SPHERE irradiation. Sander van Til Elio d Agata (JRC-IET) Ralph Hania Alexander Fedorov Raymond Okel Dennis Boomstra

Transcription

1 SPHERE irradiation Sander van Til Elio d Agata (JRC-IET) Ralph Hania Alexander Fedorov Raymond Okel Dennis Boomstra

2 Homogeneous recycle fuel tests in the world Japan: AM-1 test (finished) Effects at first startup: 10 minutes and 24 hours Linear power up to 430 W/cm US: AFC-1 test (PIE ongoing) Medium burn-up (4-8% FIMA) Linear power W/cm at startup Metallic and nitride fuel in addition to oxides Europe: SPHERE test (irradiation completed) Medium burn-up (4-8% FIMA) No neptunium Linear power W/cm at startup Comparison of pellet and sphere-pac fuel 2

3 3 SPHERE Starting Points A direct comparison of Am-bearing MOX fuel in Sphere-Pac and Pellet form under similar conditions What are these same conditions? Same cladding temperature ( o C) Same linear heat rate (~300 W/cm) Due to differences in fuel smeared density, the final burn-up will be slightly different. The design is based on CONFIRM: Double contained, sodium-filled experiment in a wet trio 2 connected Phenix-type pinlets

4 4 Fuel composition Pin Nr. Composition Isotopic composition Fuel Density [g cm -3 ] 241 Am contents [g] 238 U content s [g] 239 Pu contents [g] 1 S-Pac U 0.75 Pu 0.22 Am O 2-x MOX Am 8.33 * Pellets U 0.76 Pu 0.2 Am O 2-x MOX Am % TD *This overall density takes into account both the density of the sphere and the packing density

5 5 Cross section of the experiment Na 150 μm gap between SS 1 st and 2 nd containment Water in wet trio channel Molybdenum shroud (TZM) containing Thermocouples and flux detectors 15-15Ti fuel pin, Ø o 6.55 mm Mo shroud, Ø i 9.2 mm, Ø o 14 mm 2 SS containments + Hf shield, Ø i 19.8 mm, Ø o 25.5 mm SS wet TRIO channel, Ø i 31.5 mm Ø o 33.5 mm

6 Axial view 6

7 7 Pin fabrication and transport (JRC-ITU) He-filling / welding, and subsequent leak tests and weld inspections were performed (He contains 1% neon). The sphere-pac column length is lower than intended (48 mm vs. the nominal length of 60 mm) due to losses during fabrication

8 8 Location HFR A B C D E F G H Fuel Control rod Be reflector Irradiation position Initial SPHERE position

9 9 Results of safety calculations 1-dimensional thermal calculations show that for a linear power of 300 W/cm, the central temperature of both pins stays well below 2500 o C: Using measured thermal conductivity for the pellet fuel Using PINTEMP (PSI) to obtain effective conductivity of the sphere-pac column Not taking into account neutron self-shielding For unrestructured fuel MCNP calculations of SPHERE in HFR position G7-south yield: The vertical position of the experiment at which the equal power condition is satisfied The required thickness of the Hf shield (~0.75 mm)

10 10 Linear power evolution Linear power [W/cm] Power [W/cm] sphere pellets Irradiation days

11 11

12 Sample holder fabrication 12

13 13 First cycle Align pins for linear power Reloading U-targets in neighbouring positions Adjust gas mixture to reach target temperature of 450 o C

14 14 Restructuring after first cycle cycle Before irradiation After 1 cycle of irradiation ( ~28FPD) Central hole diameter of 1.05mm ± 0.09mm

15 15 Irradiation history cycle cycle start-up cycle shut down Pos. cycle time irrad time T Mo, pin 1 FPD FPD C C T Mo, pin : :30 G HFR shutdown : :00 G : :00 G : :10 G : :00 G : :00 G : :00 G : :30 G : :00 F : :00 F : :00 F

16 16 Last cycles of SPHERE Clad temperatures are stable at o C (about 70 o C above thermocouple temperatures)

17 End of Irradiation - neutronradiograph 17

18 18 Schedule remainder FAIRFUELS Irradiation completed on 26 April month cooling time (neutron radiogram taken) Delivery of D (will complete in coming months) Continuation in PELGRIMM Dismantling and PIE from July - November 2015 Profilometry Gamma-scanning Puncture and gas analysis Ceramography on cross-sections for comparison to Fuel Performance Code simulations Cutting & preparation for transport Monitor set analysis and burn-up calculations Transport to ITU: Q1 2016, but uncertain

19 END 19

20 20

21 AM-1 test (1) * Maeda et a. JNM 389 (2009),

22 AM-1 test (2) Conductivity is roughly that of (U,Pu)O 2-x for same x 1 day is enough for full restructuring No sign of fuel melting at high power * Maeda et a. JNM 389 (2009),

23 AM-1 test (3) Fuel structure: negligible difference with MOX fuel * Maeda et a. JNM 389 (2009),

24 AM-1 test (4) Migration of Am and Pu less at lower O/M Np does not show the same tendency to migrate to center * Maeda et a. JNM 389 (2009),