3. DESCRIPTION
These fuel performance data concern 4 Gd2O3 doped UO2 rods irradiated in the BelgoNucleaire GAIN Project. The rods are identified as rods 9, 10, 11 and 12 or GD0301,GD0302, GD0701 and GD0702. GD0301 and GD0302 contain pellets doped with 3wt% Gd2O3 and rods GD0701 and GD0702 contain 7wt% doped pellets.
All rods were irradiated in BR3 to a final burn-up of approaching 40 MWd/kgU. In addition, rod GD701 underwent 2 overpower transients in BR2. The sequence of irradiation, and the reports covering these periods is given below:
1) All rods irradiated in BR3 cycle 4C, GN85-08
2) GD0701 rod 11 transient tested in BR2, GN84-13
3) All rods irradiated in BR3 cycle 4D1, GN86-29
4) GD0701 transient tested in BR2, GN86-25
5) All rods irradiated in BR3 cycle 4D2, GN88-40
Non destructive PIE was performed at the end of each irradiation measuring: creep-down, rod and fuel length changes. After final discharge, destructive PIE was performed either at PSI in Switzerland or Windscale in the UK.
Maximum and rod average burn-up (MWd/kgM) at end-of-cycles:
Rod ----BR3/4C---- ----BR3/4D1---- ----BR3/4D2----
av. max av. max av. max
GD0301 rod 9 13.7 18.3 26.2 34.2 38.8 49.7
GD0302 rod 10 13.9 18.5 26.2 34.2 37.9 48.6
GD0701 rod 11 13.0 17.7 25.9 33.9 38.9 49.9
GD0702 rod 12 12.7 17.2 25.7 33.6 38.9 49.8
Conditions for first transient after cycle 4C, GD0701 rod 11.
Parameter Pre-conditioning stage Transient
Peak pellet power kW/m 16.3 26.5
Positive ramp rate kW/m/s - 0.29
Hold time at power ~4 days ~ 1 min
Ramp down kW/m/s 0.75
Unperturbed thermal neutron flux at 100% reactor power
= 1.82E14 n/cm2/s
Unperturbed epithermal neutronflux at 100% reactor power
= 0.083E14 n/cm2/s
Conditions for second transient after cycle 4D1, GD0701 rod 11.
Parameter Pre-conditioning Transient
stage
Peak pellet power kW/m 18.2 34.0
Positive ramp rate kW/m/s - 0.05 between 18.2 & 21.2 kW/m
1.0 above 21.2 kW/m
Hold time at power 21.5 h ~ 55 secs
Ramp down kW/m/s 1.0
Unperturbed thermal neutron flux at 100% reactor power
= 3.04E14 n/cm2/s
Unperturbed epithermal neutron flux at 100% reactor power
= 0.179E14 n/cm2/s