallout • Internal Dose • Primarily inhalation pathway.
Radiography Source Plastic Explosive Radiological Dispersion Devices can vary in complexity and design.
OR Lid w/explosive bolts Cooling system for decay heat is required High Level Source MegaCuries or more Mechanism for introducing explosive charge and detonating weapon Shielding
Types of RDD • Improvised • Purpose Built • Manufactured
Most Likely RDD • Economy of force and physics • Improvised • Explosive • Possibly incendiary
Potential Radionuclides. • Primary • Co-60 • Cs-137 • Ir-192 • Sr-90 (Y-90 in equilibrium) • Am-241 • Based on availability and manufactured quantities.
Other Radionuclides • Pu (Generally Pu-239 or Pu-238) • U-235 • Thorium • Heavy Metal issues - ~ 109 mCi/metric ton • Radium • Issues with obtaining sufficient quantities.
As the Cloud Moves Down Wind Radioactive material is deposited as fallout.
Radiation Issues • Ionizing Radiation • Emission of energy • X & Gamma Radiation • Beta and Alpha • Measured in rem and millirem • Rates: rem/hr; mrem/hr • 100 rem = 1 Sievert
Radiation Issues • Dose = Dose Rate X Time • 120 mrem/hr X (½ hr) = 60 mrem • Immediate damage does not occur until after 100 rem of dose. • Annual radiation worker limit: 5 rem/yr • Public dose limit: 100 mrem/yr • Long term effects have not been detected at these low levels.
Radioactive Contamination • Contamination is the presence of radioactive material in a place where it is not wanted. • Radiation Contamination • Contamination does emit radiation. • Major concern is inside people.
First Responder Issues • TURN ON YOUR SURVEY METERS! • Use ICS and SEMS • Life saving takes precedence over radiation control issues. • Do keep track of first responders radiation dose. • Remember: dose rate X time = dose.
First Responder Issues • Call for help. • Use SEMS to ask for: • Radiologic Health Branch Strike Teams • Ca National Guard Civil Support Team • DOE Radiological Assistance Program (RAP) Team.
Care for Contaminated & Injured • Contamination levels on patients • Will not cause radiation injuries to care givers. • Will not cause care givers to become “casualties.” • Are a hygiene issue. • TAKE CARE OF MEDICAL ISSUES FIRST!!!
Care for Contaminated & Injured • When the patient is stabilized • Survey – where is the contamination? • Remove clothing as needed. • Use gauze, sponges, small amounts of soap and water, or “baby wipes” to clean the contaminated areas. • Use sheets and blankets to contain any contamination that can not be cleaned in the field.
Care for Contaminated & Injured • At the ER • Do use a special area to survey and receive the patient. • At the same time do the usual medical screening. • Take care of the patient’s medical problems. • Decontaminate last. • Don’t lose track of patient’s condition.
Controlling ContaminationAt the ER OUT IN PATIENT
Downwind Issues • Assessment • When to evacuate? • Mass decontamination and screening • Recovery
Assessment • Use computer models and measurements. • Project where contamination is and levels. • Determine projected dose rates • Rapid • Recommendation to Incident Command and Emergency Operations Center
When to evacuate? • Use EPA Protective Action Guides (PAG). • Based on dose from deposition. • Greater than one rem in 24 hours. • Greater than two rem in one year. • Use State Dose Assessment Center. If not available use: • Radiologic Health Branch Teams • Radiation Assistance Team (RAP)
Mass Decontamination and Screening • Radioactive contamination is easily removed – soap and water, waterless cleaners, etc. • Radiation dose to contaminated individuals is small. • Major issue is decompression of individual and collective fears and concerns.
Mass Decontamination and Screening • A plan is necessary. • Gives the population direction and hope. • Prevents mass exodus to hospitals. • Must plan for large numbers ~ one million persons. • Reception centers.
Mass Decontamination and Screening • Giving everyone a shower is not the answer! • ~ 10% of the population is medically challenged. • Not all will be contaminated. • Worried well problem. • Some will only be partially contaminated.
Reception Centers • Enough survey meters. • Supplies. • Decontamination • Clothing • Concentrate on minimum use of water. • Documentation • Volunteer Nuclear Medicine Doctors and Radiation Oncologists
Public Communication Clear Multiple Languages Provide Good Information
Public Communication • Can help to prevent panic. • Key to keeping uninjured from going to hospitals. • Must be followed up by educational materials. • What is radiation? • What is the danger? • What can I do?
Law Enforcement Issues • Evidence Collection and support. • Security for first responders with respect to issues such as secondary devices. • Security of the site to assure that unauthorized personnel do not enter. • Crowd control and assistance for evacuees. • Traffic Control
Surveillance Issues • Determine contamination levels. • Plume projections help. • Need teams to survey ground. • Sample for loose and fixed contamination. • Loose contamination is radioactive material that is easily transferred from one surface to another. • Fixed contamination does not move easily. • Suitable air, water, and other environmental testing.
Laboratory Issues • Identification of the radioactive materials • Will occur almost immediately. • Field methods are sufficient. • Laboratories will be needed to: • Analyze large numbers of samples for radioactive materials content. • Air Plants • Water Meats Dairy Products
Laboratory Issues • Does not require environmental sampling sensitivities – e.g., picocuries or less. • High throughput • Shorter count times. • Good documentation. • Sample dose rate limits should be based on equipment limits.
Laboratory Issues • Laboratory personnel should be able to easily stay within radiation dose worker limits. • Contamination control will be an issue. • Storage and documentation of samples. • Radioactive • Non-radioactive
Some Thoughts • How big – kilotons • What will it do? • How far? • How many?
Nuclear Weapon Basics • What is an explosion? • A very fast fire that has no place to go. • Chemical Explosion • Powered by chemical changes • Nuclear Explosion • Powered by nuclear changes • Fission • Fusion
Fission Process • Fissionable Materials – U-233, U-235, Pu-239. • Atom is split by a neutron and you get: • Two or more smaller atoms • Two to three neutrons. • Other atoms may or not be split.
Criticality • Sub Critical • Does not sustain fission • Critical • Neutron Population Steady • Cannot extract power • Supercritical • Neutron population growing slowly • Can extract useful power.
Prompt Critical • Neutrons are increasing very fast. • Nuclear reaction is running away • Result: A very, very fast burning nuclear fire. • If confined, so that the explosive forces build up, then an explosion occurs.
Types of Fission Bombs • Gun type
Types of Fission Bombs • Implosion Type High Explosive Subcritical Core
Construction Issues • Gun type is easiest to make. • Less efficient • Larger and heavier • Implosion type is much harder • More efficient • Lighter and smaller
Type of Weapon Used • Stolen • “Suitcase” bombs ~ 0.1 to 10 kt • Tactical Warheads ~ 1 to 20 kt. • Improvised • Gun type • ~10 to 20 kt Range
National Planning Scenario • Ten kiloton Weapon • Major urban area • Business Centers • Ports • Malls • California CDPH Scenario • Ground Burst
Effects Part One • Intense nuclear reaction lasting for a tens to hundreds of microseconds. • Fireball formation • Light in the form of visible light, heat, and high energy photons (x and gamma rays). • Neutron Radiation • Electro-magnetic Pulse (EMP) • Shock or concussion wave. • Radioactive materials leading to fallout.
The Fireball • Temperature starts at millions of degrees centigrade and falls to about 3,000 degrees centigrade at the maximum radius. • Size varies with strength. • R ≈ 145 (kt)0.4 for contact surface. • R ≈ 110 (kt)0.4 for air burst. • R ≈ 90 (kt)0.4 for surface burst.