by A swedish kind of death
Mon Sep 11th, 2006 at 07:30:26 PM EST
This summer - the 25th of July - there was an incident at the nuclear plant Forsmark in Sweden. Now the analysis performed by SKI - the swedish governmental agency in charge of nuclear safety - is nearly completed.
I just read an article on the incident by an journalist that has read the nuclear plants report with aid from the investigators. If you can read Swedish I suggest you read it yourself (open the flash graphics on the right), but for you who do not, here is a summary:
The original problem was a shortcircuit in switchgear (the article does not mention this, but I have heard that it was a bird that caused the shortcircuit). The problem transplanted itself in 37 seconds through a number of safety layers and left the reactor without electricity to monitoring equipment, waterpumps (to the keep the core with water). However (and it is unclear why) all power was not lost. After 22 minutes the staff manages to get the reactor power from the grid and power and control is restored. In the meantime half the water above the reactor has been lost.
All reactors of the same type has since been down awaiting this report.
From the step by step analysis in the article and its list of 9 faults, I find one thing that was broken: an oilpump. There is also one faulty installation and one possibly broken gasturbine. Other then that there are the original shortcircuit and then a series of no less then five consecutive faults that are all more or less the consequences of the original problem.
It is as of now unclear why not all power was lost, and as far as the analysis goes it could just as well have been lost. If all power had been lost, the finnish version of SKI claims that there would have been of nuclear meltdown within two hours, while the nuclear plant maintains that they would still have been able to control the blackout and get power from the general grid.
So, now you know. (For the record, the paper in question - Dagens Nyheter - is pro-nuclear in their political leanings.)