Mad Science: The Nuclear Power Experiment

by Joseph Mangano

The area’s climate is typical of Southern California, with hot summers and mild winters. There is little rainfall other than in the winter months. The area remained rural for decades, even as Los Angeles grew into a large metropolitan area. Not until about 1960 did suburban sprawl begin to take hold in the Simi Valley. Since that year, the population of Simi Valley city has jumped from 8,000 to 130,000, while the number of residents in Ventura County soared from 200,000 to 830,000, according to US Census Bureau data. The area is essentially a bedroom community for commuters to Los Angeles, which now has over ten million residents (below):

  Source: US Census Bureau

  For years, Simi Valley was best known as a site for filming movies. It made front-page news in 1991 when it was selected as a site for the racially charged trial of white four Los Angeles police officers who savagely beat Rodney King, a black man; the acquittal of all the officers set off riots in Los Angeles and across the nation. Simi Valley is also the site of Ronald Reagan’s grave and presidential library.

  It was this sunny, country setting that officials from North American Aviation visited and reviewed in 1947. The company had been founded in 1928, and enjoyed tremendous growth, first as a maker of civilian planes and then military aircraft during World War II. Executives recognized Southern California as a place where flying could take place throughout the year, compared to the original headquarters in Michigan (it was part of General Motors Corporation), with its long, cold, snowy winters. Simi Valley also had much more needed space for company operations. In 1948, GM spun off NAA as a public company.

  The amount of work at NAA had dropped sharply from its peak during World War II, but the company recovered quickly by identifying new products it could develop. The military was interested in using rocket engines in its aircraft, and continued as NAA’s best customer. The company operated Rocketdyne, a large division focused on developing liquid fueled rocket components and propulsion systems. In 1947, Rocketdyne fired the first rocket engine in the US. Three years later, the XLR43-NA-1 large liquid propellant rocket engine was successfully tested, and by 1956, the first Atlas, Thor, and Jupiter engines that powered rockets were successfully constructed. In time, many models of rocket propelled aircraft were made at the site, giving Rocketdyne a prominent place in American development of rockets.

  The military presence at NAA continued to be strong during the Cold War. In fact, of the 2,558 acres at the Santa Susana site, 451 are owned by the federal government.

  The federal government’s atomic program was the perfect solution to propel NAA expansion back to wartime levels. The Manhattan Project and the bomb program’s aftermath did not escape the eye of NAA officials, who gave the atom high priority. In 1948, NAA founded its Atomic Energy Research Department, whose mission was to develop nuclear technology and nuclear reactors, for military and civilian uses. Seven years later, as the national push for more civilian nuclear power moved into high gear, the department was renamed Atomics International, whose major customer was, again, the federal government, and whose primary mission was to test different types of reactors.

  The brains behind the development of the atomic bomb during World War II were located at several sites. The core group of researchers, including luminaries like Dr. J. Robert Oppenheimer, was placed at the Los Alamos National Lab in a remote region of northern New Mexico. In addition, the Oak Ridge and Hanford installations that produced fuel for and assembled nuclear weapons included a research component. After the war, the government expanded its research program by adding a number of research sites, including:

  – Idaho National Laboratory, in an isolated section of eastern Idaho

  – Argonne National Laboratory, just outside of Chicago

  – Lawrence Livermore National Laboratory, in the San Francisco bay area

  – Brookhaven National Laboratory, on Long Island, sixty miles from New York City

  Each of these places was dedicated to atomic research, for both military and civilian purposes (although military was the principal priority). Some had connections with large universities; for example, Argonne was affiliated with the University of Chicago, and Livermore with the University of California at Berkeley. This link with academia helped expand the schools’ fellowships, research funding, teacher training programs, equipment, and job opportunities for graduates. Each of the new labs enjoyed generous funding from the federal government. And even though the public knew of their existence, there was little public accountability required in return for the large number of dollars that rolled in each year from Washington. The process was simple; labs told the AEC what they needed in general terms, the AEC made budgetary requests, the very pro-nuclear and compliant Joint Atomic Energy Committee accepted these recommendations, and Congress voted them into annual budget bills, with few or no questions asked. The culture of secrecy in the atomic field continued into its research component.

  But while the four national laboratories bore the large brunt of nuclear research, the federal government was still interested in supporting companies that could push the nuclear technology envelope. NAA officials, who were well respected in military circles for their work towards the war effort, made themselves known in Washington as able and willing to join in the nuclear development effort. Applying expertise in aviation in the nuclear field made sense, as delivery systems were a critical part of the American atomic weapons program.

  After several years in the planning stage, Atomics International began work developing nuclear power reactors at the Santa Susana site in 1955. The first such US reactor that had produced electrical power was built in 1951 at the Idaho National Lab, but there were several types of power reactor designs on the drawing board that needed to be explored before nuclear plants could be built. Prominent among the projects given to Atomics International was the Sodium Reactor Experiment (SRE).

  Sodium is a metal that converts to liquid at high temperatures. Thus, sodium can theoretically be used as a coolant of the hot core of uranium (and its many fission products from splitting uranium) in a nuclear reactor. Sodium was seen as a viable alternative to water, which was typically used as the coolant of choice in the earliest reactors, forcing reactor to be situated on a large body of water. A sodium-cooled reactor could be placed literally anywhere.

  In the Sodium Reactor Experiment, hot liquid sodium was pumped through pipes, which in turn needed to be cooled to prevent the pipes from melting and the sodium from escaping. This process was especially critical, since sodium burns when combined with air, and explodes when combined with water. The substance chosen to cool the pipes was tetralin, an oily organic fluid.

  The sodium reactor’s core was placed in a building, or “vessel,” lined with stainless steel. The core contained forty-three fuel elements, each of which contained seven fuel rods (skinny six-foot-long steel tubes filled with uranium fuel). As with all reactors, this uranium was used in fission, in which neutrons bombarded the uranium atoms to create high heat – as well as hundreds of radioactive chemicals like strontium-90 and iodine-131. Hot liquid sodium passed beneath the core and was absorbed by the fuel elements into a pool above the core; at this point, the sodium’s temperature was 950 degrees Fahrenheit. Heat exchangers shifted this heat to a “loop;” which in turn transferred the heat to a steam generator; the generator boiled water to make steam to be used in a turbine; and finally the steam in the turbine produced electricity.

  This process was a highly technical, complicated one. It required huge amounts of uranium, sodium, and tetralin to operate even a small experimental reactor of 6.5 megawatts (today’s reactors are typically just over 1,000 megawatts). The pipes could circulate 50,000 pounds of hot liquid sodium at one time. A large amount of uranium was loaded into the fuel elements in the core, even though this type of reactor had never been tested before. So even on a small scale, the testing of the sodium-cooled reactor was a challenging one that included significant amounts of hazardous chemicals. Workers were situated behind thick walls, in case something went wrong
.

  Another nine small reactors were built in one section, known as Area IV, at Santa Susana, primarily for purposes other than conducting the Sodium Reactor Experiment. Atomics International worked with Southern California Edison to develop the system, which first “went critical” – that is, produced electrical power – through a nuclear reaction, in April 1957. Only a small amount of electricity was produced, but the Sodium Reactor Experiment at Santa Susana technically became the first commercial nuclear plant in the US when it sold electricity to some local customers in the nearby Southern California city of Moorpark.

  The publicity given this new (and untested) idea was, in the spirit of the Cold War, highly positive. A nuclear reactor that had generated and sold electrical power – the first to accomplish this task worldwide – was a great headline for the media, which typically supported government efforts.

  During the Cold War, being “in first place” was of great importance, perhaps no more so than in late 1957. In September of that year, the Soviet Union had successfully shot Sputnik, the first unmanned capsule, into space. The Khrushchev regime took maximum advantage of the event to boast of the superiority of Soviet technology and of communism in general. This event and the propaganda that followed were met with dread in the West, especially in the US. America had been the first to develop an atomic bomb, and promised to lead the post-war world in a peaceful direction; could it be that the Soviet Union was actually as proficient, or even more sophisticated? Was the US falling behind?

  America needed its own “first” success late in 1957, and the Sodium Reactor Experiment served the purpose perfectly. The success at Santa Susana made page one headlines in the Los Angeles Times (“la gets first power from atomic reactor”), and was quickly recognized by national media. In November of that year, television host Edward R. Murrow chose it as a subject for his popular show See It Now. The show’s crew was allowed to film the lighting of Moorpark with electricity from Santa Susana. Murrow gave the nation – and actually, the world – a glittering review of the atomic breakthrough in the hills of Southern California:

  Enrico Fermi once looked at a reactor and said “Wouldn’t it be wonderful if it could cure the common cold?” Here at Moorpark, a chain reaction that started with him washed the dishes and lit a book for a small boy to read.

  The Murrow piece was seen by millions of American television viewers. Atomics International followed up by making a movie about the Sodium Reactor Experiment, which was released and distributed in the summer of 1958. The AEC, and the entire nuclear field, was delighted. The Santa Susana program continued in a spirit of optimism and progress.

  Up to July 1959 – and for years after – Santa Susana enjoyed a lofty public reputation. In military and Congressional circles, it was an integral part of America’s rocket and atomic programs. In the Los Angeles area, it was a high-tech beacon of which local residents could be proud. Among workers, Santa Susana remained a desirable place to which research technicians and support staff wanted to devote their careers.

  Bonnie Klea worked for decades at the Santa Susana site in various capacities, beginning at age twenty-two. Years later, after developing cancer, she became a leader of Santa Susana workers seeking to publicize unhealthy practices at the site. She commented on the loyalty that she and all workers had to Atomics International in particular, and the US nuclear program in general:

  The AEC did an extensive background check on me and gave me a “Q” clearance. I never questioned the job or the project and made it a point not to know what I was working on. I was never briefed on dangers or the meaning of signs posted around. I never questioned the safety. Many of the workers were right out of high school and working at this high paying job to afford college or they were right out of military duty, were loyal to America and enjoying the benefits of higher pay and health benefits.

  For those wishing to help move America forward in the new technological era, there was seemingly no better place to be than Santa Susana. It was fully integrated into both the US space missions and its atomic program – in a place that promised warm weather to boot. At its height, 16,000 persons were employed by Rocketdyne in Southern California.

  This shiny image that the program championed in the Simi Valley changed, abruptly and permanently, in July 1959. The unit used for the Sodium Reactor Experiment was preparing for a Power Run that tested its ability to generate electricity while using sodium as a coolant. This was to be the fourteenth Power Run overall, and the seventh to date in 1959; these events typically lasted one to three weeks.

  Run #3 was the exciting effort in 1957 that put atomic electricity in the homes of Americans – and Santa Susana in the news – for the first time. But since then, a number of problems had occurred. After Run #8 in January 1959, operators removed fuel elements from the reactor core, and noticed a sticky black substance on the elements for the first time. This was probably tetralin that had penetrated the pipes carrying the hot sodium, which in turn penetrated into the core with the uranium-laced fuel elements. The problem was merely observed and noted, and managers did nothing to slow down the schedule of future runs. After Run #13 in May 1959, operators were generally in agreement that tetralin had leaked again. The sodium used in the reactor was washed with nitrogen to remove contamination.

  Another problem with Run #13 occurred at about the same time. While washing a fuel element, an explosion occurred. The inexperience with the new sodium-based reactors limited operator knowledge as they attempted to diagnose the problem. Once again, the most likely cause of the explosion was that the tetralin leaks had limited cooling of the sodium, which then was able to penetrate into the uranium-based fuel elements. Again, no halt or slowdown of schedules for further tests was made. Atomics International was flirting with disaster.

  Early on July 12, 1959, Power Run #14 began. Soon after, technicians noticed something was going wrong. The sodium was obviously not cooling the reactor core, as temperatures climbed to levels much greater than during any of the previous tests. The question was why, and soon an answer was found – an all-too-familiar one. The oily tetralin that was supposed to cool the sodium had again leaked through the pump seals protecting the pipe through which sodium flowed, and was overwhelmed when it came into direct contact with the extremely hot sodium liquid. The tetralin turned into a tar, making it powerless to cool the sodium, which made the sodium able to penetrate into the fuel elements.

  A blazing-hot bull in a china shop now existed in the core. The uranium (and its hundreds of radioactive byproducts formed when it was bombarded with neutrons) that was supposed to be cooled by sodium hadn’t been cooled at all. The fuel rods containing uranium pellets began to melt and large amounts of radioactive gases were formed. Operators had seen this before, but never close to these levels of heat and radiation. Technicians tried to remedy the situation by adding more fuel rods (control rods) into the reactor core, a maneuver known as a “scram.” But this action only raised the heat – and the danger. Finally, they succeeded in manually shutting the reactor down, on July 13.

  At this point, Atomics International leaders knew that they had a problem on their hands, of a magnitude the company had never before experienced. The creation of high levels of radioactive gas that could not be cooled was not new, but had never before approached the amounts they were seeing on this Power Run. Even over half a century later, not much is known about who made the decisions, and on what basis decisions were made; but for reasons that appear to be inexplicable and reckless, the reactor was restarted, after just an hour and a half of deliberation.

  John Pace, a twenty-year-old trainee who had worked at Santa Susana for six months, believed that the problem could not be identified while the reactor was shut down:

  It’s like if you had a problem with an automobile, and you check it out to see what might be wrong. The only way that they could figure out what happened with the Sodium Reactor Experiment is by running the reactor at low levels for short periods.

  But
Dan Hirsch, a professor at the University of California at Santa Cruz who later became president of the Committee to Bridge the Gap, an advocacy group concerned with Santa Susana, voiced a different opinion when he testified in 2008 to a US Senate Committee chaired by Barbara Boxer of California:

  So many difficulties were encountered that, at least in retrospect, it is quite clear that the reactor should have been shut down and the problems solved properly. Continuing to run in the face of a known tetralin leak, repeated scrams, equipment failures, rising radioactivity releases, and unexplained transient effects is difficult to justify. Such emphasis on continued operation can and often does have serious effects on safety and can create an atmosphere leading to serious accidents. It is dangerous, as well as being false economy, to run a reactor that clearly is not functioning as it was designed to function.

  For nearly two weeks more, Power Run #14 continued; this period could be compared to someone slamming his head repeatedly against a brick wall – the damage to the head would only get worse with each attempt. On July 14, the reactor was restarted gradually, and radiation levels in the reactor building jumped again. The power produced by the reactor jumped far faster than expected, due to a failure in coolant. The increase in the temperature of the sodium as it traveled through the pipes was also far greater than ever seen before. Operators were aware of these abnormalities, but tried to figure them out while continuing the power run.

  Atomics International officials knew that radiation levels in the reactor were higher than they had ever been before. Pace remembers that starting on the second day of the meltdown, “the holding tanks were all full. They still didn’t know how much radiation we were dealing with – the monitors went clear off the scale.”

  Each day for the next two weeks, radiation in the holding tanks was gradually released into the air. Pace recalls that the exercise took place every day, sometimes twice a day. “They liked to do it at night, since not as many were on the graveyard shift,” he says. But the greatest concern among officials was which direction the wind was blowing. “They tried to make sure it was blowing towards the Pacific Ocean, instead of the San Fernando Valley, so it would affect fewer people.”