Regional Basic Professional Training Course in Korea

Operation at a power level < 1 MW.
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4. DESIGN OF NUCLEAR REACTORS
The safety actions relating to this operating mode and associated with the neutron
parameters of the core are identical to those of the low power regime and, as in the case
of the latter, they are established by mobile start‐up systems.
Operation at a power level ≥�1 MW.
Table 4.1. Core Parameters of OSIRIS Reactor (U3Si2)
235U enrichment 19.75%
Number of core elements 38
Size of the element 82.4 mm x 82.2 mm
Number of plates per element 22
Plate cladding
Size of a plate (mm)
AG3
fissile height
630
fissile length
68.4
total thickness
1.27
fissile core thickness
0.51
cladding thickness
0.38
235U mass per plate 20.83
235U mass per element (g) 458.26
Width of the water‐filled space between 2 plates(mm)
Mass of boron 10 / element (g) 0.4
When the operating power level of the reactor is 1 MW or greater, the safety actions of
the high‐level systems are validated and the safety actions of the start‐up systems are
prevented from operating. From this point onwards, all the safety actions associated with
neutron parameters are established by the high‐level systems.
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