Missing Features

Most Americans worry about the safety of nuclear power. These concerns usually include:

• Vulnerability to terrorist attack;
• Production of fissile material to make nuclear bombs;
• Environmental impact; and,
• Danger of a meltdown.

Sadly, none of these are real risks to Nuclear power. Modern plants are built with solid concrete walls, have round the clock armed guards and use electronic monitoring. So concerns about terrorist attacks are out.

It’s terribly difficult to make any kind of dirty nuclear bomb from nuclear plant waste, so scratch that risk. Compared to other forms of power, nuclear power is quite clean and spent nuclear material has a safe, permanent home. And with the introduction of modern computer and control systems the danger of a meltdown is far reduced from the days of Chernobyl.

The Real Threat of Nuclear Power

So what is the real threat? Here is a clue. Take a look at the below picture, of the control room from the (now deceased) Trojan Nuclear Power Plant:

See it now?

The greatest danger to nuclear power on this planet is bad usability in the control room.

Believe it. The partial meltdown at Three Mile Island was due largely to a badly designed warning system:

“In order to prevent that pressure from becoming excessive, the pilot-operated pressurizer relief valve (PORV), located at the top of the pressurizer, opened. The valve should have closed again when the excess pressure had been released but it did not do so. The indication to the plant’s operators that the signal to close the valve had been sent was, in the absence of any indication to the contrary, taken by them to mean that the valve had closed.”
* Source: Wikipedia: Three Mile Island accident

The designers of the control system thought that indicators of action were more important than indicators of state. On the contrary, well designed control rooms (contrary to the name, you mostly monitor modern nuclear power plants, not control them) tend to indicate both what actions have occurred AND what the current state of the system is.

Of Bad Controls

Modern computer and control systems using really expensive artificial intelligence can dramatically reduce the risk of a meltdown at a plant. But they don’t stop a control room employee from pressing the “big red meltdown button” when the designers decided to make the button green and labeled it “happy chill out control.”

This is no exaggeration: the control boards of nuclear power plants are notoriously badly designed. Donald Norman’s Design of Everyday Things includes a photo of a nuclear plant control room where operators replaced the identical looking knobs on several controls with beer keg taps of different beers, because the buttons were designed to look identical and the staff easily (and frequently) confused them.

This way they could easily make out whether they wanted to reduce the Heineken level or tweak the Michelob setting.

Recommendations

What can be down to reduce the risk the world faces of nuclear power? Here are a few suggestions:

• Build a testing lab that includes an exact model of the entire control room. Bring in actual nuclear plant control room operators and simulate different scenarios. Simulate a meltdown. Simulate a terrorist attack. Simulate different kinds of mechanical, computer and communication failure. See what kinds of buttons they press in high stress situations.
• Conduct annual usability audits at the working plant. Send a team to monitor the control room, setup cameras and watch controllers in their environment. Interview the actual technicians that work on the scene, not just their supervisors.
• Design each control with care, using natural cues to indicate the function of a control.
• Design similar controls with common visual cues and design dissimilar controls with dissimilar visual cues (cues might be position, form, color, style, type of control, etc).
• Reduce the risk of habituation to false positive error messages by designing warning indicators that vary in color, tone, pitch and loudness while going off.

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