Not far from the fabled Silk Road city of
Dunhuang in northwestern Gansu province, Chinese
scientists are drilling boreholes deep into the
Beishan Mountains. It is here that China expects
to permanently store the radioactive wastes that
are accumulating from its rapidly expanding
nuclear power industry.
In the next few
weeks - before the end of the year certainly -
Beijing is expected to make a decision on who will
get contracts to provide reactors for four new
nuclear power plants being built along China's
coast, two at Sanmen in Zhejiang province and two
others at Yangjiang in Guangdong province.
Everyone in the nuclear power industry
from Moscow to Pittsburgh is watching this deal
closely. The four new plants are
likely to be only the first
installments of a wave of new nuclear power plant
construction, which is likely to see as many as 30
new plants constructed in China by 2020.
Currently, China gets only about 2.5% of its
electricity from nuclear power - compared with
about 30% in Japan.
Explosive economic
growth has made China probably the most
power-hungry nation on earth. The burning of coal,
China's most abundant fuel, has polluted the air
in many of China's cities and contributes to the
buildup of greenhouse gases. That, plus concerns
about petroleum depletion over time and the need
for energy independence, lead logically to an
increased reliance on nuclear power.
A glossary of
nuclear waste terms
Low-level waste: Radioactive
residue that builds up in the normal operation
of a nuclear power plant except for the fuel
itself. Often, but not always, of low radiation
content. Usually disposed in specially designed
landfills.
Spent fuel: The fuel
assemblies removed from the core of the reactor
during refueling. Usually stored temporarily
(often for years) in a kind of swimming pool,
called a spent fuel pool.
High level
waste: The liquid residue that remains after
spent fuel is reprocessed (if it is reprocessed)
to recover and reuse uranium and plutonium. The
residue is held temporarily in underground
tanks, then turned into a glass-like substance
and placed in a repository.
Repository: An engineered,
underground storage receptacle designed to
safely store vitrified nuclear waste for
centuries. Not to be confused with a "dump".
Closed fuel cycle: Refers to a
system in which uranium is mined, refined,
enriched, turned into fuel, burned in a reactor
and then reprocessed so that unused uranium and
the plutonium created can be made into new fuel.
China plans a closed fuel cycle system.
Open fuel cycle: Same as above except that spent
fuel is not recycled but treated as waste and
placed in a repository. This is the system
planned for the
US.
Nuclear power has many attractions.
Nuclear plants emit no greenhouse gases, as do
coal-burning power plants. They can run for more
than one year without refueling, saving on fuel
costs. The raw material, uranium, is more
plentiful in China than petroleum, holding out the
promise of lessening dependence on imports. But
nuclear power does have one downside. What do you
do with the waste?
China has nine civilian
nuclear power plants in operation. So far they've
accumulated approximately 1,000 metric tons of
wastes. By the year 2020, if its plans for new
power plants pan out, China will be producing
roughly 1,000 metric tons a year that year and
every year thereafter. By 2040, when China hopes
to have a permanent nuclear waste repository in
operation, it will have accumulated 32,000 tons.
For the moment and for the near future,
the waste is being stored temporarily in spent
fuel pools close to the reactors. Many in the
nuclear industry would not consider these rods
"waste", strictly speaking, since they can be
processed chemically to retrieve valuable
"unburned" uranium and newly created plutonium,
which, in turn can be made into new fuel. This, in
fact, is what the Chinese plan to do. For the time
being, however, the rods remain safely in the
spent fuel ponds.
There is nothing unusual
about this arrangement. The United States has
operated more than 100 nuclear power plants for
the better part of 30 years and still depends
largely on on-site storage. A permanent
underground repository at Yucca Mountain in the
state of Nevada, about 100 miles from Las Vegas,
has yet to get a license. China's equivalent of
Yucca Mountain is the Beihan Mountain area in
northwestern China, where for the past eight years
technicians have been investigating the terrain.
"They are zeroing in on three sites near each
other close to the city of Dunhuang," said an
American government official who recently visited
Dunhuang and attended a Chinese presentation on
nuclear waste disposal there.
Dunhuang and
surrounding desert are the location of the Mogao
Grottos, hundreds of caves containing wall
paintings and painted statues, dating from the 6th
century. Also preserved are thousands of pages of
Buddhist sutras. The Chinese actually pointed to
the survival of these documents for over 1,500
years as evidence of the region's dryness, the
American official recounted.
Why the
concern about humidity? Because dryness is
critical to the safe permanent storage of nuclear
waste. Waste contains many radioactive isotopes
(an isotope is a form of a chemical element) that
last a very long time before the radioactivity
becomes depleted. For example, plutonium-239 has a
half-life of 24,000 years, which means that the
isotope loses only half of its radioactive potency
in that time. These isotopes must be prevented
from leaching into ground water for centuries to
come. That's one reason why most permanent storage
sites are located in deserts, like the Gobi.
One of the most important technical
solutions yet proposed to the problem of
indefinitely containing the radioactive isotopes
in nuclear waste is called "vitrification". This
involves reprocessing the spent fuel to recover
usable material, then converting the liquid
residue into a glass-like solid. The resulting
glass rods are covered with a stainless steel
casing and inserted into specially bored holes in
a suitably dense rock. The Chinese favor granite,
which is abundant in northwestern Gansu province.
The American official who visited the site
recently said the Chinese have been investigating
this region for the past eight years and have
zeroed in on three locations near Dunhuang. If all
goes well, they expect to pick a suitable site
within the next five years, leading to the
construction of a permanent waste repository on
the site, according to this timetable:
2010: Completion of site
surveys and site
selection 2020: Repository
design completed 2050: Site
excavated and ready to receive waste
The
Chinese expect to design and build a civilian
chemical reprocessing complex, probably within 100
kilometers of the waste repository, by this time,
the official said. Spent fuel from nuclear power
plants will be taken there and chemically treated
to recover unused uranium and plutonium. The
latter substances will be recycled into fresh
nuclear fuel; the residue will be vitrified and
buried.
The China National Nuclear
Corporation (CNNC), the operational authority, is
responsible for site selection, construction and
operation of the repository. The State Bureau of
Environmental Protection has oversight authority
for waste disposal. The Everclean Environmental
Engineering Corporation, a subsidiary of CNNC, is
responsible for the disposal of low-level and
intermediate-level waste.
The American
official said their Chinese counterparts were much
concerned about the safe transportation of the
spent fuel from reactor sites to the interior. All
of China's currently operating nuclear plants and
most of the planned new ones are concentrated on
the coast, close to the centers of electricity
demand. The fuel thus has to be moved safely
thousands of kilometers into the interior.
That means upgrading rail networks and
designing safe, fire- and impact-resistant
receptacles to carry spent fuel rods over long
distances. The American delegation reportedly was
generous in sharing US specifications and designs
for special shipment casks, and explaining the
certification processes. China is only at the
beginning stages of developing standards and
regulations for coping with radioactive wastes,
the official said.
"The Chinese are
cooperating with the International Atomic Energy
Agency to adopt guidelines concerning various
aspects of the nuclear fuel cycle, especially the
transportation of wastes by surface means. They
indicated to us that they were going to comply
with all international standards," he said.
China at least has the benefit of time in
its waste disposal efforts, since the waste
repository plans are being made concurrently with
the early stages of nuclear power plant
construction. On-site water-storage spent fuel
ponds can keep fuel safely for 15 years or longer,
before it is sent to other storage pools located
away from the reactors, presumably closer to the
plants where it will be ultimately reprocessed.
China's commercial nuclear
reactors China currently has nine
commercial nuclear power plants in operation and
two more under construction. The Daya Bay and
Lingao plants were designed and built by
Framatome, the French national company that builds
reactors for both domestic use and exports. These
are Pressurized Water Reactors (PWR), the most
common type of civilian reactor, found in nuclear
industries around the world.
The first
three Qinshan plants are PWRs of Chinese design.
The latter two, Qinshan 3-A and Qinshan 3-B, are
heavy water reactors (HWR) of Canadian design.
These so-called CANDU reactors are used
extensively in India and South Korea.
The
two plants being built at Tianwan in Zhejiang
province are PWRs of Russian design and
manufacture, known by the Russian acronym of VVER.
They are an entirely different design from the
Russian plants at Chernobyl, which was a type
called RMBK-1000.
Name
Type
Location
Capacity
Daya Bay
1
PWR
Guangdong
944 MWe
Daya Bay
2
PWR
Guangdong
944 MWe
Lingao
A
PWR
Guangdong
938 MWe
Lingao
B
PWR
Guangdong
938 MWe
Qinshan
1
PWR
Zhejiang
279 MWe
Qinshan
2-A
PWR
Zhejiang
610 MWe
Qinshan
2-B
PWR
Zhejiang
610 MWe
Qinshan
3-A
HWR
Zhejiang
665 MWe
Qinshan
3-B
HWR
Zhejiang
665
MWe
Note:
1,000 MWe, or "megawatts electrical", is
sufficient power to serve a city of about half a
million people.
Veteran Asia
correspondent Todd Crowell comments on
Asian affairs at Asia
Cable. He has worked
in the nuclear power industry.
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