Why Truman Dropped the Bomb

[Shapley]

Big Jon,

That's the answer, according to legend. There is another theory that disputes that, in which an electrician claims that, after he installed the button to drop the rods, he asked what label to put on it. The asked him what you would do when you pushed the button, and he said he would scram, so he labeled it thusly.

I find that one hard to believe, and Dr. Hilberry was up on the walkway with an axe, although he says he never heard the term SCRAM until years later.

V/R
Shapley

[dai bread]

I'm inclined to agree with the electrician. I'd certainly scram from a pile that had to be shut down in a hurry.

[OperaTenor]

Hi Shap,

Awfully interesting my Dr. Koehler isn't on that list. Dr. Hilberry is looking more credible all the time. Besdies, in nuc scholl they said it stood for "Safety Control Rod Axe Man" instead of Dr. Koehler's "Safety Cut Rope Axe Man".

So there you have it. Enrico Fermi and his assistants, under the bleachers at the squash courts, with a guy(most likely Dr. Hilberry) holding an axe to cut the rope attached to the control rod in case the fission started to go out of control.

Delicate scientific instrument, that axe.

[OperaTenor]

Additionally, it would appear both Hilberry and Wallace Koehler worked on the Manhattan Project. Internet references on Koehler, however, are scarce.

[juan j]

Hello All,

Thank you for your kind welcome.

SCRAM indeed stands for Safety Control Rod Axe Man. Its origins appear to be in the Chicago reactor built by Fermi et al. and started up in 1942. The control rods had to be lowered manually, and an operator with an ax was nearby in case the "system" failed. It is considered a sort of "archaism" in nuclear jargon.

In those pioneering days Wigner discovered that the neutron flux made the graphite in the rods to emit hidrogen and swell. Therefore the rod diameter increased and it was necessary to replace them periodically. This phenomenom was later known as "Wigner's disease."

Interestingly, nuclear reactors also need coolant to remove the heat generated by fission. The control rods moderate the neutron flux but the heat continues to build up. And since the fissile material is shaped to optimize heat transfer the consequences can be catastrophic, as the core heats up, melts its way outside the reactor vessel and ignite the hydrogen, another fission by-product, as well as any surrounding materials.

It is not only the axe man and its automated successors but also the cooling system that make a reactor safe.

[Shapley]

OT,

I'm inclined to believe that Koehler was a graduate assistant or some such. I did find reference to him being there, but he's not listed as a scientist on the project (neither is Hilberry, but he is listed as being present in several references).

Safety Control Rod Axe Man is the term I'm familiar with. I discount the electricians claim because of the statement made by Hilberry, that he felt foolish standing up there, because they all had confidence in the science involved, and no one seemed to be afraid at the time.

V/R
Shapley

[rwcrooks]

Detailed discussion on the origin of SCRAM in the nuclear reactor world can be found in an article in Nuclear News (journal of the American Nuclear Society), August 1988. Entitled "The Etymology of "SCRAM," the author is Raymond L. Murray, professor emeritus of nuclear engineering at North Carolina State U.

http://www.vanderbilt.edu/radsafe/9710/msg00067.html


By the way, whenever you want to find the origin of a word, do a google search with the word in question followed by etymology.

[rwcrooks]

Of course, if anyone has a subscription to the OED, that would be the definitive answer. Anyone out there have an OED subscription, or the OED on CD?

[piqaboo]

It doesnt seem convincing, either way. But if the acronym story was true, the name probably survived because "scram" as in "to leave in a hurry" was already in use (since ~ 1920's), and "scramming after scramming" makes a lot of sense! Had the initial acronym been AMSCR, I bet the process would have gotten a new name with the first redesign.

My 1996 Webster's encyclopedic unabridged Dictionary doesnt give an etymology.

[OperaTenor]

I thought I'd contact the folks on NPR's A Way With Words program and sic them on the definitive answer. They love etymological stumpers like this.

Hi Juan,

I excluded Hal and Shapley from guessing because they were Naval nuclear techies like me, and Analog because he seems to have had a nuclear background as well.

You bring up an interesting point, however, with regards to reactor coolant. Almost without exception, we in the U.S. use water as a coolant, because of its tremendous thermal properties. In the past, experiments had been done with sodium and graphite as moderators(coolants). Both have been found to be extremely finicky to work with(sodium will solidify if you look at it the wrong way, and I believe Chernobyl was a graphite-cooled reactor - no need to go into that one). Water is much more forgiving.

[piqaboo]

Sodium is also very caustic.


Was Berylium part of the early nuc work?
I went down the list Shap provided,and a lot of those folks had cancer. It seemed higher than average, tho I did no analysis of that, or of a control group other than by the PITOOMA method.

[rwcrooks]

Originally posted by piqaboo:
Had the initial acronym been AMSCR, I bet the process would have gotten a new name with the first redesign.

Like Amscray?

Most mainline dictionaries do a fairly poor job with etymologies, some good ones are the OED and DARE (Dictionary of American Regional English) which is like an OED for American slang. The last I knew DARE wss up to volume 4 (through words beginning with Sk so SCRAM may be in there).

I don't recall the Dictionary of American Slang giving much historical context for words.

[Shapley]

Piq,

Beryllium is used in Nuclear power plants and nuclear weapons, according to a couple of sources I found by Googling it. I was aware of its use in electronics (beryllium-copper alloys are common in electronics circuits).

The Navy had at least one sodium-cooled reactor built, but none were deployed at sea. OT's already mentioned the solidification problems, another was the danger of a sodium-water reaction in the event of primary leak. I believe yet another problem was the fact that certain isotopes of sodium have lengthy half-lifes, so it takes a long time for the waste to "cool off", radiologically speaking. With the exception of Tritium, pure water does not have that problem (corrosion residue, however, is a different matter).

I believe we still have one or more graphite-moderated reactors in operation in the United States, as research reactors operated by various Universities. I believe there is one in Tacoma, Washington, which is supposed to be the closest in design to Chernobyl operating in the U.S.

V/R
Shapley

[OperaTenor]

I've sent an e-mail to Martha Barnette and Richard Lederer at A Way With Words to see if they find it worthy of investigation.

:crossed fingers:

[OperaTenor]

Hey, I thought Beryllium(in spherical form) was what powered the NSEA Protector?!!

[Shapley]

Beryllium is apparently found in many industrial alloys. I've heard of a number of Corporations that have had to test their employees for beryllium exposure.

V/R
Shapley

[juan j]

Hi OT,

You are absolutely right about water. I think few people are really aware of its tremendous heat capacity and its benefits either as a coolant or as steam.

If I remember correctly, liquid sodium needs exotic conductivity-based pumps and must be used in an alloy form. You are right, if you miss one detail it will freeze and will render the reactor and its associated equipment unusable.

The US Navy evaluated a sodium-cooled reactor in the 1960s but dropped the idea after these problems. The Soviets, on the other hand, went ahead and used this system in their Alfa-Class submarines. A couple times they experienced failures that ended up in the submarine having its reactor changes and scuttled in Novaya Zemlya. I understand it was one of the reasons why the Alfa-Class project was terminated. A sodium-cooled reactor and a titanium hull made these boats a very expensive failure.

Interestingly, many early reactors were graphite-moderated and designed to produce plutonium; electricity was a "by-product." The Chernobyl reactor was one of these "military" reactors, modified to produce electricity. One thing, however, that the designers did not take into account, was a safeguard system to prevent low power operation, and a backup cooling circuit.

The infamous reactors at Yongbyon in North Korea are also of the graphite-moderated type, hence the concern for its use as weapons-grade plutonium sources. What were the Soviets thinking when they supplied those reactors?

Juan

[OperaTenor]

Hey Juan, were you a nuc?

Water is one of the most amazing molecules, IMO. It is unsurpassed in its ability to absorb and release energy through latent heats of evaporation and condensation. Its only pitfall is its flash temperature when used as a refrigerant - necessitates almost perfect vacuum(i.e., absorption ari conditioning).

[lliam]

At the end of World War II, few questioned Truman’s decision to drop the atomic bombs on Hiroshima and Nagasaki. Most Americans accepted the obvious reasoning: the atomic bombings brought the war to a more timely end. They did not have a problem with over one hundred thousand of the enemy being killed. After all, the Japanese attacked America, and not the other way around. In later years, however, many have begun to question the conventional wisdom of “Truman was saving lives,” putting forth theories of their own. However, when one examines the issue with great attention to the results of the atomic bombings and compares these results with possible alternatives to using said bombs, the line between truth and fiction begins to clear. Truman’s decision to use the atomic bomb on Japan was for the purpose of saving lives and ending the war quickly in order to prevent a disastrous land invasion.

[DavidS]

Lliam, you are absolutely right.
After all, how much compassion did the Japanese Empire show to civilians when they invaded Korea and Malaya in WW2, or to POW's? So what other way was there of stopping them in their tracks?
I sincerely trust that Japan, Germany, and other former adverseries have by now joined the family of nations with true humane values.

<small>[ 08-23-2005, 11:23 AM: Message edited by: DavidS ]</small>