A 10 kiloton Nuclear Weapon Attack: Consequences and Response Challenges Victor E. Anderson, C.H.P. Radiologic Health Branch California Public Health Department

Some Thoughts How big – kilotons What will it do? How far? How many?

Effects Intense nuclear reaction lasting for 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.

Immediate Ionizing Radiation Effects Large burst of X, Gamma, and Neutron radiation is given off during the explosion. A prompt dose of 1,000 rad for unprotected persons may occur out to 0.75 miles from the explosion center. A prompt dose of 300 rad for unprotected persons may occur out to 0.88 miles from the explosion center. “Natural” shields such as hills, concrete structures, etc. can provide some protection.

Shock Wave The explosion will create a “wall” of compressed air that expands outward. This creates the blast or concessive effects. Damage is highly dependent on height of burst. Air or Ground

Shock Wave Ground Burst Wave moves up and along the ground. –Broken up by terrain features. –Hills –Valleys –Buildings Less efficient in causing damage.

Shock Wave Difficult to predict Destructive Effects Rough Guides –Generally an over pressure of ~ psi will severely damage most structures. –10 kt airburst should severely damage all structures out to about 1 mile from the explosion’s center (ground zero). –Severe damage distance from a ground burst is strongly dictated by terrain features.

Shock Wave Damage Fragments Secondary fires Explosions from gas tanks Damage to vehicles and aircraft.

Fallout Probably the most dangerous effect from a nuclear weapon. The amount depends on size and type of burst. Ground burst yields the largest amount. Air burst yields the lowest. Weapon can be surrounded with Cobalt or other materials to enhance fallout.

~ 27,000 ft ~ 1.6 miles

Fallout Spread and extent is highly dependent on weather conditions. Individuals may be killed from radiation exposure. Arrival time depends on wind speed.

Composed of fission fragments, activation products, and unused nuclear fuel. Initially decays off very rapidly. A(t) = A o t -1.2 Time = t A(t) = activity after a period of time (t) A o = equal activity at start. Fallout

First Hour

First Six Hours

First 24 Hours

Putting It Altogether 100 % Deaths ~ 50% 3 rd Degree Burns ~ EMP Limit

Response Challenges Major event Potential loss of majority of elected officials. Initial confusion and chaos. Response organization operations. Approximately 100,000 or more injured. Infrastructure Damage. Fallout.

Continuity of Government Operations A real bad day –Maximum loss of life. –Entire upper elected officials dead. Evacuation decisions may fall to a much lower ranked official. Head of the EOC. COGO is a vital part of a nuclear weapons attack response plan.

Response Operations Chaos and confusion. Communications gone. Normal methods of organizing Incident Command structures will be challenged. Individual fire stations and precinct stations may be isolated. ICS/SEMS PRINCPLES.

Work Areas  Emergency Zone  Areas where workers can maintain doses less than or equal to 5 rem per year. (State radiation worker limits).  25 rem limit for non-life saving operations deemed vital to the response.  Contamination control may require level A or equivalent PPE.  Search and Rescue will be difficult.  Life Saving Zone  Entry only to save lives.  Doses must be less than 100 rem per entry.  Lethal Zone  No Entry  Dose Rates are too high.

Work Zones Zones will shrink as fallout decays. Controlling rescue worker’s dose is a must. Survivors who have greater than 1,000 rad are dead. Organization will be the key to survival. ICS/SEMS

Fallout Injuries Subject to factors of evacuation and time in area. For a 10 kt ground burst, potentially 60,000 deaths. Fatal Levels will arrive quickly depending on the wind speed and other meteorological conditions.

Evacuation Challenges TIME!!!! A delay of one hour post denotation can mean 10 to 15 thousand dead from radiation syndrome. Thousands more with serious radiation sickness. Evacuation plan is vital to saving thousands.

Evacuation Challenges Where is the fallout? –Real fallout patterns vary with wind shear. –High areas may “skip.” How do you get the word out? Dust, smoke and confusion closer to “Ground Zero.”

Fallout Shelters Remember dose rate is a function of t Thus integrated dose: Where: T i = the start time (not zero) and T f = the finish time; and R = the dose rate (R/hr) at T i. Time is in hours. Start out in 1,000 rad/hr field and stay one hour you get about 650 rad of dose.

Fallout Shelters Dose for staying and leaving should be well under 100 rad. –How much? Attenuation Factors –Glasstone lists many. –Building practices have changed.

Fallout Shelters Things to See and Do What are the realistic attenuation factors for underground parking and sub-floors of large buildings, and so forth? Stocks of food, water, and other supplies? How long? Dose for sheltering in upper stories. ?????, etc.

Ingestion Pathway Fallout can and will extend for a long ways. Currently our best assessments for radioactivity limits in food are via the EPA PAG manual. Clearly hundreds of square miles of agricultural land will affected. Economic affect will be huge. Need to reassess from a technical perspective what is allowable/not allowable.

Ingestion Pathway Environmental Monitoring Who eats what? And how much? Effects of sequestering food stuffs? –Export market –Local availability of food. Resupply?

Miscellaneous Stuff Flash Blindness Secondary damage – fires and such. Medical Surge Refugee Housing

Summary The single nuclear weapon attack scenario needs closer scrutiny. Response planning will require much thought and analysis. Recovery is also important.

Hiroshima Today. Ground Zero is near the Center of the Picture

Concluding Remarks With correct planning and training a good response can happen. Clear objectives, good equipment, and a well led and organized response organization can prevail.