Confessions of a nuclear power safety expert

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“I soon came to the conclusion that neither international cooperation nor technological advancements would guarantee human societies to build and safely run nuclear reactors”

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by John Perlin
Miller-McCune,  Junec 14, 2011

When Italy decided in the mid-’70s to add nuclear power to its power portfolio, young mechanical and nuclear engineer Cesare Silvi was among those attracted to the opportunities it presented. His work centered on nuclear safety issues — in particular, what might happen if something unexpected struck a power plant.

Corners he saw cut there eventually soured Silvi on that endeavor. His next position — at the Italian Commission on Nuclear and Alternative Energy Sources, which included work on nuclear disarmament — eventually soured him on nuclear energy itself.

“[If we] continue with nuclear power, there will definitely be worse accidents,” he argued in the wake of Japan’s Fukushima Daiichi disaster. Over the weekend, Italian voters agreed and overwhelming rejected restarting nuclear power in their country.

“Why not consider Three Mile Island, Chernobyl and Fukushima as warnings of greater catastrophes to come and avoid the inevitable by shutting them down, much like changing your diet and/or lifestyle after finding out that your cholesterol or blood pressure is elevated, rather than continuing down the same path until a heart attack or stroke strikes?”

In the meantime, he suggests that wrangling existing power plants requires a global response toward the dangers he predicts.

“Instead of a Kyoto accord,” he says, “we will have to have some kind of multilateral nuclear agreement to deal with such threats.”

In the last two decades, Silvi has gone on to acclaim in the world of solar energy, where has been president of the International Solar Energy Society and founder of the Italian Group for the History of Solar Energy.


Silvi originally worked in the north of Italy as a engineer. He did not like the polluted Po River valley, where the smell from various industries near his flat — despite his boss’ assurances of “You’ll get used to it” — annoyed him.

Then the 1973 Arab-Israeli War and its attendant oil crisis prompted the Italian government to consider nuclear energy, and a door opened for Silvi. The newly formed Italian National Commission on Nuclear Energy sought out young engineers like Silvi, who saw the opportunity as a means to return home to Rome. His top scores on the entrance tests won him a spot in the Directorate for Nuclear Safety and Radioactive Protection, and in 1975, the directorate tasked Silvi to examine and analyze threats to the well-being of nuclear power plants from the outside environment.

“I was looking at low-possibility events, like a meteor striking the housing of a reactor or a car thrown at it by a tornado. These definitely had a small chance of happening, but the end result would have been horrific.” Plus, he says now, the proliferation of nuclear plants just adds more targets.

“Many laughed at such speculation and planning,” he says, “but then again, how many would have taken seriously a recommendation of extending the height of the seawall at Fukishima another six meters? They would have questioned your sanity, if you had argued that the 10-meter barrier was inadequate.

“Our problem is that we don’t know what will happen on any scale of time. Such uncertainty is OK when dealing with train trips or dinner choices. But it becomes problematic when considering the possible spread of very dangerous material that will stay deadly for hundreds, if not thousands, of years.”

In his introduction to risk analysis, Silvi provides a very simple equation: R=PxC. In English, that translates to the probability of something happening (the P) times the consequences if it does (C) equals the risk to society (R).

He illustrates this by comparing driving on the Italian highway, the Autostrada, with running a nuclear power station. Driving on the Autostrada has a low risk to the general population. A possibility does exist that you will crash, and perhaps die as a result, but the consequences of the accident to the general society will be next to nil. That’s why countries let almost anyone drive. So a moderately high P times a very low C equals a small risk to society as a whole.

On the other hand, the chance of an earthquake and tsunami of the magnitude that hit Japan are quite remote, especially occurring in tandem, which makes for a tiny P. But the consequences — the C — of them imperiling a nuclear power plant are huge, leading to a much higher risk to society.

That equation played out in the Soviet Union a quarter-century ago at Chernobyl, and the aftereffects still ripple throughout Europe. A 1,600-square-mile exclusionary zone in Ukraine and southern Belarus remains off limits. Students gestated during the Chernobyl disaster in contaminated regions as far north as Sweden and Norway have shown poorer performance in school and lower verbal IQ scores.

Silvi’s sincere assessment of outside threats ultimately butted up against unfortunate human constraints.

“One day,” Silvi recalls, “the boss said, ‘Figure out how far should a nuclear plant be from an airport.’ As I did my study, I found that it wasn’t too easy to protect the reactor from a plane crash. The plant can be perfect from the inside, but the problem arises: How many low-probability events that could result in devastating consequences do you protect against through proper construction before such expenditures make the plant too costly to operate? Even if we could affordably, say, pay to reinforce the plant to withstand a hit from a plane or missile, the question never leaves you — ‘Have I figured in everything that might damage the nuclear reactor over its long lifetime?

“I left the field because I couldn’t do my analyses as I thought necessary. There was this nuclear power plant [the Caroso Nuclear Power Plant] in the north of Italy, along the Po River. An oil pipe broke and caught fire six kilometers from the plant. Oil also spilled into the river. It clogged the reactor’s condenser. After that, my team discovered there were four pipelines less than 500 meters from the plant. I felt it was necessary to determine what was flowing through them.

“But the boss complained, ‘You’re trying to get at too many details,’ and stopped the study. It turned out that some very powerful person owned the pipelines and was hiding what was going through those pipes for tax purposes.”

(Italian voters in 1987 decided to shutter all the nation’s nuclear plants and by 1990 they were closed, although the government opted to restart nuclear power in 2008. Post-Fukushima, the country has placed a moratorium on those plans and over the weekend the country’s voters decisively rejected a return to nuclear power.)


So in 1981, Silvi shifted his work to nuclear disarmament with the Agency for the Promotion of European Research, and was working in that field as the Soviet Union spun out of existence. Suddenly, many Warsaw Bloc bases containing atomic arms essentially were abandoned, leaving them vulnerable to nuclear thievery. Silvi was part of a NATO delegation sent to Moscow to account for and inventory atomic supplies throughout Russia.

While at the job, Silvi had an epiphany: “If we are struggling to control the spread of nuclear weapons, why should we extend the technology to civilian use?”

Named a resident fellow of the East West Institute in 1986, being the first physical scientist to labor among its political scientists changed his perspective, he explained on the East West Institute’s blog.

With Chernobyl then in everyone’s mind, he spent his early time there explaining how all nuclear reactors are not created equal.

“With a sheet of paper and a pencil, I illustrated the difference. Cupping the curved sheet in my hand, I placed the pencil at the bottom of the curve to simulate the behavior of a western nuclear reactor. If its equilibrium changes, it rolls back and forth until it finds the stable position again. To simulate nuclear reactor such as the one in Chernobyl, I flipped the curved sheet over and placed the pencil on the top of the curve, illustrating that once equilibrium is lost, it is impossible to control.

“… I soon came to the conclusion that neither international cooperation nor technological advancements would guarantee human societies to build and safely run nuclear reactors in all possible conditions on Earth (earthquakes, floods, droughts, tornadoes, wars, terrorism, climate change, tsunamis, pandemics, etc.). I am sadly reminded of this turning point in my life as I listen to the news about the earthquake, tsunami and extremely worrying nuclear crisis in Japan.”

Upon leaving the Institute, he added, he moved away from nuclear energy and focused on solar energy.

“Nuclear today only generates about 12 percent of the developed world’s electricity. By instituting an energy efficiency program,” Silvi suggests, “we could fill the gap caused by shutting them all down and put this malevolent genie back into the bottle.

“Human history is full of madness, full of catastrophes. Imagine if we had nuclear reactors when we fought wars in the past. If you try to consider all the events that might happen over the years, you start to ask, ‘What are the benefits of such an effort, especially when you have opportunities to get electricity in many other ways?’”


1 Comment

  • Odd, now, that Italy still uses so much nuclear energy. Why is that? Simple: it “exported” it’s nuclear plants to France where these plants produce generation exported to northern Italy…Italy, which thanks the shuttering in 1990, now has the highest carbon footprint in Europe. Congratulations to all anti-nuclear activists in Italy!