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Human error helped worsen a nuclear meltdown just outside Los Angeles, and now human inertia has stymied the radioactive cleanup for half a century.

By Joan Trossman Bien and Michael Collins

Miller-McCune – August 24, 2009

For Release Saturday A.M., August 29, 1959

“During an inspection of fuel elements on July 26 at the Sodium Reactor Experiment, operated for the Atomic Energy Commission at Santa Susana, California by Atomics International, a division of North American Aviation, Inc., a parted fuel element was observed.

The fuel element damage is not an indication of unsafe reactor conditions. No release of radioactive materials to the plant or its environs occurred and operating personnel were not exposed to harmful conditions…

In each case, all seven tubes of the fuel element remained in the core. This fuel loading, nearing the end of its useful life, was scheduled to be removed in the near future.”

This press release — issued five weeks after the end of the United States’ worst nuclear reactor meltdown — was the public’s first notification that something unusual had happened up on “The Hill.” For the next 20 years, it remained the only public notification about the accident at the Santa Susana Field Laboratory on a mountaintop in California’s eastern Ventura County, on the border with the San Fernando Valley.

In fact, from July 12 through July 26, 1959, an unknown amount of radioactive gases were intentionally vented to prevent the Sodium Reactor Experiment from overheating and exploding.

Unlike most conventional reactors that circulate water to be heated by the fuel rods in the core in order to turn steam turbines, the SRE used sodium because it could operate under lower pressure. Pure sodium — not to be confused with table salt, or sodium chloride — was a risky metal to use since it catches fire when exposed to air and explodes when mixed with water.

Due to the experimental nature of the SRE, it was built without a containment structure — the distinctive large dome associated with nuclear power plants — so any radiation vented hot out over the San Fernando Valley, which the city of Los Angeles was busily annexing. What exactly vented remains in contention.

“We know there was a fuel meltdown,” said William Taylor, the current spokesman for the U.S. Department of Energy. “We don’t know how much [radiation] or if any was released.”

[SEE EnviroReporter.com‘s “Double Vision” for extended interviews, photographs and videos]

According to an analysis of a five-year study by a panel of independent scientists convened years after the incident, the SRE accident spit out up to 459 times the amount of radiation released during the 1979 meltdown at Three Mile Island.

Fifty years later, the contaminated site has yet to be cleaned up, although this month two federal agencies promised to plow ahead without the site’s current owner, Boeing. And in March, the Department of Energy provided $38.3 million in funds to complete the radiologic survey of “Area IV” as part of the American Recovery and Reinvestment Act. Unlike the then-remote hilltop it once was, now more than a half million people live within 10 miles of The Hill, and downtown Los Angeles is 30 miles away.

The Race to Conquer the Atom

The Santa Susana Field Laboratory was built on 2,850 acres in the mid-1940s. A portion of the facility was dedicated to nuclear research, while other portions were marked to develop powerful rocket engines such as the Delta II. The federal Atomic Energy Commission and the private Atomics International chose the land high in the hills above the farthest end of the west San Fernando Valley precisely because the work could be dangerous and the population sparse.

The site was owned by Atomics International, a division of North American Aviation. It was merged into Rocketdyne, which Boeing acquired when it bought Rockwell International in 1996. Four years ago, United Technologies bought the Rocketdyne unit from Boeing, but Boeing kept the contaminated site.

Santa Susana hosted other sensitive projects, which in turn left their own more-public toxic legacies. Three other main areas of the lab were devoted to rocket testing, which polluted the land and groundwater with the toxic rocket fuel oxidizer perchlorate and the engine solvent trichloroethylene. Perchlorate has been found in water wells circling the site, including in adjacent Simi Valley.

There are varying estimates of the amount of TCE in Rocketdyne’s groundwater from tens of thousands of rocket tests at the lab. Boeing’s groundwater remediation system, which consists of “air-stripping” towers that allow the TCE to evaporate into the open air, removed 10 gallons of the toxic goo from the water annually.

“Since acquiring our site in 1996, Boeing has made significant progress in our cleanup efforts,” Boeing spokesperson Kamara Sams said recently, although the company turned off the water-purifying system in 2001.

Meanwhile, the SRE was but one of 10 nuclear reactors at the site, plus a “hot lab” to cut apart and work on nuclear fuel for Santa Susana, Department of Energy and the Atomic Energy Commission facilities from around the country. The site also hosted a plutonium fabrication fuel facility which Dan Hirsch, president of the nonprofit anti-nuclear group the Committee to Bridge the Gap, called “perhaps the most dangerous facility they had on the property.”

Hirsch, who has been a key figure in investigating and publicizing the 1959 nuclear accident, said there also had been serious accidents in at least three of the other SSFL reactors, plus “numerous nuclear fires and spills and releases.”

And there were other dangerous practices on the site. “They had a sodium burn pit where they took radioactively contaminated components and illegally burned them in open pits in the open air,” Hirsch said.

Additionally, workers routinely disposed of barrels of highly toxic waste by blowing them up with shotguns and releasing the contents into the air. That practice was halted in 1994 when two workers were killed and one severely injured when the procedure went terribly wrong. One worker was blasted so forcefully into a rock that all that remained was a gruesome petroglyph.

Summer of ‘59: Two long, hot weeks

John Pace had only been at the SSFL for four months 50 years ago this summer when the accident occurred. He was hired as a 20-year-old trainee to learn how to become an atomic reactor operator and mechanic in March 1959 (he was let go the following November). Due to his inexperience, Pace said he often was just an observer of many procedures at that time.

He is now the last surviving worker to have witnessed the 1959 meltdown and its immediate aftermath — an often chaotic attempt to prevent an even larger disaster as workers compromised their own safety to keep the SRE from overheating into a runaway meltdown.

They were only partially successful. Unknown to the workers, the coolant Tetralin had leaked into the sodium and gummed up the SRE, causing the fuel rods to overheat. When the reactor was finally shut down permanently after two weeks of starting and stopping the power and then venting the building radiation, one third of the fuel rods ruptured and had begun melting.

Pace said he arrived at work on July 13 for the shift immediately after the accident; he was told that the operators had noticed that something was not quite right. “They had little indications before that there was something a little edgy about the reactor, but they weren’t quite sure,” he said.

Hirsch said the accident actually began on July 12. “Radiation readings were very high,” he said. “They had a power excursion [an out-of-control nuclear reaction] on July 13 and barely were able to shut the reactor down, spent a couple of hours trying to figure out what happened and couldn’t figure out what happened and started it up again, and inexplicably ran it until July 26. The radiation monitors went off scale. They were too hot to measure.”

Pace recalled that part of his job was to check which way the wind was blowing at the SSFL weather station. “A few hours after it happened, I found out that the reactor had run away from them and they had to release the gases. After leaking the gases, they discovered that the winds were headed toward the San Fernando Valley. All of our families lived [there] and all that radiation went over their homes.”

A 2006 report by David A. Lochbaum, the nuclear safety engineer with the Union of Concerned Scientists, determined that up to 30 percent of the reactor’s radioiodine and cesium could have vaporized during the accident.

After the reactor was shut down two weeks later, Pace said the workers started cleaning up the immediate contamination so that they could reach the fuel rods and see what had happened. “We scrubbed it down with water and sponges,” Pace said. “We tried mops. They’d get contaminated real quick and that was getting pretty expensive, so we ended up using Kotex.”

All this was done without protective clothing beyond coveralls and cotton caps that read, “Your Safety is Our Business — Atomics International.” There were no fully-enclosed radiation suits with face masks that nuclear workers routinely use today, designed to be dissolved and disposed of after one use.

“This had never happened before,” Pace said, “so it was a learning experience of how to clean up contamination.”

As the workers removed the fuel rods, one broke off. The worker accidentally dropped the broken rod back into the reactor. “He realized what had happened and panicked,” Pace said. “All he could think of doing is run. And as he was running, he was pulling alarms and ran out of the building and got outside.”

Pace said the situation deteriorated from there. “Now you have the rod up out of the shield. They were realizing radiation was leaking out into the atmosphere. There was one more fuel rod in there. They pulled it out and it broke off and hit the reactor floor. Now you have two broken off in the reactor. I could tell from the looks on their faces something was wrong.”

Looking back with the benefit of 50 years experience, Pace realized that many mistakes were made. Experts, also with the benefit of hindsight, agreed.

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