Safeguards Modeling for Pyroprocessing Studies and Fuel Impacts

SAFEGUARDS MODELING FOR STUDIES OF PYROPROCESSING INPUT ACCOUNTANCY AND FUEL IMPACTS ON ID AND SEID Presented by Eva Barker Eva Barker1, Abigayle I. Hargreaves1, Chris Gundersen1, Matthew Lambert1, Salvador Munoz1, Jaden Palmer1, Sweet Shanahan1, Nelson Snow1, Jolanna Witt1,Evan Dolley2 and Chad L. Pope1 1Idaho State University 2General Electric Global Research

Outline Outline Introduction to safeguards for reprocessing Input accountancy in pyroprocessing RADMASS project and DINO detection Pyroprocessing modeling Active inventory, ID, and SEID calculations SEID sensitivity studies for fuel parameters and more Preliminary results Ongoing research 2

Safeguards for Reprocessing Prevent diversion of SNM and proliferation of nuclear weapons IAEA: Material Unaccounted For (MUF) and MUF MUF < 2.42 kg Pu, Max Pu: 8 kg, MUF < 25 kg LEU, Max LEU: 75 kg MUF = ID = BI EI + G L MUF = ???? = (????? ??????)2 MUF / SEID contributions from input and mass measurements and uncertainties. Ten reprocessing safeguards approaches (1) Material Balance Areas (MBA) for nuclear material accounting (2) Defined Key Measurement Points (KMPs) for flow and inventory (3) Defined Strategic Points for containment and surveillance (C/S) (4) Nuclear Material Accountancy, review of operating records (5) Annual Physical Inventory Verification (PIV)- shutdown cleanout (6) Verification of domestic and international transfers of nuclear material (7) Statistical evaluation to determine Material Unaccounted for (8) Monthly interim inventory verifications (IIVs) for timely detection (9) Verification of facility design information (10) Verification of the operator s measurement system NRC Limits for Category 1 facilities SEID 0.1% of active inventory 235U ID 3 SEID and 200 g of Pu/233U or 300 g of 235U (HEU). Inventory assessment frequency unclear. 3

Sellafield nuclear reprocessing plant Sellafield, UK Overview of Reprocessing Aqueous reprocessing of UNF is the separation of actinides from fission products by chemical solvent extraction in nitric acid. Pyroprocessing uses electrochemical means of separation in molten salts in an electrorefiner. No commercial reprocessing in the US for decades, only DOE facilities. LaHague, Rokkasho and other aqueous facilities follow varied safeguards requirements. No commercial pyroprocessing. The DOE has a few programs with FCF most notable among them for scale. Korea has three plants under development. SHINE is pursuing aqueous reprocessing, while Curio pursues a novel reprocessing method. Oklo intends to pyroprocess UNF commercially. 4

Input Accountancy in Pyroprocessing Destructive Assay (DA) incompatible with input accountancy for pyroprocessing. Existing non-destructive assay (NDA) methods are not rapid and accurate enough to determine uranium and plutonium content in UNF for meeting safeguards requirements. Enter DINO detection, studied under Resonance Absorption Densitometry for Materials Assay Security Safeguards (RADMASS), funded through ARPA-E ONWARDS, awarded to GE Vernova Advanced Research Center with ISU subcontracted. 5

NDA: DINO Detection The Dual Isotope Notch Observer (DINO) method uses a quasi- monochromatic photon beam tuned the NRF energy of the isotope of interest, U-235 and Pu-239. DINO identifies the target s resonant isotope concentration by measuring the quantity of photons removed due to NRF. J. M. Hall et al, "Numerical Simulation of Nuclear Materials Detection, Imaging and Assay with MEGa-rays, INMM Conf 2011 RADMASS Program goal: <1% error with 300 s latency in MCNP model 6

FRPSPM: Fast Reactor Pyroprocessing Safeguards Performance Model A SimEvents model in Simulink to track materials, collect data, and calculate ID and SEID. Error comes from DINO detection and material content from SCALE depletion analysis. 7 7 15 11

LWRPSPM for Oxide Fuel Pyroprocessing Modeling Light Water Reactor Pyroprocessing Safeguards Performance Model (LWRPSPM) An electrolytic reducer converts oxide to metallic UNF for processing. 8

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation 9

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation 10

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 Process inventory only U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation 11

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 ID average of 0 expected Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation 12

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation ID < 3 SEID 13

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 ID not < 200 g Pu Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation 14

Example Inventory, ID, and SEID for U-235 and Pu (kg) Inv Period 1 2 3 4 5 6 7 8 9 10 11 12 U235 Inv 21.68 22.18 22.88 23.44 24.12 24.73 25.27 25.84 26.46 27.10 27.81 28.41 U235 ID U235 SEID -2.701 -2.758 -2.429 -2.827 -2.959 -3.015 -2.740 -2.559 -2.050 -2.729 -3.245 -2.647 Pu Inv 24.51 25.12 25.83 26.35 26.98 27.79 28.23 28.97 29.59 30.29 30.94 31.54 Pu ID -0.223 0.147 -0.233 0.245 -0.324 -0.223 -0.093 -0.204 -0.167 -0.334 0.015 -0.325 Pu SEID 2.113 2.114 2.114 2.110 2.109 2.113 2.109 2.109 2.109 2.111 2.109 2.109 UNF specifications: 25 MT throughput 120 MW/MTU 20 at.% burnup 1 year decay FFTF fuel composition 1.608 1.607 1.610 1.610 1.608 1.609 1.607 1.607 1.608 1.607 1.605 1.606 All safeguards model error values 1% Assumption of continuous operation IAEA: Pu SEID < 2.42 kg 15

Parameters for SEID sensitivity study Fuel burnup (5 at.% through 25 at.%) Reactor power (100-130 MW/MTU) Fuel enrichment (10, 17.75 and 20 wt.%) Fuel composition (oxide vs metallic) Throughput rates (25, 50, 100 MT) Input accountancy error values Output and ER error values Active inventory size Actinide recovery rates (95%, 99%, 99.5%) Process timing ER flushout timing RADMASS Program Requirements: SEID < 0.1% Active Inventory (storage + process inventory) ER flushout frequency not more than annually 16

Enrichment data maximum values (kg) Enrichment U235 Inv U235 ID U235 SEID Pu Inv Pu ID Pu SEID 10% 19.25 -3.40 2.08 87.35 2.72 10.85 17.775% 59.32 -10.48 6.43 67.92 2.16 8.44 20% 76.27 -13.48 8.26 61.88 1.96 7.69 100 MT throughput model 20 at.% at 120 MW/MTU 1% error values for all measurements Maximums from any of 12 balance periods Burnup and power fuel variations show the same trend: more U-235, less Pu and vice versa. All have the same target input accountancy of 0.38% for U and 0.19% for Pu for chosen AI. 17

Preliminary SEID Sensitivity Study Results Parameters with largest impact for NRC safeguards: Plutonium input accountancy error value Active inventory quantities Not sensitive to burnup, enrichment, throughputs unless 200 g Pu ID is a hard limit in reprocessing Single most limiting factor is plutonium input accountancy error value Parameters with largest impact for IAEA safeguards: RADMASS success depends on DINO capability: Low error requires more time which lowers throughput. Throughput Burnups with high plutonium content Plutonium input accountancy error value Not dependent on hot cell storage quantity 18

Ongoing research Study of recovery rates vs. process times to investigate effects on safeguards compliance. All data to train a ML model for digital twin development by ARC LWRPSPM finalization and development of multiple throughput versions, beginning with 100 MT. Lower enrichment means less plutonium. Parameter identification for figure of merit (FOM) development to indicate commercial pyroprocessing viability through the incorporation of the most impactful factors in safeguards compliance. 19

Questions? Grant Information The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0001611. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Acknowledgements General Electric Company (GE) and Idaho State University (ISU) recognizes the contribution of the following former GE employee(s): Andrew Hoffman in addition to contributions from Lumitron Technologies, Inc. 20

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