ML18029A768
| ML18029A768 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/16/1985 |
| From: | Blake J, Coley J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18029A766 | List: |
| References | |
| 50-259-85-33, 50-260-85-33, 50-296-85-33, GL-84-07, GL-84-11, GL-84-7, TAC-55590, TAC-55591, TAC-55592, NUDOCS 8508090329 | |
| Download: ML18029A768 (11) | |
See also: IR 05000259/1985033
Text
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, N.W.
ATLANTA,GEORGIA 30323
Report Nos.:
50-259/85-33,
50-260/85-33,
and 50-296/85-33
Licensee:
Valley Authority
500A Chestnut Street
Chattanooga,
TN
37401
Docket Nos.:
50-259,
50-260
and 50-296
License Nos.:
and
Facility Name:
Browns"Ferry 1, 2,
and
3
Inspection
Conducted:
June
17-21,
1985
Inspector:
J.
Coley
Approved by:
J
~ J.
Blake, Section
Ch ef
Engineering
Branch
Division of Reactor
Safety
Date Signed
7 g(/r
Date Signed
SUMMARY
Scope:
This routine,
unannounced
inspection entailed
34 inspector-hours
on site
in
the
areas
of reactor
coolant
piping,
specjal
welding
applications
and
inservice inspection
observation
of work activities.
Results:
One violation was identified - visual
and ultrasonic
examinations
of
overlay repair weld GR-2-15 were not adequately
controlled to insure
a meaningful
examination
paragraph
6.a.
8508090329
850719
ADOCg 05000259
Q
REPORT
DETAILS
Persons
Contacted
Licensee
Employees
- G. Jones,
Plant Superintendent
"S. Wells, Supervisor - Inservice Inspection
Group
- 0. Butler, Level III Examiner - Inservice Inspection
Group
T. Cardin,
Codes
and Standards
Branch
R. Wall, Engineer - Modifications Group
J.
Rinne, Supervisor - Modifications Group
J.
Savage,
Supervisor - Modifications Group
Other'icensee
employees
contacted
included engineers,
technicians,
security
force members,
and office personnel.
NRC Resident
Inspectors
0
- G. Paulk,
Senior Resident
Inspector
- C. Patterson,
Resident
Inspector
- Attended exit interview
Exit Interview
The inspection
scope
and findings were
summarized
on June
21,
1985, with
those
persons
indicated
in paragraph
I
above
.
The inspector
described
the
areas
inspected
and
discussed
in detail
the
inspection
findings.
No
'dissenting
comments
were
received
from the
licensee.
The
following
new
items were identified during this inspection.
Violation 50-260/85-33-01,
Visual
and Ultrasonic
Examinations
Of overlay
Repair
Weld GR-2-15
Were
Not Adequately Controlled to Insure
a Meaningful
Examination
paragraph
6.a.
Insp'ector
Followup
Item
50-260/85-33-02,
Supervision/Surveillance
of
Inservice Inspection
Examiners,
paragraph
6.a.
The licensee
did not identify as proprietary
any of the materials
provided
to or reviewed
by the inspector during this inspection.
3.
Licensee Action on Previous
Enforcement Matters
4
This subject
was not addressed
in the inspection.
Unresolved
Items
Unresolved
items were not identified during the inspection.
b~
5.
Reactor
Coolant Piping Special
Welding Applications
Review of Records-
Unit 2 (55178B)
The inspector
reviewed
completed
records
associated
with the overlay weld
repair of recirculation
system
weld GR-2-15
(Work Plan
2096-85)
and
the
replacement
of the jet
pump
instrument
seal
safe-ends
on reactor
vessel
nozzles
N8A and
N8B
(Work Plan
2069-85).
The
review
was
conducted
to
determine
whether special
welding applications
such
as overlay weld repairs
and complex welding of specialized
replacement
components
were performed
in
accordance
with the
requirements
established
by the
American
Society of
Mechanical
Engineers
(ASME) Boiler and Pressure
Vessel
(B&PV) code
and other
licensee/contractor
requirements.
The applicable
codes
are
Section
XI 1977 Edition,
Summer
1978
Addenda,
Section III, 1980 Edition,
Summer
1982
Addenda
(overlay weld repair)
and Section III, 1983 Edition,
Summer
1983 Addenda (jet pump instrumentation
seal
safe-ends).
The
licensee
had
used
Welding Services
personnel,
equipment,
and welding
procedures
for
the
overlay
weld repair
of weld
GR-2-15.
The
Nuclear
Services
Branch of the Tennessee
Valley Authority (TVA) Office 'of Construc-
tion
was
used
to weld the jet
pump instrumentation
seal
safe-ends.'he
inspector verified that:
Work plans
were
reviewed
by (}uality Assurance
(gA) prior to releasing
the documents for production work- activities.
(}uality control
(gC) hold points were established
to insure control of
processes.
Welding procedures
used for each welding application
were qualified in
accordance
with applicable
code requirements.
Repair
procedure
specifications
included all
special
requirements
pertaining
to welding technique,
electrode
control,
preheat
and
base
metal conditioning
as specified in the code
and applicable construction
specification.
Welder performance qualifications were in conformance with all applic-
able
code requirements.
Base
metals
and filler materials
were specifically referenced
in the
code or oiher requirements.
Repairs
and modifications to base
metals
were properly documented.
Nondestructive
examination of the repairs
were performed in accordance
with ASME requirements.
The inspector's
review of the documentation
associated
with the above work
plans
revealed, that
when
compared with previous
overlay work packages
and
drawings,
the
quality of work performed
at
the
Browns
Ferry site
has
definitely
improved.
Consistent
evidence
of prior planning,
coordination
of responsi-
bilities, clear
understanding
of technical
objectives,
and
increased
gA/gC
involvement were apparent
in these
documents.
Within the areas. examined,
no violations or deviations
were observed.
6.
Inser vice Inspection (ISI) - Observation of Work Activities Associated with
Generic Letter 84-11 - Unit 2 (73753B)
On April 19,
1984,
NRC
issued
to all licensees
of
operating
reactors,
applicants
for operating
license,
and
holders
of
construction
permits for boiling water reactors.
This letter
addressed
the
problem that inspections
conducted
at several
boiling water reactors
(BWRs)
revealed
intergranular
stress
corrosion
cracking
(IGSCC) in large diameter
recirculation
and
residual
heat
removal
piping.
These
inspections
were
conducted
pursuant to IE Bulletins 82-03,
Revision
1,
and 83-02
and the
NRC
August 26,
1983 Orders.
The letter expressed
the Commission's
opinion that
the results of the above inspections
mandated
an ongoing program for similar
reinspection
at all operating
BWRs.
The Generic Letter also described
those
actions which licensees
should take to provide
an acceptable
response
to the
IGSCC concern.
TVA's letter of response
dated
June 7,
1984,
was
reviewed by'egion II.
In this letter,
TVA committed
to ultrasonically
inspect
100% of the Unit 2 accessible
stainless
steel
equal
to or
greater
than
four
inches
in diameter,
prior to
induction
heat
stress
'improvement
( IHSI).
In addition,
TVA stated
that
they would inspect
a
twenty-five percent
sample of the welds (greater
than four inches) following
IHSI.
The
sample
would be
selected
from welds which required
recording/
evaluation
of indications prior to IHSI.
Any additional
needed
to
complete
the
25%
sample
would
be
from weld locations
shown to
have
the
highest propensity for cracking.
a.
TVA reported that during IHSI,
a circumferential
crack
had promulgated
through
the
reducing fitting of weld joint
number
GR-2-15
on
the
A-loop cross
connection.
This
area
had
been
inaccessible
to
the
pre-IHSI Ultrasonic
(UT) examination
due to the reducer's
configura-
tion.
A full strength
overlay
weld .was
used
to repair
the
crack.
Welding of the
overlay
repair
had
been
completed
prior to
the
inspector's
arrival
at
the
Browns
Ferry
site
on
June
17,
1985.
Activitiey
associated
with the
overlay
weld repair,
however,
were
reviewed
as delineated
in paragraph
5 above.
4
The ultrasonic
examination
of the weld overlay repair
and the ultra-
sonic
examination
to re-establish
the
base
line for weld joint
No. GR-2-15 were observed
by the inspector in the following areas:
Approved nondestructive
examination
(NDE) procedures
available
and
NDE equipment specified.
,I~
NDE personnel
with proper level of qualification and certification
performing the various examination activities.
Examination
results,
evaluation
of results,
and
any corrective
actions/repairs/replacements
recorded
as
specified
in the
program
and
NOE procedures.
The type of apparatus
used,
including frequency
range
as well as
linearity and signal attenuation
accuracy.
The extent of coverage
(beam angles,
scanning
surface,
scanning
rate
and directions)
as well as the scanning
technique.
Calibration,
methods
and- frequency
including
the
type,
size,
geometry
and material of identified calibration blocks
as well as
location
and size of calibration reflectors within the block are
clearly determined
and recorded.
The sizes
and frequencies
of search units.
Beam angle or angles.
Methods of compensation
for the distance
traversed
by the ultra-
sonic
beam
as it passes
through
the material
including distance"
amplitude correction
and transfer
mechanisms.
The reference
level for monitoring discontinuities
is as defined
and the scanning
gain setting is as specified.
Methods of demonstrating
Levels or limits for evaluations
and recording of indications.
Method of recording significant indications.
During the
angle
beam
examination
of the overlay repair the inspector
observed
the following areas
of concern:
(2)
The examination
was being performed at
a sensitivity of two times
the reference
level.
This was entirely too high for the
examina-
tioo- of this weld overlay due to the inherent
noise level produced
by the
grain
structure
of the
weld metal.
TVA's
examination
procedure
N-UT-28, paragraph
9. 1,
allowed the
examiner. to reduce
the scanning sensitivity when variables
beyond the control of the
operator
precluded
obtaining
a meaningful
examination.
However,
the examiner did not elect to take advantage
of this option.
TVA's Level III examiner
(who
was
accompanying
the
inspector)
observed
the examination
and
immediately instructed
the
Level I
examiner
scanning
the weld, that
he was scanning
too fast for the
examination
of weld metal.
The
speed
at which the
examiner
was
scanning
further
complicated
the
screen
presentation
and
the
evaluation
of indications.
TVA's examination
procedure
N-UT-28
requires
that
scanning
speeds
not exceed
four inches
per
second
unless
test
system calibration is verified at the higher
speed.
TVA's Level III stated that, if the
Level
I examiner
had
scanned
the calibration block at the
speed
he was traveling, the calibra-
tion reflectors would not have
been detected.
The
Level I scanning
the weld was not in visual contact with the
presentation
on
the
screen,
and
the
Level II observing
the
presentation
on
the
screen
had
his
back
turned
away
from the
Level I.
The inspector
was in visual
contact with the presenta-
tion
on the
screen
and
the
Level I.
When
the
Level I started
scanning
the
back
side of the
weld the
inspector
noted
that
signals
on the
screen
were
caused
by couplant
and
no horizontal
movement of any signal
was observed
on the screen.
The inspector
examined
the area
where the examiner
was scanning
to determine
why
the
sound
was not penetrating
the weld and discovered
that the
weld surface
had significant ridges
which allowed the transducer
to bridge across
the
low areas.
Attachment
G to Work Plan 2096-85
for the
overlay welding
process
stated,
in part,
that overlay
surfaces
must
be
ground flat
and
smooth
to provide
adequate
contact
between
the weld surface
and probe with no bridging of low
areas
with couplant.
Attachment
G
had
been
signed off as satis--
factory by
a visual
examiner
from the ISI group.
The
licensee's
Level III stopped
the
examination
and
had
the
surface
prepared
correctly
for ultrasonic
examination.
The
examination
was
subsequently
performed with
a different Level II
examiner
and with the
scanning
speed
and sensitivity
problems
identified
above
under
control.
The
subsequent
examination
detected
indications that required
Level III evaluation.
The licensee
was notified that the
above discrepancies
would
be
reported
as
violation
50-260/85-33-01,
Visual
and
Ultrasonic
Examinations
of Weld Overlay
GR-2-15
Were
Not Adequately
Cont-
rolled to Insure
a Meaningful Examination.
As
a result
of discussions
with the
licensee
concerning
the
discrepancies
noted
above,
the
inspector
discovered
that
the
Lev& II that had initially ultrasonically
examined
the weld
had
never
examined
a weld overlay before.
Further,
discussions
also
revealed
that
the
group
does
not formally audit
examiners
performance
once
they are qualified.
Insufficient supervision of
examiners that are inexperienced
in the
areas
being
examined
and
lack of audit of the performance
of all examiners
on
a reasonable
basis will result in meaningless
examination
results
such
as
the
visual
and ultrasonic
examination initially observed
above.
This
item was discussed
in detail with the plant superintendent
and the
ISI group
supervisor
from Chattanooga.
Both individuals stated
that actions
would be
taken
to insure
the integrity of examina-
tions.
Corrective
action
taken
by the
licensee
on this matter
will be reviewed during
a
subsequent
inspection
and
tracked
by
inspector follow-up item 50-260/85-33-02,
Supervision/Surveillance
of Inservice Inspection
Examiners.
b.
During the inspection
the inspector
was requested
by Region II and
to review the examination
records
and
the sizing techniques
used for
examination" of weld Nos.
OSRHR-2-5A
and
RECIRC-KR-2-37.
Construction
film for weld No.
OSRHR-2-5A had
been lost.
The licensee
subsequently
radiographed
the weld to re-establish
the base-line
data
and in doing
so
discovered
an
indication
approximately
ten
inches
long.
The
licensee
had reported this indication as
a slag stringer
between
layers.
The inspector
reviewed
the film and in addition to the
ten
inch indication reported,
a second indication sixteen
inches
in length
was
observed
by the inspector.
Both indications were evaluated
by the
inspector
as
lack of fusion
between
layers.
The inspector
and TVA's
Level III examiner
re-examined
the
in
order
to verify the
throughwall dimensions of the indications.
The result of these
UT examinations
revealed
the following information
Examination of the
10 inch indication with the
sound
normal to the
surface
revealed
an indication nine inches
long located
11/32 inch
in depth
from the
O.D.
Examination of the indication with
a
45
degree
and
70 degree
angle
beam transducer
revealed
the nine inch
indication
to
be intermittent
and
at
a
.200
inch
depth.
The
indication does
not originate at the inside
surface
of the pipe
and
shows
no indication of through-wall depth.
The
sixteen
inch indication
could
not
be
detected
with ultra-
sonics.
Had the indication originated
at the inside
surface
of
the pipe it would have
been detectable
by UT.
The inspector
concluded
from the above information that the indications
were
lack of fusion
between
layers with no appreciable
through-wall
dimension.
The inspector
also
concluded
from observing
the
Level III
examiner calibrate
and
size
the indication using
a variety of trans-
ducers
and
methods
that
he
had
a
good
understanding
of the
state
techniques
needed
to size indications correctly.
As
a
result
of
the
confidence
obtained
in the
examiner's
sizing
'capabilities,
records
were only reviewed for weld No. KR-2-37.
Within the
areas
examined,
no violations
or deviations
were identified
except
as noted in paragraph
6.a.
above.