By Donella Meadows
–December 3, 1987–
Hearings on one of the most elaborate, comprehensive, and expensive evacuation plans ever made for a nuclear power plant — the Seabrook plant — are just being completed by the Atomic Safety and Licensing Board in Concord N.H..
Dozens of experts have been consulted. They have taken aerial photos of Hampton Beach and counted the tens of thousands of cars. They have mapped every traffic intersection, listed every hospital and nursing home, figured how many minutes it takes to load a disabled person onto a bus. They have thought about snowplows in winter and cars overheating in summer. They’ve even calculated “gapers’ block” — the slow-down from drivers taking a good look as they pass the site of an accident.
The result, the State of New Hampshire Radiological Emergency Response Plan for the Seabrook nuclear power plant, fills 38 thick loose-leaf binders.
The plan has been subjected to unusual scrutiny. Like every nuclear evacuation plan it not only spells out what to do in an emergency, it is also one of the last steps in getting a license to operate the plant. Predictably, the utilities and the Nuclear Regulatory Commission are more interested in licensing than in evacuation, not only for crass financial reasons, but also because they don’t really believe an accident is likely. But the nearby New Hampshire communities and the state of Massachusetts, with six towns in the evacuation zone, take the possibility of evacuation most seriously. They have gone over every detail, argued every number, corrected many mistakes, and brought a much greater sense of reality to the plan.
Still, after thousands of hours of effort and days of tedious argument, what the plan primarily shows is how little anyone knows about moving hundreds of thousands of people to safety within a few hours at short notice under what could be frightful conditions.
An evacuation isn’t as simple as turning all roads into one-way streets leading AWAY. Emergency vehicles have to come in while residents are going out. Commuters are expected to drive home and pick up their families, parents to pick up children at school. Tow trucks will cruise around to refuel cars that run out of gas and move cars that break down. Buses have to pick up people who can’t drive. There must be decontamination centers so cars and people don’t carry radioactive materials into safe areas.
The heart of the plan is a computer model called I-DYNEV, developed by KLD Associates of Huntington Station, Long Island. Thousands of critical facts are entered into the model — the population distribution, road network, plant location, capacities of on-ramps. A lot of assumptions have to be entered too — how many people can be mobilized how soon to direct traffic, how likely is an accident at a critical intersection. The program takes in all the facts and guesses, simulates an evacuation, and tells you how long it would take before the last person leaves the danger zone.
For the first time in any evacuation hearing, plant opponents as well as advocates have had access to I-DYNEV and have been able to put their own numbers into the model. The range of numbers generated by the two sides gives a revealing estimate of the amount of uncertainty hidden under the impressive detail of the evacuation plan.
There’s uncertainty, for instance, about how many cars are likely to be at the beach on a hot July weekend. (New Hampshire says 29,293, Massachusetts says 38,825. These numbers are expressed to the last blessed car, though they’re 9,500 cars apart). This one disagreement makes the estimated evacuation time vary from 6 hours to 13 hours, a vital difference if those hours are spent exposed to radiation. It’s also a vital difference when it comes to the greatest uncertainty of all — how people will really behave in an evacuation.
Would bus drivers be willing to go back again and again into a contaminated area to fetch the elderly and disabled? Would teachers stay at their posts or rush off to their own families? How many hours would you spend stuck in a traffic jam on Route 51, with a crippled nuclear plant in plain sight, before you abandoned your car and started walking? If you were told to turn north to a decontamination station, but home is south in Boston, what would you do?
I-DYNEV assumes that everyone will be helpful, patient, and obedient for 6 or 13 or however many hours. If people start acting wildly, the evacuation time could increase greatly. And in spite of all the computing, the expert testimony, the cross examination, no one will ever know how people will act, unless an accident really happens.
On the basis of this evacuation plan, decisions will be made that could impact hundreds of thousands of lives. How much of an emergency should trigger a signal for evacuation? Should shelters be built so the beach population doesn’t have to be evacuated? Should major road upgrades be required? Should the plant be allowed to operate at all?
It’s one thing to make those decisions under smug certainty — the computer model says that under the worst possible conditions everyone within a 10-mile radius can be evacuated within 6 hours. It’s anothing thing to admit that even after the best effort that the scientists and computers can muster, we simply don’t know how long an evacuation would take.
Copyright Sustainability Institute 1987