Mile Island: The Inside Story
Five days of crisis
4.1. Looking east from Goldsboro, on the far
side of the Susquehanna River from Three Mile
Wednesday, March 28
Although a general emergency has been declared before breakfast,
it will be days before any general emergency is felt. By evening
the condition of the reactor seems to be improving and radiation
levels in the TMI-2 buildings seem to be falling. Now begins the
oddly long, slow process of accepting that major damage to the reactor’s
core has in fact occurred in the early morning hours.
Thursday, March 29
A day of relative calm—until evening, by which time nuclear
engineers and public health officials are beginning to confront
the fact of major damage to the reactor. And major damage implies
the possibility of large quantities of radioactivity escaping from
Friday, March 30
Nuclear Regulatory Commission (NRC) officials in Washington, after
48 hours of underestimating the seriousness of the accident, now
overestimate the danger. Unsubstantiated reports of dangerous releases
of radioactivity lead Pennsylvania Governor Richard Thornburgh,
on the NRC’s advice, to recommended that pregnant women and
young children leave the area.
Late that night Food and Drug Administration officials rouse chemical
manufacturers from bed with urgent requests for a quarter-million
bottles of potassium iodide solution. A few drops of this taken
in time will block the uptake in the thyroid gland of cancer-causing
radioactive iodine, perhaps the most immediately dangerous of the
radioactive substances to which reactor fuel is converted by nuclear
4.2. Two-ounce (50 ml) bottle
of potassium iodide solution prepared and labeled
in haste for shipment to Harrisburg, PA.
There are, in fact, no releases of radioactivity that constitute
a danger to public health. Alarm about reported releases of radioactive
gases soon after the accident arose from misunderstandings. And
later concern about the possibility of dangerous releases arose
from a mistaken conclusion that hydrogen gas accumulated in the
reactor vessel could explode.
Saturday, March 31
It is accepted that early on Wednesday morning much of the reactor’s
core had stood above the water level. Consequently, it was certain
that the zirconium tubes forming the cladding around the intensely
hot fuel pellets would react chemically with the hot steam, pulling
the oxygen out of H2O molecules and releasing hydrogen. This scenario
is supported by the fact, not at first explicable, that at midday
on Wednesday there had been a sudden rise in the pressure in the
containment building of almost two atmospheres. Almost certainly,
this resulted from the rapid burning of hydrogen that had escaped
through the PORV from the reactor vessel and cooling system into
the reactor containment building. Moreover it is known that some
oxygen (and some more hydrogen) is continually being produced in
the once-again-water-covered reactor core by the action of radiation
on water molecules, breaking them apart into hydrogen and oxygen.
Is there then, or will there soon be, enough oxygen inside the reactor
vessel and cooling system for the large amount of hydrogen it holds
to burn explosively? Again NRC officials—albeit supported
by the opinions and calculations of many experts—unnecessarily
heighten fears by telling reporters that an evacuation out to 10
or 20 miles (15 to 30 km) might become necessary.
4.3. President Jimmy Carter and Mrs. Carter
in the control room of the TMI-2 reactor.
Sunday, April 1
Assured that any explosion is at least a couple days away, President
and Mrs. Jimmy Carter tour the TMI facility early in the afternoon.
In the hours following their visit, the expert consensus swings
around to the opposite view—that a hydrogen explosion is simply
not possible. The crisis is over—although no one says that
loud and clear.