Transcript Securing Fissile Materials What are fissile materials and how are they made? • U-235 is fissile but there isn’t enough pure U235

Securing Fissile Materials
What are fissile materials and how are
they made?
• U-235 is fissile but there isn’t enough pure U235 anywhere to worry about.
• Why not?
U-235
• U-235 is less than 1% of naturally occurring
uranium.
• “Enriching” can increase the concentrations of
U-235 to what is called “highly enriched
uranium” levels > 20% enriched.
• HEU of 80% or 90% is good enough for bombs.
• Nothing requires 100% U-235 so no large
quantities of U-235 exist.
What are fissile materials and how are
they made?
• Highly Enriched Uranium (HEU) is fissile.
• Highly Enriched Uranium (HEU) contains more
than 20% U-235.
• Mined uranium must be enriched to produce
HEU.
What are fissile materials and how are
they made?
• Plutonium (Pu) is fissile.
• Pu is produced in nuclear reactors when U-238 absorbs a
neutron.
How much fissile material is there?
• As of January 2013, the global stockpile of
highly enriched uranium (HEU) is estimated to
be about 1390 tonnes.
• The global stockpile of separated plutonium is
about 490 tonnes, of which about 260 tonnes
is the material in
civilian custody.
Fissile Material Stocks, 2013
Country
HEU tonnes
Military Pu tonnes
Civilian Pu tonnes
Russia
695
128
50.1
United States
604
87
0
France
31
6
57.5
China
16
1.8
0.014
United Kingdom
21.2
3.5
91.2
Pakistan
3
0.15
0
India
0.8
5.2
0.24
Israel
0.3
0.84
-
North Korea
0
0.03
-
Others
15
-
61
Total
1390
234
260
Info from International Panel on Fissile
Materials: www.fissilematerials.org
• Numbers for weapon plutonium for the United
States and United Kingdom are based on official
data.
• Most numbers for civilian plutonium are based on
declarations submitted to IAEA and reflect the
status as of December 31, 2011.
• Other numbers are non-governmental estimates,
often with large uncertainties.
• HEU amounts are 90% enriched HEU equivalent
(with the exception of the number for nonnuclear weapon states).
IPFM
Production of military fissile materials continues in
• India, which is producing plutonium and HEU for
naval propulsion,
• Pakistan, which produces plutonium and HEU for
weapons,
• Israel, which is believed to produce plutonium.
• North Korea has the capability to produce
weapon-grade plutonium and highly-enriched
uranium.
IPFM
• France, Russia, the United Kingdom, Japan,
and India operate civilian reprocessing
facilities that separate plutonium from spent
fuel of power reactors.
• China is operating a
pilot civilian reprocessing
facility.
IPFM
• Twelve countries - Russia, the United States,
France, the United Kingdom, Germany, the
Netherlands (all three are in the URENCO
consortium), Japan, Argentina, Brazil, India,
Pakistan, and Iran – operate uranium
enrichment facilities.
• North Korea is also believed to have an
operational uranium enrichment plant.
1400 tonnes HEU
• A metric ton (tonne) is about 2200 lbs.
• It takes about 50 lbs of HEU to make an atomic
bomb.
• One tonne of HEU could make 44 atomic
bombs.
500 tonnes Pu
• It takes about 10 lbs Pu to make an atomic
bomb.
• One tonne Pu would make 220 atomic bombs.
Which bomb is easier to make?
• The HEU weapon is much easier to make than
a Pu weapon.
• The HEU weapon that destroyed Hiroshima,
Japan had never been tested.
How can HEU be permanently
eliminated?
HEU + DU = LEU
DU is the U-238 discarded during the
enrichment process. HEU can be
“downblended” or unenriched to a lower level
of enrichment that is not explosive and can be
used to fuel existing nuclear reactors.
Why isn’t this being done?
• It has been done!
Megatons to Megawatts
• In February 1993, the Russian Federation and the United
States signed a 20-year, government-to-government
agreement for the conversion of 500 metric tons of Russian
highly enriched uranium from nuclear warheads to lowenriched uranium to fuel U.S. nuclear reactors.
• The agreement became known as the Megatons to
Megawatts program.
• Over the life of the Megatons to Megawatts program, the
low-enriched uranium produced under the agreement
provided about one-third of the enrichment services
needed to fabricate fuel for U.S. nuclear reactors.
• The program was finished in December 2013.
• http://www.eia.gov/todayinenergy/detail.cfm?id=13091
What is being done with US HEU?
• For its part, the US government initially
declared just over 174 tonnes of HEU (of
various enrichments) to be surplus from
military stockpiles.
• Of this, USEC took delivery of 14.2 tonnes.
What is USEC?
• United States Enrichment Corporation
• USEC carried out the Megatons to Megawatts
downblending of 500 tons of excess weapons
HEU to reactor fuel from 1993 to 2013.
• USEC went bankrupt in 2014.
• USEC emerged from bankruptcy as Centrus
Energy.
USEC
• Downblending of the UF6 was completed in
1998, to produce 387 tonnes of LEU.
• Some 13.5 tonnes of the HEU oxide or metal
had been processed by September 2001 to
produce 140.3 tonnes of LEU.
• In 2004 the Nuclear Regulatory Commission
issued a license for downblending 33 tonnes
HEU by Nuclear Fuel Services in Tennessee.
What is Nuclear Fuel Services?
NSF is located in Erwin, Tennessee
• Erwin, Tennessee is just over the mountain
north of Asheville.
• HEU TO LEU CONVERSION (DOWNBLENDING)
• A significant tool in America's nonproliferation effort, NFS' patented HEU-to-LEU
conversion technology is now considered the
best available technology for eliminating HEU
as a potential target of terrorists.
Nuclear Fuel Services
• “Our Erwin, Tennessee operation is committed
to manufacturing specialty nuclear materials
for the U.S. Navy's nuclear fleet and other
customers while protecting its workers, the
public and the environment.”
• US Navy submarines use HEU fuel and the fuel
assemblies are produced by NFS.
• France’s submarines run on LEU which is
better from a nonproliferation perspective.
NNSA
• DOE's National Nuclear Security Administration (NNSA)
in 2005 announced plans to remove a further 200
tonnes of HEU from military stockpiles.
• Of this, 160 tonnes was retained for naval propulsion,
thus postponing the need for building a new uranium
high-enrichment facility for at least 50 years.
• An additional 20 tonnes was reserved for space
missions and for research reactors.
• The final 20 tonnes was to be downblended to LEU for
research reactors, power generation and for 17 tons,
the new reliable fuel supply initiative.
Boring details
• Also in 2005, NNSA said that it was committing
about 40 tonnes of off-specification HEU (with
elevated levels of U-236) to the Blended LowEnriched Uranium (BLEU) program.
• This material would be used by TVA.
• In 2008 NNSA was negotiating with TVA to
release a further 21 tonnes of HEU under the
program, which would yield about 250 tonnes of
LEU, some of which might be sold to other
utilities.
More boring details
• In mid-2007 the NNSA awarded contracts to Nuclear
Fuel Services and Wesdyne International to downblend
17.4 tonnes of HEU from dismantled warheads to be
part of a new international fuel reserve.
• NFS downblended the material in Tennessee to yield
some 290 tonnes of LEU (4.95% U-235) by early 2012.
• Wesdyne, the prime contractor, is then storing 230
tonnes of the LEU at the Westinghouse fuel fabrication
plant in South Carolina to be available for the American
Assured Fuel Supply (AFS).
What is the AFS?
• This first batch of LEU will be available for use in
civilian reactors by nations in good standing with
the International Atomic Energy Agency that have
good nonproliferation credentials and are not
pursuing uranium enrichment and reprocessing
technologies.
• It will also now be available to domestic utilities.
• The fuel – worth some $500 million – will be sold
at the current market price.
Assured Fuel Supply (AFS)
• Access to the fuel reserve will be open to "eligible recipients that
meet certain nonproliferation criteria in the case of supply
disruptions in the nuclear fuel market." The notice, however, does
not specify what these "certain nonproliferation criteria" are.
•
In addition, the Department of Energy would have to confirm that
"there is a fuel supply disruption that cannot be addressed by
normal market mechanisms.”
•
In case all the criteria are met, the recipient would be able to
purchase the LEU through a U.S. intermediary.
• The fuel would apparently be considered "U.S. obligated," so the
recipient would have to obtain U.S. consent regarding handling of
the fuel after it is irradiated in a reactor.
Assured Fuel Supply (AFS)
• Down-blending of 17.4 tonnes will produce about 290
tonnes of LEU, of which about 230 tonnes will
constitute the reserve.
• The rest will be used to pay for the costs associated
with down-blending and processing of the material.
• Most of the down-blending has been already done,
with the rest to be completed in 2012.
• DoE announced that it is ready to accept requests for
purchase of the material from the AFS reserve.
• http://www.fissilematerials.org/blog/2011/08/united_
states_announces_d.html
• In June 2009 NNSA awarded a further contract ($209
million) to NFS and Wesdyne for 12.1 tonnes of HEU which
will yield some 220 tonnes of LEU by 2012.
• This second batch of LEU is to provide fuel supply assurance
for utilities which participate in DOE's mixed-oxide fuel
program utilising surplus plutonium from US weapons.
• (The AFS scheme is consistent with international concerns
to limit the spread of enrichment technology to countries
without well-established nuclear fuel cycles. Russia has
agreed to join the initiative.)
• In the short term most US military HEU is likely to be
blended down to 20% U-235, then stored. In this form it is
not useable for weapons.
• http://www.world-nuclear.org/info/Nuclear-FuelCycle/Uranium-Resources/Military-Warheads-as-a-Sourceof-Nuclear-Fuel/
How is Pu disposed of?
• Sad question!
• Let’s start with the US/Russia “dual track”
program to try and dispose of 34 tonnes of
excess weapons Pu belonging to each country.
• Basically the plutonium can be mixed with DU
and made into mixed oxide reactor fuel (MOX)
or it can be enclosed in glass logs and buried
(vitrified).
• MOX or Vitrify? Russia wants MOX.
Dual Track Program
• In June 2000, the USA and Russia agreed to dispose of at least 34 tonnes
each of weapons-grade plutonium by 2014.
• The USA undertook to pursue a dual track program (immobilisation and
MOX), self-funded, while the G-7 nations were to provide some US$ 2.5
billion to set up Russia's program.
•
The latter was initially MOX-oriented for VVER reactors, the high cost
being because this was not part of Russia's fuel cycle policy.
• The USA agreed to allow the Russian plutonium to be used in BN-600 and
BN-800 fast neutron reactors, and the timeline stretched to 2018.
• However, the G7 funding was not available on this basis and Russia is
funding most of the program, with the USA contributing $400 million.
• http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/UraniumResources/Military-Warheads-as-a-Source-of-Nuclear-Fuel/
In Russia, a few existing reactors can
use MOX
• In 1996, the United States and the Russian Federation completed an initial
joint study that evaluated the candidate options for the disposition of
surplus weapons-derived plutonium in both countries.
•
While Russia advocates building new reactors for converting weaponsderived plutonium to spent fuel, the cost is high, and the continuing joint
study of the Russian options is considering only the use of the existing
VVER-1000 LWRs in Russia (and possibly in Ukraine) and the existing BN600 fast-neutron reactor at the Beloyarsk Nuclear Power Plant in Russia.
• The BN-600 reactor, which currently uses enriched uranium fuel, is
capable with certain design modifications of converting up to 1.3 metric
tons (MT) of surplus weapons-derived plutonium to spent fuel each year.
Promising beginning in US
• After environmental and safety reviews, the US Nuclear
Regulatory Commission authorised construction of a MOX
fuel fabrication plant (MFFF) at the DOE Savannah River site
in South Carolina.
• Construction started in August 2007.
• It would make about 1700 civil MOX fuel assemblies using
DU and 34 tonnes of weapons-grade plutonium unlike
other MOX fuel plants which use fresh reactor-grade
plutonium having around one third non-fissile plutonium
isotopes.
• US reactors using MOX fuel will need to be licensed for it.
• European reactors run on MOX made of fresh Pu extracted
from spent fuel.
• Excess weapons Pu has different characteristics and turns
out to be more problematic.
Original cost projections were called high: $4.8 billion
They didn’t yet know what “high” meant
• Shaw Areva MOX Services is under contract to the National Nuclear
Security Administration (NNSA), which will own the plant, originally
expected to be in operation from 2016, then 2019.
• The high cost of the plant – $3.5 billion plus $1.3 billion contingency
and $183 million per year to operate - is justified on nonproliferation grounds.
• Annual cost would be offset by revenue.
• However, early in 2014 the project was excluded from the DOE
budget request for NNSA due to cost escalation, so faces being shut
down while 60% complete. This will leave the USA in default on the
2000 bilateral agreement, while Russia has fulfilled its side.
http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/UraniumResources/Military-Warheads-as-a-Source-of-Nuclear-Fuel/
Converting reactor to burn MOX
• The steps needed to convert BN-600 to a plutoniumburner core will be discussed.
• The step involving the hybrid core allows an early and
timely start that takes advantage of the limited
capacity for fabricating uranium–plutonium mixedoxide fuel early in the disposition program.
• The design lifetime of BN-600 must safely and reliably
be extended by 10 yr to at least 2020 so that a
sufficient amount of plutonium (∼20 MT) can be
converted to spent fuel.
• http://www.sciencedirect.com/science/article/pii/S016
8900298005245
However Duke’s MOX did not work
• In June 2005 the first four fuel assemblies with mixed oxide fuel
made from US military plutonium (plus depleted uranium) started
generating electricity in Duke Power's Catawba-1 nuclear power
plant in South Carolina, on a trial basis.
• They incorporated 140 kg of weapons-grade plutonium.
• The plutonium had been made into 2 tonnes of pellets at the
Cadrache plant and then fabricated into fuel assemblies at the
Melox plant in France
• Duke’s attempts to use MOX made in France from US excessweapons Pu in the Catawba Reactor that was modified to burn it
ultimately failed and Duke withdrew from the program.
MOX fabrication plant in SC grew
absurdly expensive
• The older study led by John MacWilliams, an
advisor to Energy Secretary Ernest Moniz,
estimated the lifetime cost of the so-called Mixed
Oxide (MOX) plutonium elimination project in
South Carolina at over $25.1 billion.
• But the new study, conducted by a U.S. Air Forcefunded research and development center known
as the Aerospace Corporation, says the effort
could cost at least $30.7 billion to complete,
according to a summary that was presented to
lawmakers on Capitol Hill.
• After the summary was obtained by the Union of
Concerned Scientists, a nuclear safety advocacy group,
Energy Department officials confirmed that the
study concluded this cost might even balloon to
$47.5 billion.
• The higher pricetag would ensue if, as MacWilliams’ study
assumed last year, annual spending on the program is
capped at $500 million annually, which would drag out its
completion. If spending were limited to $375 million a year
— an amount close to what Congress has recently
appropriated — the cost of the overall project could
eventually reach $110.4 billion, the summary stated.
• http://www.publicintegrity.org/2015/04/23/17218/projected-costgovernments-most-expensive-nonproliferation-effort-rises-again
Cheaper to downblend and bury in
WIPP, a new idea
• To downblend the plutonium, highly radioactive ground
SNF would be added to plutonium oxide to inhibit recovery.
• This downblending process would involve mixing the
plutonium with inhibitor materials to reduce the plutonium
content to less than 10 percent by weight.
• Downblending would be conducted at SRS. Two additional
gloveboxes would be installed for this option.
• The containers of downblended plutonium would be
characterized (non‐destructive assay, digital radiography,
and headspace gas sampling) to ensure that they meet
waste acceptance criteria prior to shipment to a TRU‐waste
repository.
What is WIPP?
• Waste Isolation Pilot Plant in Carlsbad, NM
• Bedded salt is free of fresh flowing water, easily
mined, impermeable and geologically stable
– an ideal medium for permanently
isolating long-lived radioactive wastes from the
environment. However, its most important
quality in this application is the way salt rock
seals all fractures and naturally closes all
openings.
WIPP
• Throughout the 1960s, government scientists
searched for an appropriate site for
radioactive waste disposal, eventually testing
a remote desert area of southeastern New
Mexico where, 250 million years earlier,
evaporation cycles of the ancient Permian Sea
had created a 2,000-foot-thick salt bed.
Underground Salt Cavern Burial
WIPP Waste Isolation Pilot Plant
• Once shipped to a repository, the packages containing the
plutonium would be emplaced in the salt bed.
• Over time, high pressure on the salt formation would cause
the salt to creep, filling in the voids in the disposal rooms,
and entombing the packages permanently.
• This disposal method has been proven and continues to be
used to dispose of surplus plutonium from various DOE
sites.
• Approximately 4.8 MT of plutonium that was downblended
have been shipped to WIPP, mostly from six sites: RFETS,
Hanford, INL, LLNL, LANL, and SRS.
http://www.nnsa.energy.gov/sites/default/files/nnsa/0414-inlinefiles/SurplusPuDispositionOptions.pdf
WIPP