features an interview published in "The Chronicle" of Livorno on Monday 14 March, the engineer Paul Forzano, 63, spent 28 years at Ansaldo Nuclear.
D. Savonanews.it: Engineer, his impressions of the nuclear situation in Japan?
R. Paul Mechanical Engineering Nuclear Force: are not good, unfortunately. They were not already by the news last night, when it became known that "lacking the power the cooling system was not working." This is a story not credible, because the problem of cooling is always very sensitive when designing a power plant, and we always put in a position to have generators in case replacement is a power failure. You use the special diesel, which does not need heating as the traditional diesel engine but going full speed as they are lit: we had them in the middle we were building a Caorso 40 years ago, so there should be necessarily even in Fukushima.
D. SN: So what could have happened?
Ing Force: difficult to make assumptions based, but the quake may have damaged the diesel, either directly or indirectly: enough for a truck parked nearby, due to the earthquake, is thrown against a generator, and that goes into failure. assumptions may be a thousand. The fact is that the only interruption of electricity "normal" could not have caused a problem of this size.
D. SN: What, exactly, when a reactor is overheating?
Forzano Ing: It 'a very serious problem because the plant does not operate as traditional ones in which you load each time the fuel that is necessary: \u200b\u200b a nuclear power plant is loaded with the power to go on a year and a half to two years. you put in the maximum amount of uranium fuel rods.
Then you have two control systems, which are called "control rods" and that in practice are two different systems:
- the first is used for regulating and limiting the power, and almost never touch it. At most you can give some small adjustment when needed.
- The second is that which allows the " shut down" or "close all", turn off the nuclear reaction. If these systems are faulty, are serious problems. Very serious.
To understand why we need to understand how it works a nuclear reaction: that is a bit 'as a pool table. When it hits another ball, two balls fall speed: a slow and the other accelerates. To have nuclear energy we must create the maximum amount of these "bumps" between the balls (or neutrons), and the best way to have more impact is to reduce the speed. This requires a "moderator", which is water. Water has two functions: it acts as a moderator of the speed, but at the same time serves to cool. Unfortunately, when the water heats, it becomes steam, which turns air: air, on the contrary water, is a "heater" and not a cooler. If a bar is hit by steam instead of water, you can get the merger.
D. SN: But you can not intervene with the control bars?
R. Ing Forzano No, because the bar, before melting, is deformed. And the system through which control rods act is quite specific: it is a sort of "cage" within which runs the bar of uranium but does not have much game ... around. If the bar is deformed, no longer passes.
D. SN: But then the disaster becomes inevitable?
R. Ing Force: Fortunately not, because there is still a chance: the so-called " poisoning", which is done by the boron. If you fill the nucleus of boron, the nuclear reaction stops.
D. SN: to have done in Japan, hopefully ...
R. Ing Strengths: Hopefully, yes. But there is a problem for uranium poisoning need electricity.
D. SN: We could say that would be another Chernobyl?
R. Ing Force: Unfortunately yes, it could be. Also because there was an explosion, then an emanation of a very high heat: then the reactor should be considered out of control in the sense that if you burn a slash and burn all the other. What they say the various sources, there has already been a leak of cesium, which is a very bad score because it falls on water, vegetation, and then the food chain. The situation can not be considered comforting, even if you just keep calm and not panic.
D. SN: The fact of life elsewhere in the world puts us safe from the risks?
R. Ing Force:
We were never safe: we Italians have been affected by the explosion of Hiroshima and also the tragedy of Chernobyl. Of course you try to hide the fact, as was done in those opportunities and how it is done every day on our own territory for the effects of burning coal, which is not many that do less damage.
But until they tell us, we remain ignorant and quiet ... almost. One thing is certain: the radiation is something you pay for generations. There are isotopes that disappear in fifteen years, but there are others who take millions of years before leaving. of leukemia caused by Chernobyl is still dying today ... and the same will happen to any nuclear disaster, beyond what the media say.
D. SN: It 's a show that nuclear is not sure how often you try to pretend?
R. Ing Force: We need to understand three points:
- First nuclear power, understood as "nuclear", is actually safer - as they are more controlled - for many other industrial products: this has Chicco Testa reason that we heard yesterday evening (Otto e Mezzo, La7 ed) But only in this, unfortunately.
- Second, we must consider that Engineering the risk factor is calculated always and only in a statistical sense: that is, according to the probability of occurrence of an event. The probability of a nuclear accident is very low statistically , having examined all the security systems and all the controls that are executed, but unfortunately the story goes to show that "low" does not mean "nonexistent." Also, when / if the nuclear incident occurs, the consequences are always larger epochal.
- Third as it seems almost minimal in comparison to the consequences of the accident is that the real, big problem of the nuclear waste. that no one has yet figured out how and where to dispose of. It must be remembered that the plant waste is a small part of the whole chain, because they produce waste extraction, and then transport, and then processing, particularly of uranium. The incident is certainly much more impressive, but the most serious risks of nuclear power are unable to treat / dispose of waste. And this must always be remembered, not only when a disaster happens, because maybe now we will say that the plant was the second-generation Japanese, who had 40 years, now there are modern ones and more secure (Same thing already known to Chernobyl ...), but no one can yet say "we have solved the problem of waste." Because it has never been solved and you can not see the horizon, no concrete solution.
D. SN: After recent events, therefore, we should say a firm NO to nuclear power?
- must clarify one thing, though: Before you make any assessment on energy production must take into account a host of factors. You can not say "yes" or "no" based solely on emotion, or a single factor. You have to assess i costi, gli investimenti necessari, la possibilità di approvvigionamento; non dimenticando che diversi combustibili ci costringono a dipendere da terzi e quindi a rimanere legati, nel bene e nel male, alla politica internazionale, l’impatto ambientale e i costi sanitari.
Se teniamo conto di tutto questo ad per esempio, il carbone non è meglio del nucleare: anzi, forse è anche peggio, anche se finora sono stati trascurati elementi che per fortuna oggi cominciano ad emergere, come l’impatto sanitario non solo delle emissioni, ma anche delle radiazioni, superiori a quelle che si riscontrano vicino a una centrale nucleare.
Insomma, l’approccio should be both scientific and economic but unfortunately the only real yardstick for today seems to be an indication that comes from the industrial lobby.
Needless to say, only by investing in renewable energy, solar thermal, you could have Today clean energy, safe and above all endless, but it would be important also to make sure the construction industry, because a third of the energy we consume is due to households and small craft. Even improving the insulation of our homes would result in an energy-saving importance.
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