Fuel Rod Design and Analysis

Smaller fuel rod diameter, smaller P/D and longer heated length of the fuel rods require higher mass flux and flow velocity in order not to violate the criterion of the MCST. Such higher flow velocity might cause excessive hydrodynamic excitation along the fuel rods. FIV limits the lower bound of the fuel rod diameter, P/D, and heated length. 

The limiting flow velocities for each diameter and P/D are determined so that the cladding surface temperature reaches the limiting value with given MLHGR of 39 kW/m. Then, degree of FIV is evaluated from those flow velocities. All the evaluations are conducted by single channel analyses. 

Incore fuel management path number C= Previous burn cycle number, for example F=fresh fuel 

The nuclear performance is evaluated by the SRAC system with the core arrangement illustrated in Fig. 7.15 [1] and the fuel assembly configuration illustrated in Fig. 7.16 [1], where the total number of the fuel rods in the seed assembly, wrapper 

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