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AREA IV Santa Susana Field Laboratory

In the light of recent media coverage regarding a lawsuit against the California Department of Toxic Substance Control (DTSC) and the California Department of Health, I felt that it was important to address a term that I see in almost every media story related to the Santa Susana Field Laboratory site – “partial meltdown”. My goal of this history is to draw attention to the fact that there is no evidence of a widespread radiation release from a discrete incident at this site that many people in my community believe have caused their cancers or other illnesses, their family member’s or friend’s cancers, or other health problems.

This history is not meant to say that there was not a serious nuclear incident at the Sodium Reactor Experiment. And it is also not meant to state that there is no radiological contamination remaining at the Santa Susana Field Lab site. My goal is to put this reactor into its historical context, and its physical scale and the type of reactor in its proper relation to other nuclear reactors that are much greater in size, and that this reactor cannot be compared to any of the other larger commercial reactors such as Three Mile Island, Chernobyl, or Fukushima.

In the Simi Hills west of Los Angeles there is a facility called the Santa Susana Field Laboratory (SSFL).  At this research facility there was a small, relative to today’s standards, nuclear research reactor called the Sodium Reactor Experiment or SRE. It was designed to run experiments and to be the first sodium cooled reactor, a prototype for other sodium reactors that were to be used to produce nuclear energy for commercial and other purposes.

This reactor had gone online in 1957, and it had a series of problems from seal failures which in 1959 lead to a failure in the cladding material around the fuel rods.  This in turn led to a power excursion. Radioactive gases (Xenon and Krypton) were deliberately vented to the atmosphere, but according to the technical documents, there was no “breach of the core” as there was in Chernobyl or Fukushima.

There were accidents at this facility as there are at any government research facility. The SSFL was a facility that was originally designed as a remote location for research on missile and later rocket engine technology.

Around 1976, an antinuclear activist with a group called Another Mother for Peace found documents in Sacramento that referred to an incident at Santa Susana. She took this story to what was then the Valley Greensheet, but the story never really went anywhere.

 In 1979, the problems at the Three Mile Island reactor prompted a UCLA film student to research if there had been any similar accidents in California’s nuclear reactors. The movie The China Syndrome had just been released, and there was a lot of fear in the United States regarding the safety of nuclear reactors. This student found reference to the 1959 Santa Susana incident in the UCLA library, and he and a member of another antinuclear group took the story to NBC News.

The NBC News in Los Angeles did a Freedom of Information Act request, and they broadcast a story for a week related to this incident at Santa Susana.  NBC News did not report that there was a “meltdown” or that there was any harm to the community from that incident.

In 1989, The Daily News began publishing a series of stories on the toxic contamination that was at the SSFL site. A group of community activists became alarmed by these stories, and they created a community group that is still involved in the cleanup today.

Over the years, the 1959 incident at the SSFL has been called “a meltdown” or “a partial meltdown”. But how do the media define a “partial meltdown”?    On the 50th anniversary of this “incident”, there were media stories about widespread radioactive contamination. There were stories saying that there was only one employee that was still alive that worked on that reactor. Both of these stories are either misleading or false. People are still alive today that worked on the reactor; they are now in their late 70s to early 90s.  In fact, there is no evidence that anyone who was working on the reactor when the incident in question occurred died from radiation exposure or died prematurely.

Even the physicist that did the studies on atmospheric deposition in 2006 (Dr. Jan Beyea) has stated in the media that he never used the term “meltdown”, and that he had revised his original calculations related to the impact of this incident. He has also stated that he never intended the community to believe that radiation was released and just fell locally; radiation would have gone into the atmosphere and it would have been dispersed over a wide area.

In the summer of 2009, the Department of Energy held an Expert Panel Workshop on the Sodium Reactor Experiment. That event was attended by more than a 100 former Atomics International employees, and many local stakeholders. There were no media reports of this historically important six hour workshop.

These experts explained that this incident in July 1959 could not be compared to any events at Three Mile Island (TMI) because the SRE was not of the same scale as traditional nuclear reactors. According to Dr. Thomas Cochran of the NRDC, one of the experts at the SRE Expert Panel Workshop, the power at TMI was 128 times greater than that at the SRE.  Dr. Cochran also referred to this incident as a “partial fuel meltdown”. However, a better term for this incident to explain what actually happened is that there were seal failures and cladding failures that may have allowed some of the fuel to melt that was bound to the cladding.

It has been estimated by nuclear physicists including Dr. Paul Pickard of Sandia Labs, that about than 1%  - 2% of the fuel may have melted, and in his opinion, any radionuclides that were released during that incident would have bound with the sodium coolant or with the uranium fuel.

The SRE was also designed as a sodium cooled reactor to prevent an explosion as we have seen in Fukushima. The SRE was remediated after its “major incident”, a new core was inserted (there were plans for two new cores as an upgrade for higher energy output), and the SRE went back online a year later to run for three more years.  If there had been a major incident as is implied in the media, how could the SRE have gone back online?

Since there was no media coverage of this DOE Workshop, and because the State law that deals with this site (SB 990) refers to a “partial meltdown” at Santa Susana, the media seems to have only one focus issue at Santa Susana; that it was the site of a “partial meltdown”. In the past four years, the Federal EPA did a thorough historical site assessment of Santa Susana’s AREA IV and the Northern Buffer Zone.  AREA IV was where the nuclear research was performed.  While the EPA did find exceedances of radiation above “local background” at the Santa Susana Field Lab site, there is no evidence that these radionuclides came from a discrete incident in 1959. In fact, in the area where the Sodium Reactor Experiment was once located, most of that area did not have radiological exceedences above local "Background" radionuclides. Where there were exceedences of local Background near the SRE, most were in an area where there was a historic leak of a radioactive storage tank on the hillside above it.

In order to alleviate the fears of the community stakeholders that have heard rumors of a “meltdown” or “partial meltdown” at the site, the lead agency (DTSC), and the Department of Energy, should use the proper terminology for what happened at the SRE. In light of what has occurred at Fukushima, and in light of the fact that the term “partial meltdown” was used by the media at the Fukushima reactors in the early days of that incident, it is irresponsible for our agency leaders, our elected officials, or the media to use the term “partial meltdown” to refer to what happened at Santa Susana more than 50 years ago.

Note: This blog has been updated on 12/30/2018 to reflect changes to agency websites because of bad links due to updated or changed websites. Please note that for numbers 3 and 4 below, that when I copy their URLs, the links do not seem to work for this blog.

You can search the DOE ETEC website if any of these DOE links do not work:

 1)      Sodium Reactor Experiment (SRE):

2)      The SRE Accident:

3)      SRE Workshop:

4)      Historical Videos:

5)      Consulting in the Public Interest: “Dr. Beyea on Nuclear Issues and Radiation Exposure”:

6)      EPA Radiological Characterization Study Results: Note that the Federal EPA has taken down their Santa Susana Field Laboratory website. Therefore, to update this document, I am using the DTSC website:

SRE Accident Recovery Video url:

SRE Decommissioning Video url:








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