Wednesday, March 16, 2011

A Healthy, Glowing Imagination

Certain larGE companies seem to have something to do with just about anything and everything. 

We have all watched with fascination and horror the televised images of the Japanese earthquake, the tsunami that ensued, and the aftermath of both.  In particular, those of us whose bills are paid by radiation have followed the potential tragedy at the Fukushima Daiichi electrical station with almost morbid interest.  Personally, I'm rather frustrated by the limited information available to the public.  Exactly what has been vented into the atmosphere?  Iodine?  Cesium?  What is the temperature of the reactor cores?  And so on.  But I'll leave that sort of thing for the main outlets, as I have no inside information on any of it.

Some of those same mainstream outlets are giving us some unusual pieces of information, some tidbits that are not complementary to the Administration's favorite larGE company.  It seems that the reactor in use was designed by said company in the 1960's. . .

From the New York Times:

The warnings were stark and issued repeatedly as far back as 1972: If the cooling systems ever failed at a “Mark 1” nuclear reactor, the primary containment vessel surrounding the reactor would probably burst as the fuel rods inside overheated. Dangerous radiation would spew into the environment.

Now, with one Mark 1 containment vessel damaged at the embattled Fukushima Daiichi nuclear plant and other vessels there under severe strain, the weaknesses of the design — developed in the 1960s by General Electric — could be contributing to the unfolding catastrophe.

When the ability to cool a reactor is compromised, the containment vessel is the last line of defense. Typically made of steel and concrete, it is designed to prevent — for a time — melting fuel rods from spewing radiation into the environment if cooling efforts completely fail.

In some reactors, known as pressurized water reactors, the system is sealed inside a thick steel-and-cement tomb. Most nuclear reactors around the world are of this type.

But the type of containment vessel and pressure suppression system used in the failing reactors at Japan’s Fukushima Daiichi plant is physically less robust, and it has long been thought to be more susceptible to failure in an emergency than competing designs. In the United States, 23 reactors at 16 locations use the Mark 1 design, including the Oyster Creek plant in central New Jersey, the Dresden plant near Chicago and the Monticello plant near Minneapolis.

G.E. began making the Mark 1 boiling-water reactors in the 1960s, marketing them as cheaper and easier to build — in part because they used a comparatively smaller and less expensive containment structure.

American regulators began identifying weaknesses very early on.

In 1972, Stephen H. Hanauer, then a safety official with the Atomic Energy Commission, recommended that the Mark 1 system be discontinued because it presented unacceptable safety risks. Among the concerns cited was the smaller containment design, which was more susceptible to explosion and rupture from a buildup in hydrogen — a situation that may have unfolded at the Fukushima Daiichi plant. Later that same year, Joseph Hendrie, who would later become chairman of the Nuclear Regulatory Commission, a successor agency to the atomic commission, said the idea of a ban on such systems was attractive. But the technology had been so widely accepted by the industry and regulatory officials, he said, that “reversal of this hallowed policy, particularly at this time, could well be the end of nuclear power.”

In an e-mail on Tuesday, David Lochbaum, director of the Nuclear Safety Program at the Union for Concerned Scientists, said those words seemed ironic now, given the potential global ripples from the Japanese accident.

“Not banning them might be the end of nuclear power,” said Mr. Lochbaum, a nuclear engineer who spent 17 years working in nuclear facilities, including three that used the G.E. design.

Questions about the design escalated in the mid-1980s, when Harold Denton, an official with the Nuclear Regulatory Commission, asserted that Mark 1 reactors had a 90 percent probability of bursting should the fuel rods overheat and melt in an accident.

Industry officials disputed that assessment, saying the chance of failure was only about 10 percent.

Michael Tetuan, a spokesman for G.E.’s water and power division, staunchly defended the technology this week, calling it “the industry’s workhorse with a proven track record of safety and reliability for more than 40 years.”

Mr. Tetuan said there are currently 32 Mark 1 boiling-water reactors operating safely around the globe. “There has never been a breach of a Mark 1 containment system,” he said.

Several utilities and plant operators also threatened to sue G.E. in the late 1980s after the disclosure of internal company documents dating back to 1975 that suggested that the containment vessel designs were either insufficiently tested or had flaws that could compromise safety.

The Mark 1 reactors in the United States have undergone a variety of modifications since the initial concerns were raised. Among these, according to Mr. Lochbaum, were changes to the torus — a water-filled vessel encircling the primary containment vessel that is used to reduce pressure in the reactor. In early iterations, steam rushing from the primary vessel into the torus under high pressure could cause the vessel to jump off the floor.

In the late 1980s, all Mark 1 reactors in the United States were also retrofitted with venting systems to help reduce pressure in an overheating situation.

It is not clear precisely what modifications were made to the Japanese boiling-water reactors now failing, but James Klapproth, the chief nuclear engineer for General Electric Hitachi, said a venting system was in place at the Fukushima plants to help relieve pressure.

The specific role of the G.E. design in the Fukushima crisis is likely to be a matter of debate, and it is possible that any reactor design could succumb to the one-two punch of an earthquake and tsunami like those that occurred last week in Japan.

Although G.E.’s liability would seem limited in Japan — largely because the regulatory system in that country places most liability on the plant operator — the company’s stock fell 31 cents to $19.61 in trading Tuesday.
From ABC News comes this piece, citing an insider to the design, someone whose futile attempts to warn those in charge are eerily remniscent of the Challenger fiasco:

Thirty-five years ago, Dale G. Bridenbaugh and two of his colleagues at General Electric resigned from their jobs after becoming increasingly convinced that the nuclear reactor design they were reviewing -- the Mark 1 -- was so flawed it could lead to a devastating accident.

Questions persisted for decades about the ability of the Mark 1 to handle the immense pressures that would result if the reactor lost cooling power, and today that design is being put to the ultimate test in Japan. Five of the six reactors at the Fukushima Daiichi plant, which has been wracked since Friday's earthquake with explosions and radiation leaks, are Mark 1s.

"The problems we identified in 1975 were that, in doing the design of the containment, they did not take into account the dynamic loads that could be experienced with a loss of coolant," Bridenbaugh told ABC News in an interview. "The impact loads the containment would receive by this very rapid release of energy could tear the containment apart and create an uncontrolled release."

. . . GE told ABC News the reactors have "a proven track record of performing reliably and safely for more than 40 years" and "performed as designed," even after the shock of a 9.0 earthquake.

Still, concerns about the Mark 1 design have resurfaced occasionally in the years since Bridenbaugh came forward. In 1986, for instance, Harold Denton, then the director of NRC's Office of Nuclear Reactor Regulation, spoke critically about the design during an industry conference.

"I don't have the same warm feeling about GE containment that I do about the larger dry containments,'' he said, according to a report at the time that was referenced Tuesday in The Washington Post.

"There is a wide spectrum of ability to cope with severe accidents at GE plants,'' Denton said. "And I urge you to think seriously about the ability to cope with such an event if it occurred at your plant.''

Bridenbaugh told ABC News that he believes the design flaws that prompted his resignation from GE were eventually addressed at the Fukushima Daiichi plant. Bridenbaugh said GE agreed to a series of retrofits at Mark 1 reactors around the globe. He compared the retooling to the bolstering of highway bridges in California to better withstand earthquakes. . .When asked if that was sufficient, he paused. "What I would say is, the Mark 1 is still a little more susceptible to an accident that would result in a loss of containment."
GE has placed a response of sorts on its website

GE’s thoughts and condolences continue to be with the people of Japan affected by the devastating impact of last Friday’s unprecedented natural disaster. And GE officials continue to closely monitor the events at the Fukushima Daiichi Power Plant, which suffered a loss of power after the tsunami struck the site.

During the magnitude 9.0 earthquake (the fifth largest earthquake in recorded history), the GE Boiling Water Reactors (BWR), performed as designed and initiated safe shut down processes. We understand that the back-up generators performed as designed to begin the cooling process. Shortly thereafter, we understand that the tsunami disabled the back-up emergency generation systems.

The fleet of GE Hitachi Nuclear Energy (GEH) BWR reactors has a proven track record of performing reliably and safely for more than 40 years.

GE has been in the nuclear industry for more than half a century. There are currently 92 GE-built BWR plants and plants using the licensed GE BWR design operating globally. Our BWR designs meet the rigorous regulatory requirements of the U.S. Nuclear Regulatory Commission (NRC) and other government regulators and have proven to be safe and reliable. Our reactors are one of the workhorses of the industry.

The Unit 1 reactor at the Fukushima Daiichi site went into commercial operation in 1971; it is a BWR-3, with a Mark I containment system. That means that the reactor is the third generation of the BWR design. The reactor in Unit 1 is the same type as several reactors in the U.S., although every reactor is designed specifically for each project and site. All GEH BWR designs meet all NRC requirements for safe operation during and after an earthquake for the areas where they are licensed and sited.

BWR reactors are designed to be able to safely shutdown in the event of an earthquake or other natural disaster.
A rather bare-bones explanation, but I wouldn't be saying too much at this point, either.

Is there any culpability here?  We will probably never know.  But as usual, it all really comes back to listening.  To your employees with expertise in such areas. Or to your customers.  It is all about remembering that one's ego, personal or corporate, needs to end where the life and livelihood of others begins.

It's rather ironic, really.  No one would have been at all surprised had the containment vessels ruptured outright in the 9.0 earthquake.  That would have been tragic, but acceptable at some level.  After all, the structures were never designed to withstand that sort of an impact.  But since the reactors did survive, only to fail from what may be a lesser design flaw, the pressure is on (pun intended). 

Let us hope and pray for the best.


Anonymous said...

What did GE say when their scanners resulted in overexposed patients for CT Perfusion studies: "The equipment performed as it was designed".

23 Skidoo said...

As to perfusion studies... I would think that whoever sets the protocols within the machine would know that X amount of KVp X Ma X time or MAS would =X amount of radiation...before that protocol ever exposed a patient... so, why isn't the person who designed the protocol in trouble? regardless of whether or not the machine had alarms built in at a certain amount of radiation, the protocols should never drive the machine so blindly that they emit that much.
If my CR shot some incredible amount of radiation based on presets for a particular study...someone surely would be in trouble...If someone got 60 minutes of fluoro time for an upper GI, soneone would say something hopefully long before it got that much time...why is it any different here...?

Q8PACS said...

Industry should diffenitly be blamed but not responsible. Hospitals are the ones responsible they should have done enough effort to check radiation doses. Moreover, Vendors are to be blamed because they have to have enough measures on the machine to avoid such overdose. I have heard vendors complain many times that regulations are obstructing breakthroughs in medical imaging..I wonder if vendors still want to have less rules & regulations in radiation protection.