Nuclear Power Revisited

By Dave Pulver:

Countries worldwide increasingly view nuclear power as an important part of the green power transition, France and South Korea, for example.  Currently, France gets 70% of its electricity from nuclear.  South Korea recently restarted construction on two nuclear power plants.

The Russian war in Ukraine and heat waves worldwide have again brought energy policy into focus.  European governments are debating energy policy as they work through sanctions on Russia for its aggressive actions in Ukraine.  In a way, the European Union is a microcosm of the world’s energy policy challenges.  The EU has found itself in a challenging position as it struggles to expand renewable energy capacity alongside its greenhouse gas reduction goal.  As of 2023, The EU’s renewable energy production is 20.5% of its total energy consumption.  This figure is up from 17% in 2017, an increase of only 3.5% in the last six years.  The renewable energy challenge is not limited to the EU, as global renewable energy only reached 13.8% of total energy consumption as of 2018.

In a policy move antithetical to fossil fuel reduction, former Chancellor Angela Merkel placed Germany on a path to decommission all its nuclear power plants by the end of the year.  This strategy placed a premium on cleaner-burning natural gas, delivered in part by the Nord Stream II pipeline between Russia and Germany, to reduce greenhouse gas emissions.  However, the Nord Stream II pipeline is opposed by the US government out of concerns that it would increase Russian influence, and Germany has yet to approve its operation.  If approved, Nord Stream II would provide an additional (55) billion cubic meters of natural gas per year to the European Union.  Natural gas is a fossil fuel that emits carbon dioxide and is not a renewable energy source.

While renewable energy production has become more competitive with fossil fuels, engineers have yet to solve the technological problem of energy storage.  Renewables must be able to supply power in sufficient quantity, regardless of weather, before they can become viable as a 100% replacement for fossil fuel.  Currently, engineers solve the problem of the intermittent power nature of wind and solar by applying what is known as “baseload.”  Baseload refers to generators that run year round and are independent of the weather.  Examples are hydroelectric, coal, natural gas, and nuclear.

Conversely, EPA regulations in the US are making it even more difficult to build new fossil fuel generator plants, according to AP News.  Activists maintain that baseload power is not required and that renewable energy can support all our needs and is a green energy source.  However, there are new questions about how the wind and solar industry will dispose of the huge windmill blades and how the precious metals in solar panels will be recycled economically.  One plan calls for them to be buried, just as Finland is doing with nuclear waste.

In the US, nuclear power proponents point to the lack of carbon emissions and the high generation capacity of nuclear.  The Biden administration, recognizing the importance of nuclear energy, recently announced a $6 Billion credit program to delay the closing of aging nuclear plants nearing the end of their operating license.  There are (93) operational nuclear power plants in the US, supplying up to 19.7% of the country’s electrical power.  Renewable Energy sources in the US currently total only 11.9%, by contrast.

Nuclear power opponents point to the reactor accidents at Three Mile Island, Fukushima, and Chernobyl as evidence that nuclear power is unsafe, presenting environmentally catastrophic consequences.

The nuclear power industry, now (68) years old, began in 1954 with the launch of the USS Nautilus.  In addition to the (93) commercial nuclear power plants in the US, the US Navy operates another (79) shipborne reactors.

All nuclear reactors in the world share a common attribute: they all use a PWR (Pressurized Water Reactor) design.  By definition, a PWR reactor requires a pumped water-cooling system that conducts the thermal energy from the reactor vessel to the steam generator but also prevents the reactor’s solid fuel core from melting down.  In other words, the cooling system, a mechanical system susceptible to failure, must absolutely work to prevent a reactor core from melting in an accident.   The nuclear accidents at Three Mile Island, Fukushima, and Chernobyl all involved cooling system failures in one way or another.   Three Mile Island combined an instrumentation failure with human error.  An earthquake and resulting tidal flood triggered the Fukushima reactor failure.  And Chernobyl combined a serious design flaw with human error.

Molten Salt Reactors or MSR is a design alternative to the Pressurized Water Reactor.  The Oak Ridge National Laboratory successfully operated an experimental MSR reactor from 1965 through 1969.  MSR reactors can use liquid fuel; typically Thorium suspended in molten salt.  MSR reactors differ from PWR designs because the cooling pump must operate to “keep” the nuclear reaction going.  Should the cooling pump fail, a “freeze plug” at the bottom of the reactor vessel melts, dumping the liquid fuel into a large containment tank.  The fuel then expands and solidifies in this tank, increasing the relative distance between the atoms within the nuclear fuel, squelching the atomic reaction, all without human intervention.  In this way, MRS reactors operate in a “failsafe” mode as opposed to PWR reactors which can fail catastrophically if the cooling system stops.

Molten Salt Reactor design is not yet mature, and engineering work remains.  In 1965, when Oak Ridge conducted their experiments, materials science had not evolved sufficiently enough to deal with molten salt’s corrosive properties effectively.  European countries, as well as China, are researching reactors based on the MSR theme.

Nuclear proponents cite renewable energy’s slow buildout as a clear case for adopting next-generation nuclear power to combat global warming.

Bio: Dave Pulver is a staff writer at NFN.  A retired communications engineer of 35 years, his interests include technology, history, civics, and politics.

davepulver.com