[cdn-nucl-l] PBMRs vs Fast Reactors

[George Stanford <gstanford@aya.yale.edu>]

The article below (thanks to John Jacobus & Radsafe)
looks at China's ambitious plans for the pebble-bed
reactor.  As I understand it, although the burnup in such a
reactor can be considerably better than in a thermal reactor
(even with recycle), there is still an inventory of
actinides to dispose of.  It is also my understanding that
spent PBMR fuel is very difficult to recycle -- someone
please correct me if I'm wrong -- to recover the actinides
for burning in a fast-neutron spectrum, which could extract
the (very considerable) unexploited energy and eliminate the
long-term waste.

The IFR concept, for example (metal-fueled fast reactor with
molten salt coolant), offers all the advantages touted for the
PBMR, except it can't run at a high enough temperature to
generate hydrogen by thermal dissociation of water.  The IFR
can provide power for generating hydrogen by electrolysis,
of course -- but with appreciably less efficiency.  On the
other hand, electrolysis can produce hydrogen at or near
the point of use, bypassing many of the troublesome handling
and distribution problems.

Someone should do a dispassionate long-term economic
analysis of IFR (or some other fast-reactor concept) versus
PBMR, taking into account the entire fuel cycle (from mining
to waste management) and energy cycle (from production to
end-use). 

Or has it been done?

        George Stanford
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Wired looks at China's plan for nuclear power.
http://www.wired.com/wired/archive/12.09/china.html

Issue 12.09 - September 2004

   

Let a Thousand Reactors Bloom 
Explosive growth has made the People's Republic of
China the most power-hungry nation on earth. Get
ready for the mass-produced, meltdown-proof future
of nuclear energy.

By Spencer Reiss

China is staring at the dark side of double-digit
growth. Blackouts roll and factory lights flicker,
the grid sucked dry by a decade of breakneck
industrialization. Oil and natural gas are running
low, and belching power plants are burning through
coal faster than creaky old railroads can deliver
it. Global warming? The most populous nation on
earth ranks number two in the world - at least the
Kyoto treaty isn't binding in developing
countries. Air pollution? The World Bank says the
People's Republic is home to 16 of the planet's 20
worst cities. Wind, solar, biomass - the country
is grasping at every energy alternative within
reach, even flooding a million people out of their
ancestral homes with the world's biggest
hydroelectric project. Meanwhile, the government's
plan for holding onto power boils down to a car
for every bicycle and air-conditioning for a
billion-odd potential dissidents.

What's an energy-starved autocracy to do?

Go nuclear.

While the West frets about how to keep its sushi
cool, hot tubs warm, and Hummers humming without
poisoning the planet, the cold-eyed bureaucrats
running the People's Republic of China have
launched a nuclear binge right out of That '70s
Show. Late last year, China announced plans to
build 30 new reactors - enough to generate twice
the capacity of the gargantuan Three Gorges Dam -
by 2020. And even that won't be enough. The Future
of Nuclear Power, a 2003 study by a blue-ribbon
commission headed by former CIA director John 
Deutch, concludes that by 2050 the PRC could
require the equivalent of 200 full-scale nuke
plants. A team of Chinese scientists advising the
Beijing leadership puts the figure even higher:
300 gigawatts of nuclear output, not much less
than the 350 gigawatts produced worldwide today.

To meet that growing demand, China's leaders are
pursuing two strategies. They're turning to
established nuke plant makers like AECL,
Framatome, Mitsubishi, and Westinghouse, which
supplied key technology for China's nine existing
atomic power facilities. But they're also pursuing
a second, more audacious course. Physicists and
engineers at Beijing's Tsinghua University have
made the first great leap forward in a quarter
century, building a new nuclear power facility
that promises to be a better way to harness the
atom: a pebble-bed reactor. A reactor small enough
to be assembled from mass-produced parts and cheap
enough for customers without billion-dollar bank
accounts. A reactor whose safety is a matter of
physics, not operator skill or reinforced
concrete. And, for a bona fide fairy-tale ending,
the pot of gold at the end of the rainbow is
labeled hydrogen.

A soft-spoken scientist named Qian Jihui has no
doubt about what the smaller, safer,
hydrogen-friendly design means for the future of
nuclear power, in China and elsewhere. Qian is a
former deputy director general with the
International Atomic Energy Agency and an honorary
president of the Nuclear Power Institute of China.
He's a 67-year-old survivor of more than one
revolution, which means he doesn't take the notion
of upheaval lightly.

"Nobody in the mainstream likes novel ideas," Qian
says. "But in the international nuclear community,
a lot of people believe this is the future.
Eventually, these new reactors will compete
strategically, and in the end they will win. When
that happens, it will leave traditional nuclear
power in ruins."

Now we're talking revolution, comrade.

Known as China's MIT, Tsinghua University sprawls
across a Qing-dynasty imperial garden, just
outside the rampart of mirrored Blade Runner
towers that line Beijing's North Fourth Ring Road.
Wang Dazhong came here in the mid-1950s as a
member of China's first-ever class of homegrown
nuclear engineers. Now he's director emeritus of Tsinghua's Institute of
Nuclear and New Energy
Technology, aka INET, and a key member of
Beijing's energy policy team. On a bright morning
dimmed by Beijing's ever-present photochemical
haze, Wang sits in a spartan conference room lit
by energy-efficient compact fluorescent bulbs.

"If you're going to have 300 gigawatts of nuclear
power in China - 50 times what we have today - you
can't afford a Three Mile Island or Chernobyl,"
Wang says. "You need a new kind of reactor."

That's exactly what you can see 40 minutes away,
behind a glass-enclosed guardhouse flanked by
military police. Nestled against a brown
mountainside stands a five-story white cube whose
spare design screams, "Here be engineers!" Beneath
its cavernous main room are the 100 tons of steel,
graphite, and hydraulic gear known as HTR-10
(i.e., high-temperature reactor, 10 megawatt). The
plant's output is underwhelming; at full power -
first achieved in January - it would barely
fulfill the needs of a town of 4,000 people. But
what's inside HTR-10, which until now has never
been visited by a Western journalist, makes it the
most interesting reactor in the world.

In the air-conditioned chill of the visitors'
area, a grad student runs through the basics.
Instead of the white-hot fuel rods that fire the
heart of a conventional reactor, HTR-10 is powered
by 27,000 billiards-sized graphite balls packed
with tiny flecks of uranium. Instead of superhot
water - intensely corrosive and highly radioactive
- the core is bathed in inert helium. The gas can
reach much higher temperatures without bursting
pipes, which means a third more energy pushing the turbine. No water
means no nasty steam, and no
billion-dollar pressure dome to contain it in the
event of a leak. And with the fuel sealed inside
layers of graphite and impermeable silicon carbide
- designed to last 1 million years - there's no
steaming pool for spent fuel rods. Depleted balls
can go straight into lead-lined steel bins in the
basement.

Wearing disposable blue paper gowns and booties,
the grad student leads the way to a windowless
control room that houses three industry-standard
PC workstations and the inevitable electronic
schematic, all valves, pressure lines, and
color-coded readouts. In a conventional reactor's
control room, there would be far more to look at -
control panels for emergency core cooling,
containment-area sprinklers, pressurized water
tanks. None of that is here. The usual layers of
what the industry calls engineered safety are
superfluous. Suppose a coolant pipe blows, a
pressure valve sticks, terrorists knock the top
off the reactor vessel, an operator goes postal
and yanks the control rods that regulate the
nuclear chain reaction - no radioactive nightmare.
This reactor is meltdown-proof. 

Zhang Zuoyi, the project's 42-year-old director,
explains why. The key trick is a phenomenon known
as Doppler broadening - the hotter atoms get, the
more they spread apart, making it harder for an
incoming neutron to strike a nucleus. In the dense
core of a conventional reactor, the effect is
marginal. But HTR-10's carefully designed
geometry, low fuel density, and small size make
for a very different story. In the event of a
catastrophic cooling-system failure, instead of
skyrocketing into a bad movie plot, the core
temperature climbs to only about 1,600 degrees
Celsius - comfortably below the balls'
2,000-plus-degree melting point - and then falls.
This temperature ceiling makes HTR-10 what
engineers privately call walk-away safe. As in,
you can walk away from any situation and go have a
pizza.

"In a conventional reactor emergency, you have
only seconds to make the right decision," Zhang
notes. "With HTR-10, it's days, even weeks - as
much time as we could ever need to fix a problem."

This unusual margin of safety isn't merely
theoretical. INET's engineers have already done
what would be unthinkable in a conventional
reactor: switched off HTR-10's helium coolant and
let the reactor cool down all by itself. Indeed,
Zhang plans a show-stopping repeat performance at
an international conference of reactor physicists
in Beijing in September. "We think our kind of
test may be required in the market someday," he
adds.

Today's nuclear power plants are the fruits of a
decision tree rooted in the earliest days of the
atomic age. In 1943, a Manhattan Project team led
by Enrico Fermi sustained the first man-made
nuclear chain reaction in a pile of uranium blocks
at the University of Chicago's Metallurgical Lab.
A chemist named Farrington Daniels joined the
effort a short time later. But Daniels wasn't
interested in bombs. His focus was on a notion
that had been circulating among physicists since
the late 1930s: harnessing atomic power for cheap,
clean electricity. He proposed a reactor
containing enriched uranium "pebbles" - a term
borrowed from chemistry - and using gaseous helium
to transfer energy to a generator.

The Daniels pile, as the concept was called, was
taken seriously enough that Oak Ridge National
Laboratory commissioned Monsanto to design a
working version in 1945. Before it could be built,
though, a bright Annapolis graduate named Hyman
Rickover "sailed in with the Navy," as Daniels
later put it, and the competing idea of building a
rod-fueled, water-cooled reactor to power
submarines. With US Navy money backing the new
design, the pebble bed fell by the wayside, and
Daniels returned to the University of Wisconsin.
By the time of his death in 1972, he was known as
a pioneer of - irony alert - solar power. Indeed,
the International Solar Energy Society's biennial
award bears his name.

By the mid-1950s, with President Eisenhower
preaching "atoms for peace" before the United
Nations, civilian nuclear power was squarely on
the table. The newly created General Atomics
division of General Dynamics assembled 40 top
nuclear scientists to spend the summer of 1956
brainstorming reactor designs. The leading light
was Edward Teller, godfather of the H-bomb, and
his message to the group was prophetic. For people
to accept nuclear power, he argued, reactors must
be "inherently safe." He even proposed a practical
test: If you couldn't pull out every control rod
without causing a meltdown, the design was
inadequate.

But Teller's advice was ignored in the rush to
beat the Russians to meter-free electricity.
Instead of pursuing inherent safety, the nascent
civilian nuclear industry followed Rickover into
fuel rods, water cooling, and ever more layers of
protection against the hazards of radioactive
steam emissions and runaway chain reaction. To try
to amortize the cost of all that backup, plants
ballooned, tripling in average size in less than a
decade and contributing to a crippling financial
crunch in the mid-'70s. Finally, partial meltdowns
at Three Mile Island in 1979 and Chernobyl in 1986
pulled the plug on reactor construction in most of
the world.

Even where the pebble-bed concept took root, the
industry's woes conspired against it. In Germany,
a charismatic physicist named Rudolf Schulten
picked up the idea and by 1985 a full-scale
prototype was online - too large, in fact, to meet
Teller's inherent safety test. Barely a year
later, with Chernobyl's fallout raining over
Europe, a minor malfunction at the German reactor
set off nightmare headlines. Before long, the
plant was mothballed.

The twin disasters in Pennsylvania and Ukraine
proved Teller's point and inverted his hopeful
formulation: The Union of Concerned Scientists
pronounced nuclear power "inherently dangerous."
The industry, already staggered by overbuilding
and runaway budgets, ground to a halt. The newest
of the 104 reactors operating in the US today was
greenlighted in 1979. And there our story might
have ended, except

Even as the nuclear establishment was putting all
its efforts into avoiding the klieg lights,
scientists in two faraway places were carrying the
torch for a better reactor. One was South Africa,
where in the mid-1990s the national utility
company quietly licensed Germany's cast-off
pebble-bed design and set about trying to raise
the necessary funds. The other was China, where
the Tsinghua team pursued a Nike strategy: Just do
it.

Frank Wu's glass-walled ninth-floor office at
Innovation Plaza offers a commanding view of
Tsinghua University's leafy campus. That's no
accident: The university co-owns this complex of
gleaming silver towers, designed as a magnet for
high tech startups. Likewise Wu's company,
Chinergy, is a 50-50 joint venture between
Tsinghua's Institute for Nuclear and New Energy
Technology and the state-owned China Nuclear
Engineering Group.

"I just had a call from a mayor in one of the
provinces," says Wu, who came on board as CEO
after a decade spent running financial services
companies in the US (where he adopted the English
first name). "He asked me, 'How much do we have to
pay to get one of those things here?'"

If Wu's pebble-bed "thing" is, well, hot, it's
because Chinergy's product is tailor-made for the
world's fastest-growing energy market: a modular
design that snaps together like Legos. Despite
some attempts at standardization, the latest
generation of big nukes are still custom-built
onsite. By contrast, production versions of INET's
reactor will be barely a fifth their size and
power, and built from standardized components that
can be mass-produced, shipped by road or rail, and
assembled quickly. Moreover, multiple reactors can
be daisy-chained around one or more turbines, all
monitored from a single control room. In other
words, Tsinghua's power plants can do the two
things that matter most amid China's explosive
growth: get where they're needed and get big,
fast. 

Wu and his backers aim to have a full-scale
200-megawatt version of HTR-10 by the end of the
decade. They've already persuaded Huaneng Power
International - one of China's five big privatized
utilities, listed on the NYSE and chaired by the
son of former premier Li Peng - to pick up half of
the estimated $300 million tab. Concrete is
scheduled to be poured in spring 2007.

By the usual glacial standards, that timeline is
nuts for a reactor still on the drawing board.
South Africa's pebble-bed group has been working
on plans for a demonstration unit near Cape Town
since 1993. But with an estimated $1 billion
budget and local environmentalists on the warpath,
the project remains stuck where it's been for
nearly a decade: five to 10 years from completion.

Five to 10 years ago, a lot of today's China was
little more than blueprints. And Wu, who likes to
tell visiting Americans how one of his previous
companies beat Sun Microsystems for the contract
to wire West Point, has distinct advantages. The
INET team, some of whose members studied with
Schulten in Germany, has been prototyping
pebble-bed designs since the mid-1980s. Also
courtesy of the Germans, they have the best
equipment in the world for what is probably the
stickiest technical problem: fabrication of fuel
balls in quantities that could quickly grow to
millions.

By the time Chinergy's pilot plant is up and
running, it's likely that the 30 reactors the
government has planned for 2020 will already be
under way. By then, however, China's grid is
expected to be market-driven, and companies like
Huaneng will have a free hand to put plants where
they're needed and charge whatever the market will
bear. Chinergy's strategy is tailored for this new
environment. Power companies operating in regions
making the transition from rural to industrial to
urban will need to start small, but may suddenly
find themselves struggling to meet unexpected
demand. That's where the modular concept comes
into play: Wu plans to sell power modules -
200-megawatt reactors plus ancillary gear - one at
a time, if necessary. Growing utilities will be
able to add modules as needed, ultimately reaching
the gigawatt range where conventional reactors now
reign. Such installations will be affordable to
start - and they'll become cheaper to operate as
they grow, thanks to economies of scale in
everything from security and technicians to fuel
supply.

Too good to be true? Not according to Andrew
Kadak, who teaches nuclear engineering at MIT
(including a course titled "Colossal Failures in
Engineering"). Kadak is a big-nuke guy by
background. From 1989 to 1997, he was CEO of
Yankee Atomic Electric, which ran - and ultimately
closed - the '60s-vintage plant in Rowe,
Massachusetts. Now he's helping INET refine its
fuel ball technology and working with the US
Department of Energy to build a high-temperature
gas-cooled reactor at the Idaho National
Engineering and Environmental Research Lab.

"The industry has been focused on water-cooled
reactors that require complicated safety systems,"
Kadak says. "The Chinese aren't constrained by
that history. They're showing that there's another
way that's simpler and safer. The big question is
whether the economics will pay off."

In May, British eminence green James Lovelock,
creator of the Gaia hypothesis that Earth is a
single self-regulating organism, published an
impassioned plea to phase out fossil fuels in
London's The Independent. Nuclear power, he
argued, is the last, best hope for averting
climatic catastrophe:

"Opposition to nuclear energy is based on
irrational fear fed by Hollywood-style fiction,
the Green lobbies, and the media. … Even if they
were right about its dangers - and they are not -
its worldwide use as our main source of energy
would pose an insignificant threat compared with
the dangers of intolerable and lethal heat waves
and sea levels rising to drown every coastal city
of the world. We have no time to experiment with
visionary energy sources; civilization is in
imminent danger and has to use nuclear, the one
safe, available energy source, now, or suffer the
pain soon to be inflicted by our outraged planet."

Coming to terms with nuclear energy is only a
first step. To power a billion cars, there's no
practical alternative to hydrogen. But it will
take huge quantities of energy to extract hydrogen
from water and hydrocarbons, and the best ways
scientists have found to do that require high
temperatures, up to 1,000 degrees Celsius. In
other words, there's another way of looking at
INET's high-temperature reactor and its potential
offspring: They're hydrogen machines.

For exactly that reason, the DOE, along with
similar agencies in Japan and Europe, is looking
intently at high-temperature reactor designs.
Tsinghua's researchers are in contact with the
major players, but they're also starting their own
project, focused on what many believe is the most
promising means of generating hydrogen:
thermochemical water splitting. Researchers at
Sandia National Laboratories believe efficiency
could top 60 percent - twice that of
low-temperature methods. INET plans to begin
researching hydrogen production by 2006.

In that way, China's nuclear renaissance could
feed the hydrogen revolution, enabling the country
to leapfrog the fossil-fueled West into a new age
of clean energy. Why worry about foreign fuel
supplies when you can have safe nukes rolling off
your own assembly lines? Why invoke costly
international antipollution protocols when you can
have motor vehicles that spout only water vapor
from their tail pipes? Why debate least-bad
alternatives when you have the political and
economic muscle to engineer the dream?

The scale is vast, but so are China's ambitions.
Gentlemen, start your reactors.

Contributing editor Spencer Reiss
(spencer@upperroad.net) interviewed Bjrrn Lomborg
in Wired 12.06.