Nuclear Plant Journal, September-October 2014 NuclearPlantJournal.com
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time installation, minimal installation
and removal time, remote controlled
automated fail safe operation of the tool
delivery platform, and a camera designed
to withstand the extremely high dose
rates in the weld examination areas. To
support personnel safe tool installation/
removal, the Project Team used a
questioning attitude towards the original
plan to use the Core Barrel Lift Rig
platform for CB access. Access to the
Lift Rig would have been by use of a 25
foot ladder placed on the Refueling floor
and the Lift Rig assembly. The project
Team pushed back that this was unsafe for
personnel to access the component with
large tooling in the high dose rate area.
The Project Team identified the critical
need for a shielded work platform to meet
the project’s radiological and industrial
safety objectives. Dominion designed and
fabricated the special shielded platform
with input from the vendor on the required
interfaces. The SPS water shield tanks
also required modifications to support
installation of the shielded platform
on top of the tanks. The shielded work
platform provided the inspectors with
safe access to the top of the water shield
tanks, stable access to 360 degrees of the
core barrel assembly, and supported the
need for timely tool installation/removal
activities. The shielded platform design
eliminated trip hazards by utilizing
decking plate to enable walking above
the shielding. This design also protected
workers by incorporating separate hand
rails for personnel safety and mounting
of inspection tool accessories. This also
eliminated the need for fall protection
harnesses. Staging of the shielding
facilitated timely tool installation
without impeding the motion of the
technicians. To remove additional safety
risks, innovative technical features were
built into the examination that enabled
simultaneous deployment of multiple
tooling components (two camera systems
for different examination areas and on-
board hydro lazing wand for cleaning).
The remote control operation and highly
automated nature of the tool minimized
or eliminated Human Performance
issues by using encoders to track both
the circumferential and axial position
of the weld areas being examined and
recorded. Once installed onto the CB,
the automated tool platform allowed the
performance of three inspection tasks.
These features removed personnel from
the reactor building who typically would
be required to manipulate and perform the
visual examinations from pole delivered
cameras. The on-board hydro lazing
system removed personnel from “line of
fire” risk of high pressure energy release
by automatically positioning the wand
and performing the hydro laze cleaning
of weld areas remotely. Once the tool
was installed, the automated tool features
contributed to removing personnel from
the reactor building and the corresponding
radiological and industrial safety risk of
the work environment. Once installed the
use of the tool also eliminated multiple
independent teams performing the three
individual tasks (Lower Girth Weld
inspection, Hydro Lazing, and Lower
Flange weld inspection). Mock-ups to
duplicate the Surry unique Core Barrel
configuration were fabricated at the
vendor facility and used extensively for
both tool development and personnel
training. Extensive use of mock-ups
supported personnel efficiency training
and tool performance testing. The tool
was operated in “run to failure mode” to
determine weak links in the design and
components were replaced accordingly.
This was important in establishing the
fail safe feature of the tool to eliminate
unnecessary removal and installation
activities. Personnel performance
efficiency training was conducted on
the mock-up for the safe and timely
installation and removal of the tool.
This repetitive performance efficiency
training resulted in a 66% improvement
of the installation and removal times,
eliminating stay times in the high
Elevations of Reactor Vessel
Internals and Lifting Rig in Storage
Stand.
When it
matters
most. . .
Who would
you want to
be tied to?
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Ascendent
Supporting the Nuclear
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• And many related
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