(quiet electronic tune)
- [William] This is the second most powerful
supercomputer on the planet.
It is 7000 square feet of racks, wires, and blinking lights.
It has a few hundred thousand times more punch
than your laptop.
Its name is Sierra.
(computer music)
The computer is housed
at the Lawrence Livermore National Laboratory,
just east of the San Francisco Bay.
It's been up and running for most of 2018,
but the lab just recently held
an official dedication for it,
and we checked it out.
We took a tour of the computer room,
we got commemorative coins,
and experts told us all about the exciting work
that Sierra's been doing.
It's been modeling earthquakes,
doing cancer simulations,
exploring traumatic brain injuries,
and a lot more.
And then:
- Howdy.
- [William] We were all greeted by Rick Perry,
the Secretary of Energy for the United States.
- To the countless engineers and the technicians,
the electricians, designers, and code developers
who made Sierra a reality,
America applauds your magnificent achievement.
(applause)
- That happened because, early next year,
Sierra will be air gapped.
That means that it'll be completely cut off
from any computer network,
and it will mostly stop studying earthquakes
and brain injuries.
It'll turn into a little island of processing power,
and its operations will be classified.
And that's when its real job begins.
(computer music)
Sierra's story begins in 1992,
with the last nuclear bomb the United States ever tested.
Called Divider, the bomb capped off almost 50 years
of nuclear weapons tests and more than 1000 explosions.
Since then, the US has neither tested a nuke,
nor designed any entirely new warheads.
This is thanks, in part,
to a landmark nonproliferation treaty
signed by most of the world back in 1970.
Among other things,
the treaty called for an end to the arms race
and a good-faith effort to reach complete disarmament.
There's been a lot of progress since then,
and today the global stockpile is maybe a sixth
of what it was in the '80s.
But, of course, the US never did disarm entirely.
Neither did Russia or most other nuclear nations.
Today, the United States maintains a stockpile
of about 4000 aging, yet untestable, nuclear weapons.
Which leaves the government in a bind.
- When they were built, they weren't intended to last
for 30 to 40 or even 50 years.
We were on a cycle of replacing weapons
on a regular schedule.
A decade or two in the stockpile would be kind of average.
- [William] Brian Pudliner is a code physicist
at the Livermore Lab, and starting next year
he's going to use Sierra to tackle this Catch-22
in our defense policy.
As nuclear weapons age past their lifespan,
their reliability becomes suspect.
But with testing out of the question,
it's harder and harder to answer basic but scary questions
about our arsenal.
If we ever had to use a 40 year old nuclear missile,
would it launch properly?
Would it reach its target?
Would it explode?
- The things that we're concerned about is exactly that.
The performance from using the weapon,
but also in transporting the weapon,
how it's stored,
will it be safe if it falls into the wrong hands,
will its safety features keep it from being used?
- Sierra is the latest answer to that problem.
All those stacks of processors
can simulate questions the military might have
about its arsenal.
Exactly what questions, that's classified.
But, as the weapons age,
parts degrade and need to be repaired or swapped out.
This could be anything from the weapon's enclosure
to the core of plutonium sitting inside.
Sierra's job will be to model these changes
and run simulations to predict
whether anything would break in a real-world detonation.
And that job?
It gets harder the older the bombs are.
- As the weapons age,
and we have to refurbish them to keep them alive for longer,
we keep making more and more changes
that take them further and further away
from what was tested.
- One example is the W80 Warhead.
They were manufactured as far back as the early 1980s,
and the military hopes to keep them online
for years to come.
But they need work.
The conventional explosives
used to trigger the bomb's fission stage
need to be replaced,
but those original compounds have been retired.
Sierra needs to simulate new explosives
until it finds one that we can trust with a real detonation.
One that, hopefully, will never happen.
Sierra's work falls under the government's
Stockpile Stewardship Program.
Over the years,
the program has included 12 other supercomputers,
the world's largest laser,
and even explosive tests (alert sound)
using plutonium,
(crash)
just not enough for a full nuclear chain reaction.
We wanted an outside take on all of this,
so we called Daryl Kimball,
the executive director of the Arms Control Association.
He's glad that there are no more live nuclear tests,
but he hasn't forgotten that big treaty from 1970.
That commitment to disarm.
- If the United States today, 50 years later,
is continuing to seek to maintain its existing stockpile,
and in some ways improve and upgrade it, as we are,
now I see that as fundamentally incompatible in the long run
with our legal obligation to pursue nuclear disarmament.
- Daryl pointed to a nuclear posture review
that the Trump administration published this year.
He says that the review is bullish
on new nuclear capabilities for the military.
Which means the line could further blur
between maintaining old weapons
and turning them into new ones.
- The door is open, in the sense that, you know,
we don't have a hard and fast policy
against new nuclear warhead designs.
This research could, in my view, go in the wrong direction
if the policymakers in Washington allow it to.
- [William] The researchers at Lawrence Livermore,
they don't wade too far into that debate.
- What we do is we answer questions
for the Department of Energy.
- [William] Terri Quinn runs
Livermore's entire computing center,
and to her, stockpile stewardship is specific and practical.
- We get requirements from the military
as to what they want these weapons to do,
and then we do the analysis of it,
and whatever experiments and testing we can do,
and we run things on computers,
and then we give them answers back.
They make the decisions.
We're here as, really, scientific and technical experts
to answer those questions.
- The need for supercomputers isn't going anywhere,
and Sierra's successor, El Capitan, is already in the works.
It'll be another huge leap forward,
and another supercomputer reserved for the military.
- And they want to do even more complex 3-D problems,
and many, many, many more of them,
than we believe that we can do on Sierra.
And we'll need something that's at least
an order of magnitude, which is 10 times bigger,
in order to carry out those calculations.
- [William] For now, Livermore's other science work,
the earthquake simulations,
the precision medicine,
the astrophysics,
it'll still happen here and there at Sierra,
if there's time.
The weapons come first.
- As long as we have nuclear weapons,
we will need simulation.
Being able to predict, you know,
if this weapon is around for a hundred years,
what happens?
Is going to be something
that we'll be working on for a while.
(computer music)
- For what it's worth,
the number one most powerful supercomputer on the planet
is called Summit,
and it's at the Oak Ridge National Laboratory in Tennessee.
It has a similar architecture to Sierra,
but it's unclassified,
so it spends all its time on biology and astrophysics.
Basically, all the civilian stuff.