Nuclear Plant Journal, July-August 2016 NuclearPlantJournal.com
23
Research &
Development
VERA Software
Like an engaging host, VERA invites
researchers to take a walk through the
core of a nuclear reactor—in full-scale
virtual 3-D—to observe in luminous color
the neutron population density in the fuel
rods. At Oak Ridge National Laboratory,
scientists are using the western world’s
most powerful supercomputer, named
Titan, to operate VERA, short for Virtual
Environment for Reactor Applications.
The VERA software is made up of
many interacting computer codes that will
enable researchers to simulate the atomic-
level physics of any reactor core element
at any time, with unprecedented clarity.
Some founding industry-related
partners have established Test Stands, or
platforms, for testing VERA’s modeling
and simulation capabilities. Each partner
focuses on a specific technical challenge.
Westinghouse is examining the core’s
reactivity and power distribution behavior
of its advanced reactor, the AP1000
®
, and
TVA is looking at coolant flow in the reactor
vessel of its Watts Bar Unit 1 plant. EPRI’s
focus is a problem involving nuclear fuel
rods called pellet-clad interaction.
Cylindrical fuel pellets, less than a
quarter of an inch in diameter and roughly a
half of an inch long, are stacked one on top
of the other in the hollow fuel rods. “Under
some circumstances, if operators power
up the reactor too quickly, the pellet can
expand and crack the cladding, releasing
radioactive material from the fuel rod,” said
Feldman. “Or, if pellets aren’t perfectly
round due to manufacturing, the stress on
the cladding will be concentrated in certain
regions, which can also lead to distortion
and cracking.” EPRI is using VERA on its
high-performance computer called Phoebe
for modeling and simulating pellet-clad
interaction. Effective solutions can lower
costs, provide more operating flexibility,
and lead to more complete fuel burnup.
Contact: Heather Feldman, EPRI,
email:
.
Classification Scheme
A term of art in cybersecurity is “attack
surface analysis,” and it’s a key to the process
that EPRI is developing for nuclear plants
to help identify and block entry points for
cyber attacks before hackers can find them.
The U.S. Department of Homeland
Security logged more than 256 industrial
cyber security incidents in 2013, more than
half of them in the energy sector. Targets
included power plants and critical grid
infrastructure. Power plants historically
operated with isolated, proprietary control
systems, but with the advent of regional power
pools and smart grids, they’re increasingly
connected to the outside world. Cyber
attackers can potentially exploit hundreds
of digital components. These range from
simple switches and measuring devices to
complex computerized systems that monitor
and balance electricity flow to and from the
plants. All of these create myriad electronic
pathways that must be properly secured.
EPRI is developing and validating
an integrated classification scheme that
recognizes when attack surfaces of different
plant equipment are the same. Based on
the classification, researchers can identify
measures to block each potential attack
pathway, regardless of the specific device.
To
classify
attack
surfaces
methodically, researchers began with small,
single-function digital devices, which
typically have fewer external interfaces.
Devices such as valve actuators, valve
positioners, and instrument transmitters
do not have general purpose network
connections or memory cards and other
removable media. Researchers are finding
that they have smaller attack surfaces.
EPRI will apply the analysis to
progressively more complicated equipment,
such as network interfaces and programmable
devices, which tend to have larger attack
surfaces as a consequence of multiple points
of interface with other systems.
The attack surface approach is
enabling EPRI to develop a methodology
that can be applied consistently across
devices, nuclear plants, and the industry.
The project’s first technical report was
issued in 2015. EPRI will test the approach
at operating nuclear plants in 2016.
Contact: Matt Gibson, EPRI, email:
.
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