[LINK] Is it just me, or is this daft?

[Roger Clarke]

Pardon me if this has already been discussed and I missed it.

There's an important design principle that's all too frequently overlooked.

The principle seems to have been overlooked in the case of the 
Japanese nuclear power plant, and that seems to have at least 
exacerbated the problem, possibly in two separate ways.


Maybe the logic went like this:

We're a power plant, right?  Power is what we produce.

We won't be short of power here.  So we can design our monitoring 
systems, and our control systems, and our fallback systems, on the 
assumption that we have power.

And it doesn't matter if those systems are power-hungry, because, 
well, we're a power plant.

And hence:
-   the towers can be tall
-   we can put the entry-points for the coolant high up the towers
-   we can store the spent rods up on top of that


And then maybe what happened was:

-   2 of the 6 reactors were closed down at the time.
     Nothing unusual about that.

-   a 9.0 earthquake happened close by.
     Not a big problem.  We designed for that, and it worked okay.
     We may be down briefly, but we have systems and procedures.

-   a several-metre tsunami ran through the power plant.
     A bit more of a problem that, but nothing too grave.
     We may be down for a while but we have systems and procedures.

-   the tsunami also ran through the local area.
     So?

     Oh, *those* power poles?!
     But we're a power plant, so we'll be okay.

     Oh, you mean we can't generate power while we're running the
     systems and procedures that we need to in order to recover from
     the effects of the earthquake and the tsunami?
     Ah, but we have diesel generators, so we'll be okay.

     Oh, you mean they only generate enough to keep the lights on,
     the door-controls operational, and the control-boards working.
     Well, bring in some more generators.

     Oh, so the power needed to push water up the towers in the volume
     that we need to cool the rods is more than diesel generators can
     deliver?

     Ah, so.


-- 
Roger Clarke                                 http://www.rogerclarke.com/

Xamax Consultancy Pty Ltd      78 Sidaway St, Chapman ACT 2611 AUSTRALIA
                    Tel: +61 2 6288 1472, and 6288 6916
mailto:Roger.Clarke at xamax.com.au                http://www.xamax.com.au/

Visiting Professor in the Cyberspace Law & Policy Centre      Uni of NSW
Visiting Professor in Computer Science    Australian National University