RRFM 2009 Transactions - European Nuclear Society

U 3 Si 2 particles in
Al matrix
Fig 4.a
AlFeNi cladding
Fig 4.b
2.2 Fuel operating conditions; safety and functional requirements for the fuel
The reference core configuration is a core loaded with 34 fuel elements and a 100MW core
operation. Table 1 gives fuel parameters and operating conditions :
Fuel type and 235 U enrichment U 3 Si 2
(first operation phase)
Clad material
AlFeNi
In core residence (cycle number x cycle length)(EFPD) 102,8 (4 X 25.7)
Hydraulic gap (mm)/ coolant velocity (m/s) 1.95 / 14.6
Average (1) / Max (2) / Peak (3) Heat flux (W/cm2) 152 / 420 / 516
Average (1) / Peak (3) wet temperature (°C) 65 / 165
Average (4) / Max(4) Burn-up (% 235 U) 51/53
Average (4) / (10 21 f/cm 3 ) 2
(1) Core average; (2) local 3D; (3) All uncertainties included; (4) for discharged fuel elements, at End Of Life
Table 1: RJH fuel operating conditions
The general safety framework required for the JHR fuel underlies the objectives of the
qualification program of the fuel element. More precisely stated, as the first discussions
progressed on the JHR safety options, the ASN issued a certain number of fuel
recommendations which led the CEA to set the following functional requirements for the fuel
[1]:
Operating category
Fuel functional requirements
OC1- Normal conditions
Cladding integrity
OC2- Incidental conditions
Cladding integrity
OC3- Emergency conditions Several fusion possible though no fusion
OC4- Faulty conditions
Fusion possible though limited
Table 2: Operating categories and associated functional requirements for the fuel
Based on these requirements, the fuel plates and elements are designed to guarantee three
fundamental reactor safety functions:
- Confinement of radio-elements,
- Removal of decay heat,
- Control over reactivity
This led to a detailed description of the fuel functional requirements regarding the fuel and
the plates, which need to be transposed into quantitative criteria for safety analysis in order
to demonstrate that the safety objectives are being met (Table 3).
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