Have Deliberately Small Reactors Come Of Age? Daniel Ingersoll Oak Ridge National Laboratory

1. Have Deliberately Small Reactors Come Of Age?Daniel IngersollOak Ridge National Laboratory American Nuclear Society Annual Meeting June 14-18, 2009  Atlanta, GA

2. Small Nuclear Power Plants Were First Developed for Defense Applications • The United States and Russia began developing small nuclear reactors for naval propulsion beginning in the early 1950s • The U.S. Air Force explored nuclear powered aircraft, but discontinued the program in 1961 • The U.S. Army built 7 small stationary power plants and 1 floating power plant for remote operations: ANS Annual Meeting, June 14-18, 2009

3. 1400 Palo Verde 2 U.S. Experience 1200 1000 Watts Bar 1 800 Electrical Output (MWe) 600 400 Shippingport 200 Fort St.Vrain 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Date of Initial Operation Many Countries Initially Built Smaller Sized Commercial Nuclear Power Plants ANS Annual Meeting, June 14-18, 2009

4. Some Basic Terminology IAEA definitions: Small: < 300 MWe Medium: 300-700 MWe Large: > 700 MWe } • SMR = < 700 MWe Related but less precise terms: Low-Capacity Nuclear Power Plants (LCNP) Small Modular Reactors (SMR) Deliberately Small Reactors (DSR) ANS Annual Meeting, June 14-18, 2009

5. Several Countries Have Explored Merits of Smaller, Simpler NPPs • In the United States: • Weinberg study (1985) • Advanced Light Water Reactor program (1985-present) • Advanced Liquid Metal Reactor program (1985-1995) • International Organizations: • Nuclear Energy Agency Expert Group (1991) • The Generation IV International Forum (2000-present) • The International Project on Innovative Nuclear Reactors and Fuel Cycles (2000-present) • Common user considerations • International Atomic Energy Agency Coordinated Research Projects (2003-present) • Passive safety features • Technology options (with or without on-site refueling) • Economic competitiveness ANS Annual Meeting, June 14-18, 2009

6. Sampling of SMR Concepts Under Development World-Wide • Integral PWR: CAREM (Ar), IMR (Jp), IRIS (US), NuScale (US), mPower (US) SCOR (Fr), SMART (RoK) • Marine derivative PWR: ABV (RF), KLT-40S (RF), NP-300 (Fr), VBER-300 (RF) • BWR/PHWR: AHWR (In), CCR (Jp), MARS (It) • Gas-cooled: GT-HTR-300 (Jp), GT-MHR (US), HTR-PM (Ch), PBMR (SA) • Sodium-cooled: 4S (Jp), BN-GT-300 (RF), KALIMER (RoK), PRISM (US), RAPID (Jp) • Lead/Pb-Bi-cooled: BREST (RF), ENHS (US), LSPR (Jp), STAR/SSTAR (US), SVBR-75/100 (RF) • Non-conventional: AHTR (US), CHTR (In), Hyperion (US), MARS (RF), MSR-FUJI (Jp), TWR (US) ANS Annual Meeting, June 14-18, 2009

7. Interest in Smaller Sized Reactor Designs Are Beginning To (Re)Emerge • Benefits • Enhanced safety • Improved fabrication and construction logistics • Greater operational flexibilities • Favorable economics • Applications • Countries with small or limited electrical grid infrastructure • Smaller private utilities in large-grid countries • Special power applications such as defense • Non-electrical customers ANS Annual Meeting, June 14-18, 2009

8. Safety Benefits of DSRs • Elimination of accident initiators (integral designs) • No large pipes in primary circuit means no large-break loss-of-coolant accidents • Increased water inventory means slower system response to power transients • Internal control rod drive mechanisms mean no rod-ejection accidents or David Besse-type events • Reduced source term • Reduced shielding, site radius, emergency planning zone, etc. • Improved decay heat removal • Lower decay heat generated • More efficient passive decay heat removal from reactor vessel (volume-to-surface area ratio effect) ANS Annual Meeting, June 14-18, 2009

9. Integral Primary System Configuration External Loop PWR (Sizewell B) Integral PWR (SIR*) • Enhances safety by eliminating major classes of accidents. • Simplifies design by eliminating loop piping and external vessels. • Allows for compact containment (small plant footprint) to enhance economics and security.  *Safe Integral Reactor, R. Dettmer, IEE Review, 1989 ANS Annual Meeting, June 14-18, 2009

10. Fabrication and Construction Benefits • Physically smaller components • Eliminate or reduce number of large forgings • More in-factory fabrication; less site-assembly • Reduces schedule uncertainty • Improves safety • Reduces cost • Reduce size and weight for easier transport to site • Access to a greater number of sites • Well suited for remote or undeveloped sites • Smaller plant footprint • Place nuclear system further below grade to improve resistance to external events and sabotage ANS Annual Meeting, June 14-18, 2009

11. 93% of all generating units have capacities < 500 MWe 8000 7000 6000 18,602 Power Plants Globally 5000 Number of Plants 4000 3000 2000 1000 0 < 1 1-50 50-500 500-1000 >1000 Plant Size (MW) Operational Flexibilities • Site selection • Potentially reduced emergency planning zone (EPZ) • Use of seismic isolators • Lower water usage • Load demand • Better match to power needs for many non-electrical applications • Grid stability • Closer match to traditional power generators • Smaller fraction of total grid capacity • Demand growth • Ability to add (and pay for) capacity as demand dictates ANS Annual Meeting, June 14-18, 2009

12. Economic Benefits • Total project cost • Smaller plants are cheaper • Improves financing options and lowers financing cost • May be the driving consideration in some circumstances • Cost of electricity • Economy-of-scale (EOS) works against smaller plants but can be mitigated by other economic factors • Accelerated learning, shared infrastructure, design simplification, factory replication • Investment risk • Maximum cash outlay is lower and more predictable • Maximum cash outlay can be lower even for the same generating capacity ANS Annual Meeting, June 14-18, 2009

13. SMR Applications • Baseload electricity generation • Smaller utilities with low demand growth • Regions/countries with small grid capacity • Installations requiring independent power • Non-electrical power needs • Potable water production (desalinations • Advanced oil recovery for tar sands and oil shale • Hydrogen production • Advanced energy conversion such as coal-to-liquids conversion • District heating ANS Annual Meeting, June 14-18, 2009

14. SMR Challenges – Technical • All designs have some degree of innovation in components, systems, and engineering • Integral primary system configuration • Internal control rod drive mechanisms and pumps • Multiplexed control systems/interface • A prototype unit may or may not be needed • Many LWR designs plan to go directly to first-of-a-kind • Most non-LWR designs will need a prototype • Sensors, instrumentation and controls development are likely needed for all designs • Power and flow monitoring in integral systems • Advance prognostics and diagnostics • Control systems for co-generation plants ANS Annual Meeting, June 14-18, 2009

15. SMR Challenges – Institutional • Too many competing designs • Mindset for large, centralized plants • Fixation on economy-of-scale • Economy-of-hassle drivers • Perceived risk factors for nuclear plants • Traditional focus of regulators on large, LWR plants • Standard 10-mile radius EPZ (in the U.S.) • Staffing and security force size • Plant vs module licensing • Fear of first-of-a-kind • New business model as well as new design must be compelling ANS Annual Meeting, June 14-18, 2009

16. Summary • Most countries using nuclear power started with smaller sized plants • To gain experience with new technology and designs • For special applications such as propulsion or defense • After initial experience with small plants, plant size and complexity grew rapidly • New SMRs offer many potential benefits • Enhanced safety • Improved fabrication and construction flexibility • Greater operational flexibility • Favorable economics (affordability) • Deployment schedules will differ significantly among spectrum of SMR designs ANS Annual Meeting, June 14-18, 2009

17. THINK SMALL ! “Deliberately Small Reactors and the Second Nuclear Era,” Progress in Nuclear Energy, 51, p 589-603, 2009. ANS Annual Meeting, June 14-18, 2009