A leak had caused two pumps feeding crucial cooling water to the reactor at Three Mile Island to grind to a halt. An emergency pump engaged automatically, but its pressure valve was closed for maintenance. A relief valve was on hand, but that too failed.
The incident perfectly illustrates the dangers of nuclear power, and as Richard Bookstaber writes in A Demon of Our Own Design (Wiley 2007), it bears an uncanny resemblance to our banking system. First, nuclear reactors are highly complex systems, creating a high probability that any one element may fail. Second, they are 'tightly coupled', so if one thing goes wrong it can set off a chain reaction. The sub-prime market is similarly complex, and close-coupled to the wider economy: a toxic combination.
Note the importance of the control room. On the night of the accident, more than 750 alarm lights colour-coded to rival the Blackpool illuminations flashed at the controllers, rendering them helpless in identifying the source of the problem. In the run-up to our present economic woes, Bear Stearns had no shortage of data, but this did little to paint a clear picture of the perils ahead. Brussels' answer is an EU-wide super-regulator (no surprises there). But if greater scrutiny just adds more dials to the control room, it risks loading in further complexity, aggravating the very problem it seeks to resolve.
There is, though, a key difference. Three Mile Island's potential devastation was, ultimately, successfully contained within a concrete safety vessel, and no-one was harmed. The full fallout from sub-prime, however, may be yet to come.