CBS Jericho

FALLOUT

There are two types of nuclear detonations...ground burst and air burst.

In the case of a surface burst, this cloud will also contain large quantities of dirt and other debris which are vaporized when the fireball touches the earth's surface or are sucked up by the strong updrafts afterwards, giving the cloud a dirty brown appearance. The dirt and debris become contaminated with the radioisotopes generated by the explosion or activated by neutron radiation and fall to earth as fallout.

Following an air burst, condensed droplets of water give it a typical white cloudlike appearance.

For the sake of argument we will assume that in this series the type of detonation that hit Denver was ground burst.

There will be large amounts of particles of less than 100 nm to several millimeters in diameter generated in a surface burst in addition to the very fine particles which contribute to worldwide fallout. The larger particles spill out of the stem and cascade down the outside of the fireball in a downdraft even while the cloud rises, so fallout begins to arrive near ground zero within an hour and more than half the total bomb debris is deposited on the ground within about 24 hours as local fallout.

So here is the problem. Denver is 3-500 miles from Jericho. It appears that episode one of Jericho was "day one", episode two is "day two' and so on. From the time the fireball was spotted to the time they noticed a rain storm approaching up to 24 hours had elapsed.

Now if you see a mushroom cloud to your immediate west, taking into account prevailing winds travel west to east.....you had better find some place to sit tight for the first several days. All that radioactive debris taken into the atmosphere and stratosphere by the mushroom cloud will start to fall back immediately. The closer one is to the cloud the more immediately he needs to seek shelter.

But these people in this town were out and about for up to 24 hours after the explosion???

At a nuclear test at the Bikini Atoll in 1954 it took 16 hours for fallout to travel just shy of 300 miles. This was a 15 mega ton bomb so the spread of "local fallout" will depend on several factors, two of which would be bomb yeild and weather. Not knowing the bomb yield (KT or MT) or having access to any weather forecasts the population of Jericho had already been exposed to an amount of radioactive fallout before they even sought shelter from the oncomming storm.

In one scene, the deputy mayor described radioactive poisoning. He describes the effects of the sickness and the certain death seemingly within days if not hours. The character playing pool was going to stay there and supposedly die by what he thought would be nuclear blast. If he had stayed there playing pool during the rainstorm that was comming he may have gotten a larger dose of radiation but think of fallout more like dust. Of course the rain was going to dump much more concentrated amounts of radioactivity onto Jericho but by staying inside and not frolicking outside in the rain improves survivability tremendously.

At 1 hour after burst the radiation from fallout in the crater region is 30 grays per hour (Gy/h) for a surface burst. A cumulative dose of 3.5 Gy is fatal to half of a population of humans.

The Gray

The unit of actual exposure is the Roentgen which is defined in ionisations per unit volume of air, and all ionisation based instruments (including geiger counters and ionisation chambers) measure exposure. However, effects depend on the energy per unit mass not the exposure measured in air. A deposit of 1 joule per kilogram has the unit of 1 gray. For 1 MeV energy gamma rays, an exposure of 1 roentgen in air will produce a dose of about 0.01 gray, i.e., 1 centigray (cGy) in water or surface tissue. Because of shielding by the tissue surrounding the bones, the bone marrow will only receive about 0.67 cGy when the air exposure is 1 roentgen and the surface skin dose is 1 cGy. Some of the lower values reported for the amount of radiation which would kill 50% of personnel (the 'LD50') refer to bone marrow dose, which is only 67% of the air dose.

At 1 hour after burst the radiation from fallout in the crater region is 30 grays per hour (Gy/h) for a surface burst. A cumulative dose of 3.5 Gy is fatal to half of a population of humans (it has been estimated that the LD50 dose under the conditions of nuclear war {poor diet, poor medical care etc} would be 2.5 Gy). There have been few documented cases of survival beyond 6 Gy.

So...a question would be: If the person shooting pool decided to stay there during the storm would have received a lethal dose of radiation with symptoms described by the deputy mayor??? Chances are no. He may receive a lethal dose but from prolonged exposure and not from one meterological event where he did not suffer direct exposure.