From: ems@michael.apple.com (E. Michael Smith)
Newsgroups: sci.energy
Subject: More on condoms (was Re: Nuke Stupidity Rebuttal)
Date: 29 Sep 92 04:59:09 GMT
Organization: Apple Computer Inc, Cupertino, CA

In article <1a4jo7INNf10@gap.caltech.edu> carl@SOL1.GPS.CALTECH.EDU writes:
>In article <1992Sep26.083414.8780@michael.apple.com>, ems@michael.apple.com (E. Michael Smith) writes:
>>In article <1992Sep23.195247.1075@nuchat.sccsi.com> kevin@nuchat.sccsi.com (Kevin Brown) writes:
>>>
>>>Since more average-case failures have occurred than worst-case failures,
>>>it seems ludicrous to suggest that a worst-case analysis is a better
>>>means of comparison than an average-case analysis.
>>>
>>>And so I reiterate my question: what is this obsession you have with
>>>worst-case failure modes?
>>
>>By this logic, since I've never died and I've lived a relatively 
>>long time already, and all the bad things I've ever experienced
>>were far less than 'worse case' (i.e. dying) I shouldn't worry
>>about the possibility that I might someday die, since it has never
>>happened in my history and must therefore be so remote as to be a
>>ludicrous thing to even consider...
>
>Bullshit.  You've presumably seen (or heard of) other people dying.

Oh, but the NUMBERS say otherwise!  I've seen a calculation that
showed that of all the people ever born, most of them are still
alive today!  My odds of dying are, thus, less than 50%, the 
calculations prove it!   To look at the SUBJECTIVE evidence that
other people died would not be OBJECTIVE, and thus ILLOGICAL.

(Do I need a smiley face?  This is a real calculation, BTW.  I don't
remember where I saw it, but it showed that STATISTICALLY most people
never die ... I think it was from my Stat class ...  The point?  That
blind following of a calculated risk without looking at the SUBJECTIVELY
observed reality is just as bogus as not examining the calclulated risk.)

Both of these metrics DO support the position that one should not
worry too much about the worst case scenario of dying, since it is
statistically unlikely.  Interestingly enough, most people do live
their life in exactly that way ... 

>>Ditto the case for condoms.  Since I've got a very low chance of getting
>>AIDS (or getting someone pregnant) why worry about it?  Ditch that 
>>condom today!
>
>Again, there are numerous examples of people getting AIDS or getting pregnant.

But that is a LOW PROBABILITY WORST CASE SCENARIO, and you thought 
people shouldn't pay so much attention to them!  The AVERAGE case is
MUCH more reasonable to use for planning behaviour, you told me so!

>>The 'average-case' failure of lack of a condom is that
>>you have a great time.  Once in a while you get some treatable disease.
>>Only very rairly would you get AIDS or have a pregnancy.  So what is
>>this obsession with the worst-case failure modes?
>
>Well, what if I were to tell you that there's some horrible disease, much worse
>than AIDS that you might get.  Of course, nobody's ever been known to have this
>disease, it's just that it's possible to imagine it, and the action of the
>disease is plausible.  Is the possibility of getting that imagined disease
>going to be a deterrent to you?

Well, given that this was EXACTLY the case pre aids (substitute syphylis
for AIDS in your paragraph...) then wearing a condom would have made alot
of sense in the '70s, pre-aids discovery ...  Oddly enough, I was in Jamaica
then and had the chance to 'get to know the natives'.  The insistance of
my buddy that I'd bring back more than I'd bargained for restrained me
and may likely have saved my life (given that 'ladies of the evening'
have high infection rates...).  So I guess my answer is 'yes' and 'it has
already, thank you'.

>>The fact is that we havn't had enough reactor-years of experience to 
>>have had the very low probability modes of failure manifest.
>
>Right.  Now, look closely at the circular argument you just made:  No matter
>HOW MANY reactor-years of experience we have, you can STILL make that claim.

BZZZT.  Wrong again.  There is nothing circular here at all.

I've stated that we need more reactor-years, but not infinite reactor
years.  I did not say 'infinitely low probability modes'.  There is 
some FINITE number of reactor-years that will with high probability
manifest the very low probability modes of failure that have been
identified and quantified by the extant risk analysis.   (I'm not one
of those who want a zero risk and want ALL modes of failure accounted
for with 100% assurance...)

If you want to say that an accident is not going to have bad 
consequences and the accident has a likelihood of 1 in 1000 reactor
years; it is fairly obvious to me that it is premature to claim at
400 reactor-years that the accident just can't happen.  I'd vote
for waiting until you have 2000+ reactor-years and have had one
of the accidents to see if you can, in fact, recover from it
with little damage.

If you have a 1 in 1000 reactor year probability that a Bad Thing will
happen, you damn well better have 2000+ reactor years under your belt 
befor you claim that the Bad Thing just Can't Happen in current designs.

(And even then I'd rather it be stated as 'Our calculations of 
risk were over pessimistic and the probability of occurance is 
likely lower than predicted.')

So I'm not a 'shut em all down' type.  I'm willing to let a 'reasonable
number' run and see how well they work.  I just don't see that 'reasonable
number' being orders of magnetude higher than what we have right now ...

Can someone with accurate numbers for # of operational sites and for 
calculated probabilities of worst case failures do the math to 
see how long it would take to have a worst case failure?

If it is a 1:100,000 reactor-years risk  and we have 1000 reactors, 
that is 100 years and argues for building more reactors (!) so that 
we can get a decent answer in our lifetime ... 

We already have the answer for graphite moderated reactors ... 

-- 

E. Michael Smith  ems@apple.COM

'Whatever you can do, or dream you can, begin it.  Boldness has
 genius, power and magic in it.'  -  Goethe

I am not responsible nor is anyone else.  Everything is disclaimed.