Submitted by PROS Member
Safety Control-Rod Ax-Man, not. The debunking text that follows is from an article by David Baurac in ``logos -- A magazine about research at Argonne National Laboratory'' (ANL). The article reports anecdotes told at the ``Symposium Celebrating the 100th Birthday of Enrico Fermi and His Contribution to the Development of Nuclear Power.'' (The SBF Glossary Content Advisory Commission has recommended not describing this symposium at all.)
All over the world, reactor control panels have emergency shutdown buttons labeled "SCRAM." One often-heard story holds that the term is an acronym for Safety Control Rod Ax Man, an homage to Norman Hilberry, Argonne's second director, who stood poised with an ax during the start-up of the first reactor, ready to cut a rope and release the control rods that would stop the reaction should all else fail. But during the break after the symposium's first panel, [Volny] Wilson laid this myth to rest.
He said that he and Wilcox Overbeck were working in the squash court [at the University of Chicago's Stagg Field] where the reactor was under construction while an electrician wired the control panels. The electrician finished wiring the red emergency-shutdown button, turned to them, and asked how he should label it.
According to Wilson, Overbeck responded by asking, "Well, what do you do when you push the button?"
And Wilson replied, "You scram out of here as fast as you can."
More about the construction of the Stagg Field pile at the CP-1 entry. See also the Martinmas entry.
This article found at http://en.wikipedia.org/wiki/Scram
Scram is usually cited as being an acronym for "safety control rod axe man", however the term is probably a backronym. The actual axe man at the first chain-reaction was Norman Hilberry. In a letter to Dr. Raymond Murray (January 21, 1981), Hilberry wrote:
When I showed up on the balcony on that December 2, 1942 afternoon, I was ushered to the balcony rail, handed a well sharpened fireman's ax and told that was it, "if the safety rods fail to operate, cut that manila rope." The safety rods, needless to say, worked, the rope was not cut... I don't believe I have ever felt quite as foolish as I did then. ...I did not get the SCRAM [Safety Control Rod Axe Man] story until many years after the fact. Then one day one of my fellows who had been on Zinn's construction crew called me Mr. Scram. I asked him, "How come?" And then the story.
Other sources state that the term may actually mean super-critical reactor axe man, referring in that case to a person who would use an axe to cut a rope to drop a control rod into a reactor to shut it down. This became another meaning of the word "SCRAM" after people working at the first nuclear reactor pile in Chicago, Illinois, known as CP-1, incorporated it into their emergency procedures. (An alternative derivation is that it stood for Simulated Chicago Reactor Axe Man and yet another that suggests that it was Start Cutting Right Away Man). Many attribute the usage to Enrico Fermi, who supposedly wrote the "axe man" phrase into the original reactor design. There were multiple safety systems in place at the Chicago pile, with some electrically-controlled control rods as well as vessels containing a cadmium solution available to stop any reactions if necessary. Therefore, the job of the "SCRAM" to drop another control rod by the force of gravity was most likely superfluous.
Other sources indicate that the term stands for safety cut rope axe man. Wallace Koehler, a technician working for Enrico Fermi and later a research physicist himself, is reported to have been atop the Manhattan Project pile when the term was coined The workers at CP-1 labeled an emergency shutdown button "SCRAM," since they would immediately be scramming (running) from the premises (or to their emergency positions) as soon the button was hit. (In modern nuclear power plants, the operators do not leave the control room in the event of a SCRAM or even a major accident.) Still other sources in the U.S. Navy reactor operator circles have defined SCRAM as "super critical reaction abatement mechanism".
Leona Marshall Libby, who was present that day, recalledthat the term was coined by Volney Wilson:
[T]he safety rods were coated with cadmium foil, and this metal absorbed so many neutrons that the chain reaction was stopped. Volney Wilson called these "scram" rods. He said that the pile had "scrammed," the rods had "scrammed" into the pile.
If you have any news you would like posted, please submit to: