Wednesday, February 15, 2012

On the Brink of Yellow Journalism

The US has approved the production of its first civilian nuclear reactor in thirty years. This despite sensationalistic reports about the dangers of a Russian ballistic missile sub that caught fire in late December. I'm not surprised the Russian government lied about this for two reasons 1) It's the Russian government. 2) The danger is overstated.

If the fire had spread from the outside of the hull to the interior--a dangerous turn which could have been prevented/addressed by sinking the boat--it might have reached either the nuclear missiles or the nuclear reactor. Because the reporters involved don't know any more about nuclear power than that it's scary, they're saying Russia was on "the brink of a nuclear disaster." Having only been taught about US Navy nuclear reactors, I can't say definitively that it wasn't, but I feel more qualified than the political and cultural writer who penned it, even if his Facebook pic is a thousand times cooler than mine.

The Nuclear Missiles
If the fire were to have reached the nuclear missiles, they wouldn't have detonated. Nuclear detonations require a series of very specific events to happen for a nuclear blast to occur and they are designed to fail, break, and decay in such away that those events are less likely to happen. The only real nuclear threat would have been the fissile material in the warheads themselves. For that to become an issue, the fire would have had to progress unchecked inside the sub for hours. Then, the fires would have had to have become hot enough to burn through the casing and into the warheads, 'boiling' the radioactive material into the air.

I don't know how much fissile material is in nuclear warheads. If I had to guess, I'd say 5 to 15 kg (which is the range of small dumbbells to checked baggage [1]). I don't know what they keep in warheads, but I'm pretty sure it's plutonium. Again, not an expert on Russian subs but one or two dozen missiles wouldn't be a bad guess and if I had to estimate how many separate warheads per missile, I'd say six. [Okay, after reading some of the articles from December, it looks like those numbers are 16 and 4, respectively.]

So, given a fire that burns unabated through the boat for hours, makes its way into the area where they keep the sub-launched ballistic missiles (which would be anywhere amidships, really), and burns through a casing designed to protect the warheads through a flight that starts underwater, features a sub-orbital apogee, and is subject to, let's call it well motivated, ground resistance on final approach and then burns anywhere from 320 to 960 kilograms of highly active material into the atmosphere.

Given what little I can remember of a lot of this, I've worked up the following chart to illustrate the exposure rates at various distances and the amount of time you can hang out at that distance before approaching some generous (un)safety limits. Note that these times don't delineate between the time when you stop giving birth to normal babies and start creating fin-headed cyclo-babies; it's an arbitrary point on a continuum which is just beyond fin-headed cyclo-babies and on the path to birthing live uterine cancers. You get exposed to radiation every day, which is why we have fin-headed cyclo-babies and Newt Gingriches in the first place. Because of the incremental nature of radiation, there's are no points of exposure where things are suddenly bad.

Distance Low Estimate (mRem/hr) Time High Estimate (mRem/hr) Time
100 m 1537 8 min 4613 3 min
500 m 61.5 3 hrs 185 1 hr
1  km 15.4 13 hrs 46 4 hrs
10 km 0.15 8 weeks 0.46 2.5 weeks

Since, if I'm not mistaken, most plutonium isotopes have a half life of a few thousand years, the radioactive particles will fall into the earth/groundwater/etc long before they quit emitting. I don't know what they emit. If they emit gammas (which is light, but can kill/cancer you), then they'll punch right through all kinds of things and will only do damage in mass quantities over time. If they emit alpha particles (which are hydrogen atoms without any electrons), then they will do massive damage if they can get past a local person's skin by being in their food/water/etc..

"But Kris," you might say, "Didn't you say that calling this fire an 'the brink of a nuclear disaster' wasn't accurate? That sounds a lot like a nuclear disaster" Yes I did, but before I address that, there's that second scenario I'd like to outline:

The Nuclear Reactor
Just like in the missiles scenario, the fire has to burn through the ship, but this time it burns past the missiles and towards the engine room on the aft end. It then cuts through the engine room unchallenged by either automatic fire suppression systems or firefighting measures taken by any crewmen on board (the reports are unclear on the crew on board at the time. It's safe to assume, "enough to submerge it" were on hand). There, it causes either a fantastic problem or a somewhat simpler one. The first is that despite all of the physical, kinetic, and thermal isolation of the nuclear core, the fire heats up the nuclear reactor core. Yes, the one that makes heat. It's technically possible for reactor cores to get too hot and it's quite normal for temperature transients to negatively affect core dynamics, though rarely beyond the ability of a trained operator to deal with and the ability for a simple fire to burn that hot is far from likely.

It would be fantastic to think of a crew so incompetent and a fire so voraciously strong and hot that the could burrow unchallenged through a submarine, through a sealed chamber, through reactor shielding designed to act as a thermal barrier while the crew does nothing. In fact, the crew shouldn't have to to anything; there should be a fail-safe activation of...well deactivation of the systems which keep the control rods from self-inserting into the core, soaking up all of the radiation, and turning the entire apparatus into a harmless rice cooker filled with exotic elements [2].

Maybe, if the fire is even more fantastically hot--and I'm talking on a scale where, if the first fantastic fire was trying to take out a life insurance policy on your imaginary friends, this one is actually having that policy approved--then it could melt the core elements and result in the dispersion of radioactive elements throughout the propulsion and power plant on the ship with incidental leakage. Not a disaster.

Most improbably--which forces me to extend the metaphor to collecting on the life insurance policy for The Imaginary Mr. Wigglestein or whatever--is if the fire itself can burn a hole in the bottom of the sub and drop the core into the dock which would make most of the harbor radioactive and probably have an adverse effect on the local water table, which, after you move some of the locals and begin periodically testing the water supply for activity, is probably the only nuclear accident you could legitimately shrug and say "oops" to.

The less fantastic thing is the same, but it involves operating the core in the middle of a fire with a sudden loss of fresh saltwater to cool it and only goes up that second tier of improbability, which sucks because I had a nice version of the graph where the fissile products of the reactor core are released and every data entry is just the word "Dead." Sadly, I just don't think that's possible. Unless... 

A Regular Torpedo Explodes, Resulting in Accidentally the Whole Nuclear
Oh yeah, some of the articles mentioned this as a possibility. This is like all of the other scenarios, but all of the nuclear material isn't burned off or melted; it's just hanging out. Maybe in a few pieces. Trapped in or around the wreckage of a blasted sub under a few tenth-thicknesses of water. Some radioactive material might be broken up and blown into the air, but I wouldn't think much. I admit that everything I know about conventional submarine torpedoes I learned from The Hunt for Red October and pro topics at The Academy and I'm pretty sure that Alec Baldwin, Tom Clancy, and Sean Connery were probably the more educational source.

But we're still backing up to mention the deadliness of cooking off the fissile material of sixteen nuclear warheads and how that qualifies as a nuclear disaster.

It does. Having to evacuate 300,000+ people from a 10km area around the largest city in the arctic circle would be a disaster. A nuclear disaster. But it's one who's physical improbability is comfortably high. It's not that there was no danger, it's that the people who are informing the public about this danger weren't doing the same analysis I was. I offer my rendering of their likely thought process: 

I know that people will read articles that scare them. I get it. But nuclear power is an amazing technology that is incredibly important for the world as it goes forward. It has a number of drawbacks and I'd never want it to become a primary source of power for the United States or the world at large. It is dangerous. I'd go so far as to say that of all the technologies we've developed to date, it is the most powerful and the one most demanding of the utmost levels of responsibility.

But just as we criticize The Russian government for lying about this, exaggerating the threat of these things is the exact same brand of self-serving distortion. For a long time, the debate about nuclear power has been an emotional one, when it comes to our future, especially our energy future, we have to be objective and well-informed. Iran proves that we live in a nuclear world. And the difference between living in that world safely depends on whether we treat nuclear power with fear or with respect. And the difference between those two is education. Sensationalistic journalism does nothing to help.

[1] *Sigh* ...10 to 30 lbs.
[2] Do not eat the rice from this rice cooker.

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