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Nuclear Energy Explained: How does it work?

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    Have you ever been in an argument
    about nuclear power?
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    We have, and we found it
    frustrating and confusing,
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    so let’s try and get to grips
    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
    and the use of the atomic bomb,
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    nuclear energy promised to be a peaceful
    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
    settle the Antarctic?
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    Would there be nuclear-powered cars,
    planes, or houses?
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    It seemed that this was just a few
    years of hard work away.
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    One thing was certain: the future
    was atomic.
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    Just a few years later, there was a sort
    of atomic age hangover;
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    as it turned out, nuclear power was very
    complicated and very expensive.
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    Turning physics into engineering
    was easy on paper,
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    but hard in real life.
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    Also, private companies thought that
    nuclear power was much too risky
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    as an investment; most of them would much
    rather stick with gas, coal, and oil.
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    But there were many people who
    didn’t just want to abandon
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    the promise of the atomic age;
    an exciting new technology,
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    the prospect of enormously
    cheap electricity,
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    the prospect of being independent
    of oil and gas imports,
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    and, in some cases, a secret desire to
    possess atomic weapons
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    provided a strong motivation
    to keep going.
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    Nuclear power’s finest hour finally came
    in the early 1970s, when
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    war in the Middle East caused oil prices
    to skyrocket worldwide.
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    Now, commercial interest and investment
    picked up at a dazzling pace.
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    More than half of all the nuclear reactors
    in the world were built
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    between 1970 and 1985.
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    But which type of reactor to build,
    given how many different types
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    there were to choose from?
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    A surprising underdog candidate
    won the day:
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    the light water reactor.
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    It wasn’t very innovative, and it wasn’t
    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
    terribly expensive.
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    So, what does a light water reactor do?
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    Well, the basic principle is shockingly
    simple:
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    it heats up water using an artificial
    chain reaction.
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    Nuclear fission releases several million
    times more energy
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    than any chemical reaction could.
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    Really heavy elements on the brink of
    stability, like uranium-235,
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    get bombarded with neutrons.
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    The neutron is absorbed, but the result
    is unstable.
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    Most of the time, it immediately splits
    into fast-moving lighter elements,
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    some additional free neutrons, and
    energy in the form of radiation.
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    The radiation heats the surrounding water,
    while the neutrons repeat the process
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    with other atoms, releasing more
    neutrons and radiation
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    in a closely controlled chain reaction,
    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
    is needed to control the neutrons’ energy.
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    Simple, ordinary water does the job, which
    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
    because it’s simple and cheap.
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    However, it’s neither the safest, most
    efficient, nor technically elegant
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    nuclear reactor.
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    The renewed nuclear hype lasted barely
    a decade, though;
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    in 1979, the Three Mile Island nuclear
    plant in Pennsylvania
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    barely escaped a catastrophe when
    its core melted.
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    In 1986, the Chernobyl catastrophe
    directly threatened Central Europe
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    with a radioactive cloud, and in 2011
    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
    reactors went live,
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    their number and nuclear’s global share of
    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
    the world’s energy demand.
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    There are about 439 nuclear reactors
    in 31 countries.
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    About 70 new reactors are under
    construction in 2015,
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    most of them in countries
    which are growing quickly.
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    All in all, 116 new reactors are
    planned worldwide.
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    Most nuclear reactors were built more than
    25 years ago with pretty old technology.
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    More than 80% are various types of
    light water reactor.
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    Today, many countries are faced with
    a choice: the expensive replacement of
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    the aging reactors, possibly with more
    efficient, but less tested models,
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    or a move away from nuclear power towards
    newer or older technology
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    with different cost and environmental
    impacts.
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    So, should we use nuclear energy?
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    The pro and contra arguments will be
    presented here next week.
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Title:
Nuclear Energy Explained: How does it work?
Description:

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Video Language:
English
Duration:
05:18

English subtitles

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