There’s a management phenomenon, which is magnified by politics: if some unusual circumstance occurs, doing nothing is usually deemed worse than doing the wrong thing. There’s usually no easy way to quantify the nothing that you did, even if you actually investigated carefully. There’s the though that “we have to do something!” and even if the action is inappropriate or ineffective, management can point to it and say, “See! We did something about it.” (I think our current terrorism responses too often fall into this category.)
I was reminded of that lesson when I read this story: Tainted nuke plant water reaches major NJ aquifer
The tritium leaked from underground pipes at the plant on April 9, 2009, and has been slowly spreading underground at 1 to 3 feet a day. At the current rate, it would be 14 or 15 years before the tainted water reaches the nearest private or commercial drinking water wells about two miles away.
But the mere fact that the radioactive water – at concentrations 50 times higher than those allowed by law – has reached southern New Jersey’s main source of drinking water calls for urgent action, Martin said.
Now, it’s possible that what is being reported isn’t the whole story, and there is legitimate cause for concern. But based on what was in the story, I think the call for urgent action is based on the sphincter-clenching response the general public has to the word “radiation.” Let’s look at the details.
— The half-life of Tritium is 12.33 years. Which means that less than half will be left when it reaches the drinking water. 50x becomes <25x
— If the diffusion is isotropic, and only in the radial direction, the Tritium will be diluted by another factor of 14 or 15. 25x becomes less than 2x.
— Diffusion rates depend on the gradient of the concentration. As the Tritium becomes diluted, the diffusion should slow down. It's not clear that the estimates take this into account. The story gives the current rate as 1-3 feet per day. 2 feet per day is 2 miles in 15 years.
— Tritium is delicious and wholesome
So, based on the information given, it's possible the tritium concentration will be at or below the legal limit by the time it enters the drinking water (which could dilute it even more). The person calling for urgent action works for New Jersey's environmental protection department, so one would hope that the science was considered. But I suspect that "urgent action is required" is the response because trying to assuage peoples' fears would be viewed as a smokescreen, and simply levying a fine (which I'm all for — the power plant should not be let off the hook) might be taken as the company buying their way out of the problem.
While I agree with your comment about it taking 15 years (as well as the knee-jerk reaction to the word ‘radioactive’), I think that they should at least be monitoring things to make sure it isn’t an issue. The real problem is that if it does reach the wells in a fairly high concentration, it will be too late to fix the issue. These systems are slow, and any solution will probably be slow, as well. The other problem is that most groundwater doesn’t usually behave in an isotropic fashion, so chances are that the concentration will be higher than your calculations imply.
I agree that the situation should be monitored, and further, make the nuke plant pay for it.