CATS Technological Hazards

CATS Nuclear Weapon Scenario

Example Scenario Description

Nuclear Weapons Effects

CATS contains utilities to model the effects of nuclear weapon detonations and the consequences to the population, infrastructure, and critical facilities. Such explosions produce a high-energy blast, radioactive fallout, and neutron radiation, to name just a few phenomena. CATS is capable of modeling the transport and dispersion of the radioactive material, the air pressure blast wave produced by the burst, radiation damage to human tissue, and radiation damage to silicon, both from gamma rays and neutrons. (This is important for determining the effect of the radiation on electronic equipment.) CATS also can determine the effect of radiation on the population as a result of a nuclear reactor accident where radioactive material is released into the atmosphere. CATS determines the numbers of casualties by using sophisticated health effects models, and combining these with actual United States Census Data.

Example of a Nuclear Weapon Effects simulation performed with CATS' Comprehensive Hazards Assessment System (CHAS) utility.

CHAS is a general hazard assessment utility for NBC materials released from NBC weapons.
CHAS includes various codes for predicting NBC hazard extents:

Propagation of Radiation, Blast, and Thermal Hazards from Nuclear Weapons.
VLSTRACK for propagation of Chem/Bio Hazards.
NATO compliant Allied Technical Protocol 45 (ATP-45) for defining initial NBC hazard extents.

CHAS results are imported into CATS, overlaid upon detailed maps, and used for determining population at risk, infrastructure, casualties, and critical facilities affected.

CHAS is easily launched from within CATS:

Inputs

Definition of hazardous incident or source is created from within CHAS. The delivery system (weapon type), yield (explosive energy of the burst expressed in kilotons of TNT equivalents), burst type (location relative to ground surface), location and incident time are chosen by the user within the CHAS architecture. In this case, the example is of a Nuclear Weapon Terrorist attack in New York City.
The user selects the weather data and inputs it to the model. CHAS weather data includes quantities such as precipitation, wind speed, wind direction , atmospheric pressure, temperature, and relative humidity. The example shown is for an overcast, cool day, with wind velocity due east at 4 km/sec. These weather data are input at various heights above ground (corresponding to certain atmospheric pressure levels) four, in this example.

Surface weather observations of some of these same quantities are collected in automated fashion by using the Get Weather function in CATS, which identifies weather stations near the area of interest, and downloads the pertinent data for use in the hazard prediction program:

The user inputs all the incident data by using a simple series of GUIs, an example of which is shown below:

Outputs

Outputs include various types of color-coded "footprints" that are overlaid upon georeferenced maps:

24-hr. Fallout Dose: gamma radiation (from fallout) ionization to human tissue accumulated over a 24-hour period beginning at the time of the burst.
Prompt Dose: "initial" gamma radiation ionization to human tissue accumulated over the first 60 seconds after burst.
Prompt Neutron Fluence: Neutron flux measured in neutrons/cm² ; used for estimating damage to solid state electronics and electronic system infrastructure.
Prompt Silicon Dose: gamma radiation ionization to silicon; used for estimating damage to solid state electronics and electronic system infrastructure.
Prompt Blast Peak Overpressure: refers to overpressure (psi) in excess of that provided by the atmosphere (approximately 15 psi). Footprint contours are based on injury criteria for human exposure to blast waves.
Prompt Thermal Fluence: heat projected by the hot mass of gas created by x-rays from the burst. Footprint contours are in terms of effects of burns to persons exposed in the open in normal clothing.
Mortality Probability: Footprint contours expressing probability of mortality from radiation exposure.
ATP-45: initial hazard extent definition based on NATO-compliant Allied Technical Protocol 45 methodology.

The example below shows a footprint for human mortality probability resulting from radiation from nuclear fallout. Displayed are probabilities (shown as color-coded contour areas) with ranges:

<1%,
1% - 20%,
20% - 50%,
50% - 90%,
>90%.

The example also displays the initial hazard definition as computed by ATP-45, to be used for evacuation purposes, for example.

Consequences Assessment

For CATS Technological Hazards scenarios, consequences assessment refers to determination of population at risk, infrastructure, casualties,and critical facilities lying within the extent of the hazard plume.

Population at risk refers to the total population lying within each of the plume contours. (The population data is provided with CATS and is 1990 Census Data.) This utility provides a quick and easy way to determine the total number of persons who might be in harm's way. For the example shown above, the user may determine the population at risk in each of the plume contours. The output is provided in a text report and is grouped by county:

Affected infrastructure is also provided in a text report, detailing numbers of infrastructure (whose types are selected by the user) lying within footprint areas. This example displays numbers of water supply stations, wholesale groceries, and hospitals lying within mortaility probability contour areas. Many more types of infrastructures (approximately 60 total) are available for examination.

Casualties are also provided in a text report, displaying numbers of persons (1990 Census Data) projected to suffer mortality. The casualty determination utility is one of the most powerful consequences assessment utilities in CATS, and uses state-of-the-art computer codes for determining deaths from nuclear radiation. Casualties are modeled to occur to healthy persons in young adulthood.

The first step in performing a casualty calculation is to display and select the mortality theme in order to perform the calculation. (Casualties can only be determined with this theme, in contrast to population at risk, which can be determined with any theme.)

Next, CATS determines casualties. The output is provided in the form of a text report and is shown below. Numbers are grouped by County.

Critical facilities are shown as map data, and their availability in the aftermath of an attack is determined by their proximity to the hazard plume. The figure below displays the hazard plume and nearby New York area airports and radio/television stations. The user can click on any of the icons representing these facilities to produce their vital data: Phone Number, Hospital Name, Address, Zip Code, etc.

CATS Example Scenarios