IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
system. A gas mixture of 97%
argon and 3% helium was used
for the pressurisation. After
pressurising, the gas entry path
is sealed with a soft gasket and
welding is carried out to close
the special end plug with a cap.
The diameter of the special end
plug has been designed to
accommodate all features
within the diameter of 6.6 mm.
The length of the pressurised
capsule is about 74 mm. The
pressure of gas in the
pressurised capsule was
determined using the pressure
gauge connected in the
pressurising system and by
using gas laws. These
pressurised capsules were
fabricated using the specially
developed pressurising set up.
All the components required for
this work were machined in
house. The final end caps were
welded using laser welding to
avoid over-heating of the
sealing portion. The finished
capsules (Fig. 1) were helium
leak tested and found to be
acceptable.
Fifteen numbers of such D9
pressurised capsules have been
fabricated and arranged in five
partitions in an irradiation
capsule along with D9 disk
specimens. Out of these 15
pressurised capsules, 5
numbers each were filled with
pressures of 2.1 MPa, 4.2 MPa
and 6.3 MPa at room
temperature respectively. The
corresponding pressures at the
irradiation temperature of
about 623 K are 4.4, 8.8 and
13.2 MPa and the hoop
stresses that are developed in
the pressurised capsules at the
irradiation temperature are 30,
60 and 90 MPa respectively.
The second irradiation capsule
contains D9 tubular tensile
specimens, small size flat
tensile specimens and disk
specimens of D9. A few
specimens of type 316 stainless
steel (FBTR Quality) are also
included in this irradiation
capsule. Holes have been
drilled on the wall of irradiation
capsules to allow the reactor
sodium to enter and surround
the pressurised capsules /
specimens during irradiation.
The irradiation temperature of
pressurised capsules /
specimens is same as
temperature of sodium (619 to
623 K). The irradiation
capsules are assembled in two
special steel subassemblies and
have been loaded presently in
the 4th ring of FBTR for
irradiation (Fig. 1). The desired
duration of irradiation is one
year or above. After irradiation,
the capsules will be discharged
from the reactor and taken to
Radiometallurgy Laboratory
and post irradiation
examination will be conducted
on the pressurised capsules
and other specimens.
III.C.13B. Development of Fly Ash Concrete for
Nuclear Power Plant Structures
To conserve precious natural
resources, and to use industrial
waste materials gainfully in
nuclear projects, use of fly ash
in project sites at Kalpakkam
was explored, by consolidating
knowledge gained in various
units of DAE.
Positive effects of using fly ash
in concrete are as below:
• Better quality of concrete;
better rheology, higher
strength, enhanced durability.
• Eco-friendly, minimizing
greenhouse gas emissions
associated with the
manufacturing of Ordinary
Portland Cement (OPC),
environment friendly disposal of
millions of tones of fly ash.
• Preservation of resources,
saving in energy requirements
R&D FOR FBRs 63