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Post-‐Fukushima Nuclear Power:
Where do we go from here? —Nuclear Issues and
Perspec8ves
Presented by Glenn Sjoden, PhD, PE With
Collec8ve Contribu8ons from G. Sjoden, B. Petrovic, and F. Rahnema Professor of Nuclear and Radiological Engineering and Medical
Physics Program George W. Woodruff School
Overview • Introduc8on • NRE/MP Program at Georgia Tech • Fukushima Daiichi Accident • Plant Design and Chain of Events – Decay Heat Removal
• The Nuclear Op8on • Where from here? • The “True Cost of Energy” and Long Term Needs
NRE/MP Program at Georgia Tech Nuclear and Radiological Engineering and Medical Physics Program • Close to 300 undergraduate and graduate students • Educa8on and research in all areas relevant for nuclear power and medical
physics • Sustainable nuclear power ini8a8ve
SSNFM-‐2011 Symposium -‐-‐ 23 Aug 2011 • Recently organized a Symposium on Sustainable Nuclear Fuel Management
(SSNFM-‐2011) • Speakers and panelists from government, industry, academia; included a BRC
member • Georgia Tech – iden8fied strategic areas, including:
– Sustainability, Energy – Nuclear power and renewable energy solu8ons in tandem
Fukushima Daiichi Accident • Japan, March 2011: Earthquake, Tsunami, Nuclear Disaster • Terrible devasta8on, destruc8on and death occurred in Japan
– 9.0-‐magnitude earthquake and resul8ng tsunami • Sta8on blackout at 40yr-‐old Fukushima Daiichi Plant ini8ated
– Ini8ally, reactors stable, containments isolated aGer immediate shutdown
• Auxiliary cooling designed for 6m Tsunami; actual height was >8m – Tsunami wipes out auxiliary cooling – Related failure of a number of redundant backup safety (diesel)
generators needed to power auxiliary cooling systems • Nearby Fukushima Diani nuclear plant 10 km away
– Cooling systems built several meters higher escape similar fate
Plant Schema8c, Reactors I -‐ IV
Thermal Efficiency ~33% Unit 1: 460 MWe (~1300 MWt) Units 2-‐4: 768 MWe (~2300 MWt)
Chain of Events • Lack of “ac8ve pumping” led nuclear fuel in reactor core(s) to be
"uncovered" -‐-‐not covered with cooling water – Temperatures > 2200 F Led to degrada8on/mel8ng of zirconium-‐based nuclear
fuel cladding • Cladding is metal shell making up fuel rods containing stacked uranium oxide fuel pellets
– Zirconium-‐steam reac8on • Hydrogen gas released, ven8ng to outer building led to secondary containment explosions
• Heat and pressure in building threatened spent fuel pools – Spent Fuel pools located in top of reactor building – Pools open to air, 40G depth pools boiled down – Led to addi8onal fuel damage
• Fission products and some fuel par8cles released – Serious local damage and local contamina8on (<6 km from plant) – Released vola8le fission products and some ac8nides – Background radia8on elevated outside local area
hfp://en.wikipedia.org/wiki/File:Fuel_pool.jpg
Decay Heat Removal • Nuclear fission reac8ons libera8ng heat for power genera8on were
stopped immediately from a reactor "SCRAM" – Many fission products are radioac8ve nuclides, nuclear decay chains – Nuclides emit radia8on that ends up as heat energy (“Decay Heat”)
• Decay Heat is – 4.7% of reactor power 10 s aGer reactor SCRAM;
• 2.3% aGer 7 min; 0.5% aGer 1 hour – 0.3% (3.9 MWt Unit 1, 11.5) aier 10 days
• Con8nued heat release over a protracted period – Likely months, depending on the reactor's opera8ng history, etc – Most fuel remains in ac8ve cooling as “used” fuel for a few years
• Maintaining FD reactors in current state not a short term effort
• Modern reactor designs (e.g. Wes8nghouse AP1000) have natural convec8on cooling established in the event of complete site power loss – “Passive Safety” feature avoids repeat of scenario in Japan
Poten8al role of Nuclear Power in sustainable energy development (i)
• Several prominent “founding fathers” of the environmental movement endorsing nuclear, based on evalua8ng feasible alterna8ves-‐-‐posi8on that nuclear power offers a valid op8on to address environmental concerns – Patrick Moore -‐ Greenpeace founder – Stewart Brand -‐ Whole Earth Catalog founder – James Lovelock -‐ Gaia theorist – Recent UN IPCC report (May 2007) acknowledges the potenNal role of
nuclear power
• Nuclear power has a role to play in sustainable development. Otherwise, it is difficult to postulate how to saNsfying energy needs without exhaus8ng resources and significantly impac8ng the environment
• But, is Nuclear Power itself sustainable? Yes, if we act. Now.
• Nuclear a Good Solu8on for energy needs: – Low emissions, low land area use, favorable output/input energy factor, high energy density, compe88ve cost
– Even with high startup costs, low external cost, thus low true long term total cost
– One part of the energy “mix” • Clearly, “smart” site/loca8on is important to mi8gate risk! • U/Th resources sizeable
– On the order of hundred(s) years for once through fuel cycle, thousands years with reuse of irradiated fuel)
• Waste must be addressed – Reprocessing technologically manageable and tractable, but a poli8cal football exists in “closing the fuel cycle”
Poten8al role of Nuclear Power in sustainable energy development (ii)
Where from here? (i) • Cleanup for Daiichi plant will be costly and require 10 years – Design of Backup Diesel generators under more scru8ny for worst case natural disasters
– Loca8on and integrity of spent fuel to be re-‐evaluated • Emphasis on “passive safety” designs used for new plants – If reactors at Daiichi very newest power reactor designs, no “ac8ve cooling” required
– Decay heat removed through automa8c “passive” convec8on cooling mechanism
Where from here? (ii) • Reality: energy use growing by 19% over next 25 years
– Compe8ng markets in China, India, others will increase energy demand
• Despite hype, renewables (solar, wind, etc) are limited – Currently 4% of electricity needs – Renewables can supply a pracNcal upper limit 20% of future needs
• Nuclear must be a major component of non-‐fossil fuels – Issues must be resolved – Casts light on nuclear fuel handling and waste policies (95% of fuel is recyclable)
• Consider French model?? – Complete, integrated nuclear power and fuel cycle
Permanent geological repository for UNF • Technically feasible ... A poli8cal decision. • Closing nuclear fuel cycle is the sustainable long-‐term solu8on
-‐-‐Reduces the amount of ul8mate high-‐level nuclear waste by 90% • Otherwise, we would need a new repository every N years ... (see below)
Refs: B. Petrovic et al., 11 IEMPT, San Francisco, CA, Nov 2010; M. Carelli et al., Radwaste SoluNons, May-‐June 2011)
True cost of genera8ng energy – including externali8es
Study ExternE, performed in Europe (European Commission), examined external costs of electricity produc8on…
Source: EU / EUR 20198
Take Away: Nuclear power and renewable sources have significantly lower external costs than fossil plants – therefore nuclear should be strongly considered.
Long-‐Term Needs and Necessary Ac8ons • Long-‐term na8onal energy policy to close nuclear fuel cycle
– Reduce backlog of US waste – Past experience: change of direc8on every 4 years
• Comprehensive strategy needed to close fuel cycle -‐-‐don’t con8nue to postpone this decision
Long-‐Term Needs and Necessary Ac8ons • Address externali8es of energy costs, compare to other
power genera8ng op8ons, on societal level
– Not typically addressed; necessary for adequate assessment of nuclear power
• Adequate educa8on, training and research support for undergraduate and graduate Nuclear Engineering programs
– Basis and fundamentals, in addi8on to the very specific (”boxed”) research currently supported
• Current projec8ons es8mate a human capital shorXall in the USA as high as 50% over next 30 years
Summary and Conclusions • New nuclear plants needed to fill US non-‐fossil energy needs • “Smart” si8ng of plants that use “passive safety” designs for all
new plants • A strong push is needed for fuel cycle closure to minimize waste – Focused path forward to mi8gate USG regula8ons and policies to enable recycling of all fuel, as done in Europe, Far East
– A specific posi8on on Yucca Mountain would be, in our view, appropriate
• Adequate, broadly scoped educa8on, training and research support needed – Undergraduate and graduate Nuclear Engineering programs is essen8al to meet future energy needs
