IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
Fig.1 Schematic of the RV cooling system
emerges out of the insulation.
To mitigate this hot spot, it was
essential to increase the
circumferential conductance in
the RV liner. This is achieved by
interconnecting the cooling
pipes by 10 mm thick carbon
steel plates for a height of 1.2
m, as shown in Fig. 1. Also, the
water flow rate has to be
doubled for the lower lateral
shield region of RV. The number
of cooling tubes and the water
flow rate in the additional
cooling loop of SVSE have been
determined to be 288 and 60
m 3 /h respectively. The
temperature distribution in RV
with these modifications is
depicted in Fig. 2.
Fig.2 Temperature distribution in reactor vault around SVSE embedment during
normal and SGDHR conditions
that the cooling pipes are
welded to the liner (through
out) the length. But, near the
safety vessel support
embedment, the cooling pipes
cannot penetrate the support
flanges. Hence, a part of
concrete trapped inside the
flanges remains un-cooled.
Further, from the point of view
of avoiding use of sharp bends
in the pipes, the cooling pipes
have to be re-routed during
construction. The effects of
these changes on the concrete
temperature around the safety
vessel support embedment
(SVSE) have been assessed by a
comprehensive Computational
Fluid Dynamic (CFD) analysis
and suitable design provisions
have been identified and
implemented at the
construction site.
As a part of the analysis,
many parametric studies (12
configurations) have been
carried out and the need of
additional cooling loop in the
SVSE zone is identified. Also, it
is seen that there is a local
hotspot in RV where the conical
support of the safety vessel
From limitations in space
around SVSE, the number of
headers that can be connected
to the SVSE cooling loop and
the size of headers are to be as
minimum as possible. However,
from heat removal
considerations, the flow rate
that is required to be sent
through each and every cooling
pipe should be more than a
Fig.3 Header with "end-in & end-out"
configuration for SVSE cooling
PROTOTYPE FAST BREEDER REACTOR 15