Three-Day Fabrication of Expansion Joint
Keeps Nuclear Power Plant On-line
On January 9th VEPCO’s North Anna Nuclear Generating
Station, Unit 2 was told by the NRC that they
had just seven days to replace a failing pump discharge metal bellows expansion
joint on
their recirculation
spray line or shut
down the
975-MW unit.
The expansion
joint’s centerline
had moved 3
inches out of
alignment with its
flanges due to
“squirm” failure.
The verbal order
from VEPCO
was received by
Senior Flexonics
Pathway Bellows
on January
10th. The replacement
(10
inch diameter by 23 inch long metal bellows expansion
joint, rated at 180 psig, 260°F and fabricated from 0.037
inch thick type 304 stainless steel) was manufactured
“from scratch” and shipped from Oak Ridge, Tennessee
via VEPCO’s private plane at 7:15 PM on the 12th
-order-to-shipment was less than 60 hours!
According to one VEPCO representative at the North
Anna Plant, “I would never have believed that this fast
turn around was even possible. On the 9th, we were
certain we faced an unscheduled outage in a week.
On-site NRC officials were as amazed as I was.”
The chronological summary of these three days between
order and shipment attests to the cooperation between
VEPCO,Senior Flexonics Pathway and Path way’s vendors,
and the Senior Flexonics Pathway “can-do-it” spirit.
January 11th
VEPCO’s on-site inspector and Senior Flexonics Pathway
engineers review requirements, material procurement,
and shipping schedule.
Reynolds Aluminum in Cincinnati breaks into their production
schedule, and a truck is dispatched to pick up
special plate for the expansion joint lugs. Flanges are
ordered from Houston to be shipped via Delta Dash for
same day delivery.
This replacement expansion joint did not require Senior
Flexonics Pathway to have an ASME nuclear stamp and
ASME Section Vlll materials could be used. However, a
total of six tests would be required to insure integrity
necessary for a nuclear installation.
10:30 AM - Engineering revises drawings to reflect current
standards, and the job is released for manufacture.
11:30 AM - Material samples are sent to an independent
laboratory for physical and chemical testing.
1:30 PM - Quality Assurance beings a documentation
package.
4:00 PM - Fabrication starts with VEPCO’s witness
present.
8:00 -11 :30 PM -Vendor materials arrive by truck and
plane. Fabrication continues.
January 12th
9:00 AM - Bellows is now complete; final assembly
begins.
1:00 PM -
Dye-penetrant check
completed.
3:15 PM - The test results
come back from
the independent laboratory,
and final documentation
proceeds.
4:00 PM - The ASME
Code inspector arrives,
and hydrostatic testing
begins
6:45 PM - The expansion
joint is packaged
for shipment.
7:15 PM - SHIPPED!
For more information contact: Senior Flexonics Pathway.