Molten Salt Reactor Technical Working Group Licensing Perspective

Nicholas V. Smith Senior Engineer GAIN Fuel Safety Research Workshop Southern Company Services Advanced Energy Systems R&D

Lance K. Kim, M.P.P., Ph.D. Senior Nuclear Engineer Southern Research Our life’s work is to create prosperity through future generations

Waiting is a decision that isolates options.

Change isn’t the enemy. Fear is.

The only risks worth taking are the ones with the greatest potential.

Nothing worth doing has ever been described as easy. 50The multiple MILLION of energy released from the nuclear fission of a uranium nucleus as compared to the chemical combustion of a carbon atom. Potential Courage Value = ( Fear )

Nuclear Reactor History →

1920 – Ernest Rutherford (Experiments with Alpha Particles) 1932 – James Chadwick (Discovers Neutron) 1939 – Niels Bohr (Classical Analysis of Fission) 1942 – Enrico Fermi (Chicago Pile 1 Reactor) 1953 – Admiral Hyman Rickover (Father of Nuclear Navy) 1960 – Yankee Rowe (Westinghouse 250 MWe PWR) Nuclear Reactor Design →

Fast Thermal

Breeder vs Burner Liquid Fuel Solid Fuel Thorium Uranium

COOLANT CHOICE Salt, Water, Gas, Metal Nuclear Reactor Design →

Fast Thermal

Breeder vs Burner Liquid Fuel Solid Fuel Thorium Uranium

COOLANT CHOICE Salt, Water, Gas, Metal Advanced Reactor Features →

Wide range Complete 30+ years of High Low Online Sustainable High power of fuel cycle walkaway R&D temperature pressure refueling fuel cycle density options safety conducted

LWR

HTGR

SFR

MSR Molten Salt Reactor TWG →

ONE TWO THREE FOUR FIVE SIX TerraPower Thorcon Terrestrial Flibe Transatomic Elysium

Fast Thermal Energy Energy Power Industries Breeder Burner Thermal Thermal Hybrid Fast Liquid Fuel Liquid Fuel Burner Breeder Burner Breeder Salt Cooled Salt Cooled Liquid Fuel Liquid Fuel Liquid Fuel Liquid Fuel Uranium Thorium Salt Cooled Salt Cooled Salt Cooled Salt Cooled (Could use Th) Uranium Thorium Uranium Uranium (Could use Th)

Flibe Energy LFTR

 Design objectives: − 600 MWt/250 MWe modular core − conversion ratio >= 1.0 − Replaceable core internals − fuel salt in graphite tubes − Reactor vessel shielded by thorium blanket and graphite reflector  Materials and fluids: − 7 LiF-BeF2-UF4 fuel salt − 7 LiF-BeF2-ThF4 blanket salt − 7 LiF-BeF2 coolant salt − Graphite moderator and reflector − Hastelloy-N reactor vessel and piping TerraPower’s Molten Chloride Fast Reactor (MCFR) advances nuclear in key areas

• No fuel fabrication • Online refueling • High temperature

• Non-reactive coolant • Strong negative temperature & void coefficients • Near-zero excess reactivity

• Only startup enrichment • Consume DU, NatU, and/or UNF • Start with partial UNF load

• No ongoing enrichment • Strong non-proliferation traits • Reduced water use • Opens up non-electric markets

• Actinides stay in core, daughter core, or closely-coupled clean-up system • Actinides always mixed with lanthanides

Design Features: • Moderator: Zirconium Hydride

• Fuel Salt: LiF-UF4 • Actinide Content: 5% LEU • Power Output: 520 MWe • Spectrum: Epithermal/Thermal

Figure 1. A conceptual depiction of a reactor vessel design that uses moveable or additional moderator rods for reactivity control. Elysium Industries Molten Chloride Salt Fast Reactor (MCSFR) Safety Economic Competitiveness Low Environmental Impact Design Objectives Efficient Nuclear Fuel Use Enhance Non-Proliferation and Safeguards Plant Concept Safety & Proliferation Resistance Low operating pressure – Fuel < Secondary • 1 GWe/2.5GWth • • Secondary Tcold > Fuel Tm.p. • Chloride fuel salts • Negative reactivity/void coefficients, • Fast spectrum neutron flux • self regulating/shutdown • Fuel drain system • Breeding ratio ~1 • No actinide removal/separation • Core outlet: ~ 600 ºC • Simple Chlorine based soluble fission product removal • Core inlet: ~ 500 ºC • FP Vitrification with Cl recycling • Passive corrosion control • High TRL purification systems • Passive safety, incl. decay heat removal • Design for maintainability • No exothermic reactions • Fuel Flexible: DU/LEU/SNF/RGPu/WGPu/Th • Low excess reactivity

Reactor Core Monte-Carlo CFD Computational Design Approach Design Neutron Flux Salt Temperature Chemical Analysis • Integrated Physics-Fluid design methodology • Computational chemical analysis

• Test & validate 15 ThorConIsle - 500MWe Factory Built

Use shipyard to build the entire power plant in a Each hull is 500 MWe. Ballasted to sea bed. factory to minimize cost and schedule risk. Use 50% the size of UltraLarge Crude Carriers the ocean/big rivers as our highway. Existing (In 2001 we build four ULCCs at $89M each) shipyard capacity is enough to build more than Graphic shows two 500 MWe hulls plus a 100 GWe of new capacity per year. jetty surrounding them

Use proven technology from MSRE to minimize risk and schedule.

Full passive safety to shutdown, cool, and contain. No electricity or operators required to handle accidents.

Several months grace period.

Cost to compete with coal ($1.2B/GWe, 3 cents/kwhr). Two years order to grid (assuming site already approved and permitted).

Actually test accident conditions.

Experienced team. Built four largest crude carriers in the world, gmail, streetview, google books. MSR TWG: December 2016 Letter

• Appreciates DOE’s interest in performing a feasibility study for a MSR Engineering Facility. • Recommends that DOE – Establish a Separate Effects Test (SET) program – Support early development of supply chain infrastructure • Proposes four-year, $200M program beginning in FY 2018 Six Focus Areas Base Studies of basic data e.g., salt purification, determination of key salt Technology properties, and corrosion testing.

Modeling & Dynamic behavior of fuel (including boundary layers, turbulence, Simulation recirculation and other fluid phenomena), fission source term, temperature distribution, density variations, and time dependent chemistry evolution

Flow Loops & Several small-scale forced convection flow loops, likely electrically heated Dynamic at 250-500 kW, constructed from a variety of materials, a variety of salts, Corrosion and include coupon testing. Followed by 3-4 medium scale loops, likely be electrically heated at 2-3 MW. Irradiation Coupon irradiations of candidate materials at appropriate facilities (e.g., Studies HFIR, ATR, BOR-60), and post-irradiation analysis to characterize the (Coupons & effects on materials over time. Salt capsules should be irradiated to study the effects of radiation-enhanced corrosion. Capsules) Irradiation Consideration of in-pile loops for fertile and/or fissile containing fuel salts in Studies (In- existing test reactors: one in a thermal spectrum accommodating fluoride Pile Loops) salts, and one for fast spectrum studies of chloride salts.

Vendor Engage vendors to shorten the critical path to MSR deployment e.g., Development nuclear grade molten salt pumps, heat exchangers, or valves. Funding Priorities If we want our regulators to do better, we have to embrace a simple idea: regulation isn't an obstacle to thriving free markets; it's a vital part of them.

~James Surowiecki MSR Licensing Perspective

• Non power test reactors licensed as part 104(c)

• Expected that NUREG 1537, appropriately modified, will provide guidance

• Gap analysis of Chapters 4, 5, 6, and 9 underway

• Could be used as input to NRC for ISG on MSRs

• Commercial reactors likely to use NUREG 800

• Gap analysis needed on Chapters 4, 5, 6, 9, and 11

• Need for Fuel Qualification definition in MSRs

• Special considerations of MSR materials and chemistry challenges (Radiation, Temperature, and Corrosion)

• Safeguards approaches for MSRs Assumptions in current LWR based documents that will need to be evaluated for MSRs:

• Heterogeneous fuel

• Swelling of fuel

• Delayed neutron migration to outside of core

• Fluid fuel, not fuel rods or fuel elements

• There is no cladding

• Water moderation

• Assumptions that fuel and coolant are distinguishable

• Xenon and Samarium override in MSRs, Spectrum matters

• Potential for fuel salt makeup systems

• New accident/hazard scenarios for MSRs, many LWR scenarios don’t apply Safeguard by Design: Safeguards Technology Development Needs

4. Design Information Verification 1. Core Mass/ Volume

3. Inventory Change 2. Fuel Composition

5. Containment & Surveillance Preliminary Comparison of Nuclear Materials Accountancy

Parameter Fast Breeder Molten Salt Reactor Reprocessing Reactor Safeguards Item facility Non-item reactor Bulk handling facility Approach Inputs Unirradiated Direct Initial load: Irradiated Irradiated Direct Use Use Direct Use Make-up feed: Indirect Use Outputs Irradiated Direct Irradiated Direct Use Unirradiated Direct Use Use Holdup N/A Easier cleanout? Annual cleanout Throughput Items <<800MTHM/year 800 MTHM/year In-Process Items >4MT Irradiated Direct 4MT Inventory Use Operating Years Years 200 days Period Innovative Safeguards Approaches

Process Monitoring State Level Concept [1] Physics-based signatures of Reduced safeguards frequency diversion and intensity based on Broader Conclusion Undeclared Facility

Declared Source Target Declared Facility Material Material

Undeclared Undeclared Source Material Facility

[1] Kim, Lance K., Guido Renda, and Giacomo G. M. Cojazzi. “Methodological Aspects of the IAEA State Level Concept and Acquisition Path Analysis: A State’s Nuclear Fuel Cycle, Related Capabilities, and the Quantification of Acquisition Paths.” ESARDA Bulletin 53 (December 2015).

Q&A

[email protected] (205) 257-1419 Survey Says…

Describe the design basis transient Full loss of flow, partial loss of flow, over fissile addition, cold events that have been developed for fuel insertion, earthquake pressure wave, gas cycling, your reactor concept. reactivity addition with circulating gas What are the relevant fuel safety criteria Fuel boiling, fuel freezing, lack of fuel draining, pressure pulse and fuel design limits that have been induced density increase, gas/volatile FP release fraction for defined that will be used to demonstrate leak, release after freezing, UCl4, UCl5, UCl6 production and compliance with 10CFR50 App A: release after freezing, mobility temperature to prevent General Design Criteria? radiological separation. Structural failure after exceeding creep limits over time. What integral system tests are required Fuel dumping speed, heat capacity for decay heat minimizing to validate your fuel system failure temperature rise. modes and the efficacy of the defined fuel safety criteria? What capabilities should test devices Static & flowing systems, corrosion control systems have to meet your testing needs?

What separate effects studies could be Simulated fuel tests used to assess specific fuel system behavior of interest prior to or in parallel with integral systems tests? What are the sources of fresh and SNF oxide fuel, U, Pu, DU, Unat, U3O8, UO2SNF metallic irradiated fuel materials available to fuel, but it is a bit harder conduct relevant experiments? If you need access to historical reports IFR handling reports & estimated test & production system and/or data, please list them below. cost, FP removal efficiencies for pyro-processing.