Creating a Nuclear Detonation Scenario Handbook – Part Two

In Part One, I gave an example of how I did a very basic analysis on potential targets in my AO. At the end of my target section, I included a set of handy reference material and images that would be tied to the scenario book. There were a few main sources I used for this information.I only show a portion of what I copied in for two reasons. First, you may decide to include more or less information than I did, so it is more important to just show you the source. Secondly, I don’t want to take their content away from their page in its entirety despite the fact that I am citing my source.

The first source of information I used was from the FAQs over at www.radmeters4u.com – specific, their Q&A on the differences between Roentgen, Rad, and Rem radiation measurements and their description of alpha, beta, and gamma particles. I don’t want to copy all of their content, so here is an example of a small part of their information that I included in my references section

Q: What’s the Difference Between Roentgen, Rad and Rem Radiation Measurements?

A: Since nuclear radiation affects people, we must be able to measure its presence. We also need to relate the amount of radiation received by the body to its physiological effects. Two terms used to relate the amount of radiation received by the body are exposure and dose. When you are exposed to radiation, your body absorbs a dose of radiation.

As in most measurement quantities, certain units are used to properly express the measurement. For radiation measurements they are…

• Roentgen: The roentgen measures the energy produced by gamma radiation in a cubic centimeter of air. It is usually abbreviated with the capital letter “R”. A milliroentgen, or “mR”, is equal to one one-thousandth of a roentgen. An exposure of 50 roentgens would be written “50 R”.
• Rad: Or, Radiation Absorbed Dose recognizes that different materials that receive the same exposure may not absorb the same amount of energy. A rad measures the amount of radiation energy transferred to some mass of material, typically humans. One roentgen of gamma radiation exposure results in about one rad of absorbed dose.
• Rem: Or, Roentgen Equivalent Man is a unit that relates the dose of any radiation to the biological effect of that dose. To relate the absorbed dose of specific types of radiation to their biological effect, a “quality factor” must be multiplied by the dose in rad, which then shows the dose in rems. For gamma rays and beta particles, 1 rad of exposure results in 1 rem of dose.

Other measurement terms: Standard International (SI) units which may be used in place of the rem and the rad are the sievert (Sv) and the gray (Gy). These units are related as follows: 1Sv = 100 rem, 1Gy = 100 rad. Two other terms which refer to the rate of radioactive decay of a radioactive material are curie (Ci) and becquerel (Bq).

Bottom Line: Fortunately, cutting through the above confusion, for purposes of practical radiation protection in humans, most experts agree (including FEMA Emergency Management Institute) that Roentgen, Rad and Rem can all be considered equivalent, especially in an emergency. The exposure rates you’ll usually see will be expressed simply in terms of roentgen (R) or milliroentgen (mR).

The second source of information came from the NukeMap FAQs. This was included so that I could reference back to the assumptions and decisions made in the model so I could better understand the scenario and, if needed, try and tweak the output for real world events. Again, this is just part of what I included in my reference section.

What is the difference between an airburst and a surface burst in this context?

There are several differences between surface and airbursts that this model attempts to demonstrate (you can see them if you set an airburst with an altitude of “0”, which is not exactly the same in this model as a surface burst). Essentially, the model seems to assume that a surface burst will result in a decreased amount of thermal output, but with a wider fireball (probably on par with the semi-circular fireball photos of the familiar shots of the “Trinity” test). Blast and radiation ignore this setting and treat every shot as an airburst of some altitude.

There are several airburst options. One is “Maximize airburst radii for all effects,” which will show what the maximize size of each effect ring would be if the idealized airburst height for that effect ring was chosen. This can be a bit misleading, because it is really showing you a spread of different altitudes (each of the blast effects will indicate what the optimized height of burst is).

Another is “Optimize for overpressure.” This means that for a given radius of maximum overpressure (e.g., 5 pounds per square inch), the code will figure out the altitude of detonation of the weapon that would maximize it. The reason that such optimized altitudes exist is because at certain detonation heights, the blast wave will reflect off of the ground and interact constructively with itself. This is graphed in a so-called “knee curve” that shows how at certain heights there is a big “bulge” in the radius of a given overpressure:

NUKEMAP’s code uses data from Glasstone and Dolan’s charts (like the one above) which has been translated into raw numbers. Unknown points are interpolated. More details on this are available in this blog post. In the case of the optimized choice, NUKEMAP will figure out the optimal burst altitude and then render the effects as if you have selected an arbitrary burst height (see below).

The “burst height” option allows you to set an arbitrary height of burst. It will scale all effects except the fireball for what the effects on the ground would be. (Generally speaking, the fireball radius matters only for ground effects if the bomb is detonated at surface or near-surface heights.) In the case of the blast effects, it takes into account whether there is Mach reflection or not (using charts like those shown above). For thermal and radiation effects, it calculates an idealized sphere of maximum effect and then uses slant range to find where it would intersect with the ground.

None of these models do not take into account terrain, building shielding, atmospheric reflection (e.g. off of inversion layers), or atmospheric opacity (e.g. there are different thermal propagation rates depending on humidity). This is because modeling these effects is much more difficult, and requires accurate information about the terrain, buildings, and atmosphere, which I do not have access to (as of yet), and even if I did, might require computational resources exceeding those of a web browser. Including these sorts of effects in a future version of the NUKEMAP is a potential goal, but there are technical limitations involved. One should consider the NUKEMAP’s visualized effects to be “back-of-the-envelope,” “order of magnitude” estimations that might be either increased or decreased under different local environmental situations or different assumptions about the targets.

I then included some conversion charts and tables (both original and taken from Google) as well as some general rules.

The 7-10 Rule for Fallout

The danger of radiation from fallout also decreases rapidly with time due in large part to the exponential decay of the individual radionuclides. A book by Cresson H. Kearny presents data showing that for the first few days after the explosion, the radiation dose rate is reduced by a factor of ten for every seven-fold increase in the number of hours since the explosion. He presents data showing that “it takes about seven times as long for the dose rate to decay from 1000 roentgens per hour (1000 R/hr) to 10 R/hr (48 hours) as to decay from 1000 R/hr to 100 R/hr (7 hours).” This is a rule of thumb based on observed data, not a precise relation.

7-10 Rule: For every sevenfold increase in time after detonation, there is a tenfold decrease in the radiation rate. So, after seven hours the radiation rate is only 10% of the original and after 49 hours (7 x 7 = 49) it is 1%.

Finally, I included some information of the health effects of radiation depending on dosage – timeline, symptoms, and some potential treatments.

 

TOTAL EXPOSURE ONSET & DURATION OF INITIAL SYMPTOMS & DISPOSITION

30 to 70 R

From 6-12 hours: none to slight incidence of transient headache and nausea;
vomiting in up to 5 percent of personnel in upper part of dose range. Mild
lymphocyte depression within 24 hours. Full recovery expected. (Fetus damage
possible from 50R and above.)

70 to 150 R

From 2-20 hours: transient mild nausea and vomiting in 5 to 30 percent of
personnel. Potential for delayed traumatic and surgical wound healing,
minimal clinical effect. Moderate drop in lymphocycte, platelet, and
granulocyte counts. Increased susceptibility to opportunistic pathogens.
Full recovery expected.

150 to 300 R

From 2 hours to three days: transient to moderate nausea and vomiting in
20 to 70 percent; mild to moderate fatigability and weakness in 25 to 60
percent of personnel. At 3 to 5 weeks: medical care required for 10 to 50%.
At high end of range, death may occur to maximum 10%. Anticipated medical
problems include infection, bleeding, and fever. Wounding or burns will
geometrically increase morbidity and mortality.

300 to 530 R

From 2 hours to three days: transient to moderate nausea and vomiting in 50
to 90 percent; mild to moderate fatigability in 50 to 90 percent of personnel.
At 2 to 5 weeks: medical care required for 10 to 80%. At low end of range,
less than 10% deaths; at high end, death may occur for more than 50%.
Anticipated medical problems include frequent diarrheal stools, anorexia,
increased fluid loss, ulceration. Increased infection susceptibility during
immunocompromised time-frame. Moderate to severe loss of lymphocytes.
Hair loss after 14 days.

530 to 830 R

From 2 hours to two days: moderate to severe nausea and vomiting in 80 to
100 percent of personnel; From 2 hours to six weeks: moderate to severe
fatigability and weakness in 90 to 100 percent of personnel. At 10 days to
5 weeks: medical care required for 50 to 100%. At low end of range, death
may occur for more than 50% at six weeks. At high end, death may occur
for 99% of personnel. Anticipated medical problems include developing
pathogenic and opportunistic infections, bleeding, fever, loss of appetite,
GI ulcerations, bloody diarrhea, severe fluid and electrolyte shifts, capillary
leak, hypotension. Combined with any significant physical trauma, survival
rates will approach zero.

830 R Plus

From 30 minutes to 2 days: severe nausea, vomiting, fatigability, weakness,
dizziness, and disorientation; moderate to severe fluid imbalance and headache.
Bone marrow total depletion within days. CNS symptoms are predominant at
higher radiation levels. Few, if any, survivors even with aggressive and
immediate medical attention.

I haven’t quite finished the document yet, so there may be additional resources  to be had. I also plan to determine a specific map scale for a physical map and scale the NukeMap to match. Then, I can create what amounts to a template of an 800kt blast at that scale as well as the Fallout clouds for different wind speeds so that I can print them, cut them out, and use them on the physical map (like how kids used to learn how to tell time using a clock that had hands that could spin). That way, I can adapt the model to current local conditions if I need to.

Did I miss anything that you would include in your own document?