ML18052B505
| ML18052B505 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/04/1988 |
| From: | Danielson D, Schapker J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML18052B503 | List: |
| References | |
| 50-255-88-04, 50-255-88-4, IEB-87-001, IEB-87-1, NUDOCS 8802110336 | |
| Download: ML18052B505 (7) | |
See also: IR 05000255/1988004
Text
U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Report No. 50-255/88004(DRS)
Docket No. 50-255
License:
Consumers Power Company
212 West Michigan Avenue
Jackson, MI
49201
Facility Name:
Palisades Nuclear Generating Plant
Inspection At:
Palisades site, Covert, MI
Inspection
Inspector:
Con~1/j;-*
January 5-7,
- +
F. Schap er
12-14, 21, 22, 1988
h<Uf-~_,y~A.)jv.-"\\..
Approved By:
D. H. Danielson, Chief
Materials and Processes
Section
Inspection Summary
License No. DPR-20
Dat'e
7
Date
Inspection on January 5-7, 12-14, 21, 22, 1988 (Report No. 50-255/88004(DRS))
Areas Inspected:
Unannounced safety inspection of licensee actions in response
to IE Bulletins (92703); review of inservice inspection (!SI) program (73051)
and procedures (73052); observations of !SI work and work activities (73753);
!SI data review and evaluation (73755); and of the Steam Generator Sludge
lancing (73051, 73052, 73753).
Results:
No violations or deviations were identified.
The activities
inspected appeared to meet the safety objectives of the applicable regulatory
requirements.
8802110336 ~~ggg~55
ADOCK
Q
Details
1.
Persons Contacted
Consumers Power Company (CPCo)
- D. P. Hoffman, Plant General Manager
J. G. Lewis, Technical Director
- C. S. Kozup, Technical Engineer
- R. P. Margol, QA Administrator
- B. V. VonWagner, Inservice Inspection (ISI) Supervisor
- K. V. Cedarquist, ISI Engineer
- K. E. Osborne, Projects Superintendent
- M. C. Sniqowski, Steam Generator Outage Manager
- R. D. Orosz, Engineering and Maintenance Manager
S. R. Willman, NOT Project Supervisor
R. M. Rice, Operations Manager
T. D. Fouty, ISI Engineer
G. Y. Yeisley, QA Engineer
Allen Nuclear Associates, Inc. (ANA)
B. L. Curtis, President, Level III ET
U.S. Nuclear Regulatory Commission (NRC) *
E. R. Swanson, Senior Resident Inspector
C. D. Anderson, Resident Inspector
N. R. Williamsen, Reactor Inspector
Other members of the plant staff and contractors were also contacted.
- Denotes those present at the exit interview.
2.
Licensee Action Taken on Bulletins
(Open) Bulletin No. 87-01 Thinning of Pipe Walls in Nuclear Power Plants.
The purpose of this bulletin is to request that licensees submit
information concerning their programs for monitoring the thickness of
pipe walls in high-energy single phase and two-phase carbon steel piping
systems.
Background
On December 9, 1986, Unit 2 at the Surry Power Station experienced a
catastrophic failure of a main feedwater pipe, which resulted in fatal
injuries to four workers.
Investigations of the accident and examination
of data by the licensee, NRC, and others led to the conclusion that
failure of the piping was caused by erosion/corrosion of the carbon steel
pipe wall.
2
Main feedwater systems, as well as other power conversion systems, are
important to safe operation.
Failures of active components in these
systems, for example, valves or pumps, or of passive components such
as piping, can result in undesirable challenges to plant safety systems
required for safe shutdown and accident mitigation.
Failure of
high-energy piping, such as feedwater system piping, can result in
complex challenges to operating staff and the plant because of potential
systems interactions of high-energy steam and water with other systems,
such as electrical distribution, fire protection, and security systems.
All licensees have either explicitly or implicitly committed to maintain
the functional capability of high-energy piping systems that are a part
of the licensing basis for the facility.
An important part of this
commitment is that piping will be maintained within allowable thickness
values.
Licensee action:
The licensee
1 s program for inspection of pipe wall
thinning was initiated in the 1983-1984 refueling outage due to a
Westinghouse Electric Corporation memo recommending an inspection of 'the
Palisades turbine crossunder piping for wear resulting from steam
erosion.
The program was expanded in 1986-87 to include the following
systems:
- Condensate
- Auxilliary Steam
- Heater Drains and Vents
The program will follow the basic outline set forth by EPRI NP-3944.
The
inspection points are selected using maintenance history, input from
other utilities and Keller
1s equation:
s=f(T)*f(x)*c*Kc-Ks.
where:
s
is the maximum local depth of material loss in mm/10 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
f(T) is a dimensionless variable denoting the influence of
temperature on E/C damage.
f(x) is a dimensionless variable denoting the influence of
K c
c
K s
steam wetness on E/C loss. For subcooled water it has been
suggested that this has a value of un~ty, but for two-phase
mixtures it has the form f(x) = (1-x) x, where x is the
steam fraction and O<K <1.0.
A value of K = 0.5 is
considered the most ap~ropriate one.
x
is a variable accounting for the effect of local geometry
on the fluid flow.
is the fluid velocity in m/s.
is a threshold value constant which the product of f(T),
f(x), c, and K must exceed before E/C is observed.
A
value of 1.0 mM/10 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> has been given by Keller.
3
This initial inspection utilizing the above guidelines was completed
January 16, 1987.
The fa 11 owing areas were inspected:
- High pressure turbine main steam supplies.
- Turbine cross over piping.
- Extraction steam lines.
- Feedwater pump turbine inlets.
- Feedwater pump inlets.
- Heater drain pumps inlet and discharge.
- Feedwater heater drain lines.
- Air ejector piping.
- Service water piping (for sand abrasion).
The result of the inspections revealed no degradation below minimum
wall.
Minimum wall was calculated utilizing ANSI 831.1, 1973 Edition,
Section 104.
The NRC inspector reviewed the secondary side ISI program specification
for the current outage, applicable procedures, and ultrasonic examination
data.
Inspection data to date has not identified erosion/corrosion which
violates minimum wall thickness.
However, substantial erosion/corrosion
was exhibited in localized areas.
The licensee elected to repair these
areas.
A trending program for erosion/corrosion wear is i~ the process
~
of development and will be incorporated in the secondary side inspection
program.
This program area requires further review as the inspection and trending
program are newly instituted and insufficient data has been gathered to
conclude the pipe wall thinning inspection program is adequate.
3.
Inservice Inspection (ISI) Program Review (73051)
_)
The NRC inspector reviewed the second ten year ISI Plan for the Palisades
plant.
The ISI plan conforms to the American Society of Mechanical
Engineers (ASME), Boiler and Pressure Vessel Code,Section XI, 1977
Edition through the Summer 1978 Addenda.
Relief requests in accordance
with lOCFR 50.55a (g)(S)(iv) were reviewed.
The licensee only performed
ISI for Class 1 components on steam generator tubes for this outage.
The remainder of the ISI will be performed in the Fall
188 scheduled
maint~nance outage.
The Program reviewed is effective with respect to meeting the safety
objectives of the ASME Section XI requirements.
4.
Steam Generator Eddy Current Examination
As a result of a steam generator (SG) tube leak indication, the Palisades
Plant was shutdown on December 4, 1987.
Eddy current examination (ET)
which was planned for the 1988 fall outage was performed during this*
forced outage due to the SG tube leak indication.
4
The NRC inspector verified that the ET was performed in Accordance with
the augmented ISI program for steam generators as specified in the
Palisades Technical Specification (TS).
A relief request was made by the
licensee concerning the ET of previously installed sleeves.
(Technical
Specification 4.14.5), due to high radiation exposure times to perform
the examination, and that the previous ET of sleeves had shown no
degradation.
The relief request was not formally approved at this date;
however, verbal approval had been granted by NRR.
The NRC inspector
informed the licensee that the exclusion of the ET of installed sleeves
would be identified as an open item pending official approval of the
relief request by the NRC (255/88004-0l(DRS)).
The NRC inspector reviewed ET tapes of examinations performed during the
1983 and the current outage, including the leaking SG tube.
The ET of the
leaking tube revealed a circumferential 90° thru wall indication, whereas
the previous examination of this tube (1983 outage) did not reveal this
indication.
The leaking SG tube was located in Row 122, Line 35, at the
lower edge (both inside and outside) of the No. 13 tube support plate
of SG
11 8
11 *
As required by the Palisades Technical Specification, ET inspection of
all unplugged tubes with ET indications of greater than or equal to 30%
in either of the previous two inspections was performed.
In addition, a~
random sample of 2% of the tubes in the hot leg and 1% of the tubes in
the cold leg of each SG was performed.
One crack-like indication was
observed in the
118
11 cold leg random sample.
Consequently, a 6%
supplementary sample was performed as required.
The licensee also
elected to inspect an additional 12% sample in the
11 8
11 SG, together with
40 tubes in the vicinity of the leaker.
The licensee utilized two ET
procedures for these examinations - NDT-ET-07, Revision 4,
11Circumferentially
Wound Bobbin Type probe (540SFW) Differential Coil, Multifrequency,
Multiparameter
11 , and NDT-ET-08, Revision 4,
11 Pancake Probe, (4C4F)
Differential, Multi coil, Multifrequency, Multiparameter.
11
The 540SFW
11 Bobbin
11 examination is required by TS and is sensitive to
tube degradation associated with wastage and pitting.
The 4C4F
11 Pancake
11
examination which is not required by TS is utilized to detect
intergranular corrosion and circumferential cracking.
The licensee utilized a motorized rotating pancake coil (MRPC) to examine
locations where 4C4F signals were indeterminate as to flaw condition.
The results of these examinations confirmed that the defects detected in
this outage are of the same size or smaller than those observed in 1983.
The MRPC is not a
11 pull through
11 technique, but a special tool to examine
selected areas of interest.
The equipment used during this inspection
was identical to that used during the 1985 inspection, except for the
MRPC probe and its signal analysis by a Zetec MIZ-18 analyzer.
As in the
previous two inspections, the 540 SFW probe was employed_~o detect and
size 11wastage 11 type defects.
The 4C4F probe was used to detect and size
circumferentially oriented defects, including volumetric IGC and cracking.
The Zetec MIZ-12 signal analyzer was used with both of these probes.
The licensee is developing programs and qualifying procedures for the use
of the MIZ-18 analyzer for future examinations.
This system enhances the
interpretation ability of the indications detected.
5
l __
The results of the ET for this outage required 14 SG tubes to be plugged
in
118
11 SG and 4 SG tubes requiring plugging in SG
11A
11 *
The licensee also
performed ~ profilometry examination to detect denting growth.
This
examination is also voluntary and is utilized to determine SG degradation
due to denting of the SG tubes.
During this examination it was discovered
that SG
11 8
11 tube in Quadrant 3, Line 2, Row 121 was misplugged in 1985.
Further investigation disclosed that the misplugging was due to the
installation of the template,. utilized for locating the correct tube
for plugging, was installed in reverse.
The licensee issued a deviation
report and took appropriate corrective action to correct the misplugging
and prevent recurrence.
The NRC inspectors review and observations
concluded that the licensee appeared to have satisfactorily completed all
required examinations with the exception of the installed sleeves for
which relief was requested.
In addition, the licensee performed
additional examinations to assure the cause of the tube leak was not due
to a prevailing degradation of the SG tubes.
Of the 18 tubes requiring
plugging, 7 crack-like indications were observable in the 1983/1985
tapes.
These indications were not reported as defects at that time due
to small amplitude signal responses, poor signal to noise ratio inherent
to the 4C4F technique, and interpreter oversight due to these conditions.
With the addition of the MRPC combined with the MIZ 18 analyzer the
ability to interpret and size defects will be greatly enhanced.
The ET program inspected appeared to be adequate to assure the steam
generators do not exhibit degradation which would be safety significant.
5.
Augmented Inservice Inspection Program For High Energy Lines
Outside of Containment
This is a Technical Specification requirement which applies to welds in
piping systems or portions of systems located outside of containment
where protection from the consequences of postulated ruptures, is not
provided by a system of pipe whip restraints, jet impingement barriers,
protective enclosures, and/or other measures designed specifically to
cope with such ruptures.
For the Palisades Plant, the applicable welds in the main steam and
main feedwater lines are located inside the Main Steam and Feedwater
Penetration Rooms.
The Tech Spec requirement for examination of the specified welds requires
volumetric examination of all welds in the first inspection interval at
each three and a third year increment of the ten year plan.
The
successive inspection intervals requires volumetric examination of one
third of the specified welds at the expiration of each one third of the
ten year inspection interval.
The welds selected during each inspection
period is distributed among the total number to be examined to provide a
representative sampling of the conditions of all welds.
The current
inspection plan is in the second ten year interval.
6
. '
i
The NRC inspector reviewed the secondary side ISI program for the high
energy lines, the ultrasonic and liquid penetrant examinations, equipment
personnel certifications, applicable nondestructive examination procedures,
and reviewed the radiographs performed for this inspection.
No violations or deviations were identified.
6.
Steam Generator Sludge Lancing
The licensee performed their initial sludge lancing of the steam
generators during this outage.
Sludge lancing is the removal of
undesirable deposits on the secondary side which can contribute to
intergranular corrosion of the SG tubes.
Eddy current examinations of
the sludge pile revealed a deposit of 15 inches at the tube sheet.
Combustion Engineering (CE) Services Inc. performed the sludge lancing.
The sludge is removed by use of high pressure, high flow, closed loop
water lancing and filtering system.
The high pressure lance is directed into the sludge pile from various
angles, once dislodged and flushed to the outside of the tube bundle, the
slurry is picked up by the filtering system suction lines and directed to
the diatomaceous earth and particulate filters where the sludge is
removed from the slurry and returned to the high pressure pump.
A total ~
of 4400 pounds of sludge was removed from the steam generators.
The
remaining sludge pile was reduced to approximately 2 to 3 inches in the
cold leg and 5 to 7 inches in the hot leg of the S.G ..
The NRC inspector reviewed the program, procedures, personnel
certifications and observed the sludge lancing process.
No violations or deviations were identified.
7.
Open Items
8.
Open items are matters which have been discussed with the licensee, which
will be reviewed further by the inspector, and which will involve some
action on the part of the NRC or licensee or both.
An open item disclosed
during the inspection is discussed in Paragraph 4.
Exit Meeting
The ~nspector met with licensee representatives (denoted in Paragraph 1)
at the conclusion of the inspection on January 22, 1988.
The inspector
summarized the scope and findings of the inspection activities.
The
licensee acknowledged the inspection findings.
The inspector also
discussed the likely informational content of the inspection report with
regard to documents or processes reviewed by the inspectors during the
inspection.
The licensee did not identify any such documents/processes
as proprietary.
7