Nuclear
Engineering
and
Design
244 (2012) 52–
60
Contents
lists
available
at
SciVerse
ScienceDirect
Nuclear
Engineering
and
Design
jo
ur
n
al
homep
age
:
www.elsevier.com/locate/nucengdes
Development
and
assessment
of
system
analysis
code,
TASS/SMR
for
integral
reactor,
SMART
Y.J.
Chung
∗
,
I.S.
Jun,
S.H.
Kim,
S.H.
Yang,
H.R.
Kim,
W.J.
Lee
Korea
Atomic
Energy
Research
Institute,
1045
Daedeokdaero,
Yuseong,
Daejeon,
305-353,
Republic
of
Korea
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
16
September
2011
Accepted
9
December
2011
a
b
s
t
r
a
c
t
A
new
requirement
has
motivated
the
development
of
smaller
reactors
since
the
1980s.
Integral
type
reactors
have
been
highlighted
as
a
promising
option.
SMART,
which
is
an
integral
type
reactor
has
been
developed
at
KAERI,
and
TASS/SMR
code
was
developed
to
analyze
the
thermal
hydraulic
phenomena
of
the
SMART
plant.
The
main
purpose
of
the
code
is
to
simulate
all
relevant
phenomena,
processes,
and
conditions
inside
the
reactor
coolant
system
that
may
occur
during
such
accidents.
Development
and
assessment
of
the
code
is
represented
in
detail.
By
means
of
the
assessment
results
using
experimental
data,
TASS/SMR
code
can
be
used
for
both
the
experiment
simulation
as
well
as
the
SMART
analysis.
The
code
predicts
thermal
hydraulic
phenomena
for
the
representative
accidents
for
SMART
reasonably.
© 2011 Elsevier B.V. All rights reserved.
1.
Introduction
The
general
trend
of
the
nuclear
market
has
been
toward
larger
unit
sizes.
However,
a
new
requirement
has
motivated
the
devel-
opment
of
smaller
reactors
since
the
1980s.
Integral
type
reactors
have
been
highlighted
as
a
promising
option
(Modro
et
al.,
2002;
OECD
NEA,
2011).
For
this
purpose,
the
design
of
a
330
MWt
inte-
gral
reactor,
SMART
(system-integrated
modular
advanced
reactor)
plant,
has
been
developed
at
the
Korea
Atomic
Energy
Research
Institute
(KAERI)
(Kim,
2010).
SMART
adopts
a
design
concept
containing
most
of
the
reactor
coolant
system
(RCS)
components,
such
as
a
core,
reactor
coolant
pumps
(RCPs),
steam
generators
(SGs),
and
a
pressurizer
in
a
reactor
pressure
vessel.
Also,
it
is
a
small-sized
advanced
integral-type
pressurized
water
reactor
with
several
enhanced
safety
features,
for
examples,
a
passive
residual
heat
removal
system
(PRHRS)
and
an
external
reactor
vessel
cooling
(ERVC).
The
existing
proven
technologies
are
basically
adopted
for
the
SMART
design.
However,
SMART
also
adopts
various
innovative
design
features
and
technologies
that
need
to
be
proven
through
experiments
and
analyses.
For
the
simulation
of
a
design
based
transient
and
accident
in
an
integral
type
nuclear
power
plant,
it
is
necessary
to
develop
a
system
thermal
hydraulic
analysis
code
for
SMART.
A
ther-
mal
hydraulic
analysis
code,
TASS/SMR,
including
a
helical
steam
generator
heat
transfer
and
condensate
heat
exchanger
models,
has
been
developed
to
simulate
thermal
hydraulic
phenomena
∗
Corresponding
author.
Tel.:
+82
42
868
8760.
E-mail
address:
chung@kaeri.re.kr
(Y.J.
Chung).
of
SMART
(Chung
et
al.,
2003).
TASS/SMR
code
can
analyze
the
thermal
hydraulic
phenomena
of
SMART
under
a
full
range
of
reactor
operating
and
accident
conditions.
The
basic
code
struc-
ture
adopts
a
one-dimensional
geometry.
A
node
and
flow-path
network
models
the
system
responses.
The
thermal–hydraulic
model
is
formulated
with
four
one-dimensional
conservation
vari-
ables.
The
application
scope
of
the
code
covers
the
analysis
of
operational
transients,
design
based
accidents
and
accidents
involving
partial
beyond
design
based
accidents
for
the
SMART
plant.
This
paper
presents
an
overview
of
TASS/SMR
code
develop-
ment
and
preliminary
assessment,
mainly
focusing
on
the
thermal
hydraulic
models,
a
numerical
solution,
and
validation
results.
Then,
three
types
of
basic
transient
conditions
including
loss
of
reactor
coolant
flow
accident,
steam
line
break
accident,
and
feed-
water
line
break
accident
are
analyzed
for
SMART.
2.
Thermal
hydraulic
models
and
numerical
solutions
TASS/SMR
code
is
developed
for
a
comprehensive
simulation
of
design
based
accidents
in
the
integral
type
reactor,
SMART.
The
main
purpose
is
to
simulate
all
relevant
phenomena,
processes,
and
conditions
inside
the
reactor
coolant
system
that
may
occur
dur-
ing
such
accidents.
To
describe
the
thermal
hydraulic
behavior
of
SMART,
a
conservative
transient
model
is
adopted
in
the
TASS/SMR
code.
The
governing
equations
are
mixture
mass,
mixture
energy,
and
mixture
momentum,
which
take
into
account
the
drift
flux
model
to
consider
the
velocity
difference
between
steam
and
liquid
velocities.
0029-5493/$
–
see
front
matter ©
2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.nucengdes.2011.12.013