Steve McLaughlin: And it seems
to me, you know,
between the time
of those disasters
and now, nuclear power
has become more acceptable;
it's viewed now
in a more positive light
as a clean energy source.
Anna Erickson: I think
the fundamental reason
is the existential threat
that we're facing right now
as a humanity
of global climate change
and the battle with the
hydrocarbon sources of energy.
Steve: But it certainly must be
the case
between those disasters
and today,
safety—I'm assuming
safety has improved,
but maybe safety
has been there all along
and we just haven't really
appreciated it, right?
Anna:  I want to point out that
there's a difference
between safety
and proliferation, right.
So safety is related to how well
can you run the reactor safe,
meaning not affecting the public
health or the reactor health.
The Chernobyl design, it was not
light water reactor-based.
It was designed with
a dual purpose in mind
to produce clean plutonium
for weapons program
and generate electricity
for a civilian program.
That reactor from a safety
standpoint was very different.
It has—it had what we call
positive reactivity coefficient.
What that means is as the
reactor gets hotter and hotter,
the neutrons that
you produce—the reactions,
the main driver of the reaction—
becomes more and more intense.
So instead of shutting down
because it's getting hotter
and less safe,
it actually instigates
the further reactions.
Light water reactors here
in the United States
operate on a different
principle.
What happens
when you heat up the water?
It expands because
its temperature goes up
and density goes down.
And when the density goes down,
the neutrons don't become
as active.
So you actually shut down
the reactor
as you're getting it hotter.
We design those systems with
such safety coefficient in mind,
I think it's safe to say
that nuclear reactors
have one of the safest records
among many industries
in the States.
