Assessment of the tritium resource available to the fusion ......Forecasts of Canadian tritium...
Transcript of Assessment of the tritium resource available to the fusion ......Forecasts of Canadian tritium...
CCFE is the fusion research arm of the United Kingdom Atomic Energy Authority.
This work was part-funded by the RCUK Energy Programme [grant number EP/I501045]
and the European Union’s Horizon 2020 research and innovation programme.
Assessment of the tritium
resource available to the
fusion community
Michael Kovari
More detail: EFDA_D_2MT7EG - PMI-2.1-T003-D001 - Report on the assessment of the tritium resource available to the fusion community
Introduction
Slide 1 Michael Kovari
• The tritium from the CANDU reactor production programme may not be sufficient to start DEMO.
• ITER will be severely delayed, and if DEMO is similarly delayed then all of the CANDU reactors will have been shut down, while the civilian tritium stockpile will have decayed.
• More than one fusion reactor may be built after ITER • Fusion Nuclear Science Facility (FNSF), • Component Test Facility (CTF), • Power reactors – Korea, China… ?
• Where will the tritium come from?
• There is no published schedule.
• Scott Willms has kindly provided an estimate:
– starting (at a significant rate) in 2032
– 12 kg total.
Tritium required for ITER
Slide 2 Michael Kovari
• A non-trivial exercise!
• Literature varies from 0.5 to 18 kg
• Fuelling circuit has much bigger throughput,
• But blanket has bigger volume.
• Urgorri et al (WCLL blanket):
– 15 g/day permeation into water coolant.
– Inventory in the coolant??
• Santucci et al:
Tritium required to start up a reactor
Slide 3
T inventory in PbLi (g) T inventory in PbLi + coolant + steel (g)
HCLL 9-23 17 – 23
WCLL 14 – 19 19
Michael Kovari
These estimates may not tell the whole story.
• Gases in metals:
– “lattice” solubility (interstitial sites)
– atoms bound to ‘traps’ (inclusions, dislocations, grain
boundaries).
• When experiments use high partial pressure gases, it
may be that most of the traps are filled.
• When results are extrapolated to low pressures, the
trapped gas concentration may not reduce according to
Sievert’s law, or at all.
• Irradiation will increase trapping
• Even liquids contain impurity atoms.
Tritium required to start up a reactor (2)
Michael Kovari Slide 4
• Difficult tokamak physics!
• Up to 170 MW of neutral beam power
• Start with no tritium at all:
– tritium from DD fusion accumulates in a few seconds,
Start-up with deuterium-rich fuel
Michael Kovari Slide 5
0
1
2
3
4
5
6
7
8
9
10
0 1000 2000 3000 4000 5000 6000 7000 8000
Elap
sed
tim
e re
qu
ired
(ye
ars)
Starting tritium inventory (g)
10
5
1.5
Time required to reach 50:50 mix
Michael Kovari Slide 6
TBR (DT) = 1.1 Tritium production ratio (DD) = 0.72
Fuel burnup = 2% Tritium residence time in breeding system (h) = 3
Availability = 0.7 Fractional T loss and retention in blanket and tritium system = 0.05
T residence time in fuelling system (h)
0
1
2
3
4
5
6
7
8
9
10
0 1000 2000 3000 4000 5000 6000 7000 8000
Elap
sed
tim
e re
qu
ired
(ye
ars)
Starting tritium inventory (g)
10
5
1.5
Start at T/D = 10/90
Time required to reach 50:50 mix (2)
Michael Kovari Slide 7
TBR (DT) = 1.1 Tritium production ratio (DD) = 0.72
Fuel burnup = 2% Tritium residence time in breeding system (h) = 3
Availability = 0.7 Fractional T loss and retention in blanket and tritium system = 0.05
T residence time in fuelling system (h)
Start at 10% tritium: interest on the capital at 5% plus electricity: $1.4 million per gram of tritium saved.
• 5 reactors have been successfully refurbished in
Canada.
• Extend the reactor’s life for an additional 30 (?) years.
• 10 reactors are due for refurbishment
• Darlington unit 2 was taken off-line on 14 October ready
for work to begin.
Canadian production and stocks
Michael Kovari Slide 8
Refurbishment and life extension - Canadian Nuclear Safety Commission. 2014, http://nuclearsafety.gc.ca/eng/reactors/power-plants/refurbishment-and-life-extension/index.cfm. http://www.durhamregion.com/news-story/6911795-refurbishment-at-clarington-nuclear-station-underway/
Tritium light sources
Forecasts of Canadian tritium inventory, with three
different ITER schedules
Michael Kovari Slide 10
Canada will not be able to provide 10 kg for DEMO in 2060.
2057
2065
0
5
10
15
20
25
30
2015 2025 2035 2045 2055 2065
kg
ITER burn starts 2032
ITER burn starts 2037
ITER burn starts 2042
“burn” is when deliveries exceed 0.5 kg/year.
Heavy water reactors outside Canada
Michael Kovari Slide 11
Operational
Under construction
Planned
Tritium available 2060
India 18 4
4
14.5 kg
China 2 1.7 kg
Argentina 3 1.6 kg
Romania 2 2 5.1 kg
Korea 4 2.5 kg
Total 25 kg
tritium generated 2.22E-04 kg/FPY/Mwe Reactor lifetime 50 years Station below 1 GWe ignored: too small for economical tritium extraction Overall reactor capacity factor (including refurbishment outages) 70% DEMO start date 2060 No consumption or loss
Lithium could be irradiated for additional tritium production.
1. The “low void reactivity fuel bundle”: – burnable absorber in the central element of the bundle (enriched fuels)
– Never used.
– Lithium absorber – 200 g/year tritium?
2. Adjuster rods: – cobalt-59 rods for cobalt-60 production
– Lithium rods – 130 g/year tritium?
3. Dope the moderator with lithium?
4. Dope the liquid zone-controllers with lithium?
Need to change the operating procedures!
Regulators will not accept this for existing plants.
BUT: New CANDUs planned.
These are reasonable possibilities.
Other options for heavy water reactors
Michael Kovari Slide 12
Commercial light water reactors
Michael Kovari Slide 13
Watts Bar
Michael Kovari Slide 14
9.7 mm
Tritium-producing burnable absorber rod
In 1999 the Department of Energy said,
No significant safety issues were identified.
(There were, in fact, safety issues. Tritium permeation into
the coolant was much more than expected.)
Tritium is produced without any significant modifications to
these facilities and does not affect electricity production.
Licensing and operation
Michael Kovari
• AP1000 has burnable absorbers
• EPR also has burnable absorber rods, but in these the
gadolinium absorber is mixed with uranium dioxide.
Adding lithium with no uranium would impair the
reactivity profile.
• Licensing would be very difficult in both cases.
• The Japan Atomic Energy Research Institute actually
did produce tritium on a trial basis in the 1980s.
Other light water reactors
Michael Kovari
Production in a particle accelerator is probably feasible.
Particle accelerator (APT)
Michael Kovari
APT
(basic configuration)
Government
estimates
ESS
Beam power 100 MW 5 MW mean
Electric power 312 MWe 35 – 45 MWe
Tritium production 1.5 kg/year n.a.
Capital cost $2.8 billion (1999)
(total undiscounted
cost over 40 years:
$7.5 billion)
€1.8 billion
Ratio
20
8 (?)
1.6 (?)
In my opinion, this is a scheme to create
huge industrial contracts.
One boosted fission bomb requires ~ 4 g of tritium.
The export of tritium and tritium handling equipment to non-
signatories of the Nuclear Proliferation Treaty has already
resulted in three prison sentences.
Tritium is not regulated under the IAEA Safeguards regime.
USA has removed all references to tritium being a “material
of strategic importance”.
But the risk of diversion must be studied in depth.
Proliferation
Michael Kovari
1. Tritium can be generated in any fission reactor or other strong source
of neutrons.
2. Start-up with deuterium-rich fuel would delay power production by up
to 6 years (depending on assumptions), and is not economically
sensible.
3. The USA has started producing tritium in a commercial light water
reactor.
4. The tritium required to start DEMO is uncertain within a wide margin.
5. Ontario may be able to supply 5 kg for fusion in 2060, but not 10 kg.
6. There are many heavy water reactors outside Canada. Romania has
definite plans to extract tritium from the heavy water, and other
countries may do the same. Each might be able to provide a few kg
by 2060.
7. The production of tritium in CANDU and other heavy water reactors
could be increased by using lithium targets.
Conclusions
Michael Kovari
8. If a reactor is started up around 2060, Canada, Argentina, China,
India, Korea and Romania will be able to ensure enough tritium for 1
or 2 machines:
– build, refurbish or upgrade tritium extraction facilities;
– extend the lives of heavy water reactors, or build new ones;
– reduce tritium sales;
– boost tritium production in remaining reactors.
9. If DEMO starts well beyond 2060, and heavy water reactors are all
shut, then light water reactors will be the only remaining source.
10. Minimise tritium inventory:
– experimental research in solubility and permeation; extraction
from the primary coolant; and improving the burn-up fraction.
11. The risk of diversion is a major concern, and must be studied in
depth.
Conclusions (2)
Michael Kovari
Thank you
1. Tritium can be generated in any
fission reactor or other strong source
of neutrons.
2. Start-up with deuterium-rich fuel is not
economically sensible.
3. The USA has started producing
tritium in a commercial light water
reactor.
4. The tritium required to start DEMO is
uncertain within a wide margin.
5. Ontario may be able to supply 5 kg
for fusion in 2060, but not 10 kg.
6. There are many heavy water reactors
outside Canada. Romania has
definite plans to extract tritium from
the heavy water, and other countries
may do the same. Each might be
able to provide a few kg by 2060.
7. The production of tritium in CANDU
and other heavy water reactors could
be increased by using lithium targets.
8. If a reactor is started up around 2060,
Canada, Argentina, China, India, Korea
and Romania will be able to ensure
enough tritium for 1 or 2 machines:
– build, refurbish or upgrade tritium
extraction facilities;
– extend the lives of heavy water
reactors, or build new ones;
– reduce tritium sales;
– boost tritium production in
remaining reactors.
9. If DEMO starts well beyond 2060, and
heavy water reactors are all shut, then
light water reactors will be the only
remaining source.
10. Minimise tritium inventory:
– experimental research in solubility
and permeation; extraction from the
primary coolant; and improving the
burn-up fraction.
11. Risk of diversion is a major concern.
EFDA_D_2MT7EG - PMI-2.1-T003-D001 - Report on the assessment of the tritium resource available to the fusion community
Back-up slides
Michael Kovari Slide 23
0.0
0.5
1.0
1.5
2.0
2.5
2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065 2070
kg/yr
year
Tritium production in Canada
Commercial demand - estimate
Upper estimate for tritium demand
ITER requirement
ITER + 5 year delay
ITER + 10 year delay
Michael Kovari Slide 24
2057
2065
0
5
10
15
20
25
30
2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065 2070
kg
year
Tritium inventory
Inventory (5 yr ITER delay)
Inventory (10 year ITER delay)
Cumulative ITER requirement