Radium Part II: Trying to Close Pandora’s Box

Tom Wellock
NRC Historian

Until 1945, radium was the best known radioactive material. It was widely found in consumer and medical products. And, as we saw in Part I of this series, it became notorious for fatally sickening radium watch-dial painters in the 1920s. With few exceptions, oversight of public and workplace safety for radium was mostly a state responsibility, and the federal government’s role was limited to such issues as preventing false advertising and regulating mail shipments.

USRadiumGirls-Argonne1ca1922-23-150dpiAt that time, radioisotopes came from just two limited sources. They were painstakingly isolated from natural ores, as was radium, or created in small batches in particle accelerators. These accelerators fire beams of electrons, protons and other particles at elements to create radioactive isotopes. Today the products of these two processes are called NARM—short for Naturally-Occurring and Accelerator-Produced Radioactive Material.

Scientists working on fission and the Manhattan Project discovered new radioactive isotopes with interesting properties. They soon became widely available to scientists, who found many uses for these products, from medical to basic research. They were under federal control and soon eclipsed the small amounts of radium and other NARM that existed before the war. Cold-War security concerns demanded federal control of nuclear technology and this new radioactive material.

Still, the 1946 Atomic Energy Act avoided intruding on state authority over NARM. It focused the Atomic Energy Commission’s oversight on fissionable material such as uranium and thorium and reactor-produced isotopes. The AEC controlled the vast majority of radioactive material.

This division of power didn’t disturb existing state authority but made little technical sense. An isotope produced in a reactor would be identical to one found in nature or produced in an accelerator.  Moreover, state oversight was uneven.

Radium_Periodic Element TableRadium had lost its luster and fallen into disuse. Safer reactor-produced isotopes and sources with shorter half-lives mostly replaced radium for medical uses. Radium consumer products disappeared from stores by the 1970s. But products made with radium during its heyday (see Part I) retain their hazard for a long time.

So, from time to time, reports would emerge of products found in someone’s attic or office, or contamination found in a building. This prompted the Public Health Service to launch a program to collect and safely dispose of old radium sources.

Beginning in the late 1960s, state radiation control officers called for legislation to give the AEC and later the NRC the power to regulate radium and other NARM. In 1985 the NRC asked to be given authority over NARM waste disposal, but Congress took no action. The status quo remained, in part due to difficulties Congress had deciding on the federal agency best suited to regulate radium and oversee cleanup.

Little changed until the 1990s when terrorism provided a new dimension of concern. Experts worried that untracked or stolen radioactive sources, including radium, could be used in “dirty bombs.” Between 1998 and 2003, as part of the U.S. delegation to the International Atomic Energy Agency, the NRC worked with member nations on a code of conduct for radioactive sources. To limit the potential for “malicious acts,” the code appealed to each country to develop a national system of regulation for a list of radioactive sources — radium among them.

In the wake of 9/11, support for the IAEA code gained momentum. Congress included a provision in the 2005 Energy Policy Act giving NRC oversight of radium and other sources of NARM. A consensus for federal regulation emerged only when national security issues joined long-standing health concerns.

Defense in Depth Part I: A War for Safety

Thomas Wellock
Historian

One hundred years ago the French and German armies of World War I devised a new defensive strategy called “defense in depth.” Its aim was to prevent an enemy breakthrough of an army’s frontline with a deep system of interconnected trench lines and strong points.

Defense in depth circa WWI. Photo courtesy of the Library of Congress
Defense in depth circa WWI. Photo courtesy of the Library of Congress

Popularized in all its desperation and grisly effectiveness in films such as All Quiet on the Western Front, defense in depth has become the NRC’s official metaphor in the battle to protect the public from radiation hazards. It is the key concept governing nuclear safety in using multiple strategies in safety-system design, operations, and emergency procedures and planning.

The NRC’s use of the term has roots in the Manhattan Project of World War II. Military metaphors seemed particularly apt for those charged with ensuring the safety of the early plutonium production reactors at Hanford, Washington. They worried about the potential for a reactor “catastrophe” from a radiation release of “explosive violence.” Their solution was to erect multiple “lines of defense” of trained operators and emergency personnel, carefully sealed fuel rods, shielding walls, backup cooling and power systems, and even a backup to the backup shutdown system—a final solution so drastic that it would destroy the reactor to save the operators lives. Fittingly, its moniker derived from another military term — the “last ditch” safety device.

After the war, the “lines of defense” in reactor safety were categorized into functions by Atomic Energy Commission safety committees:

  1. Features that made a reactor inherently safe;
  2. “Static,” or physical, barriers, such as containment buildings, were to halt the escape of radiation; and
  3. Active systems were to shut down and cool the reactor in the case of unusual conditions.

While the AEC’s safety approach became more coherent, there was no consensus among experts over the relative importance of each category. Some experts focused mostly on a design’s physical barriers, while others gave weight to all three categories and included reactor operation too.

Over time, “defense in depth” replaced the scattered concept of “lines of defense.” Its first use appears to have been in 1958 to describe safety design in the plutonium extraction processes at Hanford. In a 1965 letter to Congress, AEC Chairman Glenn Seaborg applied the term to civilian reactor safety as an accident prevention and mitigating strategy.

It provided, he wrote, “multiple safeguards against the occurrence of a serious accident, and for containment of fission product release.” The term stuck.

But the story continues. The Office of Nuclear Regulatory Research has published a report on the history of defense in depth up to the present, which covers the term’s application to the whole nuclear fuel cycle. It’s a fascinating look at how this bedrock safety concept has evolved under the influence of events and new knowledge. We’ll have more on this report on Wednesday.

 

 

REFRESH — Putting the Axe to the ‘Scram’ Myth

Tom Wellock
NRC Historian

refresh leafThe NRC glossary defines a “scram” as “the sudden shutting down of a nuclear reactor usually by rapid insertion of control rods.” But where did the word come from?

One deeply engrained legend about the origin of the word dates to the first sustained chain reaction on December 2, 1942, at the Chicago Pile (CP-1), the first atomic reactor developed for the Manhattan Project. According to the legend, Enrico Fermi created the acronym, Safety Control Rod Axe Man, for Norman Hilberry. It was Hilberry’s assignment that day to kill a possible runaway reaction by using an axe to cut a rope to allow the backup safety control rod to drop into the pile.

The axe-man story now has a life of its own. A search on Google for “scram” and “axe” yields 124,000 hits. Even the NRC’s glossary attributed scram’s etymology to the axe man story. Oak Ridge National Laboratories reported a fanciful variation of this story where Fermi, presumably unimpressed with the physical prowess of his fellow physicists, recruited a lumberjack from the Pacific Northwest to do the job. That version has now spread on the internet, and the acronym itself has mutated into Super-Critical Reactor Axe Man and Start Cutting Right Away, Man.

Hilberry, as it turns out, only learned the story second-hand years later, which lends some doubt to the axe-man version. Other members of the CP-1 team recalled a different origin for the term. Leona Marshall Libby, the only female physicist present that day, wrote in her memoir that it was Volney “Bill” Wilson who called the safety rods “scram rods.” She didn’t explain why he used the term, but her credit to Wilson was supported by others involved in CP-1, including Warren Nyer.

MB900371234I contacted Nyer recently, and he was eager to tell the “scram” story, one that squares well with Wilson’s reported version of events. Nyer’s job that day was to be Hilberry’s backup. If all safety systems failed, he and the other members of the “suicide squad” were to dump a liquid cadmium solution on CP-1 to poison the reaction. The axe-man story is, he recalls, “a bunch of baloney.”

But he did offer another explanation for the word. His recollection was that Wilson was assembling an electrical panel that included a big red button. According to Nyer, someone asked Wilson the reason for the red knob. Wilson replied you’d push it if there was a problem. “Well, then what do you do?” he was asked. Wilson reportedly replied “You scram … out of here.” The word appears to have stuck.

Further indication that “scram” was associated with Wilson’s shutdown circuitry and not Hilberry’s axe wielding comes from Enrico Fermi. The AEC declassified information on the Chicago Pile in late 1950, and Fermi authored a 1951 technical report on the reactor detailing the circuitry of the “SCRAM line” designed by Wilson’s team.  (See http://www.osti.gov/scitech/servlets/purl/4414200 ).

And so it seems likely that scram switches all over the world owe their names not to the nuclear industry’s later penchant for acronyms, but to the slang of 20th century America.

REFRESH is an occasional series where we revisit some of our previous posts. This post is slightly revised from the original, one of the blog’s most viewed posts, which first ran in May 2011.