The Sodium Reactor Experiment was a pioneering
nuclear power
Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...
plant built by
Atomics International
Atomics International was a division of the North American Aviation company (later acquired by the Rockwell International company) which engaged principally in the early development of nuclear technology and Nuclear reactor technology, nuclear ...
at the
Santa Susana Field Laboratory
The Santa Susana Field Laboratory (SSFL), formerly known as Rocketdyne, is a complex of industrial research and development facilities located on a portion of Southern California in an unincorporated area of Ventura County in the Simi Hills betw ...
near
Simi Valley
Simi Valley (; Chumash: ''Shimiyi'') is a city in the valley of the same name in southeastern Ventura County, California, United States. It is from Downtown Los Angeles, making it part of the Greater Los Angeles Area. Simi Valley borders Th ...
, California. The reactor operated from 1957 to 1964. On July 12, 1957 the Sodium Reactor Experiment became the first nuclear reactor in California to produce electrical power for a commercial power grid by powering the nearby city of
Moorpark. In July 1959, the reactor experienced a partial
meltdown when 13 of the reactor's 43 fuel elements partially melted, and radioactive gas was released into the atmosphere.
The reactor was repaired and restarted in September 1960. In February 1964, the Sodium Reactor Experiment was in operation for the last time. Removal of the deactivated reactor was completed in 1981. Technical analyses of the 1959 incident have produced contrasting conclusions regarding the types and quantities of radioactive materials released. Members of the neighboring communities have expressed concerns about the possible impacts on their health and environment from the incident. In August 2009 the Department of Energy hosted a community workshop to discuss the 1959 incident.
Location
The Sodium Reactor Experiment facility was situated in a northwestern administrative section (known as Area IV) on a mountaintop known as ''The Hill'' of the
Santa Susana Field Laboratory
The Santa Susana Field Laboratory (SSFL), formerly known as Rocketdyne, is a complex of industrial research and development facilities located on a portion of Southern California in an unincorporated area of Ventura County in the Simi Hills betw ...
, about northwest of downtown
Los Angeles
Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, ...
in
Simi Valley
Simi Valley (; Chumash: ''Shimiyi'') is a city in the valley of the same name in southeastern Ventura County, California, United States. It is from Downtown Los Angeles, making it part of the Greater Los Angeles Area. Simi Valley borders Th ...
.
When the Sodium Reactor Experiment was active, the Santa Susana Field Laboratory was operated by two business divisions of the
North American Aviation
North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F- ...
company. The
Rocketdyne
Rocketdyne is an American rocket engine design and production company headquartered in Canoga Park, California, Canoga Park, in the western San Fernando Valley of suburban Los Angeles, California, Los Angeles, in southern California.
Rocketdyne ...
division conducted
liquid-propellant rocket
A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid rocket propellant, liquid propellants. (Alternate approaches use gaseous or Solid-propellant rocket , solid propellants.) Liquids are desirable propellants because th ...
engine testing and development at the site, while the Atomics International division focused on the development of commercial nuclear reactors and compact nuclear reactors for
outer-space applications.
History
In 1954, the United States Atomic Energy Commission announced plans to test the basic nuclear reactor designs then under study by building five experimental reactors in five years. The Sodium Reactor Experiment, designed by Atomics International, was one of the chosen reactors. Design of the Sodium Reactor Experiment began in June 1954, and construction was underway in April 1955. A local utility company,
Southern California Edison
Southern California Edison (SCE), the largest subsidiary of Edison International, is the primary electric utility company for much of Southern California. It provides 15 million people with electricity across a service territory of approximate ...
, installed and operated a 6.5 MW electric-power generating system. Controlled
nuclear fission
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactiv ...
began on April 25, 1957.

The ''Los Angeles Times'' published a front-page story when Moorpark was supplied with nuclear-generated electricity.
Edward R. Murrow
Edward Roscoe Murrow (born Egbert Roscoe Murrow; April 25, 1908 – April 27, 1965) was an American Broadcast journalism, broadcast journalist and war correspondent. He first gained prominence during World War II with a series of live radio broa ...
’s television program ''
See It Now'' featured the event as a special news report, broadcast on November 24, 1957. In July 1958, Atomics International produced
filmdescribing the construction of the Sodium Reactor Experiment facility. The Sodium Reactor Experiment used
sodium
Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
as a coolant. Heat generated in the reactor was transported by liquid sodium through the reactor facility piping system. The pumps used to move the sodium were hot-oil
centrifugal pump
Centrifugal pumps are used to transport fluids by the Energy transformation, conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. They are ...
s modified for use in a sodium system. A support system used
tetralin
Tetralin (1,2,3,4-tetrahydronaphthalene) is a hydrocarbon having the chemical formula C10H12. It is a partially hydrogenated derivative of naphthalene. It is a colorless liquid that is used as a hydrogen-donor solvent.
Production
Tetralin is pr ...
(an oil-like fluid) to cool the pump seals, which prevented leakage of hot sodium at the pump shaft.

In July 1959,
tetralin
Tetralin (1,2,3,4-tetrahydronaphthalene) is a hydrocarbon having the chemical formula C10H12. It is a partially hydrogenated derivative of naphthalene. It is a colorless liquid that is used as a hydrogen-donor solvent.
Production
Tetralin is pr ...
seeped into the primary coolant system through a pump seal and was decomposed by the high-temperature sodium. The decomposed tetralin clogged several narrow cooling channels used by the sodium system to remove heat from the reactor fuel elements. As the tetralin residues clogged the reactor's internal cooling channels, 13 of the reactor's 43 fuel elements overheated and were damaged.
The exact date of the fuel damage is unknown, but is believed to have occurred between July 12 and 26.
At the time, operators were aware of unusual reactor behavior but were unaware of the damage. They continued operations for several days before shutting down the reactor for examination. When the operators attempted to remove the fuel elements from the reactor, most elements were removed normally but some were found to be jammed. Pieces of the damaged fuel elements fell to the bottom of the reactor. During the following months, Atomics International personnel removed all the jammed fuel elements, retrieved the pieces of dropped fuel elements, cleaned the sodium system and installed a new reactor core. The Sodium Reactor Experiment was restarted on September 7, 1960, nearly fourteen months after the accident. In 1961, Atomics International produced another movie explaining the accident and the recovery operation. The Sodium Reactor Experiment operated until February 15, 1964.

In 1964, several modifications were made to the reactor. These modifications were completed in May 1965, but the Atomic Energy Agency and Atomics International decided to close the reactor rather than restart it. The facility
decommissioning began in 1976 with the removal of the reactor core, support systems and contaminated soil under the structure. The source of the contaminated soil underneath the building does not appear related to the 1959 reactor incident. Decommissioning was completed in 1981. In 1982, Atomics International produced a film on the decommissioning and decontamination of the Sodium Reactor Experiment.
A group of
certified health physicists from the
Argonne National Laboratory
Argonne National Laboratory is a Federally funded research and development centers, federally funded research and development center in Lemont, Illinois, Lemont, Illinois, United States. Founded in 1946, the laboratory is owned by the United Sta ...
conducted independent sampling to determine if the then-current minimum cleanup standards for radioactive residue were met. In 1985, the
United States Department of Energy
The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...
completed its evaluation of the survey reports and certified “…that there is no evidence the facilities pose a radiological threat to either personnel or the environment”.
In 1999, the remaining structures were demolished and removed from the site.
Principles

The purpose of the Sodium Reactor Experiment was to demonstrate the feasibility of a sodium-cooled reactor as the heat source for a commercial power reactor to produce electricity. A secondary objective was to obtain operational data on slightly enriched fuel and uranium-
thorium
Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and ha ...
fuel mixtures. The reactor was designed as a flexible development facility, and was considered a development tool emphasizing the investigation of fuel materials.
Compared to water, sodium has a relatively low
vapor pressure
Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indicat ...
at the operating temperatures of the reactor. The Sodium Reactor Experiment design utilized sodium as a coolant so high-pressure water systems would not be required. The reactor did not have a containment pressure vessel, because the maximum credible accident would not release enough gas volume to require pressure containment. It was designed to retain gases at about atmospheric pressure and reduce diffusion leakage from potentially contaminated gas.
The Sodium Reactor Experiment included a complex of buildings, workshops and support systems. The reactor was housed in the main reactor building, which consisted of a high bay area and a
hot cell facility. Three cleaning cells were located in the main building. The cleaning cells were designed to wash sodium from the fuel elements with water in an inert atmosphere. The cleaning allowed examination of the fuel rods after they were removed from the reactor. Because sodium reacts violently with water, the wash cell was sealed off and flooded with inert gas to minimize the reaction during washing.
Operators worked behind thick walls to limit their exposure to radiation emitted from the fuel elements, which were loaded into the cell through a ceiling entrance hole (normally covered with a heavy shield plug).

The
reactor core sat in a lower portion of a vessel lined with stainless steel and filled with liquid sodium. The Sodium Reactor Experiment reactor core contained 43 fuel elements, each comprising seven
fuel rod
Nuclear fuel refers to any substance, typically fissile material, which is used by nuclear power stations or other nuclear devices to generate energy.
Oxide fuel
For fission reactors, the fuel (typically based on uranium) is usually based o ...
s. A fuel rod was a stainless steel tube six feet long, filled with twelve uranium fuel slugs. Many of the fuel elements in the SRE were instrumented with
thermocouples located in the center of the fuel materials at several places in the core. Two of the thermocouples were monitored in the reactor control room, while the remaining measurements were recorded on instrumentation outside the
control room
A control room or operations room is a central space where a large physical facility or physically dispersed service can be monitored and controlled. It is often part of a larger command center.
Overview
A control room's purpose is produc ...
. The sodium temperature was also monitored at several points within the reactor system.
At full power, sodium at a temperature of approximately passed through a
plenum chamber
A plenum chamber is a pressurised housing containing a fluid (typically air) at positive pressure. One of its functions is to equalise pressure for more even distribution, compensating for irregular supply or demand. It is typically relatively la ...
beneath the reactor core through the heat channels absorbing heat released from the fuel elements, and discharged into the upper pool (about deep) above the core at an average temperature of 950 °F (510 °C). This space was filled with helium gas, maintained at a pressure of approximately three pounds per square inch (gauge). Piping circulated 50,000 pounds (22,680 kg) of heated liquid sodium from the reactor vessel to one of two available heat exchangers. One heat exchanger transferred heat from the primary sodium loop, which in turn dissipated the heat in a steam generator which boiled water to make steam for use in a turbine generating electricity.
The gases used as a cover gas in the sodium systems (such as the reactor and fuel-assembly wash cells) are potentially radioactive. The design of the Sodium Reactor Experiment support facilities was to collect all such gases into a tank, compress them and put them into a gas holding tank until they had decayed sufficiently to allow discharge into the environment from an outdoor stack.
1959 incident
Limited experience
The Sodium Reactor Experiment was designed and constructed to gain experience in the use of uranium fuel in a reactor used to produce electricity. The fuel elements in the Sodium Reactor Experiment were operating under untried conditions. Fuel-design limits were based on theoretical limits, not operating experience. Cladding materials were untested, with little or no operating experience.
Before the incident
During the operation of the Sodium Reactor Experiment, its operators conducted several test cycles (known as “runs”) to correct and modify facility support systems, conduct reactor physics experiments and generate electricity. During run three, the Sodium Reactor Experiment became the first nuclear reactor in the US to produce power for a commercial power grid. During Run eight, a black residue (believed to be decomposed
tetralin
Tetralin (1,2,3,4-tetrahydronaphthalene) is a hydrocarbon having the chemical formula C10H12. It is a partially hydrogenated derivative of naphthalene. It is a colorless liquid that is used as a hydrogen-donor solvent.
Production
Tetralin is pr ...
) was noticed on fuel elements removed from the reactor. The fuel elements were washed in the wash cell, and returned to the reactor. The reactor returned to operation for high-temperature testing. Several anomalous temperature readings were occasionally noticed during the next few runs, while the operators attempted to understand the behavior and its cause. At the end of run 13, it was obvious that something had occurred which impaired the heat-transfer characteristics of the system. It was decided that a tetralin leak had reoccurred, and was the cause of the trouble. The reactor sodium was purged with gaseous
nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
, to remove volatile contamination.
Wash cell explosion
Following run 13, an attempt was made to wash a fuel element in the wash cell. During the operation, an explosion occurred of sufficient magnitude to lift the shield plug out of the wash cell. It is believed the tetralin-related decomposition products caused a substantial amount of sodium to be trapped in the fuel rod elements by blocking drain holes. There were no reported injuries or fatalities associated with the wash-cell explosion. As a result of the explosion, no further washing of the elements was done. Measurements from within the reactor building indicated extremely high radioactivity levels throughout the building. Within several days radioactivity in the high bay had been reduced to normal levels, except for the area immediately around the wash cells.
Run 14 (July 12–July 26, 1959)
Shortly after the reactor was restarted, radiation monitors inside the reactor building showed a sharp increase in airborne radioactivity within the reactor building. The reactor remained operating, while attempts were made to determine the source of the radioactivity. Airborne radioactivity then returned to normal.
On July 13, the reactor experienced a series of temperature and radiation fluctuations (known as "excursions", because they were an unexpected departure from expected conditions). The power level rose from about 4 MW to about 14 MW (70% of full power) over a period of about two minutes. The excursion required the operators to manually override a malfunctioning automatic-control switch, and the reactor was shut down. The switch was repaired, and the reactor was slowly restarted.
The following day, monitors again indicated elevated airborne radioactivity levels within the reactor building. The source was traced to two locations at the reactor core loading face, which were sealed. Airborne radioactivity within the reactor building was reduced. The reactor was restarted, but the operators noted unusual behavior over the next few days. The reactor increased power faster than expected, and the temperature difference between the reactor bottom (where the sodium entered) and the reactor top (where the sodium exited) was unusually high. Radioactivity within the reactor also increased. The operators investigated, performing several exercises to understand and correct the reactor behavior.
On July 23, it was decided to shut the reactor down because of high fuel temperature and an unacceptable top-bottom reactor temperature differential. While moving the elements to dislodge foreign material (and lower the exit temperatures), it was noticed that four reactor elements were stuck. On July 26 the reactor was shut down, and the first damaged fuel element was observed.
On July 29, 1959, an ''ad hoc'' investigative committee was established to study the incident and make recommendations. On August 21, 1959,
''The Van Nuys News'' published a story with the headline “Parted Fuel Element seen at Atomics International”. The article stated, “…a parted fuel element was observed” and “The fuel element damage is not an indication of unsafe reactor conditions. No release of radioactive materials to the plant or its environs occurred”. The investigative committee released “SRE Fuel Element Damage, An Interim Report” on November 15, 1959; the final report was made in 1961. The introductory material in both documents includes the statement, ”This report has been distributed according to the category ‘Reactors-Power’ as given in Standard Distribution Lists for Unclassified Scientific and Technical Reports", also noting that a total of 700 copies were printed.
The documents were not labeled “secret”.
Radioactivity release
The Sodium Reactor Experiment core, high bay, reactor gas and exhaust stack were routinely monitored with
particle detector
In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing elementary particle, particles, such as t ...
s. Monitoring was underway at the time of the incident. Two sets of documentation appear to exist concerning the release of radioactive gases in the 1959 incident. The first set of documents include incident reports, technical analysis and
radiation monitoring reports prepared by Atomics International personnel shortly after the incident. The second set of documents was primarily prepared to support a defense against a lawsuit against the current property owner (
Boeing
The Boeing Company, or simply Boeing (), is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles worldwide. The company also provides leasing and product support s ...
) about 45 years after the incident.
Following the incident, Atomics International personnel documented an analysis of the distribution of radioactive materials released into the reactor by the damaged fuel elements. The analysis reviewed the radioactive materials released into the sodium and cover gas above the reactor. The researchers determined the amount of radioactive materials released into the sodium, and noted the materials were removed with
cold traps; the sodium was reused when the reactor returned to service. The document states that only radioactive
xenon-133 and
krypton-85
Krypton-85 (85Kr) is a radioisotope of krypton.
Krypton-85 has a half-life of 10.756 years and a maximum decay energy of 687 keV. It decays into stable rubidium-85. Its most common decay (99.57%) is by beta particle emission with a maximum ene ...
were found in the cover gas. Attempts to detect radioactive
iodine-131 were unsuccessful; this was not explained by Atomics International at the time. Internal Atomics International memoranda show the gases were removed from the reactor following the incident and stored in tanks, where they were allowed to decay and then slowly released into the atmosphere.
A summary of radioactive gases released from the Sodium Reactor Experiment over a two-month period was prepared by Boeing. The document notes that 28
curie Curie may refer to:
*Curie family, a family of distinguished scientists:
:* Jacques Curie (1856–1941), French physicist, Pierre's brother
:* Pierre Curie (1859–1906), French physicist and Nobel Prize winner, Marie's husband
:* Marie Curi ...
s of fission gases were released into the environment through a stack, in a controlled manner which met federal requirements. Other expert estimates indicate that the available documentation does not resolve the uncertainties about how fission gases were released following the accident, and that the total amount of radioactivity released could be higher.
Controversy
Following the original July 1959 incident, it was next referenced in a 1976 report on nuclear activity in Los Angeles in a little-noticed
publication by
Another Mother For Peace. The
Three Mile Island accident
The Three Mile Island accident was a partial nuclear meltdown of the Unit 2 reactor (TMI-2) of the Three Mile Island Nuclear Generating Station, located on the Susquehanna River in Londonderry Township, Dauphin County, Pennsylvania, Londonderry T ...
sparked interest by students and faculty member Daniel Hirsch at
University of California Los Angeles, who acquired the extensive collection of documentation and film footage of the damaged reactor. The documents and film were supplied to local media, triggering extensive coverage.
In December 2003, the
United States Environmental Protection Agency
The Environmental Protection Agency (EPA) is an independent agency of the United States government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on De ...
(EPA) completed an evaluation of the portion of the Santa Susana Field Laboratory previously involved with nuclear reactor development (including the Sodium Reactor Experiment site). The evaluation was based on data which included any remaining
radiological
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes:
* ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...
impacts on water and soils in the area from the Sodium Reactor Experiment. The EPA determined, “the site is not eligible for inclusion on
Superfund
Superfund is a United States federal environmental remediation program established by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). The program is administered by the United States Environmental Pro ...
’s
National Priorities List
The National Priorities List (NPL) is the priority list of hazardous waste sites in the United States eligible for long-term remedial investigation and remedial action (cleanup) financed under the federal Superfund program. Environmental Protec ...
and no further Superfund response is warranted at this time”.
In February 2004 a
class action
A class action is a form of lawsuit.
Class Action may also refer to:
* ''Class Action'' (film), 1991, starring Gene Hackman and Mary Elizabeth Mastrantonio
* Class Action (band), a garage house band
* "Class Action" (''Teenage Robot''), a 2002 e ...
lawsuit was filed against the landowner, Boeing, alleging (in part) that the Sodium Reactor Experiment caused harm to nearby residents. The
plaintiffs produced an analysis of the incident prepared by
expert witness
An expert witness, particularly in common law countries such as the United Kingdom, Australia, and the United States, is a person whose opinion by virtue of education, training, certification, skills or experience, is accepted by the judge as ...
Arjun Makhijani, who is the head of an anti-nuclear organization. Makhijani's analysis of the Sodium Reactor Experiment estimated the incident at the Sodium Reactor Experiment may have released up to 260 times more radioactive
iodine-131 than the official estimates for the
Three Mile Island Nuclear Generating Station release.
The "260 times worse than Three Mile Island" assertion has been widely quoted.
The "Three Mile Island" conclusion presented in the legal filing did not agree with data and documents prepared at the time of the SRE incident.
In August 2004 ground water under the former Sodium Reactor Experiment was sampled to determine the presence of
tritium
Tritium () or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with a half-life of ~12.33 years. The tritium nucleus (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of the ...
, which was undetected. The results were presented at a
DOE-sponsored community meeting in June 2005 and i
handouts at the meeting
In May 2005 a response to the Makhijani analysis was prepared for the
defense
Defense or defence may refer to:
Tactical, martial, and political acts or groups
* Defense (military), forces primarily intended for warfare
* Civil defense, the organizing of civilians to deal with emergencies or enemy attacks
* Defense industr ...
by Jerry Christian, who provided a technical analysis disputing Makhijani’s claim of iodine release following the incident. Christian noted that Atomics International personnel attempted to monitor iodine-131 without success, and reactor temperature conditions did not permit a significant formation of iodine. A more-detailed analysis was prepared for the plaintiffs by John A. Daniel. Daniel focused on evaluating plant conditions, radiation monitoring and documentation to determine the amount of radioactivity released. His analysis concluded that a smaller amount of radioactive gases were released from the SRE. Christian and Daniel's technical analyses contrasted with that prepared by Makhihjani. The case was settled, reportedly with a large payment by Boeing to the plaintiffs (residents near the Santa Susana Field Laboratory who had cancer and other injuries from past site activities, including the SRE incident).
In July 2006, the
History Channel
History (formerly and commonly known as the History Channel) is an American pay television television broadcaster, network and the flagship channel of A&E Networks, a joint venture between Hearst Communications and the Disney General Entertainme ...
broadcast a video summary of the 1959 Sodium Reactor Experiment incident during episode 19 of the ''Engineering Disasters'' documentary series. The segment features quotes from Dan Hirsch, a nuclear policy analyst, and
David Lochbaum David A. Lochbaum was the Director of the Nuclear Safety Project for the Union of Concerned Scientists (UCS). A nuclear engineer by training, he worked in nuclear power plants for nearly two decades. Lochbaum has written numerous articles and repo ...
. The segment alleged that the incident was kept secret for 20 years, and the radioactivity release from the incident may have been as high as 240 times the radioactivity released from the accident at the Three Mile Island Nuclear Generating Station. The ''Engineering Disasters'' segment did not mention the technical analyses prepared for Boeing.
In October 2006 California legislators, responding to community calls for independent health studies in the wake of revelations about the site, established the Santa Susana Field Laboratory Advisory Panel. The panel consisted of independent experts from around the country (and one from Britain) and community representatives. It was a project of the
Tides Center, funded by the US Department of Energy and later by the
California Environmental Protection Agency (as mandated by the California State Legislature). The panel released a set of documents analyzing events at the
Santa Susana Field Laboratory
The Santa Susana Field Laboratory (SSFL), formerly known as Rocketdyne, is a complex of industrial research and development facilities located on a portion of Southern California in an unincorporated area of Ventura County in the Simi Hills betw ...
.
Five reports by consultants focused on the analysis of the radiological impacts of the July 1959 Sodium Reactor Experiment incident. One, by David Lochbaum, concluded that contrary to Rocketdyne's claim that no radioactivity was released into the environment, "as much as 30% of the most worrisome of the radionuclides, iodine-131 and caesium-137, may have been released, with a best estimate of 15% of each".
Scant and disconnected data prevented a quantitative assessment of exactly what gases escaped and when. In another report, Jan Beya attempted to provide an exposure estimate to epidemiologists interested in evaluating the effectiveness of radiation-induced-disease studies around the Santa Susana Field Laboratory. Beya noted that some meteorological information was withheld by the plant owner (Boeing). The estimates in the report were limited to scoping calculations with a wide range of uncertainty, but represented the current state of knowledge about the accident and its consequences according to experts who have analyzed the event.
In September 2008, Daniel Hirsch presented testimony in the U.S. Senate to the Committee on Environment and Public Works, chaired by California senator
Barbara Boxer
Barbara Sue Boxer (née Levy; born November 11, 1940) is a retired American politician, lobbyist, and former reporter who served in the United States Senate, representing California from 1993 to 2017. A member of the Democratic Party (United St ...
. Hirsch called the July 1959 event “one of the worst nuclear accidents in nuclear history” and testified that the government “covered up the seriousness of the accident”.
A contrasting viewpoint, based on the technical analysis prepared for Boeing, was not presented at the hearing.
In April 2009, the Department of Energy announced the transfer of $38.3 million to the EPA for a complete radiological survey of a area of the Santa Susana Field Laboratory. The source of the funds was the
American Recovery and Reinvestment Act of 2009
The American Recovery and Reinvestment Act of 2009 (ARRA) (), nicknamed the Recovery Act, was a Stimulus (economics), stimulus package enacted by the 111th U.S. Congress and signed into law by President Barack Obama in February 2009. Developed ...
. The DOE had provided funds earlier to the EPA for a portion of the survey, so the total funding provided for the Area IV survey is $41.5 million. The survey was scheduled to be completed in September 2011. In December 2012, the EPA released the results of testing done at the site. The Agency noted that it took 3735 soil samples during the study and of those samples more than 10% contained radioactivity higher than background level.
In July 2009, local media recognized the 50th anniversary of the July 1959 SRE incident. Local media reported that a former employee, John Pace, "broke his 50-year vow of secrecy" to describe his role in the reactor incident and recovery. A local newspaper featured photographs of Pace conducting activities at the SRE (monitoring the reactor, turning the top of the reactor core, placing sealer on asbestos piping, and seated at a console operating the reactor). The claim of secrecy contrasts with a press release, a motion picture and reports to the public following the 1959 incident. Jan Beyea was interviewed by a local newspaper; he reaffirmed his assertion that iodine-131 was released during the SRE incident, but it would "probably" not have produced a widespread effect on health.
In August 2009, the Department of Energy (DOE) hosted a public workshop in
Simi Valley
Simi Valley (; Chumash: ''Shimiyi'') is a city in the valley of the same name in southeastern Ventura County, California, United States. It is from Downtown Los Angeles, making it part of the Greater Los Angeles Area. Simi Valley borders Th ...
to explore expert and community perspectives on what occurred before, during and immediately after the July 1959 SRE incident. The workshop featured presentations from three experts: Paul Pickard of DOE's
Sandia National Laboratories
Sandia National Laboratories (SNL), also known as Sandia, is one of three research and development laboratories of the United States Department of Energy's National Nuclear Security Administration (NNSA). Headquartered in Kirtland Air Force B ...
, Thomas Cochran of the
Natural Resources Defense Council
The Natural Resources Defense Council (NRDC) is a United States–based 501(c)(3) non-profit international environmental advocacy group, with its headquarters in New York City and offices in Washington, D.C., San Francisco, Los Angeles, Chicag ...
and Richard Denning of
Ohio State University
The Ohio State University (Ohio State or OSU) is a public university, public Land-grant university, land-grant research university in Columbus, Ohio, United States. A member of the University System of Ohio, it was founded in 1870. It is one ...
. Over 185 community members and
Atomics International
Atomics International was a division of the North American Aviation company (later acquired by the Rockwell International company) which engaged principally in the early development of nuclear technology and Nuclear reactor technology, nuclear ...
retirees attended the workshop. Posters (depicting key operation and accident timelines) and an evaluation of the reactor's radioactive material inventory and release into the environment were discussed. An electronic library of over 80 technical documents describing the design, operation, the 1959 incident and the activities taken to repair and restart the SR
is maintained by the DOE Videos of the introductions, presentations, community comments and the question-and-answer sessio
Aftermath

As a result of the incident, changes were made to the Sodium Reactor Experiment. Tetralin was eliminated, the sodium system was modified, the wash-cell cleaning process used steam instead of water, instrumentation was improved and the fuel-element geometry was modified. In September 1960, following recovery and cleanup operations, the Sodium Reactor Experiment began operation with a new reactor core. At the time of the July 1959 incident, the Sodium Reactor Experiment had operated for 10,344 hours. After the repairs were made and a new core loaded, the Sodium Reactor Experiment operated for an additional 26,716 hours and generated a total of 37 GWh of electricity.
In 1966, the
Energy Technology Engineering Center was established at the Santa Susana Field Laboratory by the U.S. Atomic Energy Commission for the development and non-nuclear testing of liquid metal reactor components.
The testing and development notably improved the safety and reliability of sodium pump seals. The Energy Technology Engineering Center designed, developed and performed full-scale testing for a wide variety of sodium components (such as cold traps, flow meters and valves) from 1965 to 1998.
References
External links
Company websites
U.S. DOE ETEC Closure Project Website
Sodium Reactor Experiment videos
*
ttps://web.archive.org/web/20130217011436/http://www.etec.energy.gov/Library/Video/SRE_Video/SRE_Decommissioning.html Removal of the Sodium Reactor Experiment, March 1982
Other links
Starr & Dickinson, ''Sodium graphite reactors'' (1958).Construction of the Sodium Reactor Experiment— 1959 pamphlet
Cleanuprocketdyne.org BlogThe Aerospace Cancer Museum of Los Angeles BlogSSFL Community Advisory Group 2013 WebsiteSSFL CAG (community advisory group)— SSFL Forum
The Rocketdyne Information Society— SSFL Forum
Madeline Felkins WebsiteSanta Susana Advisory Panel— closed forum
Miller-McCune: 50 years after nuclear meltdownSSFL CAG petition
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Atomics International
Nuclear power plants in California
Nuclear research reactors
Civilian nuclear power accidents
Energy infrastructure in California
Former nuclear power stations in the United States
Former nuclear research institutes
Simi Hills
Energy infrastructure completed in 1957
1957 establishments in California
Buildings and structures in Ventura County, California
Buildings and structures demolished in 1999
Demolished buildings and structures in California
1959 disasters in the United States
1959 in California
History of the San Fernando Valley
History of Simi Valley, California
History of Ventura County, California
Rocketdyne
Nuclear accidents and incidents in the United States
1964 disestablishments in California
Former power stations in California
Energy infrastructure closed in the 1960s