IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
temperatures of 433 K and 493
K with a melt inventory of 20
kg. The debris size distribution
obtained with different melt
temperatures are shown in Fig.
4. For a melt temperature of
493 K the bed porosity
decreased to 0.466. This
information on debris bed
characteristics are being further
processed to address the reality
in a sodium cooled fast reactor
and the results can still be used
as first approximation to assess
recriticality and bed coolability
of relocated molten core
material.
Particle size (mm)
10
1
0.1
0.1 1 5 20 40 60 80 95 99 99.9 99.999
Cumulative mass percentage %
Fig.4 Size distributions at different melt temperatures
WM 371 K
WM 433 K
WM 493 K
III.E.8. Variations in Biofouling Settlement Pattern
in the Coastal Waters of Kalpakkam
Coastal power plants, which
use seawater for cooling the
condenser and other auxiliary
systems, face great monetary
losses due to the settlement of
marine sedentary organisms.
These organisms are identified
as "Biofouling organisms" or
"Biofoulers" and the process is
Fig.1 Variations in settlement
pattern of biofouling organisms
on weekly panels during the
period May 2006 - April 2007.
known as "Biofouling", which
creates major operational
problems such as condenser
tube blockages, reduction in
heat transfer, increased
pressure drop and pump
vibration etc. PFBR is going to
use about 30 m 3 /s of seawater
for cooling. In order to devise
an effective biofouling control
measure for PFBR cooling water
system, it is essential that the
present biofouling potential
(qualitative, quantitative and
their variations) at Kalpakkam
coastal water is studied. In view
of this, a study was carried out
with the objectives, to find out
a) the present settlement
Fig.2 A view of a teak wood panel
exposed to coastal water at
Kalpakkam for 7 days
pattern of biofoulers and b)
seasonal succession of
macrofoulants. Teak wood
panels (size 12 x 9 x 0.3 cm)
were suspended at 1 m depth
below the lowest low water
mark approximately 400 m
away from the shoreline on
epoxy coated mild steel frames
R&D FOR FBRs 79