Molten Salt ReactorTechnical Working GroupLicensing PerspectiveGAIN Fuel Safety Research Workshop

Nicholas V. SmithSenior EngineerSouthern Company ServicesAdvanced Energy Systems R&D

Lance K. Kim, M.P.P., Ph.D.Senior Nuclear EngineerSouthern Research

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.

Our life’s work is to create prosperity through future generations

Nothing worth doing has ever been described as easy.

50 MILLIONThe multiple of energy released from the nuclear fission of a uranium nucleus as compared to the chemical combustion of a carbon atom.

Courage

Fear( )Potential

Value =

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 →

FastBreeder

Liquid FuelThorium

ThermalBurnerSolid FuelUranium

vs

Salt, Water, Gas, MetalCOOLANT CHOICE

Nuclear Reactor Design →

FastBreeder

Liquid FuelThorium

ThermalBurnerSolid FuelUranium

vs

Salt, Water, Gas, MetalCOOLANT CHOICE

Advanced Reactor Features →

High temperature

Low pressure

Online refueling

Sustainable fuel cycle

High power density

Wide range of fuel cycle

options

Complete walkaway

safety

30+ years of R&D

conducted

LWR

HTGR

SFR

MSR

ONE

TerraPower FastBreederLiquid FuelSalt CooledUranium(Could use Th)

TWO

ThorconThermal BurnerLiquid FuelSalt CooledThorium

THREE

TerrestrialEnergyThermalBurnerLiquid FuelSalt CooledUranium(Could use Th)

FOUR

FlibeEnergyThermalBreederLiquid FuelSalt CooledThorium

FIVE

TransatomicPowerHybridBurnerLiquid FuelSalt CooledUranium

SIX

Elysium IndustriesFastBreederLiquid FuelSalt CooledUranium

Molten Salt Reactor TWG →

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:

− 7LiF-BeF2-UF4 fuel salt− 7LiF-BeF2-ThF4 blanket salt− 7LiF-BeF2 coolant salt− Graphite moderator and reflector− Hastelloy-N reactor vessel and piping

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TerraPower’s Molten Chloride Fast Reactor (MCFR) advances nuclear in key areas

• Actinides stay in core, daughter core,or closely-coupled clean-up system

• Actinides always mixed with lanthanides

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

• 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 fuel fabrication• Online refueling• High temperature

Copyright © 2017 TerraPower, LLC. All Rights Reserved.

Transatomic Power

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 rodsfor reactivity control.

Elysium IndustriesMolten Chloride Salt Fast Reactor (MCSFR)

15

Monte-Carlo Neutron Flux

CFDSalt Temperature

Reactor Core Design

Plant Concept• 1 GWe/2.5GWth• Chloride fuel salts• Fast spectrum neutron flux• Breeding ratio ~1• Core outlet: ~ 600 ºC• Core inlet: ~ 500 ºC• High TRL purification systems• Design for maintainability• Fuel Flexible: DU/LEU/SNF/RGPu/WGPu/Th

Design Approach• Integrated Physics-Fluid design

methodology• Computational chemical analysis• Test & validate

Safety & Proliferation Resistance• Low operating pressure – Fuel < Secondary• Secondary Tcold > Fuel Tm.p.• Negative reactivity/void coefficients,

• self regulating/shutdown• Fuel drain system • No actinide removal/separation• Simple Chlorine based soluble fission product removal • FP Vitrification with Cl recycling• Passive corrosion control• Passive safety, incl. decay heat removal• No exothermic reactions• Low excess reactivity

Computational Chemical Analysis

Design ObjectivesSafety Economic Competitiveness Low Environmental Impact

Efficient Nuclear Fuel Use Enhance Non-Proliferation and Safeguards

Use shipyard to build the entire power plant in a factory to minimize cost and schedule risk. Use the ocean/big rivers as our highway. Existing shipyard capacity is enough to build more than 100 GWe of new capacity per year.

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.

ThorConIsle - 500MWe Factory Built

Each hull is 500 MWe. Ballasted to sea bed.50% the size of UltraLarge Crude Carriers(In 2001 we build four ULCCs at $89M each)Graphic shows two 500 MWe hulls plus a jetty surrounding them

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 AreasBase Technology

Studies of basic data e.g., salt purification, determination of key salt properties, and corrosion testing.

Modeling & Simulation

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

Flow Loops & Dynamic Corrosion

Several small-scale forced convection flow loops, likely electrically heated at 250-500 kW, constructed from a variety of materials, a variety of salts, and include coupon testing. Followed by 3-4 medium scale loops, likely be electrically heated at 2-3 MW.

Irradiation Studies (Coupons & Capsules)

Coupon irradiations of candidate materials at appropriate facilities (e.g., HFIR, ATR, BOR-60), and post-irradiation analysis to characterize the effects on materials over time. Salt capsules should be irradiated to study the effects of radiation-enhanced corrosion.

Irradiation Studies (In-Pile Loops)

Consideration of in-pile loops for fertile and/or fissile containing fuel salts in existing test reactors: one in a thermal spectrum accommodating fluoride salts, and one for fast spectrum studies of chloride salts.

Vendor Development

Engage vendors to shorten the critical path to MSR deployment e.g., 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

3. Inventory Change

1. Core Mass/ Volume

2. Fuel Composition

4. Design Information Verification

5. Containment & Surveillance

Preliminary Comparison of Nuclear Materials Accountancy

Parameter Fast Breeder Reactor

Molten Salt Reactor Reprocessing

Safeguards Approach

Item facility Non-item reactor Bulk handling facility

Inputs Unirradiated Direct Use

Initial load: Irradiated Direct UseMake-up feed: Indirect Use

Irradiated Direct Use

Outputs Irradiated Direct Use

Irradiated Direct Use Unirradiated Direct Use

Holdup N/A Easier cleanout? Annual cleanout

Throughput Items <<800MTHM/year 800 MTHM/year

In-Process Inventory

Items >4MT Irradiated Direct Use

4MT

Operating Period

Years Years 200 days

Innovative Safeguards Approaches

Process MonitoringPhysics-based signatures of diversion

State Level Concept [1]Reduced safeguards frequency and intensity based on Broader Conclusion

Undeclared Source Material

Undeclared Facility

Target Material

Declared Source Material Declared Facility

Undeclared 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

NVSMITH@SOUTHERNCO.COM (205) 257-1419

Survey Says…Describe the design basis transient events that have been developed for your reactor concept.

Full loss of flow, partial loss of flow, over fissile addition, cold fuel insertion, earthquake pressure wave, gas cycling, reactivity addition with circulating gas

What are the relevant fuel safety criteria and fuel design limits that have been defined that will be used to demonstrate compliance with 10CFR50 App A: General Design Criteria?

Fuel boiling, fuel freezing, lack of fuel draining, pressure pulse induced density increase, gas/volatile FP release fraction for leak, release after freezing, UCl4, UCl5, UCl6 production and release after freezing, mobility temperature to prevent radiological separation. Structural failure after exceeding creep limits over time.

What integral system tests are required to validate your fuel system failure modes and the efficacy of the defined fuel safety criteria?

Fuel dumping speed, heat capacity for decay heat minimizing temperature rise.

What capabilities should test devices have to meet your testing needs?

Static & flowing systems, corrosion control systems

What separate effects studies could be used to assess specific fuel system behavior of interest prior to or in parallel with integral systems tests?

Simulated fuel tests

What are the sources of fresh and irradiated fuel materials available to conduct relevant experiments?

SNF oxide fuel, U, Pu, DU, Unat, U3O8, UO2SNF metallic fuel, but it is a bit harder

If you need access to historical reports and/or data, please list them below.

IFR handling reports & estimated test & production system cost, FP removal efficiencies for pyro-processing.