ALARA Planning and Teaching Tool Based on
Virtual
-
Reality Technologies
Di Zhang
1
, X. George Xu
1
, D. Hussey
2
, S.Bushart
2
1
Nuclear Engineering and Engineering Physics, Rensselaer Polytechnic Institute, Troy, New York, USA
2
Electric Power Research Institute, Palo Alto, CA, USA
( contact Professor X. George Xu at xug2@rpi.edu )
The
VR
Dose
Simulator
soft
package
was
developed
using
Computer
-
Aided
-
Design
model
of
a
nuclear
power
plant,
augmented
Virtual
-
Reality
computer
technology,
and
advanced
software
programming
.
All
3
-
D
CAD
models
of
the
buildings,
floor
and
radiation
facility
were
imbedded
into
a
VR
authoring
environment
called
EON
that
enables
a
high
level
of
interactivity
.
The
VR
technology
implemented
by
object
-
oriented
software
design
methodology
.
Two
avatars
were
used
to
represent
a
male
and
female
worker
who
move
around
inside
the
radiation
areas
to
carry
our
various
user
-
specified
tasks
.
Dose
calculation,
a
game
-
like
scoring
system
and
interfaces
were
designed
to
stimulate
the
interactivity
between
a
user
and
the
computer
.
Fig
.
1
shows
the
flow
chart
of
the
whole
software
development
approach
.
INTRODUCTION
MATERIAL AND METHOD
In
recent
years,
the
nuclear
power
industry
has
shown
an
increasing
interest
in
using
the
latest
computer
visualization
and
virtual
-
reality
(VR)
simulation
tools
for
job
optimization,
ALARA
training,
and
security
inspection
.
Most
of
the
software
tools
developed
from
previous
studies,
however,
have
focused
on
the
technologies
involving
immersive
VR
interfaces
.
In
order
for
the
VR
technology
to
be
useful
in
the
ALARA
planning,
such
simulations
should
be
based
on
data
on
the
effective
dose
equivalent
(EDE)
required
by
the
U
.
S
.
NRC
for
radiation
protection
purposes
.
This
paper
presents
an
on
-
going
project
to
develop
a
VR
based
interactive
radiation
dose
simulation
tool
for
the
nuclear
power
plant
.
A virtual avatar, which is used to represent a worker, is controlled by the user. This avatar is required to accomplish sever
al
virtual jobs in different ‘way points”
in
the power plant. The shorter time the worker spent in finishing these jobs, the less dose he/she would receive. A score is gi
ven
to the player based on the number of
virtual jobs that have been finished and the accumulated dose the worker has received. The software provides two navigation m
eth
ods: automatic navigation and
interactive navigation to allow the player a flexibility in carrying out the jobs.
Each player needs to select an avatar at the beginning of the game (see Fig. 3 a), and then specify both the time spent on ea
ch
way point and navigation mode (Fig.
3 b). Then, the source terms and corresponding information need to be defined (Fig. 3 c). After all the parameters are provid
ed
by a player, augmented Virtual
Reality environment offers a game
-
like interactivity to allow a player to be immersed in the environment. During the whole proce
ss, the accumulated time, the
accumulated dose to an avatar, the current position of the avatar and the current dose rate are shown in real
-
time on the screen
(see Fig.3 d).
CONCLUSIONS
ACKNOWLEDGEMENT
A
Virtual
-
reality
based
training
software
package,
VR
Dose
Simulator,
has
been
demonstrated
using
3
-
D
CAD
and
VR
authoring
technologies
.
It
provides
an
interactive,
vivid,
and
easy
way
to
educate
a
worker
about
ALARA
principle
in
a
nuclear
power
plant
.
The
interface
is
user
-
friendly
and
game
-
like,
providing
the
intuitive
interface
.
With
the
incorporation
of
EDE
dose
calculations,
the
dose
to
the
worker
is
useful
for
demonstrating
compliance
with
the
radiation
protection
regulations
.
Simulation
of
the
virtual
reality
environment
A powerful VR authoring software, EON Reality, was used as the tool to implement the
virtual environment. The 3D models of both modified nuclear power plant facility and
avatars were imported into the EON. Interactive controlling effect was added for the
user to control the movement and posture of the avatars. Collision detection module
made sure that an avatar interacts realistically with the environment including things
such as always walking on a surface and not going through the wall etc.
This project was sponsored by the Electric Power Research Institute.
3D model of the nuclear power plant
Multigen
Creator
was
used
to
modify
the
surface
model
of
the
nuclear
power
plant,
which
is
shown
in
Fig
.
2
.
Considering
the
efficiency
and
compactness,
the
original
CAD
model
was
simplified
.
Collision
Detection
algorithm
was
used
to
make
sure
that
the
avatars
will
not
walk
into
walls
.
Some
facility
components
were
divided
into
multiple
pieces
to
carefully
define
the
environment
.
Two
avatars
representing
a
male
and
a
female
workers
had
“jointed
body
parts”
so
the
arms
or
legs
can
be
positions
to
simulate
different
postures
.
Graphic
interactive
interface
Visual Basic. NET (VB.NET) was used to develop the graphic interface. It is convenient for VB.NET to combine EON files into t
he
software. For dose calculation, the
communication between EON and VB.NET is critical. So in VB.NET an “instance” (i.e., an object in computer memory), which repr
ese
nts EON file, was generated.
And the information of the avatar’s coordinate could be transmitted through this instance. The coordinate is refreshed in rea
l
-
t
ime and the dose is calculated and
accumulated per second.
Dose
calculation
Two radiation source terms are provided in the software. The first one is dose map mode, while the other one is fixed radiati
on
source mode involving a gamma
source.
For dose map mode, the environment is surveyed to define exposure rate for the entire floor. The dose
-
map obtained by a radiati
on survey can be specified by
a user for a realistic nuclear power plant environment.
When a worker is moving around for a job, he/she is exposed to radiation and the total dose is accumulated.
For the fixed source mode, the source and the corresponding radioactivity is specified by the user. The gamma
-
constant of a poin
t
-
like source is used to calculate the
dose to the worker according to the distance between the avatar and the source. In both modes, the exposure is converted to e
ffe
ctive dose equivalent that have been
using the ICRP exposure
-
to dose conversion methodologies. The effective dose equivalent per kerma is energy and geometry depend
ent.
RESULTS
Fig. 1 Flow chart of the solution
Fig. 2
3D model of the nuclear power plant facility
Fig. 3 Graphic interfaces of the virtual
-
reality software package
(a) Selection of worker
(d) Virtual working environment
(c) Definition of the source
(b) Specification of parameters of virtual work
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