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	Nuclear Explosions: Weapons, Improvised Nuclear Devices Nuclear Explosions: General Information Improvised Nuclear Devices (INDs) Categories of Medical Effects Medical Management Shelter in Place: Shielding by Buildings Size of the Event and Potential Affected Areas Radioactive Plume Radiation Response Worker Exposure Guidelines Nuclear Testing Film Clips Nuclear Explosions: General Information 1 The energy released in a nuclear explosion derives from the splitting (fission) of radioactive materials, e.g. Uranium-235 and Plutonium-239. Bombs dropped on Hiroshima and Nagasaki, Japan at the end of World War II are examples of nuclear explosions. The explosive energy from a nuclear detonation is quantified in terms of the number of kilotons (Kt) of the conventional explosive TNT (trinitrotoluene) that it would take to create the same blast effect. (Table 1, Figure 4) During and following a nuclear explosion, radiation is released including Electromagnetic radiation: ultraviolet, infrared, visible, gamma and x-ray Particulate radiation: alpha and beta particles, and neutrons A nuclear blast releases massive amounts of energy, which dissipate as a fireball, blast forces/waves, prompt radiation, light and heat (thermal energy), and delayed ionizing radiation (i.e. fallout: nuclear fragments created in the fission process which turn into radioactive elements which attach to vaporized debris particles from the explosion). Fireball Vaporization of matter by tremendous heat within the fireball Located at the epicenter of the explosion Everything inside this fireball vaporizes, including soil and water, and is carried upward This creates the mushroom cloud that is associated with a nuclear detonation/blast/explosion (Figure 1) Blast forces/waves: shock waves causing mechanical damage (Figure 2, Figure 3, Figure 4) Direct blast wave pulse overpressure forces (measured in atmospheres of pressure) propagate out from blast Indirect blast wind drag forces (measured in wind velocity) Prompt radiation dose Radiation levels are greatest near the epicenter of the explosion, and decrease rapidly with distance from the point of the burst. Carried predominantly by gamma rays and neutrons produced within the first minutes after the explosion Can cause whole body exposure and Acute Radiation Syndrome, if dose is sufficient Light and heat (thermal energy) Radiated by the fireball Wide range of electromagnetic spectrum, including infrared, visible, and UV Electromagnetic pulse Occurs at the instant of the detonation and ends within a few seconds Disruption of the electrical grid and electronic equipment by this pulse is greatest nearest the epicenter Communications infrastructure (cell towers, telecommunications switches, dishes, radar) will be significantly affected Equipment entering the area after the event will function normally, but function will be related to restoration of the infrastructure Cell phones and handheld radios have relatively small antennas, and if they are not connected to electrical power supplies during the electromagnetic pulse (EMP) they may not be affected Delayed ionizing radiation dose (fallout) (Figure 5, Figure 6) Produced by fission products and neutron-induced radionuclides in the area around the explosion, especially downwind Dispersed downwind with the fireball/debris cloud As the cloud travels downwind, the cooling and falling radioactive material settles on the ground, creating a large swath of deposited material (fallout) Fallout creates large areas of contamination and the ionizing radiation coming off the fallout, which can damage tissues and penetrate through thin walls and glass Fallout can also contaminate the soil, food, and water supply Prohibitions against eating food and drinking water from affected areas will be issued Groundshine (measured in dose rate per hour or cumulative dose over time interval, displayed on plume maps) External gamma radiation from fission products deposited on the ground in fallout area More than the beta radiation deposits, groundshine will be the most significant health hazard related to fallout Figure 1. Nuclear explosion: mushroom cloud Figure 2. Nuclear weapon explosion effects: approximate Source: Armed Forces Radiobiology Research Institute's Medical Effects of Ionizing Radiation Course on CD-ROM (1999) 50% Blast and ground shock 35% Thermal radiation 15% Ionizing radiation 5% Initial/prompt (first minute) 10% Delayed/residual (minutes to years) Figure 3. General patterns of damage from a 10-Kt nuclear explosion on the ground Source: The National Academies and the U.S. Department of Homeland Security Figure 4. Blast range and siginificant effects Source: The National Academies and the U.S. Department of Homeland Security Figure 5. Fallout: Relative rate of decline of radioactivity after a nuclear explosion Source: Armed Forces Radiobiology Research Institute's Medical Effects of Ionizing Radiation Course on CD-ROM (1999) • Summary of fallout effects from a hypothetical 10 Kt nuclear explosion. • The level of fallout decays quickly, roughly by a factor of 10 for every 7-fold increase in time. Figure 6. Factors that affect fallout Particle size: Assuming constant wind and altitude, larger particles land relatively close to ground zero and smaller particles land farther away. Altitude: The higher the initial altitude of a particle, the farther away from ground zero it lands, assuming constant wind speed and particle size. This means that the fallout pattern will be different if there is a ground burst vs. one from an altitude, and increasing altitude will also affect the fallout pattern. Wind: Wind is the most difficult factor to predict. Different altitudes through which a particle falls may have different wind speeds and directions that affect the final destination of the fallout particle. This explains how fallout can occur miles upwind of a detonation. Source: Armed Forces Radiobiology Research Institute's Medical Effects of Ionizing Radiation Course on CD-ROM (1999) top of page Improvised Nuclear Devices (INDs) 2 An illicit nuclear weapon bought, stolen, or otherwise originating from a nuclear state, or a weapon fabricated by a terrorist group from illegally obtained fissile nuclear weapons material that produces a nuclear explosion Built from the components of a stolen weapon or from scratch using nuclear material (plutonium or highly enriched uranium) Produces same physical and medical effects as nuclear weapon explosion Results in catastrophic loss of life, destruction of infrastructure, and contamination of a very large area If nuclear yield is NOT achieved, the result would likely resemble a Radiological Dispersal Device in which fissile weapons material was dispensed locally If nuclear yield is achieved, results would resemble a nuclear explosion described on this page Like nuclear explosions, IND explosions can be evaluated with a plume map Reference: Protective Action Guides for Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incidents (PDF - 481 KB), (DHS/FEMA document, published in Federal Register January 3, 2006, Z-RIN 1660-ZA02) top of page Categories of Medical Effects Blast injury | Thermal/burn injury | Radiation injuries Blast injury 3, 4 Immediate effects of blasts and explosions Primary blast injury — direct effects result from barotrauma (e.g., overpressurization and underpressurization) commonly affecting air-filled organs and air-fluid interfaces (Figure 7) Rupture of tympanic membranes: Injury to ear drum: 5 psi Pulmonary damage: Injury to lung: 15 psi Rupture of hollow viscera: Injury fatal (LD50): 50 psi Secondary blast injury Penetrating trauma Fragmentation injuries Tertiary blast injury — effects of structural collapse and of persons being thrown by the blast wind Crush injuries and blunt trauma Penetrating or blunt trauma Fractures and traumatic amputations Open or closed brain injuries Quaternary blast injury — burns, asphyxia, and exposure to toxic inhalants Types of injuries caused by blasts depend on whether blasts Occur outdoor in open air or within buildings Cause the collapse of a building or other structure Conventional bombs generate blast waves that spread out from a point source Blast wave consists of two parts Shock wave of high pressure followed by Blast wind or air in motion Damage produced by blast waves decrease exponentially with distance from the point source Reverberations occur off walls and rigid objects As outward energy dissipates, a reversal of wind back toward the blast and underpressurization occur The resulting pressure effect damages organs, particularly at air-fluid interfaces, and the wind propels fragments and people, causing penetrating or blunt injuries Enhanced-blast explosive devices (e.g., nuclear explosions) have more damaging effects than conventional explosions Primary blast disseminates the explosive and then triggers it to cause a secondary explosion High pressure wave then radiates from much larger area, prolonging the duration of the overpressurization phase and increasing the total energy transmitted by the explosion Cause a greater proportion of primary blast injuries than do conventional devices Thermal/burn injury Direct absorption of thermal energy through exposed the skin or heating or ignition of clothing (flash burns) (Figure 8) Indirect action of fires caused in the environment (flame burns) Burn casualties — and it is expected there would be many — may result from the absorption of thermal radiation energy Eye injuries Flash blindness Caused by the effect on the retina of the initial brilliant flash of light produced by the explosion Victims DO NOT have to be looking at the detonation site, as reflected/diffracted light is sufficient in many cases Victims driving at the time of the event will be unable to see, potentially causing large numbers of traffic accidents During daylight, flash blindness does not persist for greater than about 2 minutes, but lasts generally seconds At night, when the pupil is dilated, flash blindness will last longer Partial recovery may be expected within 3-10 minutes in daylight, longer at night Retinal scarring Retinal burn resulting in permanent damage from scarring results when a fireball is directly viewed May be sustained at considerable distances from the explosion, depending on blast size Location of the scar will determine the degree of interference with vision Central scarring will cause greater disability Radiation injuries During the incident Prompt radiation Gamma and neutron radiation exposure dose received within the first minutes after detonation Depending on dose, patients are at risk for Acute Radiation Syndrome Delayed radiation Fallout (Figure 5, Figure 6): Produced by fission products and neutron-induced radionuclides in surrounding materials (water, soil, structures, nuclear device debris) These radioactive products will be dispersed downwind with the fireball/debris cloud (Figure 5, Figure 6) As the cloud travels downwind, the cooling and falling radioactive material settles on the ground, creating a large swath of deposited material (fallout) (Figure 5, Figure 6) The highest concentrations (creating the most dangerous radiation levels) fall closest to the detonation site The fallout creates large areas of contamination, and the ionizing radiation coming off the fallout contamination damages tissue and can penetrate through thin walls and glass Three ways victims can get a dose of radiation from the fallout: Radiation directly from the fallout as it passes by or from the fallout that has been deposited on the ground Radiation from fallout contamination on skin, clothing, or possessions, which exposes people until they change their clothing and/or remove the contaminated material Ingestion or inhalation of radioactive material Of these, the most likely to cause injury in the first few days is direct exposure to fallout, which can be protected against using the three basic principles of distance, time, and shielding Exposure to fallout is the most dangerous in the first few hours Fallout decays rapidly with time: Example from a hypothetical 10 Kt explosion: After 3 hours, initial exposure rates are down to 20% 8 hours, down to 10% 48 hours, down to 1% Therefore, sheltering for the first few hours can save lives Long after the incident (potential long-term effects of radiation) Delayed effects of acute radiation exposure Specific organ effects depending on where a given isotope is incorporated Carcinogenesis Mutagenesis (fetal effects) Figure 7. Blast Injuries Source: Armed Forces Radiobiology Research Institute's Medical Effects of Ionizing Radiation Course on CD-ROM (1999) psi = pounds per square inch LD50 = the dose of radiation expected to cause death to 50% of those exposed without medical treatment.   Figure 8. Thermal burn on skin from nuclear explosion Source: Pictures of World War II, U.S. National Archives & Records Administration, 77-MDH-6.55b Skin burn pattern corresponding to the dark portions of a kimono worn at the time of the atomic explosion, 1945. top of page Medical Management 1, 5 Both exposure and contamination can occur. See sections of this Web site for diagnosis and treatment of Exposure Contamination Both Since the event is likely to be a mass casualty situation, the procedures used for diagnosis and treatment of patients may need to be modified from those recommended in events with a smaller number of victims Triage Treatment of Acute Radiation Syndrome modifications in mass casualty situations Where to send biodosimetry specimens Biodosimetry tools: calculating exposure dose Burn triage and treatment top of page Shelter in Place: Shielding by Buildings Buildings provide considerable protection from fallout. (Figure 9, Figure 10) A brick building provides better protection than does a brick veneer building, which is better than that of a frame building. Multiple stories increase protection as well. The interior of a one-story building reduces exposure by 50 percent. A level below ground reduces exposure by 90 percent. Additional levels provide more shielding and increase the overall effectiveness above and below ground. The five-story building illustration, below, shows that the middle floors provide better shielding than the ground floor because fallout that covers the ground emits gamma radiation along with that on the exterior surfaces of the building. Moving to a higher floor in the building increases the distance from the ground source but, at some point, increases exposure from the source on the rooftop. The best option is to move to the center of the building away from the exterior walls (and below ground, if possible) or to a middle floor above ground. Note how the position in the building and surroundings affect the percentage by which exposure is reduced in various locations. Reference: Sheltering in Place During a Radiation Emergency (HHS/CDC, May 2006) Figure 9. Buildings as radiation shielding Figure 9a: Building as shielding: Numbers inside buildings are percent reduction of exposure inside compared to exposure outside. Figure 9b: Building as shielding: Numbers represent a "dose reduction factor," not a percentage. A dose reduction factor of 200 indicates that a person in that area would receive 1/200th of the dose of a person out in the open. White graphics inside the 50, 80, 100, and 200 boxes simulate persons gathered together. The number 2 and 3 outside the building also represent a "dose reduction factor" outside the building related to shielding by the building itself, compared to exposure in open areas outside in a direct line with the radiation event center. Source: Armed Forces Radiobiology Research Institute's Medical Effects of Ionizing Radiation Course on CD-ROM (1999) Figure 10. Blast Effects on Dwellings top of page Size of the Event and Potential Affected Areas Table 1. Approximate Radii of Effects of Nuclear Weapons Effect 1 Kt 10 Kt 100 Kt 1000 Kt Ionizing radiation (50% immediate transient ineffectiveness) 600 m 950 m 1400 m 2900 m Ionizing radiation (50% latent lethality) 800 m 110 m 1600 m 3200 m Blast (50% casualties) 140 m 360 m 860 m 3100 m Thermal radiation (50% casualties, second degree burns under fatigue uniform) 369 m 110 m 3190 m 8020 m Adapted from NATO Handbook on the Medical Aspects of NBC Defensive Operations AMedP-6(B), Chapter 3: Effects of Nuclear Explosions Figure 11. Radiation lethality (LD50 — lethal dose will be received by 50% of population) will out-distance (km) the thermal and blast damage only in low yield weapons (= 1 kiloton) Source: Armed Forces Radiobiology Research Institute's Medical Effects of Ionizing Radiation Course on CD-ROM (1999) top of page Radioactive Plume A radioactive plume is the geographic area encompassed by radiation after a radiological/nuclear event. The size and shape of the plume changes over time and reflects the type and size of the incident and ambient meteorological conditions. Official government response teams (using weather information, topographic maps, principles of physics, and radiation detectors placed at various locations) employ complex computer models to prepare plume maps of areas expected to be contaminated and how much contamination is expected. The radiation map generated from the model displays a specific geographic area and is similar to a weather map displaying isotherms or isobars. The geographic location of the displayed dose rate/hour lines will change over time. Typically, the areas closest to the explosion or detonation receive the highest dose and downwind areas receive less. The typical circular or comet-like shapes of the radioactive plume represent the computer estimates of dose rate/hour at a given time, with changes expected over time due to a variety of factors, including weather. top of page Radiation Response Worker Exposure Guidelines *, **, *** Total Effective Dose Equivalent (TEDE) Guideline Activity Condition 5 rem All occupational exposures Dose limit to emergency workers: 5 rem Use all reasonable measures to minimize dose For most Radiological Dispersal Devices, radiation control measures will maintain exposures below 5 rem Some rescues may involve exposures > 5 rem When 5 rem limit is exceeded, worker monitoring must be made available and volunteers for such activities should be made fully aware of the risks 10 rem Protecting valuable property necessary for public welfare (e.g., a power plant) Exposures to emergency workers protecting valuable property necessary for public welfare may exceed 5 rem Use all reasonable measures to minimize dose When 5 rem limit is exceeded, worker monitoring must be made available and volunteers for such activities should be made fully aware of the risks For potential doses > 10 rem, special medical monitoring programs should be employed, and exposure should be tracked in terms of the unit of absorbed dose (rad) rather than TEDE (rem). 25 rem Lifesaving or protection of large populations During large incidents (e.g., Improvised Nuclear Devices) exposures to emergency workers may exceed 5 rem Emergency response activities may include lifesaving, protection of large populations, prevention of mass spread of destruction Use all reasonable measures to minimize dose When 5 rem limit is exceeded, worker monitoring must be made available and volunteers for such activities should be made fully aware of the risks For potential doses > 10 rem, special medical monitoring programs should be employed, and exposure should be tracked in terms of the unit of absorbed dose (rad) rather than TEDE (rem). *Adapted from Protective Action Guides for Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incidents (PDF - 481 KB), (DHS/FEMA draft document, published in Federal Register January 3, 2006, Z-RIN 1660-ZA02) **Emergency response decisions resulting in worker exposure doses greater than 5 rem Made by on-scene Incident Commander during incident when exceeding 5 rem is unavoidable Reflect actual incident circumstances/worker activity (e.g., need to save lives or critical infrastructure) Require informed consent from responding worker *** Decision points for restricting response workers' activities have been recommended by various other agencies. Agency Summary Information Original Document National Council on Radiation Protection and Measurement (NCRP) NCRP Radiation Protection Guidelines: Control of Radiation Dose in the Control Zones Key Elements of Preparing Emergency Responders for Nuclear and Radiological Terrorism (NCRP Commentary No. 19, December 2005, page 19, purchase required; see Free Overview (PDF - 219 KB)) International Atomic Energy Agency (IAEA) IAEA Emergency Worker Turn-back Dose Guidance Manual for First Responders to a Radiological Emergency (PDF - 2.2 MB) (CTIF, IAEA, PAHO, WHO, October 2006, page 41) Conference of Radiation Control Program Directors, Inc. (CRCPD) CRCPD Turn-back Exposure Rates and Dose Guidelines Handbook for Responding to a Radiological Dispersal Device (Dirty Bomb): First Responder's Guide: The First 12 Hours (CRCPD Publication 06-6) (PDF - 4.26 MB), page 28. Conference of Radiation Control Program Directors, Inc. Frankfort, Kentucky, 2006. International Commission on Radiological Protection (ICRP) ICRP Guidance for Occupational Exposure Protecting People Against Radiation Exposure in the Event of a Radiological Attack (International Commission on Radiological Protection, ICRP Publication 96, 2005, page 51) See also: Personal Protective Equipment (PPE) top of page Nuclear Testing Film Clips Historical Test Films (Department of Energy) top of page References "Radiation Bioterrorism", Tochner ZA, Lehavi O, Glatstein E, Chapter 207 in Harrison's Principles of Internal Medicine, Eds. DL Kasper, E Braunwald, AS Fauci , SL Hauser, DL Longo, JL Jameson, 16th Edition, pp 1294-1300, McGraw Hill, 2005 Protective Action Guides for Radiological Dispersal Device (RDD) and Improvised Nuclear Device (IND) Incidents (PDF - 481 KB) (DHS/FEMA document, published in Federal Register January 3, 2006, Z-RIN 1660-ZA02) Adapted from CDC Web site: Radiation Emergencies (HHS/CDC May 10, 2006) Radiation Emergencies: Frequently Asked Questions About a Nuclear Blast (HHS/CDC December 23, 2003) Radiation Emergencies: Casualty Management After Detonation of a Nuclear Weapon in an Urban Area (HHS/CDC May 20, 2005) Radiation Emergencies: Casualty Management After a Deliberate Release of Radioactive Material (HHS/CDC May 20, 2005) Blast Injuries Blast Injuries: Fact Sheets for Professionals (HHS/CDC August 20, 2008) Radiation Emergencies: Blast Lung Injury: What Clinicians Need to Know (HHS/CDC June 14, 2006) Radiation Emergencies: Blast Lung Injury: An Overview for Prehospital Care Providers (HHS/CDC June 14 2006) Radiation Emergencies: Explosions and Blast Injuries: A Primer for Clinicians (HHS/CDC June 14 2006) DePalma RG, Burris DG, Champion HR, Hodgson MJ. Blast injuries. N Engl J Med. 2005 Mar 31;352(13):1335-42. [PubMed Citation] Field Manual 8-9 - NATO Handbook on the Medical Aspects of NBC Defensive Operations AMedP-6(B) Recommendations for Managing a Nuclear Weapons Accident (Radiation Emergency Assistance Training Center/ Training Site [REAC/TS]) A Feasibility Study of the Health Consequences to the American Population from Nuclear Weapons Tests Conducted by the United States and Other Nations (PDF - 32.24 MB) (HHS/NCI/CDC, August 2001) Weisdorf D, Chao N, Waselenko JK, Dainiak N, Armitage JO, McNiece I, Confer D. Acute radiation injury: contingency planning for triage, supportive care, and transplantation. Biol Blood Marrow Transplant. 2006 Jun;12(6):672-82. [PubMed Citation] Waselenko JK, MacVittie TJ, Blakely WF, Pesik N, Wiley AL, Dickerson WE, Tsu H, Confer DL, Coleman CN, Seed T, Lowry P, Armitage JO, Dainiak N; Strategic National Stockpile Radiation Working Group. Medical management of the acute radiation syndrome: recommendations of the Strategic National Stockpile Radiation Working Group. Ann Intern Med 2004; Jun 15;140(12):1037-51. [PubMed Citation] The Medical NBC Battlebook (PDF - 9562 KB), US Army ChPPM, Technical Guide 244, August 2002 Radiation Emergencies: Sheltering in Place During a Radiation Emergency (HHS/CDC, May 2006) Preparing to Shelter in Place — Practical Tools for Households, Work Places, Schools and Early Childhood/Youth Programs, and Governments (Redefining Readiness, Center for the Advancement of Collaborative Strategies in Health at the New York Academy of Medicine) Nuclear Attack, News & Terrorism - Communicating in a Crisis (PDF - 112 KB) (Fact sheet from the National Academies and the U.S. Department of Homeland Security) Manthous CA, Jackson WL Jr. The 9-11 Commission's invitation to imagine: a pathophysiology-based approach to critical care of nuclear explosion victims. Crit Care Med. 2007 Mar;35(3):716-23. [PubMed Citation]

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