Nuclear Suitcase Bomb Feedback

I got a fair bit of email correspondence from LRC readers regarding my article on the blast and heat effects of a potential nuclear “suitcase” bomb. Accordingly, I felt the questions and comments generated were sufficiently high to offer this follow up article for readers’ edification.

Firstly, I realised that one has to be careful about making confident assertions in a public article. No sooner had I noted the fact that no major Taliban leader had been caught than the next day we hear about Mullah Omar being holed up and then escaping the clutches of the U.S. government via motorcycle.

The temptation to draw comparisons was too much, but I couldn’t quite envisage a turbaned Steve McQueen hollering Allah Ho Akhbar! through a massive beard as he evades the Nazis in The Great Escape.

But on that whimsical note, I now go back to our mini atomic bomb.

Yield

On the assumed bomb yield of one kiloton, one reader thought ten kilotons was less difficult to manufacture than a lower yield because a higher critical mass is easier to detonate and hence less conventional explosive is required to enclose it.

It is here that there lies some confusion as to what Bin Laden could have. Media sources I have read speak of nuclear backpacks as well as suitcases. The former can be carried whilst the latter is wieldier. The backpack is alleged to have a yield of three to five kilotons whilst the suitcase was only one kiloton.

The alleged claim that 48 out of 132 backpacks and suitcases are unaccounted for offers no clue either way, as it does not break down the numbers. But, if it is a 5-kiloton backpack that Bin Laden has then the parameters of my article need to be revised upwards by a factor of 1.7 for blast damage and 2.2 for temperature effect. In other words, the winds roar at 380 mph at one third of a mile instead of 1050 feet and metals melt up to 1470 feet instead of 670 feet.

One reader also raised the question of how viable these devices really are and how long a “shelf life” they have. That is an important question for if they do degrade without specialist maintenance and if it presumed that these devices came onto the black market in the mid-1990s then would they not have been used by now?

One article I read suggests that these devices required a constant voltage to stay alive and if the link was broken they would automatically disarm. On the other hand, how many disaffected Muslim nuclear physicists were tempted to join the Jihad against the West and offer their valuable services in maintaining these devices? The evidence is scant to say the least but it is alleged by the media that such scientists were consulted by Al Qaida.

That brings us to a more basic question of whether these devices should have been used by now if they were acquired years ago? That may well mean that Bin Laden has no fission device but I could also ask why the four-plane attack of September 11th was executed in 2001 rather than 1994? Are terrorists ultimately wary of doing such a thing and may actually be deterred by how they think America may react? Bin Laden reduced the World Trade Centre towers to rubble. America responded by reducing the Taliban to rubble and denting the Al Qaida network. Bin Laden may be bloodthirsty but he is not stupid.

Delivery

In another twist to rapidly moving news, the Cessna suicide crash a few days ago in Tampa shows that such a delivery method is feasible. Admittedly, a coastguard helicopter tracked the plane and fighter jets were scrambled but one can easily imagine the acquisition of a private plane being a much more silent operation to determined terrorists.

As to the height itself, another correspondence concerned the optimal height for an airburst and 1.8km was suggested as one such height. According to my tables, the maximal height depends on the PSI (pounds per square inch) effect the aggressor wants to maximise. For example, to maximise 30 PSI effects for a one megaton bomb (i.e. reinforced concrete structures collapse), the height should be 1 mile. If he wants to break as many windows as possible (1 PSI) then the height should be 3 miles.

What these are for a 1 kiloton bomb, I do not know and I suspect the terrorists will be mainly concerned with just being above the shielding effects of average city buildings.

Other readers suggested a plane is not necessary at all and a terrorist could just go to the top of a building and detonate. That is possible, so long as a nervous looking Arab with a funny looking backpack can get past security. I personally think terrorists would take minimal risks in displaying the device to the public but then again once they are near ground zero the bets are off.

Target and Environment

Two correspondents further informed me that the topology of Miami and Houston are as flat as pancakes plus Houston has plenty of flammable petrochemical plants. I commiserate with them but hope is offered in another reader who suggested that the political content of the target is the main priority to a terrorist and hence Washington D.C. was highest on the list. This has some merit since Bin Laden seemed to have gone to a lot of trouble to attack the highly symbolic WTC towers. Ultimately, we don’t know what the hit list priorities are.

Fireball

And, finally, one reader asked about blindness incurred by the flash and I must say that this is a major factor for anyone hoping to survive. His suggestion concerned commuters on the freeways looking steadfastly towards the city centre skyline at the moment of detonation. I readily concur that this could render many permanently blind or merely dazzled for a few minutes. The required radiation to inflict retinal burning is probably at a distance which offers low probability of survival anyway but dazzled victims are at a real disadvantage of escaping the up and coming blast wave if they cannot get out of their cars and find shelter. Unfortunately, the blast wave will only take seconds to reach everyone in the outer perimeters.

Conclusion

The statistics remain largely the same – a 1 in 7250 chance of suffering due to a nuclear terrorist attack. Most people would take a bet on surviving those odds. As I view the varying opinions, I still tend to the opinion that possession of a nuclear device by Bin Laden is closer to "not likely" than "possibly".

Once again, thank you to everyone for the interesting correspondence.

January 9, 2002