The effects of nuclear weapons

As you know, the media have been talking a lot about the possibility of nuclear war between India and Pakistan. The US Army in its infinite wisdom decided I needed the skill of nuclear target analyst, for which I was duly trained at Fort Sill, Okla., in 1982. The course was called the Nuclear and Chemical Target Analysis Course (abbreviated NCTAC, pronounced "Nicktack"). It also qualified me to be a chemical target analyst, but that was really a joke because the Army possessed almost no chemical weapons.

NCTAC was a mind-searing course. It was the only military course I ever took or heard of in which a score of 99 percent was a failing grade. The standard to pass each test was to score 100 percent, and no tests could be failed and still pass the course. It was extremely technical. In 1982 there were no personal computers, so we didn't have laptops or even programmable calculators to do the calculations. We did all the arcane calculations with slide rules, table data, pencils and paper.

The course was self-paced. It would have been impossible to teach it lockstep; with the passing grade set so high, every student had to be fully ready to take each test, and not everyone learns at the same rate. All you had to do, schedule-wise, was make progress according to certain benchmark dates, and even those dates were usually about three days duration each. Instructors monitored your progress and gave you individual tutoring if you needed it, but not a lot: if you could not intuitively grasp the course material going through the instructional materials, the Army wasn't very anxious to send you out with a credential that you didn't self-competently earn.

You had to come to class each day, but once you signed in, your time was your time. We went on break whenever we wanted and could leave for the day when we wanted. We just had to make the benchmarks. There was more than one day when I went home before noon because my brain had turned to what we called, "NCTAC mush."

Of course, all the material was pretty highly classified, so there was no homework, and no study materials could be taken out of the building wing the course was held in. Its whole floor was actually a highly secure vault.

Anyway, with the media beating the drum of potential nuclear war - and the imminent release of The Sum of All Fears, in which Baltimore gets nuked, I thought I'd offer a short primer about the effects of nuclear weapons.

Nuclear weapons' effects are achieved by blast, thermal radiation (heat) and nuclear radiation. Blast waves are attenuated by mountainous terrain, but are multiplied by fairly flat terrain. This is because in any air burst, the blast wave moves both down and away from the explosion. The downward blast wave then reflects out, away from ground zero. This reflected ground blast wave is called the "mach stem." When the mach stem crosses the other, laterally moving blast waves, the blast effects are amplified. This effect is greatly reduced by mountainous peaks and valleys. (Air bursts are more damaging than surface bursts, and air bursts do not produce fallout. US policy for decades has been not to produce fallout.)

Thermal radiation works only when there is something to burn. Thermal radiation does not penetrate the ground and would not affect contents of caves under mountains. Thermal radiation moves in a straight line only. It can be reflected under some conditions, but it doesn't turn corners.

There are four components of nuclear radiation. From least worrisome to most:

alpha particles can be stopped by a piece of paper

beta particles can be stopped by a sheet of tinfoil.

gamma waves and free neutrons are lethal, but even a well-constructed foxhole blocks gamma excellently and neutrons quite well. As for many meters of granite or limestone, as in a cave, forget it.

There are other effects of nuclear detonations, such as electro-magnetic pulse (EMP), but they are not considered militarily significant.

Blast effects get all the special effects work in movies and media attention among the chatterati, but in our planning criteria, we hardly considered blast as militarily significant, nor thermal much. It's radiation that we planned for. The relative vulnerability of human beings to nuclear radiation, based on their shelter or cover, is well known, as is the lethality of different radiation doses. (We had a saying, "Thirty days hath September, and a man with 500 rads," a "rad" being a "radiation absorbed dose," roughly comparable to a roentgen.)

Atomic weapons inherently cannot be used in a way that discriminates between valid enemy troops and innocent others, unless the enemy troops are very isolated - unlikely to occur in either India or Pakistan. But even if such an isolated formation was found, there are other concerns. Potential downwind effects could kill or make ill infants, adults, the elderly, the helpless, livestock and crops and would extend into neighboring countries. The peoples of Pakistan, India and nearby nations would be thrown into panic, creating the worst refugee crisis in history.