ML22336A105

M221208: Slides/Supporting Presentation Material - S. Van Til - Overview of Advanced Reactor Fuel Activities

ML22336A105
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Issue date:	12/08/2022
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M221208
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K6255/22.247985 EU DuC= N Nuclear fuel testing capabilities at NRG, Petten (NL)

NRC-meeting Sander van Til, MSc.

8-12-2022

Aerial view of the NRG site Petten Amsterdam Arnhem 2

The High Flux Reactor (HFR)

Tank in pool MTR 45 MW thermal power Stable and constant flux profile in each irradiation position Main applications

• Isotope production

• Nuclear energy services

• R&D 30 operation days per irradiation cycle, 9 cycles/year (~290 FPD/y)

Operational positions In-core (17)

Poolside facility (12)

Horizontal beam tubes (12) 3

HFR overview; core plan 4

Fuel and Material irradiations Fuels Materials UO2 / MOX (LWR) Nuclear graphite

• Irradiation induced creep

• Life time extension of AGRs in the UK

• Qualification of nuclear graphite for MSR application HTR

• Qualification of nuclear graphite for HTR application

• Qualification of HTR fuel pebbles Steels SFR/LFR

• RPV materials and Long Term Operation (LTO)

• High Pu-content MOX

• Scientific research on irradiation effects in RPV materials

• Pu-nitride

• He-embrittlement in Ni-based steels

• Am-transmutation candidates

• Matrix fuels MSR

• Fluoride and chloride salts

• Interaction with graphite and steels

• Radiolysis of fluoride salts 5

Example HTR fuel qualification

• 5 pebbles are in graphite samples holder

• Double containment

• A total of 48 thermocouples for accurate temperature registration

• Online gas monitoring (online R/B of fission gases)

• Including neutron fluence registration

• Self Powered Neutron Detectors

• Activation monitor sets

• Kept central temperatures at 1050 +/- 50 °C 6

Example Fuel irradiations (rodlet)

Main specs/options

• Sodium filled or dry sample holder

• Up to 700 mm

• Cd or Hf shroud for spectrum tailoring

• Instrumented sample holder

• Thermocouples

• Pressure transducers

• LVDT

• SPND

• Neutron fluence monitor sets

• Temperature control through gas gap of double containment

• Stable Ttarget within 20°C 7

Hot Cell Facility - Fuel studies SEM - EDS Flexible Inner boxes JEOL 6490 LV SEM, in alpha hot cell Fuel dismantling in inert Non-Destructive Testing Fuel dissolution studies 8

atmosphere

Overview of available PIE Non exhaustive list of Post Irradiation Examination capabilities.

On (non-)irradiated structural materials On (non-)irradiated fuels

• Dimensions and weight

• Profilometry

• Pycnometry

• Gamma-spectroscopy

• Laser Flash diffusivity

• Oxide Layer determination (eddy current)

• Thermal expansion

• Puncturing, mass spectroscopy gas-analysis

• Dynamic Youngs Modulus

• Optical microscopy

• Electrical resistivity

• Scanning Electron Microscope in cell

• Hardness testing (Vickers) (+WDS+EDS+EBSD)

• Tensile properties

• X-ray Diffraction

• Fatigue Crack Propagation

• X-ray Computer Tomography

• Fracture toughness

• Neutron Transmission Radiography

• Bending test *Tritium inventory

• Digital Image Correlation

• In-cell specimen manufacture

• Compressive strength

• In-cell capsule assembly

• Creep testing

• TEM

• Clad burst tests (under development; 2023) 9

Capabilities at NRG in summary

• Fabrication of (oxide) fuels

• Radiological labs for studies on non-irradiated fuels

• Design of experiments by dedicated engineers: Nuclear, thermal-mechanical, thermohydraulic

• Fabrication of experiments in in-house mechanical workshop

• Versatile in designing for different fuel/ reactor concepts

• Extensive options for in-core instrumentation in HFR

• Extensive options for post-irradiation examinations on irradiated fuels and materials

• Logistics units for organizing international transports

• Waste handling / disposal at national repository 10

2030s : PALLAS reactor to replace HFR 11

Thank you for your attention 12

Disclaimer:

Goods labeled with an EU DuC (European Dual-use Codification) not equal to N are subject to European and national export authorization when exported from the EU and may be subject to national export authorization when exported to another EU country as well. Even without an EU DuC, or with EU DuC N, authorization may be required due to the final destination and purpose for which the goods are to be used. No rights may be derived from the specified EU DuC or absence of an EU DuC.

Design Process

• Design process has a number of steps

• Duration of process depends on the number of iterations and complexity of the irradiation, typically 12-18 months

• The number of iterations depend on clarity of scope Neutronic Scope Concept Design T&M Calculations Final Design Manufacturing Calculations

• Test matrix

• Material selection

• Material heating

• Stress

• Fixed for approval

• In NRG Central

• Selection of core

• Instrumentation

• DPA estimates

• Temperatures by Safety Comm Workshop position

• Drawings

• Targets 14

HFR in-core irradiation facilities For in-core experiments a TRIO, QUATTRO or REFA facility is placed

• 1, 3 or 4 experiments (sample holders) can be placed in one position

• Cooled (HFR primary coolant) or dry

• Effective height 600 mm Standard HFR Irradiation capsules 15

Fabrication & Assembly 16

Separate effect irradiation experiments Fuel Creep

• Measure height change in-situ through capacitor plates

• Stable, flat temperature Bellow/LVDT

• Well-known power/fission density

• Axial load through actively pressurized bellow

(~88 bars ; 100MPa on Ø4mm discs)

• Load on samples is simultaneous, but displacements are individually

• Proof-of-principal (no fuel) loaded with (Zr,Y)O2 and TZM(Mo)

• Measuring thermal expansion

• Temperature range 500-1200°C 6 Samples UO2, (U,Pu)O2 17

Online gas monitoring: sweep loop facility

• The Sweep loop Facility

• To measure the release of fission gases online by gamma spectrometry

• For accurate temperature control

• Grab sample for external verification measurement (gammaspec, gas mass spec)

Germanium detector Helium Neon Gas volume Counts (15 cm3)

Energy [MeV]

Aerosol filter Grab sample Filtering NaI detector station CORE Polyethylene Tungsten alloy Lead Counts Energy 18 Glove Box Experimental rig

Image: Pavel Soucek, Molten Salt Irradiations JRC Karlsruhe SALIENT series

• Simulation of MSR environment:

• Temperature gradient

• Salt flow

• Fuel burn-up (typically 1-4 %FIHMA)

• Fluoride and/or chloride salts

• In-pile corrosion of structural materials

• Graphite

• Steel / Nickel-based alloys

• Fission product migration and deposition salt Zr-95 (salt-seeker)

Ru-103 Noble metal particles 19 graphite 2 0 2 4 Horizontal position (mm)

EU DuC = E001 The SAGA facility for measurement of radiolytic gas production 20

NRG in support of AGR long term operation

• Accelerated aging of AGR graphite to provide data in support of LTO

• Graphite combined oxidation and neutron irradiation

• Graphite irradiation creep testing

• Extensive post-irradiation characterization program in NRG Hot Cell Laboratories

• +40 years of operational years added to EDF Energy AGR reactor fleet AGR graphite sampling Irradiation and characterisation Analysis of results for safety case 21