ML17279A972
| ML17279A972 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 03/31/1988 |
| From: | Richards S, Wagner W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML17279A971 | List: |
| References | |
| 50-397-88-11, GL-84-11, IEB-82-03, IEB-82-3, IEB-83-02, IEB-83-2, IEB-87-001, IEB-87-1, NUDOCS 8804180417 | |
| Download: ML17279A972 (7) | |
See also: IR 05000397/1988011
Text
U.
S.
NUCLEAR REGULATORY COMMISSION
REGION V
Report
No.
Docket No.
50-397/88"11
50-397
License
No.
Licensee:
Washington Public Power Supply System
P.
0.
Box 968
Richland,
99352
Facility Name:
Washington Nuclear Project
No.
2 (MNP-2)
Inspection at:
WNP-2 Site,
Benton County, Washington
Inspection
Conducted:
March 14-18,
1988
Inspector:
M.
Wagner,
R
ctor Inspector
Date Signed
Approved By:
S.
A. Richards,
Chief
Engineering Section
~Summar
Date Signed
Ins ection Durin
the Period of March 14-18
1988
Re ort No. 50-397/88-11
Areas Ins ected:
Routine,
unannounced
inspection
by a regional
based
inspector of the licensee's
actions
taken to implement Generic Letter 84-11,
"Inspections of BWR Stainless
Steel Piping," and their response
to
NRC
Bulletin 87-01, "Thinning of Pipe Walls in Nuclear
Power Plants."
During
this inspection,
Inspection
Procedures
30702,
25589,
and 92703 were used.
Results:
Of the areas
inspected,
no violations of NRC requirements
or
deviations
were identified.
SS04lS04i7
SS0331
ADOCK 05000397
9
DETAILS
1.
Persons
Contacted
- C
AJ
S
"R.
"A.
D.
R.
C.
R.
D.
T.
D.
Powers,
Plant Manager
Baker, Assistant Plant Manager
Feldman,
gA Manager
Principal
Compliance
Engineer
Webring, Mechanical
Supervisor
Hosier, Nuclear Safety Assurance
Group Manager
Ramey,
Senior ISI Engineer
Rana,
ISI Program
Leader
King, Lead Materials
and Welding Engineer
Davis, Materials
and Inspection
Group Manager
Welch, Supervisor,
NDE Services
Hoyle, Supervisor,
Code
Programs
Thiederman,
Technical Staff Engineer
The inspector also held discussions
with other licensee
personnel
involved with piping inspection activities.
"Denotes'hose
personnel
in attendance
at the exit meeting
on March 18,
1988.
2.
Licensee
Actions Taken to Im lement Generic Letter 84-11 Ins ections
of
BWR Stainless
Steel
Pi in
A.
~Back round
The licensee's
response
to Generic Letter (GL) 84-11 is addressed
in
their letter G02-84-364 of May 30,
1984.
G02-84-364 points out that
the generic letter's reference
to IE Bulletins 82-03 and 83-02,
which required piping examinations
by operating plants, is not
applicable to WNP-2 since their operating license post-dated
these
bulletins.
However, the licensee's
response
did address
their
program which includes the scope
and schedule of planned
'inspections,
qualification of examiners,
a description of any
special
surveillance
measures,
and remedial
measures
to be taken
when cracks
are discovered.
Prior to going into commercial
operation in December
1984, the
licensee identified 202 stainless
steel
welds that were susceptible
to intergranular stress
corrosion cracking
(IGSCC).
Fifty (50) of
these
welds were determined to be conforming material; i.e., they
were either the low carbon
grade of stainless
steel
or were solution
heat treated after welding which minimizes the occurrence
of IGSCC
in
BWR piping.
In 1983, the induction heating stress
improvement
(IHSI) process
was applied to 113 susceptible
welds causing residual
compressive
stresses
in the welds,
thus inhibiting IGSCC.
The
licensee,
therefore,
went into commercial
operation with 39 welds
classified
as non-conforming, i.e., susceptible
to IGSCC.
Ins ection Pro
ram
Section 5.3.4 of the licensee's
Inservice Inspection (ISI) Program,
dated April 4, 1985,
addresses
the 'requirement for an augmented
inservice inspection of all Code Class
1 piping and components
which
are considered
susceptible
to IGSCC.
The requirement is for
inspection of 20K of the 39 welds (listed in Table 5-2 of the ISI
Program) during the first refueling outage.
Inquiring into the
inspection status of these
welds revealed to the inspector that the
four jet pump instrumentation
nozzle safe
end welds were determined
to be conforming welds.
This was based
upon
a review of the
certified material test reports
(CMTR), which were not available
when the licensee
responded
to GL 84-11.
The remaining
35 non-
conforming welds all received the IHSI treatment during the first
refueling outage.
In addition, all 35 welds were ultrasonically
examined prior to and after receiving the IHSI treatment.
Therefore, all the planned
augmented
inservice inspections
are
completed with no
IGSCC having been detected.
The requirement for inspection of 20K of welds previously inspected
and found not to contain cracks,
under IE Bulletins 82-03 or 83-02,
is not applicable since
WNP-2 was not operational
when these
bulletins were issued.
The
GL 84-11 program requi rements for inspection of all unrepaired
cracked welds
and weld overlays are not applicable
because
there are
no .unrepaired
cracked welds at WNP-2, since the piping was not
exposed to an
IGSCC environment prior to December
1984,
and
consequently,
no weld overlays were required.
This was addressed
in
the licensee's
response
to GL 84-11.
As previously mentioned in,this report,
the licensee
performed
inspections
on all the 35 welds treated
by the IHSI technique during
the first refueling outage.
For the 113 welds that received the
IHSI treatment prior to service,
10K were examined to verify that
the Preservice
Inspection results (ISI baseline)
did not change.
'he licensee's
ISI Program includes
requirements for a visual
examination for leakage of the Reactor Coolant System
(RCS) piping
during each plant outage in which the containment is deinerted.
ualifications of UT Examiners
Personnel
qualifications are addressed
in NDE and I Instruction
No.
gCI 6-2, entitled,
"Examination of Piping Welds for IGSCC," Revision
2 of March 23,
1987.
Section
3. 1.1 of gCI 6-2 states
that personnel
performing these
examinations
shall
be certified as
a Level II or
III UT examiner,
and shall
have been successfully qualified for
detection of IGSCC in accordance
with the "Coordination Plan for
NRC/EPRI/BWROG Training and gualification Activities of NDE
Personnel."
Section
3. 1.4 further states that "Personnel
not
specifically qualified for IGSCC detection,
designated
as trainee,
Level I, II, or III UT may assist
a qualified examiner in
performance
of examinations
to this instruction."
D.
Leak Detection
and
Leaka
e Limits
Technical Specification (TS) 3.4.3.2 requires
RCS leakage
be limited
to 2 gpm increase
in "UNIDENTIFIED LEAKAGE" within any 4-hour
period.
If leakage is greater
than this, Action (e) requires
identifying the source of leakage
as not service sensitive
Type 304
or 316 stainless
steel within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in at least
"HOT
SHUTDOWN" within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />
and in "COLD SHUTDOWN" within the
following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
TS 4.4.3.2. 1 states that the
RCS leakage shall
be demonstrated
to be
within these limits by monitoring the primary containment
sump flow
rate at least
once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The licensee
performs this
activity during the 8-hour shift surveillance to verify that the
2
gpm/4 hr limit is not exceeded.
This is identified on a strip chart
recorder which records
gpm vs. time.
Also, alarms
are installed to
alert the operators
whenever the
TS requirement of "5 gpm
UNIDENTIFIED LEAKAGE" is exceeded.
E.
Performance
of Ins ection
The nominal diameters
of the
35 welds subject to the augmented
requirements
were 4 and
24 inches.
The inspector
reviewed the
following reports which document the
UT examinations
performed in
accordance
with the licensee's
response
to GL 84-11:
4RRC(4)A-2
4"O.D.
Pipe to Tee
Pre-IHSI
4RRC(4)A-2
4"O.D.
Pipe to Tee
Post-IHSI
4RRC(4)B-7
4"O.D.
Elbow to Pipe
Pre-IHSI
4RRC(4)B-7
4"O.D.
Elbow to Pipe
Post-IHSI
1RRU-081
24RRC(2)B-8
24RRC(2)B-8
24"0. D.
24"O.D.
Pipe to
Sweepolet
Pipe to
Sweepolet
Pre-IHSI
Post- IHSI
1RRU"012
24RRC(l)A-201
24"0. D.
Pipe to
Sweepolet
24RRC(1)A-201
24"0. D.
Pipe to
Sweepolet
Pre-IHSI
Post-IHSI
The inspector reviewed the qualification records of the
personnel
who performed the
UT examinations
on these
All
were properly qualified, certified,
and
had demonstrated their
competence
to examine welds for evidence of IGSCC prior to
performing any
UT examinations.
The qualifications of UT examiners
are discussed
in Section
2.C of this report.
F.
Subse
vent Ins ection Activit
Section 3.3.5 of the ISI Program (Revision
0 of April 16, 1985)
provides for additional inspection
when
new cracks
are found or
existing cracks
grow to an unacceptable
size.
The ISI Program also
identifies all stainless
steel
welds to be examined for IGSCC.
No violations or deviations
were identified.
Licensee
Res
onse to Bulletin 87-01 on Pi
e Wall Thinnin
in Nuclear
Power Plants
The licensee's
response
to Bulletin 87-01 is documented
in their letter
G02-87-245 submitted to the
NRC on September
14, 1987.
The letter
addresses
their programs for monitoring the thickness of pipe walls in
high-energy single-phase
and two-phase
carbon steel piping systems.
Specifically, those
systems
susceptible to wall thinning due to the
Erosion/Corrosion
(EC) phenomena
were addressed.
The licensee's
response
specifically and adequately
addressed
each request for information
contained in Bulletin 87-01.
Their response
to guestion
2a stated that
the
EPRI developed
CHEC program
(EPRI computer
code to select inspection
points)
was not available
when the selection criteria was established
for
selecting points to make thickness
measurements.
Since the
CHEC program
is now available,
the inspector questioned
whether the selection criteria
would have
been
any different.
The licensee
said that since the
same
basic parameters
were used
by their own calculations,
no additional
inspection points were identified.
That is, all the susceptible
systems
and the worst case points are the
same
as addressed
in their response
to
Bul 1 etin 87-01.
The 'program for monitoring pipe wall thinning is described
in the Plant
Procedures
Manual,
Procedure
No. 8.3.65 entitled, "Surveillance Procedure
for Monitoring Pipe Wall Thinning," Revision
0 of April 6, 1987.
This
procedure
contains
the system
and piping location selection criteria and
also the requirement for wall thickness
measurements
by ultrasonic test
using established
plant procedures.
New information and actions
taken by the licensee
addressing
EC were
examined
by the inspector.
The results of the
UT examination of 44 pipe
locations for wall thickness,
conducted
during the 1987 refueling outage,
were reported in IOM SS2-PE-87-1241
dated October 30, 1987.
This report
entitled,
"Pipe Wall Thinning Data Report," Report
No.
WPPSS-ENT-113,
list the 44 inspection locations
and their predicted
EC rates.
The
report states
that two specific areas exhibit the characteristics
of high
EC rates
and should
be considered for interim examination if the
opportunity presents itself.
That is, prior to the next scheduled
outage
in April 1988.
The Engineering
and Plant Technical
groups agreed it
would be prudent to verify these
EC rates
and,
subsequently,
these
examinations
were performed during the
December
1987 mini-outage.
'The
two worst case
locations
were identified as 311-1,
an 18-inch diameter
bleed
steam
supply piping,
and 431-2
a 6-inch diameter
MSR heater vent
line.
The results
showed the bleed
steam pipe location (311-2),
downstream of the elbow, to be within .076 inches of Code minimum wall
thickness with an
EC rate of .076 inches per operating cycle.
No similar
problems
were experienced with test location 431-2..
Repair to 311-2 was scheduled for R-3 (April 1988 outage);
however,
the
licensee
took the opportunity to perform this task during the forced
outage in February
1988.
The localized areas
were repaired
by weld
buildup over the thinned area.
The tentatively planned activity for
EC
during R-3 is to prepare for similar repairs
on the sister bleed stream
(312) lines.
'The inspector is satisfied that the licensee
has taken appropriate
actions to address
This conclusion is based
on the
licensee's
development
and effective implementation of a surveillance
program to monitor the thickness of pipe walls in high-energy
single-phase
and two-phase
carbon steel piping systems,
as verified
during this inspection.
No violations or deviations
were identified.
The inspector
met with licensee
management
representatives
denoted in
paragraph
1 on March 18,
1988.
The scope of the inspection
and the
inspector's
findings,
as noted in this report,
were discussed.
e