Wednesday, March 16, 2011

Denying the Inevitable

The nuclear calamity in Japan has already got many people re-thinking the inherent risks associated with nuclear energy, a form a energy that until last week was enjoying a bit of a renaissance. Suddenly we're seeing nuclear energy through a new lens. Sure, this is an extraordinary set of circumstances, with a 9.0 earthquake and a 30-foot tsunami—conditions which might not happen again in the next century. But what this event makes plainly clear is how fragile nuclear power plants are, and how they operatate on the principle of denied inevitability. That is, everything that goes on at a nuclear power plant is essentially postponing the inevitable. It is not a truly fail-safe system.

To illustrate my point, I'd like to mention another piece of modern technology that exemplifies denied inevitability: the Segway. When the self-balancing Segway hit the market, I thought it was a wonderful blend of mechanics and computer technology. My 75-year-old mother was one of the first to own one. I spent a fair amount of time riding the Segway, and I became quite proficient at it. The Segway's self-balancing technology is quite extraordinary. It just takes a while to completely trust it. I was a major proponent of this two-wheeled marvel right up until it sent me to the Emergency Room. That's when I realized that there is a fundamental flaw in the engineering concept behind the Segway.

Here's the problem: The Segway is, technically, always about to fall over. Its balancing ability is entirely dependent on its internal computer, sensors and motors—unlike a bicycle which relies mostly on physics for balance. When you ride a Segway there is no room for machine error; everything must be working perfectly. To account for this, the Segway has a backup computer and its motors have dual windings. If it senses a problem, the Segway instantly switches to its backup system. But if the problem is a software glitch, you might be going down, as I did. When you ride a Segway, you are constantly denying the inevitable.

At Japan's Fukushima Daiichi nuclear plant the inevitable is a meltdown. Without a functional cooling system, a meltdown is the default mode for any nuclear power plant. Even the spent nuclear fuel stored deep in holding pools must be cooled continuously or the water in the pool will boil and evaporate, allowing the nuclear fuel to catch fire. Nuclear plants are designed with multiple cooling systems to reduce these risks, but the risk level never goes to zero; we are always pushing back against the inevitable.

It's high time that we reviewed our nuclear power plant design philosophy and begin building plants that are truly fail-safe. When dealing with nuclear materials, there is no room for denial.