IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
metal. In UT Modified HST
cracking apparently initiated in
the weld metal and extended up
to fine grained HAZ in the base
metal. In the implant test,
cracking was predominantly in
the weld metal at high stress
levels and in HAZ at low stress
levels. In Y-groove tests, cracking
was confined to weld metal both
for straight Y-groove (designed to
facilitate weld metal cracking)
and in inclined Y-groove
(designed to facilitate HAZ
cracking) confirming higher
susceptibility of weld metal to
cracking than the base metal. G-
BOP test is specially designed to
evaluate susceptibility of the
weld metal to HAC and critical
preheat temperature determined
from this test is comparable to
that determined from UTmodified
HST and implant test.
III.C.13A. Fabrication of Non-instrumented Irradiation
Capsules for Measurement of In-pile Creep and
Mechanical Properties of D-9 Material Using
Pre-pressurized Capsules and Tensile Specimens in FBTR
Irradiation induced swelling
and creep are important
phenomena that affect the
design, operation and
performance of core structural
materials of Fast Breeder
Reactors. Alloy D9 is selected
for FBR fuel cladding and
wrapper tube in view of its
enhanced swelling resistance to
neuron irradiation and
irradiation creep compared to
than those of type 316 stainless
steel. The Alloy D9 which is a
modified type 316 stainless
steel with controlled additions
of titanium and silicon has
been developed indigenously in
collaboration with MIDHANI.
The irradiation creep behaviour
of the indigenously developed
D9 alloy has to be evaluated in
order characterise and qualify
the material for use in FBR.
Pressurised capsules technique
is used for evaluating the
irradiation creep behaviour of
Alloy D9 because this method
does not require any
instrumentation during
irradiation testing in nuclear
reactors. Two numbers of noninstrumented
irradiation
capsules for irradiation of
pressurised capsules and
tensile specimens of D9 in FBTR
have been fabricated to
generate baseline irradiation
performance data on this
material at low temperature
and low fluence irradiation
conditions.
Pressurised capsules were
fabricated from indigenously
developed D9 clad tube of
outer diameter 6.6 mm and
0.45 mm wall thickness. The
tube is closed by welding at
one end and fitted with special
end plug at the other end,
which enables filling of gas at
the desired pressure into the
tube using a pressurising
Fig.1 View of irradiation capsule with D9 pressurised capsules and D9 disk
specimens (before assembly and welding)
62 R&D FOR FBRs