United States Action

UnitedStatesAction Yahoo Group

Back to Nuclear Terrorism Page

Back to US Action Home Page

IMPACT OF "LOW YIELD" NUCLEAR WEAPONS

Background on Suitcase Nuclear Device

Seismic Studies - Comparing Nuke Blast to Earthquake
 

1 KT Nuclear Device:
Powerpoint of 1 KT Device Exploded in the Center of Washington, DC

(source: "In-Depth Medical Management for Nuclear/Radiological/Conventional Terrorism Agents")
NOTE: this file is a 2.7 MB Powerpoint File

1 KT Nuclear Device
Summary of Impact of 1 KT Nuclear Blast

1 KT - Effective Range for Blast Energy
350m LD50 11m/sec - LD50 means 50% mortality (1148.29 feet = 0.2174792 mile)
550m ED50 4.3m/sec - ED50 would affect 50% population (1804.46 feet = 0.3417538 mile)
750m Penetrating Wounds 55m/sec (2460.63 feet = 0.4660284 mile)

1 KT- Blast Energy and Static Overpressure
150m LD50 50psi - LD50 means 50% mortality (492.126 feet = 0.0932057 mile)
300m ED50 20psi - ED50 would affect 50% population (984.252 feet = 0.1864114 mile)
700m Eardrum Rupture 5 psi (2296.59 feet = 0.4349602 mile)

1 KT -Safe Separation Distance for Eye Injuries
Weapon Yield - 1 KT
Detonation Altitude-300 Meters
Personnel Altitude - Sea Level
Daytime Visibility - 46 km (28.5830748 mile)
Retinal Burns - 16.7 km (10.3768989 mile)
Flash Blindness - 5.9 km (3.66609 miles)

1 KT - Effective Range for Thermal Energy Infrared
700m - 7 cal/cm2 (2296.59 feet = 0.4349602 mile)
800m - 4 cal/cm2 (2624.67 feet = 0.4970966 mile)
1200m - 2 cal/cm2 (3937.01 feet = 0.7456458 mile)
 

10 KT Nuclear Device:
The detonation of a 10kt (kiloton yield) briefcase nuke would have the follow effects. The assumption is for a ground burst of a weapon with a 10 mile per hour windspeed

doserates downwind distance and width

3000 R/Hr 2.45 Mile .05 Mile
1000 R/H 4.65 Mile .20 Mile
300 R/H 11.63 Mile .54 Mile
100 R/H 22.99 Mile 1.39 Mile
30 R/H 41.34 Mile 2.53 Mile
10 R/H 62.00 Mile 1.60 Mile
3 R/H 77.51 Mile 2.10 Mile
1 R/H 103.34 Mile 3.53 Mile

These rates are normalized at 1 hour after the detonation and note the narrowness of the fallout width as compared to the distance from ground zero.

The fireball radius is 323 feet. Radius of fireball when the shock front breaks away 312 feet. As shock front breaks away a second thermal pulse begins. Distance to 1 psi overpressure (moderate structural damage) 4.57 miles. Distance to second degree burns to exposed skin 1.45 miles
.
Cloud top will stabilize at about 25,000 feet and cloud bottom will be around 14,000 feet. The cloud will have a radius of 2.68 miles and at 1 mile the windspeed will reach 141 miles per hour. A contact burst would produce a crater about 215 feet across and a crater about 47 feet deep assuming that it was on solid granite. Twice that if wet soil or rock. At a distance of 2.07 mile causalities would be expected in the open.

It is unlikely that a normalized dose rate of greater than 5000 R/Hr will occur over any significant areas, and will be confined to very distinct hot spots created by local topography, with microweather aspects.

The following can apply to a detonation of almost any yield. Early fallout will normally consist of elements with high condensation temperatures - light and refractory elements. The krypton and xenon decay chains will be almost absent due to relative volatility. As the cloud cools the cesiums, strontiums and iodines will condense and fallout at a distance away proportional to the time of fall from the cloud bottom. Almost all fallout originates in the zone between 2/3 the height of the top of the stem and the cloud top as much as 30% will be trapped in the upper atmosphere and will be deposited over a period of years!!

The relative severity of the effects from a weapon of given yield depends on the effective energy partition.- at small yields the prompt radiation effects are predominant. As yields go up the blast takes over through a relative short range, as the yields get larger the effective illumination time increases the net thermal exposure, this effect makes the thermal effects much higher at the upper end of the yield spectrum.

If the explosion is not at a very high altitude it will have 2 distinct thermal pulses, with most of the damage occurring with the second pulse. At low yields, this is too quick to be of much use. But at high yields (Strategic type warheads, ICBM's ect) this would provide a warning effect that could allow some evasive actions. The prompt radiation doses received in the first minute after the detonation would arrive almost instantly upon the occurrence of the detonation and could not be evaded. In all circumstances casualty effects depend on distance, yield and shielding.

A weapon is detonated by bringing a mass of fissionable material into a condition of prompt supercriticality either by the explosive assembly of 2 or more subcritical masses (design to the suitcase nukes) or by increasing the density to decrease the surface area thereby reducing nuetron leakage. The weapon used at Hiroshima was of the former and Nagasaki the latter.

A significant portion of the energy appears as soft x-rays capable of penetrating about a foot in the air. These x-rays cause a change in the air's ability to transmit light, this allows the interior temperatures to rise to extremes and expand violently and this region is called the fireball. At the instance of detonation enormous quantities of nuetrons are also released with most of them released in a fraction of a second. The nuetrons serve to activate the oxygen and nitrogen in the atmosphere into products with very high gamma energies and short halflives.

The rapidly expanding fireball pushes a wall of highly compressed air in front of it called a blast wave. If the detonation was at more than a few hundred feet the blast wave will hit the terrain and reflect. This reflected wave till tend to join with the blast front and reinforce the overpressures increasing the destructive radius of the blast front. The inside structures capable of withstanding the blast fronts, internal reflection of the way can tend to focus overpressures and increase likely hood of injury however if individuals are at a distance away from reflecting surfaces a reverse effect has been noted.

From our example of a suitcase nuke of 10Kt yield the effects although horrendous are relatively mild compared to the strategic weapons. The biggest problem outside the immediate area of ground zero and the narrow width of the fallout cloud is panic on the part of the general public with the assumptions that the effects of the weapons are far greater than they really are. Of course any event would absolutely strain or break local fire/ems response and multiple events will strain/break any federal response. We simply do not have civil defense anymore except for our leaders who will be very safe in their well stocked and protected bunkers thank you.

*Note no classified or sensitive materials were used in this overview or compliation.

DC and 10kt Nuke - A Hypothetical Blast

In the unlikely event of a terrorist nuclear blast, most casualties would be caused by radiation, especially the radioactive cloud carried by winds into surrounding areas. This map adapted from a White House Homeland Security Council report - which depicts an attack on Washington - shows a hypothetical radiation plume from a 10-kiloton weapon. The plume's direction is based on prevailing winds. Other wind conditions would provide different results. The statistics are based on a scenario in which little evacuation was possible.

A Hypothetical Blas

SOURCE: Homeland Security Council | THE WASHINGTON POST

 

25 KT Nuclear Device:
The detonation of a 25kt (kiloton yield) nuke would have the follow effects. The assumption is for a ground burst of a weapon with a 10 mile per hour windspeed

doserates downwind distance and width

3000 R/Hr 3.71 Mile .11 Mile
1000 R/H 7.02 Mile .38 Mile
300 R/H 17.56 Mile 1.00Mile
100 R/H 34.73 Mile 2.40Mile
30 R/H 62.43Mile 4.23Mile
10 R/H 93.65Mile 7.07Mile
3 R/H 117.06Mile 10.08Mile
1 R/H 156.08Mile 14.18Mile

These rates are normalized at 1 hour after the detonation and note the narrowness of the fallout width as compared to the distance from ground zero.

The fireball radius is 439 feet. Radius of fireball when the shock front breaks away 424 feet. As shock front breaks away a second thermal pulse begins. Distance to 1 psi overpressure (moderate structural damage) 7.32miles. Distance to second degree burns to exposed skin 2.07miles
.
Cloud top will stabilize at about 29,500feet and cloud bottom will be around 17,500feet. The cloud will have a radius of 3.75miles and at 1 mile the windspeed will reach 218 miles per hour. A contact burst would produce a crater about 292 feet across and a crater about 64 feet deep assuming that it was on solid granite. Twice that if wet soil or rock. At a distance of 3.00mile causalities would be expected in the open.


150 KT Nuclear Device:
(source: http://www.atomicarchive.com/Example/Example1.shtml)



=================================

Summary of Radiation Effects:

http://www.fas.org/nuke/intro/nuke/radiation.htm

Metric Conversion Tools:
http://www.worldwidemetric.com/metcal.htm

http://www.onlineconversion.com/length_common.htm

=================================

Nuclear and Seismic Studies

=================================



 

Seismic Studies - Source: Distributed Seismic and Radionuclide Sensor Network