Fusion Programme - ENEA - Fusione

8. R&D on Nuclear Fission2007 Progress ReportMW2.92.72.52.32.11.9Power deposition in all the 180 fuel assemblies (MCNPX)INNERZONEINTERMEDIATEZONEOUTER ZONEFig. 8.20 - Voiding effect: a) whole-ring-by-whole ringand b) for single assembly belonging to the ring20001500Worth/ring BoCWorth/ring EoCa)1.71.5pcm10001.3 RING3RING4RING5RING6RING7RING8500Fig. 8.19 – Assembly-by-assembly power060b)A (mm)F (Hz)0.20.150403020type 1 joint5 grid0.44 0.78 1.20 1.60 1.98 mtype 1type 2type 3type 1 ref. positiontype 3 ref. position0 100 200 300 400 500Grid elasticity (N/mm)pcm/FA40200Worth/ring/FA BoCWorth/ring/FA EoC1 2 3 4 5 6RingsFig. 8.21 - Vibration amplitudes and frequencies vs spacerstiffness (5 spacers, joint constraint)Table 8.IV - Frequencies and Chen-Weber parameters vs spacer number, stiffness and constraintsGridnumberHingeJoint100 N/mm 150 N/mm 100 N/mm 150 N/mmFrequency Hz X max /d h Frequency Hz X max /d h Frequency Hz X max /d h Frequency Hz X max /d h3 13.9 0.021 13.9 0.021 16 0.016 16 0.0164 22.4 0.0081 22.5 0.0081 26.8 0.0057 26.9 0.00565 33.8 0.0036 34.0 0.0035 35.9 0.0032 36.1 0.00316 47.6 0.0018 48.7 0.0017 55.15 0.0013 56.0 0.00137 62.4 0.0010 64.3 0.00098 62.6 0.00010 68.7 0.00088than 200 N/mm, so an amplitude smaller than 0.1 mm and a frequency of about 35 Hz are expected,fulfilling the Cheb–Weber criterion of acceptance.EFIT safety analysis. The RELAP5 thermohydraulic model of EFIT and its coupling with the PARCSneutronics model were improved according to EFIT design developments and then used for accidenttransient analysis. The scheme of the EFIT reactor, characterised by a pool-type primary system andcooled by lead in forced circulation through steam generators, and the related RELAP5 model are125