Editing Scram (section)

==Etymology==
[[File:Szilard and Hilberry.jpg|right|thumb|upright|[[Norman Hilberry]] (left) and [[Leó Szilárd]] at Stagg Field, site of the first self-sustaining nuclear chain-reaction]]

There is no definitive origin for the term. United States [[Nuclear Regulatory Commission]] historian Tom Wellock notes that ''[[wikt:scram#Verb|scram]]'' is English-language slang for leaving quickly and urgently (as in scrambling to get away), and he cites this as the original and most likely accurate basis for the use of ''scram'' in the technical context.<ref name="nrc-gateway.gov">{{cite web |last=Wellock |first=Tom |date=17 May 2011 |title=Putting the Axe to the 'Scram' Myth |url=https://public-blog.nrc-gateway.gov/2011/05/17/putting-the-axe-to-the-scram-myth/ |access-date=26 May 2015 |publisher=[[United States Nuclear Regulatory Commission]]}}</ref>

Scram is sometimes cited as being an acronym for '''safety control rod axe man''' or '''safety cut rope axe man'''. This was supposedly coined by [[Enrico Fermi]] when he oversaw the construction of the [[Chicago Pile-1|world's first nuclear reactor]]. The [[Nuclear reactor core|core]], which was built under the spectator seating at the University of Chicago's [[Stagg Field]], had an actual [[control rod]] tied to a rope with a man with an axe standing next to it; cutting the rope would mean the rods would fall by gravity into the reactor core, shutting the reactor down.<ref name="ornl.gov">{{cite journal |last=Blackburn |first=Edwin |date=September 2000 |title="Scram!" - Reactor veteran recalls account of the birth of a key word in the nuclear vernacular |url=https://web.ornl.gov/info/reporter/no19/scram.htm |journal=ORNL Reporter |publisher=[[Oak Ridge National Laboratory]] |volume=19 |access-date=25 October 2014}}</ref> The axe man at the first [[chain reaction]] was [[Norman Hilberry]]. In a letter to Raymond Murray (January 21, 1981), Hilberry wrote:

<blockquote>When I showed up on the balcony on that [[timeline of the Manhattan Project#1942|December 2, 1942]] afternoon, I was ushered to the balcony rail, handed a well sharpened fireman's axe and told, "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 [[Walter Zinn|Zinn's]] construction crew called me Mr. Scram. I asked him, "How come?" And then the story.</blockquote>

[[Leona Marshall Libby]], who was present that day at the Chicago Pile, recalled<ref name="libby">''The Uranium People'', Crane, Rusak & Co., 1979</ref> that the term was coined by [[Volney Wilson]] who led the team that designed the control rod circuitry:

<blockquote>The 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.</blockquote>

[[File:Control Rod Circuitry for the Chicago Pile, The World's First Nuclear Reactor.png|right|thumb|Control rod and SCRAM circuitry for the Chicago Pile-1]] Other witnesses that day agreed with Libby's crediting "scram" to Wilson. Wellock wrote that Warren Nyer, a student who worked on assembling the pile, also attributed the word to Wilson: "The word arose in a discussion Dr. Wilson, who was head of the instrumentation and controls group, was having with several members of his group," Nyer wrote. "The group had decided to have a big button to push to drive in both the control rods and the safety rod. What to label it? 'What do we do after we punch the button?,' someone asked. 'Scram out of here!,' Wilson said. Bill Overbeck, another member of that group said, 'OK I'll label it SCRAM.{{' "}}<ref>Tom Wellock, [https://public-blog.nrc-gateway.gov/2016/02/18/refresh-putting-the-axe-to-the-scram-myth/#comments "Putting the Axe to the Scram Myth"], U.S. Nuclear Regulatory Commission Blog, February 18, 2016. {{PD-notice}}</ref>

The earliest references to "scram" among the Chicago Pile team were also associated with Wilson's shutdown circuitry and not Hilberry. In a 1952 [[United States Atomic Energy Commission|U.S. Atomic Energy Commission]] (AEC) report by Fermi, the AEC declassified information on the Chicago Pile. The report includes a section written by Wilson's team shortly after the Chicago Pile achieved a self-sustaining chain reaction on December 2, 1942. It includes a wiring schematic of the rod control circuitry with a clearly labeled "SCRAM" line (see image on the right and pages 37 and 48).<ref>E. Fermi, ''Experimental Production of a Divergent Chain Reaction, AECD-3269'' (Oak Ridge, TN: U.S. Atomic Energy Commission, January 4, 1952), https://www.osti.gov/biblio/4414200</ref>

The Russian name, AZ-5 ({{lang|ru|АЗ-5}}, in [[Cyrillic script|Cyrillic]]), is an abbreviation for {{lang|ru|аварийная защита 5-й категории}} ({{lang|ru-Latn|avariynaya zashhchita 5-y kategorii}}), which translates to "emergency protection of the 5th category" in English.<ref>{{cite web |title=Глава 6. О нажатии АЗ-5 |trans-title=Chapter 6. About pressing AZ-5 |url=https://zaotvet.info/library/glava_6_o_nazhatii_az_5 |work=Za otvyetstvennuyu vlast'! |script-work=ru:За ответственную власть!}}</ref>