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Have you ever been in an argument[br]about nuclear power?

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We have, and we found it[br]frustrating and confusing,

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so let’s try and get to grips[br]with this topic.

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It all started in the 1940s.

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After the shock and horror of the war[br]and the use of the atomic bomb,

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nuclear energy promised to be a peaceful[br]spin-off of the new technology,

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helping the world get back on its feet.

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Everyone’s imagination was running wild.

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Would electricity become free?

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Could nuclear power help[br]settle the Antarctic?

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Would there be nuclear-powered cars,[br]planes, or houses?

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It seemed that this was just a few[br]years of hard work away.

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One thing was certain: the future[br]was atomic.

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Just a few years later, there was a sort[br]of atomic age hangover;

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as it turned out, nuclear power was very[br]complicated and very expensive.

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Turning physics into engineering[br]was easy on paper,

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but hard in real life.

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Also, private companies thought that[br]nuclear power was much too risky

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as an investment; most of them would much[br]rather stick with gas, coal, and oil.

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But there were many people who[br]didn’t just want to abandon

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the promise of the atomic age;[br]an exciting new technology,

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the prospect of enormously[br]cheap electricity,

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the prospect of being independent[br]of oil and gas imports,

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and, in some cases, a secret desire to[br]possess atomic weapons

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provided a strong motivation[br]to keep going.

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Nuclear power’s finest hour finally came[br]in the early 1970s, when

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war in the Middle East caused oil prices[br]to skyrocket worldwide.

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Now, commercial interest and investment[br]picked up at a dazzling pace.

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More than half of all the nuclear reactors[br]in the world were built

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between 1970 and 1985.

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But which type of reactor to build,[br]given how many different types

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there were to choose from?

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A surprising underdog candidate[br]won the day:

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the light water reactor.

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It wasn’t very innovative, and it wasn’t[br]too popular with scientists,

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but it had some decisive advantages:

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it was there, it worked, and it wasn’t[br]terribly expensive.

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So, what does a light water reactor do?

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Well, the basic principle is shockingly[br]simple:

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it heats up water using an artificial[br]chain reaction.

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Nuclear fission releases several million[br]times more energy

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than any chemical reaction could.

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Really heavy elements on the brink of[br]stability, like uranium-235,

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get bombarded with neutrons.

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The neutron is absorbed, but the result[br]is unstable.

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Most of the time, it immediately splits[br]into fast-moving lighter elements,

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some additional free neutrons, and[br]energy in the form of radiation.

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The radiation heats the surrounding water,[br]while the neutrons repeat the process

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with other atoms, releasing more[br]neutrons and radiation

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in a closely controlled chain reaction,[br]very different from the fast, destructive

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runaway reaction in an atomic bomb.

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In our light water reactor, a moderator[br]is needed to control the neutrons’ energy.

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Simple, ordinary water does the job, which[br]is very practical, since water’s used

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to drive the turbines anyway.

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The light water reactor became prevalent[br]because it’s simple and cheap.

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However, it’s neither the safest, most[br]efficient, nor technically elegant

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nuclear reactor.

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The renewed nuclear hype lasted barely[br]a decade, though;

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in 1979, the Three Mile Island nuclear[br]plant in Pennsylvania

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barely escaped a catastrophe when[br]its core melted.

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In 1986, the Chernobyl catastrophe[br]directly threatened Central Europe

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with a radioactive cloud, and in 2011[br]the drawn-out Fukushima disaster

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sparked new discussions and concerns.

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While in the 1980s 218 new nuclear power[br]reactors went live,

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their number and nuclear’s global share of[br]electricity production has stagnated

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since the end of the ’80s.

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So what’s the situation today?

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Today, nuclear energy meets around 10% of[br]the world’s energy demand.

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There are about 439 nuclear reactors[br]in 31 countries.

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About 70 new reactors are under[br]construction in 2015,

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most of them in countries[br]which are growing quickly.

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All in all, 116 new reactors are[br]planned worldwide.

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Most nuclear reactors were built more than[br]25 years ago with pretty old technology.

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More than 80% are various types of[br]light water reactor.

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Today, many countries are faced with[br]a choice: the expensive replacement of

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the aging reactors, possibly with more[br]efficient, but less tested models,

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or a move away from nuclear power towards[br]newer or older technology

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with different cost and environmental[br]impacts.

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So, should we use nuclear energy?

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The pro and contra arguments will be[br]presented here next week.

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