Climate Change and Energy Solutions. Frank H. Shu UCSD Academia Sinica 10 Sept 2010 University of Michigan Collaborators: M. J. Cai & F. T.

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1 Climate Change and Energy Solutions Frank H. Shu UCSD Academia Sinica 10 Sept 2010 University of Michigan Collaborators: M. J. Cai & F. T. Luo

2 Grand Challenge of Attributed to John Maynard Keynes: For millennia, until the discovery of fossil fuels, the only way humans made economic progress was to enslave other peoples. According to James Hansen, tipping point for melting of polar ice is 350 ppm CO 2, which we passed in st Century

3 Essence of Global Warming Effective T of Earth: T E = (1-A) 1/4 (R S /2r E ) 1/2 T S. For A = 0.3, r E = 215 R S, T S = 5,800 K, T E = 255 K. T g = T E (3τ/4+1/2) 1/4. For τ = 1.72, T g = 295 K. Problem (nonlin feedback): CO 2 increases τ & T g. Increase T g melt polar ice. Melt polar ice, decrease A, which increases T E, which increases T g. Melt polar ice, eliminate latent-heat buffer, which increases T of oceans, which releases more CO 2 & water vapor. Milankovich cycle At 200 ppm, 14,000 yr ago, Asians could walk to America. At 280 ppm, oceans rose eliminating this option. How much will the oceans rise at 450 ppm?

4 Trends in Energy Usage Iranian Revolution Yom Kippur War New Technologies Deep Sea Drilling Mountaintop Removal Hydraulic fracking TMI Chernobyl Thorium & MSR Maxed out Metric: Coal at $0.065 per kg

5 Power Needs USA 2008 Nameplate Electricity DOE Capacity 2008 Capacity factor Coal US electricity (MWe) GWe Natural Gas GWe Petroleum 63.7 GWe Nuclear GWe Hydro 77.7 GWe Wind 25.0 GWe 0.3 Solar 0.5 GWe 0.2 X X 0.3 X 0.2 Power for world: 15 TWt in 2010, 30,000 GWt Reasonable target for US hold to current level of 3,700 GWt = 1,850 Twe, (a) without massive damage to the environment, (b) without undermining nation s competitiveness. (Wind & solar have problems when they add only 1% & 0.01% capacity in 30 yr.)

6 Coal vs. Renewables vs. Nuclear Coal is one of the most concentrated forms of chemical energy known to humanity (3 times per kg more than TNT). Coal is dirt cheap: USD per kg. Equipment for collecting, distributing, and storing dilute sources of renewable energy will probably always be more expensive than that which burns coal. The energy in 1 kg of uranium or thorium is 2.3 million times that contained chemically in 1 kg of coal. Not to be dismissed out of hand. 3,218 turbines, 615 MWe peak 2 reactors, 2,200 MWe peak San Gorgonio vs. San Onofre

7 Nuclear Power: Fusion & Fission Made in Big Bang 3 + n 1 H + γ Fusion is how Sun shines, but may be a century from commercialization on Earth. 2 H + 3 H 4 He + n 1 30 MUSD/kg 1 2 Fissile (odd number n): U-235 (0.7% of U-238) U-233 from Th n Pu-239 from U n n + From supernovae that made neutron stars. Th is 3 to 4 times more abundant in Earth s crust than U. + 2 or 3 n > 1 chain reaction > 2 breed Reactor: sub wrt prompt n, super wrt delayed n

8 Nuclear Energy: Reprocessing & Breeding Solid fuel rods need multiple refabrication, implying multiple transportation of nuclear materials, opposed by public. Proliferation concerns led Carter to ban reprocessing of spent fuel. Resurrected by DOE under Bush. US NAS (2008) study did not support DOE s plan. OMB under Obama zeroed R&D for IFR. Bipartisan commission to re-examine reprocessing & report in LWR efficiency = 1% = 0.7% 235 U + 0.3% 239 Pu before too much radiation damage of fuel pellets Use 1%,throw away 99%. Breed & use Yucca Mtn stopped remaining by Obama Adm 99% Recycle 99% until used up.

9 Tale of Two Cycles U(n,γ) 239 U(e - ν e ) 239 Np (e - ν e ) 239 Pu Th(n,γ) 233 Th(e - ν e ) 233 Pa (e - ν e ) 233 U Fermi s objection to thorium cycle: Pa-233 with half-life of 27 days, has a fairly large probability for additional n capture. Wastes n in creating U-234, and breeding ratio drops below 1. With slow neutrons, Pu-239 has same problem -- captures n to become Pu-240, etc., often enough relative to fisssioning as to require n s not to be slowed down for Pu-239 breeding -- sodium fast breeder. Wigner s answer: build a liquid-based reactor, and chemically extract Pa-233 on a short time scale (e.g., every week) before it has a chance to decay. Have to start with U-235, which comes with U-238, so Fermi s view prevailed; world followed US lead, which resulted in today s (mis)perceptions of nuclear power: unsafe, expensive, difficult waste disposal problem, with close connection to WMD. Huge mistake not to have explored both paths.

10 MSRE Built by ORNL in 1960s, originally in response to US Air Force desire for nuclear powered airplane (cancelled) Never applied to civilian power generation: Destroys Pu (does not make it) No fuel fabrication needed No enrichment needed Complete burnup if Th-232/U-233 is adopted fuel cycle However, > 1 breeding never demonstrated: Fission product removal is difficult in single-fluid MSRs where Th-232 is co-mingled with U-233 Reactors built of metal may have too much n absorption

11 Two-Fluid MSRs Can Rid LWR Waste & Safely Breed for U-233 Chain reaction, breeding, and processing done in liquid medium of molten salt LWR spent fuel U-235, U-238 Fission prod s Pu/actinides Th-232 Partition Pu in core, Transmute AB/TB Core U-233 in core, Armored Enrich 1000 yr U3/TB Tank & Reuse Ground Blanket Enough Th-232 in Lehmi Pass for 2,000 yr of USA energy use.

12 Carbon-Carbon Composite Graphite used since dawn of nuclear age to slow down n C/C composite = engineered graphite: graphite matrix (from coal tar pitch) + C fiber fabric; can withstand high T Reaction bonded above 2500 C; carbon vapor deposition to reduce porosity High thermal conductivity or insulation (depending on fiber orientation); high strength (greater than steel, but vulnerable to sharp blows); nearly zero coeff thermal expansion (leak resistant); not corroded by molten salt. Awarded grant in Taiwan to develop 5 MWt (60 cm) 3 C/C HX (enough coal for MSU).

13 Two-Fluid MSR Except for dump tank, system built from C/C composites He purge of gaseous Xe-135 Active/passive control Passive safety feature 4: If T still rises, solid plug melts, & fuel salt drains into (cooled) dump tank. Air-cooled dump tank to remove decay heat; cannot lose air coolant Patent pending Passive safety feature 2 & 3: Lose coolant salt, lose n reflector; if over-heated, fuel salt expands out of reaction zone. Breeding ratio for U3/TB can be as high as 1.12 without extracting Pa-233 (diluted in large blanket/pool). Molten salt, low vapor pressure. Fuel molten: no radiation damage, circulate until 100% burn-up, no meltdown, no TMI. Double-walled outer containment, no Chernobyl nor jet crashes. Burn Pu; U-232 accompanies U-233; no bombs.

14 How Pu-239 Becomes U-233 in USA Michigan? 1 AB/TB design goal (10-pack): 0.76 tonne critical inventory, 0.92 conversion ratio

15 How U-233 Builds U3/TBs in USA U3/TB design goals (10-pack): 3.0 tonne critical inventory, 1.07 breeding ratio

16 Application 1: Thermal- Chemical Dissociation of H 2 O For fuel cells or liquid biofuels For carbon capture & sequestra tion Kloosterman, TU Delft

17 Application 2: Artificial Coal Deep Frying Vegetation High throughput pathway to making solid, liquid, and gaseous biofuels. Patent pending

18 Taiwan Pilot Project: 140 kw input Produces 4 tonnes biocoal per day 0.4 million USD/1 yr including R&D Patent pending

19 Biofuel Breeder: Biocoal-Burning Furnace Demonstration project in USA: powered with 5 MWt biocoal-fired furnace. Produce 60,000 tonne biocoal per yr, enough to sustain campus or city of 50,000 with zero CO 2 emission. (MSU?) Estimated cost including R&D: 10 MUSD/3 years = 67 USD per person per yr Full-scale 320 MWt facility produces 4 million tonne biocoal per yr (& 100 million gallon biodiesel), enough for a 1.4 GWe coal-fired power plant.

20 We All Inhabit this Small Planet Saving the Earth is still possible (barely), but it requires environmentalists to cooperate with thorium activists to change the nuclear paradigm. John Fitzgerald Kennedy (June 1963): 2nd Youngest President of United States Apollo Mission to Moon December 1968 So, let us not be blind to our differences but let us also direct attention to our common interests and to the means by which those differences can be resolved. And if we cannot end now our differences, at least we can help make the world safe for diversity. For, in the final analysis, our most basic common link is that we all inhabit this small planet. We all breathe the same air. We all cherish our children's future. And we are all mortal. So, let us set aside our differences. Let us rally our spirits in a season of financial adversity. Let us unite in a common cause to save the world.