Biach Introduces the Next Generation Stud Tensioner
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Recognizing the need to further reduce critical path time in nuclear power plants
and lessen manpower requirements and their associated dose, Biach engineers
introduced the Biach's "SCT" (self contained tensioner) for RPV stud
detensioning and tensioning during vessel disassembly and re-assembly.
The SCT incorporates a built on pumping system thereby eliminating the need for
a central pumping station which currently takes up valuable floor space and
requires multiple distribution hoses and cables to each stud tensioner. Rigging
hoses, a labor intensive requirement at most sites, is now eliminated. It also
includes Biach's advanced features of elongation monitoring to eliminate
potential trim passes, full hydraulic operation, electronic safety interlock limit
switches, LCD text style communication system between tensioners and hoist
and tractor control handles for easy movement on the monorail by one operator.
Photos depict prototype unit with cover-on and cover-off views with the latter showing pumping system to the left side and fluid distribution valve manifold and electronic controls on the right side.
The SCT is available in QD (quick disconnect) and QD-H (quick disconnect
helical thread version) stud engagement designs. Additionally, QD or QD-H
designs currently in use can be retrofitted to convert to the SCT format.
RPV stud tensioners are utilized in multiples of 3, 4, 6 or 8 to provide effective
closure force to secure the RPV flange to the vessel by applying prescribed
tension load to the RPV studs to produce the intended stud elongation.
Stud detensioning and stud tensioning are both normally part of the costly reactor
critical path. Shortening that critical path can save utilities thousands of dollars in outage costs and replacement power costs.
Biach Industries, Inc. has designed and manufactured such systems since 1955
with designs currently in use in over 90% of the US nuclear plants and in many
overseas. Biach also provides Tech Support for maintenance of its systems and
outage support for vessel head disassembly and re-assembly, Electric Stud Drive
Tools (ESDT) for stud spin out and stud elongation measurement systems (SEMS III) for documenting final elongation readings for QC acceptance.
Dedicated to aiding utilities in their quest for shorter outages, Biach continually
integrates innovative improvements to its designs.
For further information, contact: Richard A. Hill, President 908-276-3110 email: rhill@biach.com visit Biach's website: www.biach.com.
