IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
intermediate and primary
sodium for the outer row. Fig. 5
shows the mass flow rate of
intermediate sodium from inlet
Hot pool top
DHX bottom
Fig. 3 Temperature distribution of
sodium at various elevations
plenum to the U-tubes. The
average flow rate of sodium is
0.36 kg/s/tube. However, due
to flow non-uniformity it can be
seen that the minimum flow rate
is 0.31 kg/s and the maximum
flow rate is 0.38 kg/s. In
general, the flow rate is higher
in the outermost row which is
connected to three inner rows.
That is, the flow rate is more in
the tubes where the heat
transfer is more in the upward
leg. The differences in the flow
rates among the tubes are only
marginal (-13 % to + 5 %) and
there is no flow reversal in any
of the tubes. Thus, through this
CFD study, it has been
established that there is no risk
for flow reversal in the SGDHRS
of PFBR.
Height, m
4
3.5
3
2.5
2
1.5
1
0.5
0
Inlet
Tube - 1
Tube - 2
Tube - 3
Tube - 4
Tube - 5
Tube - 6
Tube - 7
Tube - 8
Tube - 9
Tube - 10
Tube - 11
Tube - 12
Tube - 13
Tube - 14
Tube - 15
Row-1
Row-2
Row-3
Row-4
Row-5
Baffles
Outlet
500 550 600 650 700 750
Temperature of intermediate sodium in u-tubes, K
Fig. 4 Central line temperature of
intermediate sodium inside U-tubes
along the length
11 0.31
7 0.35
4 0.37 12 0.34
2 0.37 8 0.36
1 0.36 5 0.37 13 0.35
3 0.37 9 0.37
6 0.37 14 0.34
10 0.36
15 0.32
7 0.35
11 0.31
3 0.37
8 0.36
12 0.34
4 0.37
1 0.36
13 0.35
9 0.37
14 0.34
2 0.37
10 0.36
5 0.37
15 0.32
6 0.37
g. 5 Mass flow rates (in kg/s) of intermediate sodium through the
Fig. 5 Mass flow rates (in kg/s) of
intermediate sodium through the
tubes
III.A.7. Gas Entrainment - Effect of Ring Baffle Geometry
There is a large sodium free
surface in the hot pool of PFBR.
Argon, which is an inert gas, is
provided above the free surface
of hot pool to accommodate
volumetric expansion of sodium
and to prevent any contact
between sodium and
atmosphere. Presence of high
free surface velocity and
immersed components
produces surface vortices which
in turn entrain the cover gas
into the hot pool. This
entrainment of cover gas can
attract
unfavourable
Table 1 : Numerical results for free surface velocities for
different baffle plate configurations
R&D FOR FBRs 35