BMI Visual
Examination
By Edison Fernandez, Arizona Public
Service.
Edison Fernandez
Edison Fernandez received his BS
in Metallurgical Engineering from
University of Illinois. Prior to working
at Arizona Public Service, he worked
at Taussig Labs,
Chicago, Illinois
where he acquired
expertise in NDE,
metallurgy, welding
and failure analysis.
Currently, he is a
Metallurgist at the
Palo Verde Nuclear
Generating Station
focused on Alloy 600
and 690 materials,
Reactor Internals and Reactor Vessel
Integrity Issues. He has participated in
three INPO review visits as an industry
peer. His professional activities include:
past Chairman of the PWROG Materials
Subcommittee and is currently the
Chairman for the EPRI MRP Inspection
Technical Advisory Committee (TAC).
He is a two time TIP award recipient
and authored or co-authored over 30
publications and technical papers.
Nuclear Energy Institute’s Top Industry
Practice (TIP) Awards highlight the
nuclear industry’s most innovative
techniques and ideas.
This innovation won the Engineering
Vendor award.
The Arizona Public Service
team members who participated
included: Brad Berles, Director
Plant Engineering; Mike Dilorenzo,
Dept Leader; Edison Fernandez, Sr
Metallurgist; Douglas Hansen, Sr
Consulting Engineer; Ken Schrecker,
Section Leader Program Engineering.
Summary
For Bottom Mounted Instrumenta-
tion (BMI) nozzles, 10CFR50.55a,
Code
of Federal Regulations
requires a visual
examination every other outage. If a vi-
sual examination determines that leakage
is occurring from a specific BMI, addi-
tional examinations must be performed
to characterize the location, orientation,
and length of cracks. This could include
Ultrasonic (UT) examinations or other
non-visual techniques. If an axial flaw is
detected, additional examinations of oth-
er BMI’s are not regulatory driven. How-
ever, if a circumferential flaw is detected,
then addition examinations are required
and expanded to 100% if another circum-
ferential flaw is detected. Palo Verde
is the only CE plant in
the US with BMIs and
the design is unique
in comparison to the
industry (i.e. West-
inghouse and B&W
units). There were
no NDE capabil-
ity for characterizing
if a flaw existed for
the Palo Verde BMIs
prior to U3R17 out-
age in the fall 2013. In February 2013
Arizona Public Service (APS) in partner-
ship with EPRI proceeded to perform a
capability study for the Palo Verde design
BMI. This consisted of fabricating, and
ultrasonically (UT) fingerprinting a BMI
mockup to replicate the Palo Verde BMI
configuration used for conducting ultra-
sonic examinations (for a chosen inspec-
tion vendor) then documenting the results
of the demonstration. With the Mock-
up nearly complete, Palo Verde entered
U3R17 in October 2013 and during the
remote visual examination of the reactor
pressure vessels bottom head surface; a
leak was discovered surrounding the an-
nulus of bottom mounted instrumentation
(BMI) Penetration #3. As a result, APS
contracted Westinghouse to demonstrate
their capability to collect and analyze
data from the APS mockup. The mockup
information was strictly maintained and
secured at the EPRI NDE Center and
Westinghouse personnel were monitored
at all times by APS and EPRI NDE staff.
During the initial analysis of the ten flaws,
two flaws were not identified and three
flaws were characterized with the wrong
orientation. APS and EPRI staff then rec-
ommended procedure enhancements to
Westinghouse and using the additional
procedure guidance, all of the flaws in
the mockup were detected and correctly
orientated. Westinghouse proceeded to
inspect penetration #3 at Palo Verde Unit
3 and detected several axial orientated
cracks. Because of the successful demon-
stration and the concern that there could
be some part thru-wall cracks in other
nozzles, APS elected to perform UT ex-
aminations of all 61 BMI penetrations
(100%). The examination resulted in no
other unacceptable indications (cracks) in
any other nozzle. It should be noted, this
is above and beyond the requirements of
10CFR50.55a.
48
NuclearPlantJournal.com Nuclear Plant Journal, September-October 2014
The Palo Verde BMI Mock-up.
