Sunday, December 22, 2013


An Urban Legend

In 1955 I moved from New York with my wife and child to Los Angeles.  On November 15 of that year I started working at a division of one of the aircraft companies, North American Aviation, called Atomics International, often abbreviated as AI.  The purpose of this new division was to establish a foothold for the parent company in the new field of nuclear reactor power.  Nuclear power was touted at the time as being “clean” power.  Nuclear power stations did not emit black soot, oxides of carbon and sulfur, and radioactive material that occurs naturally in coal.

The company secured a number of contracts for developing types of power reactor.  Many of these contracts dealt with portable power units for military use.  These contracts developed information that was classified.  Another government contract was for a prototype reactor in which the coolant was sodium rather than water.  Coolant is the fluid that extracts heat from the fissioning fuel elements and delivers it to a rather conventional power unit through a heat exchanger.  The advantages of sodium rather than water were based on the fact that sodium remains a liquid from its melting point at 97o C to above 1,000o C.  Since it could operate at such a high temperature, the power plant would have a higher Carnot efficiency than one in which water was used to transfer the heat.  In addition to improved thermodynamic efficiency, a sodium cooled reactor had no need for pressure containment.  All parts of the reactor operated at atmospheric pressure.  Only the steam produced in the final heat exchanger operated at high pressure.

The disadvantages of using sodium relate to the chemical and physical properties of the element.  It’s chemically very reactive.  Air, and especially oxygen and water vapor, must be kept away from the liquid sodium.  In addition it has a negative reactivity coefficient with respect to the generation of neutrons.  It absorbs them and the reaction produces radioactive NA24 which decays to magnesium.  Because it absorbs neutrons, any gap or bubble in the sodium in close contact with the uranium fuel produces a slight increase in the efficiency of producing neutrons.  If a sodium cooled reactor suddenly lost all its coolant, the reactor would start a power excursion as well as experiencing an immediate rise in temperature of the fuel.  A different effect occurs with a water-cooled reactor.  Water absorbs few neutrons and also is a good moderator.  Loss of water causes a power reduction in such a reactor.  Of course, the fuel elements get very hot, just as in the case of a sodium reactor with loss of coolant.

Atomics International built the Sodium Reactor Experiment (SRE) at the Rocketdyne-AI Field Test Station in the Simi Hills between Los Angeles and Simi Valley.  The reactor began operation to demonstrate its ability to support a power plant in about 1957.  In 1959 the reactor had an accident that resulted in damage to 13 of the 42 fuel elements.  There are numerous reports written at the time about various aspects of the accident.  These reports state:

From these reports that I have read, I conclude that the accident to the SRE did not rise to the level at which one would say that there was a “melt-down.”  That term has been applied to certain other reactor accidents, particularly at Three Mile Island in Pennsylvania and a Chernobyl in Ukraine.  In those cases the reactor was cooled with water and the water boiled off and left the core with no coolant.  As a result, there was enough heat not only to damage the fuel elements but also the coolant tubes that they were in.  The result was a twisted mass of partly melted tubing, extensive release to the environment of radioactive fission products, and a mess that could only be dealt with by burying it.  None of this happened to the SRE.

In spite of what I’ve just written, there is a persistent belief among some people that there was a melt-down, a large release of radioactive material, and consequent increase in people living within a few miles of the site experiencing cancers.  Since the presumed melt-own is not reported in any official or responsible document, this belief is supported by a presumption that the government and the contractors involved (AI, Department of Energy, Defense Department) are “covering up” the truth.

I have a problem.  How do I go about convincing any of these melt-down believers that there was no melt-down and no cover-up?  

Hello there!

I've been researching this very incident lately to see if I can get a book out of it. I write novels for middle-school age kids, and have been looking for more math and science-oriented subjects to write about. In this case, I've been wondering whether a kid living in 1959 Simi Valley, perhaps who enjoys exploring up in the canyons, might have been able to stumble upon regarding the SSFL and the SRE. The idea hasn't fully taken shape yet because it's been hard for me to get an idea of what's realistic. So far, what I've been able to find has either been official reports that treat the incident as not a very big deal or exaggerated claims from hysterical anti-nuclear groups. There's been very little in between.

I think the reason so many people have accused the government of covering something up is because of when the media first paid any attention to the accident - 1979, right after Three Mile Island and The China Syndrome and twenty years after the accident took place. The idea that people involved with the accident at the time simply didn't think it was worth bothering the public about doesn't sound as believable.

But then, I think a lot of people are much too paranoid about nuclear power anyway. When the meltdowns happened at Fukushima, I was making jokes about Californians rushing out to buy iodine tablets and thinking nothing of driving down the freeway at 80mph while talking on their cell phones when they did it.
To Mr. Black,
There were two articles published on what happened at the Sodium Reactor Experiment (SRE) within a few months of the event in July 1959. I interviewed the Senior Engineer who was in charge of the SRE at the time of the incident. I met him through Al Saur. What he told me is that they really could not tell the media what happened right away because a reactor is not like other energy sources - you can't just shut them down and study them immediately. He called it a "post mortem" - after the reactor had cooled for a few weeks - certain gases such as iodine would have decayed away safely, only then could you go in with your equipment and begin to look into the core to see what had occurred. This link will provide you with the initial story given to the press, and to which newspapers it was sent to:
There were 700 copies of the "SRE Fuel Element Damage" report. There was no cover up - the issues of what happened at this reactor are covered in the literature where scientists and engineers published and learned from this experimental reactor.
Thank you to Al for your post. I will comment on it after I see if this post works.
Mr. Rowe,

Wow, thank you! That's terrific. It's always great to have original source material.

I knew the claims that the SRE was a "secret project" were inaccurate, because Edward R. Murrow did an episode of See It Now on it in 1957, when they lit up the town of Moorpark (where I live now, by the way). These days, people are much too willing to cry "cover up" whenever the facts aren't what they want.
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