The human element - By Hugh Gusterson

[bananas]

http://www.thebulletin.org/web-edition/columnists/hugh-gusterson/the-human-element

The human element
By Hugh Gusterson | 1 September 2011

The discussions about the safety of nuclear reactors in the new post-Fukushima world have focused on technical questions: Is it possible to make reactors earthquake-proof? What is the best way to ensure that spent fuel remains safe? What is the optimal design for coolant systems? Can reactors be made "inherently safe"?

Sometimes these discussions make it sound as though the reactors operate all by themselves -- both when they run smoothly or during an accident. But that is to omit the human element. Nuclear reactors are operated by fallible human beings, and at least two meltdowns have been caused by poor human decisions: the 1961 meltdown of an experimental military reactor in Idaho, which killed three operators when one of them withdrew a control rod six times as far as he was supposed to (carrying out a high-tech murder-suicide over a love triangle, according to some accounts), and the Chernobyl accident, which was caused by an ill-conceived experiment conducted outside approved protocols.

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The bottom line: Nuclear safety is threatened by human as well as technical malfunctions, and the risk of disaster can only be attenuated through attention to the principles of social engineering as well as nuclear engineering. While human behavior can always overflow the bounds of our plans for its containment, there are measures that can at least lower the risk of a nuclear disaster caused by human factors: First, the nuclear industry needs to do more to both protect and reward whistle-blowers; and, second, the industry needs regulators with a genuine desire to exercise oversight -- rather than people hoping to increase their income by later going to work for the very companies that they were regulating. Unfortunately, this goes against the ethos of the contemporary United States, where the trend-lines are going in the wrong direction.

[longship]

1. Gees! I remember hearing about the Idaho accident

The guy was manually trying to pull the control rod out of the research reactor. Suddenly it slipped and came out quicker than he could control. Unfortunately, this was the main control rod, which if drawn out too far would allow the reactor to go super-critical. The resulting explosive reaction propelled the control rod out of the reactor and propelled the operator and the control rod up, where he died by being impaled on the control rod which itself stuck itself into the ceiling along with the impaled body.

I have no citation of this. But I heard it when I was a senior in my physics education.

[COLGATE4]

2. I believe he had to be buried in a specially-constructed

heavy lead coffin.

[longship]

3. IIRC, it was a Naval research reactor

But, here's one positive thing about the nuclear US Navy. They've never had an accident with their nuclear vessels at sea. This, in spite of the fact that the Soviet Navy has had multiple incidents.

Kudos to the US Navy. From what I understand, the reactors are never run near their maximum, where they are at risk for an accident.

It's like the nuclear generators in use on deep space probes. They are inherently safe because they are not pushed beyond safety limits. Unfortunately, we cannot say the same about the nuclear power industry.

There are nuke designs which are safer than others. But they are all lower efficiency. When you need GWatts you throw out the safety margins. But when you need to power a ship, you can build them into the design.

Of course, the waste problem still remains huge.

Just saying.

[PamW]

4. It was an ARMY reactor

The US Navy's experience with reactors is spotless. The reactor accident in Idaho being described is the SL-1 reactor accident, and SL-1 was an ARMY reactor:

http://en.wikipedia.org/wiki/SL-1

"The SL-1, or Stationary Low-Power Reactor Number One, was a United States Army experimental nuclear power reactor which underwent a steam explosion and meltdown on January 3, 1961, killing its three operators. The direct cause was the improper withdrawal of the central control rod, responsible for absorbing neutrons in the reactor core."

PamW

[PamW]

5. Inherently Safe Reactors

One approach to safety that side-steps the problem of human error is to have reactors that are inherently safe. That is they rely on the laws of physics for their safety and don't let the human make an error.

This type of design is not unique to reactors; it is found in many fields, like airplanes. The Ruttan-designed Vari-EZ airplane is one type of inherently safe design when it comes to preventing wing stall. In a stall, the wing loses lift because the angle of attack is too great. The proper recovery is for the pilot to lower the nose and decrease the angle of attack. However, there is a natural tendency of a pilot to "pull up" when encountering a stall and that is precisely the WRONG thing to do.

Ruttan designed the Vari-EZ with the wing located to the rear of the center. In front, there is a smaller wing called a "canard" that is designed to stall before the main wing. The carnard also keeps the nose up since the main wing is located so far aft. Before the main wing stalls, the canard wing stalls. When the canard stops providing lift to hold up the nose, the nose is lowered, which is precisely what needs to be done. It doesn't matter if the pilot is trying to pull the nose up; that canard is going to stall and pitch the plane down regardless of what the pilot does.

One can design nuclear reactors with the same type of response where the laws of Physics ( which always work ) can do the right thing, even if the operator makes an error. The Argonne Integral Fast Reactor (IFR) was once such reactor, which also addressed the nuclear waste problem:

http://www.pbs.org/wgbh/pages/frontline/shows/reaction/interviews/till.html

PamW