ML17138B040
| ML17138B040 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 11/19/1979 |
| From: | Jernigan E, Lester Tripp, Walton G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML17138B039 | List: |
| References | |
| 50-387-79-37, NUDOCS 8001240099 | |
| Download: ML17138B040 (10) | |
See also: IR 05000387/1979037
Text
0
N
. ~50-38i 79-37
Docket No. 50-387
U.S.
NUCLEAR REGULATORY COMMISSION
OFFICE
OF INSPECTION AND ENFORCEMENT
Region I
License
No. CPPR-101
Priority
Category
C
Licensee:
Penns
lvania Power
8 Li ht
Com an
2 North Ninth Street
Allentown
Penns lvania
18101
Facility Name:
Sus
uehanna
Steam Electric Station, Unit
1
Inspection at:
Berwick and Allentown,. Pennsyl'vania
Inspection
conducted:
October 23-24,
1979
8 ../
Inspectors:
E.
p. Jernigan,reactor
Inspector
G. A. Walton, Reactor Inspector
$ >7
ate
s gne
ate sign
L. E. Tri
Chic
E
S
ranch
date signe
Approved by:
R. T;
Car iso
Chief
S
B
a
(
,5, Jn
.
E. Tripp
liief, Engineering
Support Section
No. 1,
RC8ES Branch
ate signe
//
/n
a e signe
Ins ection
Summar
ns ection
on October 23,
1979 and Meetin
on October 24,
1979
e ort
o.
-
/ 9-3
reas
Ins ecte,:
e inspection consisted of a routine,
unannounced
inspection
of on-going
mo ifications to the recirculation system
by one inspector
and one
supervisor
and of a scheduled
meeting to discuss
the inspectability of the
sweepolet to riser double weld configuration attended
by two inspectors
and two
supervisors.
The onsite effort involved 4 inspector-hours
and the meeting
involved 26 inspector-hours.
Results:
No items of noncompliance
were identified.
The
NRC positions with
respect to sweepolet to riser weld inspections
are listed in item 4 of the
tached report.
DETAILS
1.
Persons
Contacted
a.
Site Visit on October'23;
1979
Penns lvania Power
8 Li ht Com an
G. Burvis,, QA Engineer.
b..
Attendees at October
24,
1979 Meetin
Penns lvania Power
8 Li ht
Com an
(PP8L
N.
W. Curtis,
VP and Project Directoi
R.. J. Shovlin, Assistant Project Director
A. R. Sabol,
Manager,
Nuclear Quality Assurance
A. M. Male, Assistant
Manager,
Nuclear Plant Engineering
C. T.. Coddington,
Licensing Engineer
R. A.. Beckley,
NDE Coordinator
R'..L. Moore,
NDE. (Consultant)
D. B. Ritter, Engineer,
Construction
T. F. Oldenhage,
Resident= Engineer
M. Strenk,
Engineer
W. J., Rhodes,
Engineer
Bechtel
Cor oration
L. C. Oesterich,
Senior
Mechanical
Engineer
W.
C.
Koepke, Supervisor,
M. M; Rosson,. Engineering Specialist,,
NDE:.
General
Electric
J.-C. Walker, Site
QA/QC Engineering
Representative
Southwest
Research
Institute
(SwRI
G. J. Gruber, Senior Research
Scientist
W. T. Flach, Director, Engineering Services
Nuclear Ener
Services
(NES
J. J. Hobin, Project Manager
F. T., Carr, Manager,
Field Operations
Factor
'Mutual
En ineerin
Association
R.
D. Biscotti, Authorized Inspector
(ANf).'uclear
Re ulator
Commission
(NRC
Re ion I
'.
T. Carl'son, Chief, Reactor. Construction
and Engineering
Support Branch
L.. E. Tripp, Chief, Engineering Support Section
No. 1,
RC8ES Branch
E.
P., Jernigan,
Reactor
Inspector
.. G. A. Walton, Reactor Inspector
2.
Recirculation
S stem Modification Pro ram (Site)
The. inspectors
reviewed the status of the recirculation system modification
and examined the following components
and activities:
a.
Reactor
Pressure
Vessel
Recirculation
S stem Inlet*Nozzles
Safe-End
Re
acement
The inspectors
observed that welding operations
associated
with the
safe-end
replacement
were almost complete.
The inspectors
examined
the welds attaching the safe-end
to the nozzle
and the thermal
stub tube closing weld;
Additionally,. root area
and incomplete welds
were also checked.
b.
Recirculation
S stem Riser Pi
es
The inspectors
examined
the riser pipes to determine their status.
The riser pipes were extended
on the lower end by the addition of weld
metal.
This was, necessary
to compensate
for anticipated
shrinkage
during reinstallation.
These
welds. were in the as deposited
condition
with backing rings installed.
Subsequent
operations will remove the
back rings
and machine the end-joint weld prep.
The finished weld
prep will be located in the weld metal portion of the pipe on the
lower end.
c ~
Recirculation
S stem Rin
The inspectors
examined the recirculation system ring headers.
These
are in position and are located outside the
RPY and bel'ow the
recirculation system inlet nozzles.
The inspectors
observed that
machining operations
had been
completed re-establishing
the weld
preparations
to'receive
the vertical portion of the external riser
pipes.
The inspectors
noted that the new weld will be installed
approximately 3/4 inch from the original weld that remains
on each
header'opening.
The weld will result in a double weld configuration.
Additionally, the inspectors
noted the outer surface of the fabricated
(sweepolets)
iranediately adjacent to the existing welds to
contain
a steep
ramp.
In the present configuration, this surface
does
not appear to be appropriate to permit ultrasonic testing
(UT) of the
side.
Machining has
been completed
on
the ring header
openings
and the surfaces
have
been surface
examined.
The inside of the openings
have not been machined
and will remain in
the as-welded (originally) condition.
The licensee is reviewing the
examination
requirements for the inside surface.
3.
Licensee/NRC Meetin
A meeting of representatives
of the
PPEL Co.
and their consultants
and the
NRC was held at Allentown, Pennsylvania
on October 24, 1979, to assess
the
inspectability of the double welds in =the recirculation system discussed
in
Paragraph
2.c above.
This situation
was identified during a previous site
inspection
and is discussed
in ISE Report 50-387/79-30.
The removal of the nozzle safe-ends
required that two cuts
be made in each
external jet pump riser pipe located
between the ring header
and the recir-.
culation nozzle.
The licensee
determined that one cut would be at the
safe-end
weld and the other cut would be about one-inch
above the sweepolet
to riser pipe weld.
The rationale
used for this decision was, in part,
that the complete weld and heat affected
zone
(HAZ) could not be removed
due to physical limitations.
The licensee
believes that maximum assurance
against potential intergranular stress
corrosion cracking
(IGSCC) could be
gained
by overlapping the two welds- in that the riser pipe ends are clad
with a. corrosion resistant
cladding
(CRC) on the inside and outside adjacent
to the closing welds.
Since the
new weld will not affect the. unclad
base
metal in the remainder of the riser pipe=which
has
been solution heat
treated,
the licensee believes that this has
been achieved.
Additionally,
the licensee is treating this weld configuration (overlapping welds)
as
a
single weld from the standpoint of both design
and examination
requirements
with respect to Section
XI of the
ASME Code.
The licensee further contends
that Section
XI requirements
can
be satisfied
by performing
a full-vee
from only the riser side of the weld using
a standard calibration block
(one not containing
a weld).
The licensee's
contractor demonstrated
the calibration/examination
technique
developed to satisfy the minimum requirements
of Section XI.
This demon-
stration utilized a standard calibration block of the required curvature/thick-
ness
and contained transverse
and radial notches
machined into its inside
and outside surfaces.
Additionally, a section of pipe containing
an over-
lapping weld was used.
This mock-up essentially
represented
the proposed
weld configuration, the sweepolet restrictions not withstanding.
For
purposes of comparing signal
responses,
the mock-up contained
notches
similar to the calibration standard.
The
UT equipment
used for this demon-
stration
was not the type that will be used during actual
weld examinations.
PPBL and their contractors
maintained that the only area
where intergranular
stress
corrosion cracking might be initiated (at the inside unclad surface
of the
HAZ on the sweepolet
side of the sweepolet
to riser pipe weld) would
be- well covered
by this technique.
Using the code required cal'ibration standard,
the licensee's
contractor
concluded that the examination would meet the minimum requirements of
Section XI of the ASME'ode.
However, there appeared
to be
some degree of
uncertainty with respect to results interpretation/evaluation
due to the
unfavorably high signal to noise ratio (particularly for the second half of
the vee) that was observed
during the demonstration.
The licensee's
present
plans call for. the double weld configuration to be
examined from both sides.
To accomplish this examination
from the sweepolet
side, it will be necessary
to prepare
the surface
by weld buildup and
machining or grinding.
The licensee
plans to characterize
and
map the
subject weld areas
by UT and
RT during preservice
examinations.
NRC Positions
The
NRC representatives
observed
the above discussed
demonstration.
Based
on this observation
and discussions
with licensee/contractor
representatives,
the
NRC representatives
concluded:
a.
The proposed
weld configuration consists of overlapping welds
and must
be treated
as two welds,
hence falling outside the strict definition
of- a weld as defined in Section XI.
b.
Section
XI requires that the entire weld volume,
HAZ and adjacent
base
metal
be scanned
in two directions
from each side of the weld(s)
when
feasible.
Since only the first one-half vee path is effective for
examination of this configuration, examination from both the sweepolet
and riser side of the subject welds is required to provide adequate
coverage
and to meet the intent of the
ASME Code.
c.
A calibration standard
containing representative
welds must
be used
during actual
weld examinations.
This standard will provide
a block
ycousticallg representative
ai'.,the area
being examined.
d.
The use of a dual element transducer
during actual'xamination
is
required.
Although the demonstrated
equipment
was not of the field
variety, the dual element transducer
used
appeared
to be superior in
performance.
In addition, surface examinations of the exterior surface
is necessary.
e.
NRC will closely inspect the licensee's
preservice
(base line) examin-
ations/data
of the subject welds and-must
be satisfied with the weld
mapping
and characterization
to be used
as the basis for comparison
during subsequent
inservice inspections.
I'n summary, it was the
NRC position that the intent of Section
XI examination
requirements
is to detect service
induced type flaws of any nature (not
just intergranular stress
corrosion type cracks) in pressure
boundary
material
throughout the entire volume.
Since
each weld configuration
cannot
be specifically addressed
in the Code, it is important that careful
consideration
be given to all examination affecting attributes
and the
objectives
and intent of the Code.
It was understood that
some
RSD work is underway by the licensee's
contractor
relative to the signal processing
technique
associated
with clad materials.
The concept,
as presented,
seems to offer some promise.
Region I urged the
licensee
to pursue this endeavor.