SPHERE irradiation Sander van Til Elio d Agata (JRC-IET) Ralph Hania Alexander Fedorov Raymond Okel Dennis Boomstra 19-5-2015
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 300-400 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 300-330 W/cm at startup Comparison of pellet and sphere-pac fuel 2
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 (500-550 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 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 0.034 O 2-x MOX + 241 Am 8.33 * 0.320 7.167 1.869 2 Pellets U 0.76 Pu 0.2 Am 0. 03 O 2-x MOX + 241 Am 10.393 93.8 % TD 0.388 10.192 2.442 *This overall density takes into account both the density of the sphere and the packing density
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
Axial view 6
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 Location HFR A B C D E F G H 1 + + + + + + + + + 2 + 3 + 4 + 5 + + 6 + 7 + 8 + Fuel Control rod Be reflector Irradiation position 9 + + + + + + + + + Initial SPHERE position
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 Linear power evolution Linear power [W/cm] 320 300 Power [W/cm] 280 260 240 sphere pellets 220 200 0 100 200 300 400 500 Irradiation days
Temperatures @BOL 11
Sample holder fabrication 12
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 Restructuring after first cycle cycle Before irradiation After 1 cycle of irradiation ( ~28FPD) Central hole diameter of 1.05mm ± 0.09mm
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 2 12013-03 28-08-13 11:10 25-09-13 8:30 G7 27.89 27.89 448 444 HFR shutdown 22014-02 18-03-14 16:40 16-04-14 7:00 G7 28.6 56.49 449 444 32014-03 25-04-14 19:00 20-05-14 16:00 G7 24.88 81.37 444 441 42014-04 1-06-14 13:50 29-06-14 16:10 G7 28.1 109.47 449 446 52014-05 4-07-14 9:30 28-07-14 16:00 G7 24.18 133.65 446 442 62014-06 1-08-14 11:20 29-08-14 16:00 G7 28.02 161.67 443 440 72014-07 2-09-14 12:30 1-10-14 8:00 G7 27.32 188.99 442 439 82014-08 5-12-14 11:20 30-12-14 14:30 G7 24.89 213.88 443 439 92015-01 3-01-15 14:00 28-01-15 16:00 F2 24.86 238.74 446 445 102015-02 19-02-15 11:20 22-03-15 16:00 F2 31.06 266.94 445 445 112015-03 26-03-15 22:30 26-04-15 16:00 F8 30.72 295.14 445 445
16 Last cycles of SPHERE Clad temperatures are stable at 520-530 o C (about 70 o C above thermocouple temperatures)
End of Irradiation - neutronradiograph 17
18 Schedule remainder FAIRFUELS Irradiation completed on 26 April 2015 2 month cooling time (neutron radiogram taken) Delivery of D 2.2.3 (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
END 19
20
AM-1 test (1) * Maeda et a. JNM 389 (2009), 78-84 21
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), 78-84 22
AM-1 test (3) Fuel structure: negligible difference with MOX fuel * Maeda et a. JNM 389 (2009), 78-84 23
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), 78-84 24