Post Irradiation Examination for the Spent Fuel Samples

Trino Vercellese


Outline of Reactor and Post Irradiation Examination

Trino Vercellese is a PWR in Italy. At June 1964, this reactor reached first criticality. In a first cycle from October 1964 to April 1967, average burnup of this reactor became 11.6 GWd/MTU. Compensation of reactivity during the burnup is conducted by the withdrawing the control rod and the change of boric acid concentration in the moderator.

The isotopic compositions were take in the European community's laboratories at Ispra and Karlsruhe.

 

Main parameters of reactor

 

Reactor Name Trino Vercellese
Type of Reactor
PWR
Power
825 MWth
Initial U235 Enrichment (%)
2.7/3.1/3.9
Operation
1964-71
Fuel Pin Fuel Pellet Diameter (mm)
8.9
Length of Pellet Stack in Fuel Rods (mm)
2641
Clad Thickness (mm)
0.383
Clad Material
SUS304
Fuel Assembly Rod Array
15*15
Number of Rods
208
Fuel Rod Pitch (mm)
13.03
Control Rod Absorbing Material
Ag-In-Cd
Core Equivalent Diameter (mm)
2499
Active Height (mm)
2649
Number of Assembly
120
Inlet Temp (deg.)
266.5
Outlet Temp (deg.)
297.5

 

Data 1st cycle 2nd cycle
CORE
Power output 825 MW(th)
Coolant pressure 140 kg/cm2
Coolant effective flow rate 16,000 t/h
Coolant inlet temperature 266.5 deg. -
Coolant average temperature 282 deg. 269 deg.
Coolant outlet temperature 297.5 deg. -
Core average power density 64.4 kW/l(21kW/kgU) 69.9 kW/l(22.8kW/kgU)
Max. design linear power density 12.4 kW/ft 11.4 kW/ft
Max. rod surface temperature 340 deg. -
Equivalent diameter 2499 mm 2400 mm(???)
Active height 2649 mm
Number of square fuel assemblies 120 112
Number of cruciform fuel assemblies 52
Number of regions 3
Initial enrichments(square assemblies) 2.72-3.13-3.90 %
Initial enrichment(cruciform assemblies) 2.72 %
Reload Assemblies enrichment - 4.00 %
Number of control rods 28
UO2 in square fuel assemblies 42,321 kg 39,629 kg
UO2 in cruciform fuel assemblies 2,313 kg
Total UO2 weight 44,634 kg 41,939 kg
Total U weight 39,873 kg 36,968 kg
SQUARE FUEL ASSEMBLY
Rod array 15 x 15
Number of fuel rods 208
Side of square cross section 200.0 mm
Total length 3208.8 mm
UO2 weight 353.81 kg
FUEL PELLET
UO2 density 96.5 %T.D.
Diameter 8.90 mm
Length 15.3 mm
Dishing depth 0.33 mm
Number of pellets per rod (approx.) 173
Length of pellet stack in fuel rod 2641 mm
Clad-pellet clearance 0.114 mm
FUEL CLAD
Inside diameter 9.02 mm
Wall thickness 0.383 mm
Material SS AISI 304
CRUCIFORM FUEL ASSEMBLY
Number of fuel rods 26
Fuel length 2403 mm
Rod outer diameter 10.92 mm
UO2 weight 44.00 kg
CONTROL ROD
Absorbing material 5%Cd - 15%In - 80%Ag
Cladding material Type 304 SS
Number of absorber rods 32
Absorber length 2692 mm
Absorber rod diameter 10.01 mm
Clad outer diameter 10.95 mm
Clad thickness 0.432 mm

 

Operation History

Cycle Periods Days Max. power level(MWth) Core burnup(MWd/t(U)) Coolant avg. temp.(deg.) Control group insertion Approx. boron concentration(ppm)
1 23.10.1964
05.06.1965
226 615 2260 282 30% 1300-1050
Shutdown 86 -
31.08.1965
20.05.1966
263 825 4085 278 4% 1150-650
Shutdown 51 -
11.07.1966
28.04.1967
292 825 5245 278 4% 650-0
Shutdown 1117 -
2 20.05.1970
09.07.1971
416 - - 269 - -

 

Spent Fuel Composition Data

 

Sample Name
Type
U-235
Enrichment[wt%]
Burn up(GWd/t)*
Sampling Position
Laboratory
Assembly
Pin
ITLTRNPWR-1
UO2
3.13
7.24 Ispra
ITLTRNPWR-2
UO2
3.13
15.38 Ispra
ITLTRNPWR-3
UO2
3.13
15.90 Ispra
ITLTRNPWR-4
UO2
3.13
11.53 Ispra
ITLTRNPWR-5
UO2
3.13
16.56 Ispra,Karlsruhe
ITLTRNPWR-6
UO2
3.13
17.45 Ispra
ITLTRNPWR-7
UO2
3.13
12.37 Ispra
ITLTRNPWR-8
UO2
3.13
18.00 Ispra
ITLTRNPWR-9
UO2
2.719
7.81 Ispra,Karlsruhe
ITLTRNPWR-10
UO2
2.719
15.51 Ispra,Karlsruhe
ITLTRNPWR-11
UO2
2.719
12.05 Ispra
ITLTRNPWR-12
UO2
2.719
8.71 Ispra
ITLTRNPWR-13
UO2
2.719
14.77 Ispra
ITLTRNPWR-14
UO2
2.719
15.19 Ispra,Karlsruhe
ITLTRNPWR-15
UO2
2.719
11.13 Ispra,Karlsruhe
ITLTRNPWR-16
UO2
2.719
7.82(Cs-137 Destructive) Ispra
ITLTRNPWR-17
UO2
2.719
14.49 Ispra,Karlsruhe
ITLTRNPWR-18
UO2
2.719
10.19 Ispra,Karlsruhe
ITLTRNPWR-19
UO2
3.13
15.17(Cs-137 Destructive) Ispra
ITLTRNPWR-20
UO2
3.13
26.88 Karlsruhe
ITLTRNPWR-21
UO2
3.13
23.87 Ispra
ITLTRNPWR-22
UO2
3.13
24.55 Ispra,Karlsruhe
ITLTRNPWR-23
UO2
3.13
19.21 Ispra
ITLTRNPWR-24
UO2
3.13
12.86(Cs-137 Destructive) Ispra
ITLTRNPWR-25
UO2
3.13
20.60 Ispra,Karlsruhe
ITLTRNPWR-26
UO2
3.13
23.72 Ispra,Karlsruhe
ITLTRNPWR-27
UO2
3.13
24.52 Ispra
ITLTRNPWR-28
UO2
3.13
24.30 Ispra,Karlsruhe
ITLTRNPWR-29
UO2
3.13
23.41 Karlsruhe
ITLTRNPWR-30
UO2
3.13
19.25 Karksruhe
ITLTRNPWR-31
UO2
3.13
24.85(Cs-137 Destructive) Ispra
ITLTRNPWR-32
UO2
3.13
25.26 Karlsruhe
ITLTRNPWR-33
UO2
3.13
24.33 Ispra
ITLTRNPWR-34
UO2
3.13
24.31(Cs-137 Destructive) Ispra
ITLTRNPWR-35
UO2
3.13
23.93 Karlsruhe
ITLTRNPWR-36
UO2
3.13
24.70 Ispra,Karlsruhe
ITLTRNPWR-37
UO2
3.897
3.44 Ispra
ITLTRNPWR-38
UO2
3.897
7.61 Ispra
ITLTRNPWR-39
UO2
3.897
12.17 Ispra,Karlsruhe

 

* Values by Nd-148 Method. If data from both laboratories (Ispra,Karlsruhe) are available, values from Karlsruhe are shown.

 

Core Configuration and Assembly Shuffling Information

This shows the schematic figure of core of Trino Vercellese reactor. When you click a assembly name in this figure, you can see the position of fuel rod used for the post irradiation examinations.

 

 

509-104 assembly 509-032 assembly 509-049 assembly 509-069 assembly

 

References

  1. A.M.Bresesti et al. Post-irradiation Analysis of Trino Vercellese Reactor Fuel Elements. EUR4909e, 1972.
  2. P.Barbero et.al. Post-irradiation Examination of the Fuel Discharged from the Trino Ver-cellese Reactor after the 2nd Irradiation Cycle. Nuclear Science and Technology, 1977.