Scram Switch
catb.org
catb.org
> “Scram” was in origin a backronym for “Safety Cut Rope Axe Man” coined by Enrico Fermi himself.
The acronym/story we were told regarding SCRAM was “Super Critical Reactor Axe Man”; as in the guy who would cut the rope to drop the control devices into the fission pile if they detected its reactivity going TOO super critical.
Interestingly this usage doesn’t seem well known outside of those circles. It is/was, however, directly printed in rather old publications I used (60s perhaps?).
Was there really a rope, and you really cut it with an axe?
What did this do to the life expectancy of the ax operator?
Does any of this have anything to do with your HN username? If there's a story, would you tell?
There was a backup to the backup: people with a solution of something (borate?) to pour into the pile to soak up surplus neutrons. This was a really bad thing to do, for the future use of the pile: the carbon would be soaked, useless, the reactivity of the pile would be next to impossible to get back without completely re-constructing it so the Scram by lowering rods, was the preference, and was done by a counter for accellerated scaling aside from the guy with the axe after a while.
For my username: I actually started using this name before I was involved in nuclear power, and that’s the first time that’s been asked!
https://patents.google.com/patent/US3721462A/en https://patents.google.com/patent/US8811561B2/en
Another ex-Navy nuke here. When I went through nuclear power school (the West Coast one at Mare Island) in the 1970s, the version we heard was "Safety Control Rod Axe Man."
(I tried telling ESR about this several years ago, but the email bounced.)
In a computer system, you ought to be able to test systems to make sure they behave correctly under the consequences of a switch press. You could also test them—there may be times when it is ok to press the switch, or where you have redundancy such that two switches must be pressed but you only press one to test.
But I think another alternative is to not have the mechanism used extremely rarely. I think it can be good to accept cases where things go wrong a bit from time to time so that people have practice dealing with them as the alternative is to only have things go wrong under some enormous catastrophe when no one will have any idea what to do.
SCRAM drills are held regularly, but under no circumstances is any intentional level of risk in critical safety systems accepted on the plants I worked on.
So an electrician was sent to throw some switches elsewhere in the building.
I never got a clear explanation of what went wrong, only that it had been "fixed" and would work if needed in the future.
It’s stupid and I’m calling attention to it by this, and Wikipedia uses those words, but we sign NDAs and it’s the Government. No one ever claimed it all makes sense.
I’m in no way judging the other commenter. I think that particular restriction is stupid since the information is in the public domain. However it IS still a binding legal restriction. My comment was as much about the stupidity as about any possible breach.
'cause you came across as an asshole. It doesn't bother me that much. Nuclear safety relies on ~~assholes~~ attention to detail to work, to be honest.
> but no comments
Its not exactly a jumping off point for discussion, is it? I've been out for 15 years and still regularly fail to recognize when I'm being a dick. Look back at what you wrote and think about for a minute.
I appreciate the call out. We can always learn and grow!
Then it's as mechanically as simple as possible
Basically it was how they shut-down nuclear reactors by cutting a rope that would drop the controls rods into the reactor.
Side-note: I know this because I played an Atari 800 game called SCRAM growing up. It was pretty good!
Also reminds me of SNAFU - Situation Normal All Fucked Up.
https://public-blog.nrc-gateway.gov/2016/02/18/refresh-putti...