IR 05000457/1993008
| ML20035H578 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 04/29/1993 |
| From: | Jeffrey Jacobson, Schapker J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20035H577 | List: |
| References | |
| 50-457-93-08, 50-457-93-8, NUDOCS 9305060013 | |
| Download: ML20035H578 (7) | |
Text
_
.
.
.
U. S. NUCLEAR REGULATORY COMMISSION
REGION III
Report No. 50-457/93008(DRS)
Docket No. 50-457 License No. NPF-77 Licensee: Commonwealth Edison Company
.
Executive Towers West III 1400 Opus Place, Suite 300 Downers Grove, IL 60515 Facility Name:
Braidwood Nuclear Power Station - Unit 2 Inspection At:
Braceville, IL 60407 Inspection Conducted: March 23-24, 29-31, April 6 and 20, 1993
')
//2 9/9J Inspector:
.
Date
. F. Schapker
'
Accompanied By:
L. Sage, IDNS (March 23, 29-31, and April 20, 1993)
'cMM
// - 19 -93 Approve y:
_ - -
J. H. Macob on, Chief Date teYials nd Processes Section Inspection Summary
'
Inspection on March 23-24, 29-31. April 6 and 20. 1993 (Report No.
50-457/93008(DRS))
Areas Inspected:
Routine, announced safety inspection of inservice inspection (ISI) activities, including review of programs (73051), procedures (73052),
observation of work activities (73753), ISI data review (73755), and Erosion / Corrosion Program (49001).
Results: No violations or deviations were identified.
Based on the results of the inspection, the inspectors noted the following:
All ISI activities were controlled by well defined procedures.
The ISI contractor personnel were knowledgeable and utilized state of the art equipment.
The licensee's steam generator inspection program is very conservative and demonstrates commitment to safety.
9305060013 930429 PDR ADOCK 05000457 G
.
.
.
DETAILS 1.
Persons Contacted Commonwealth Edison Company (Ceco)
- D. Miller, Technical Superintendent
- G. Vanderheyden, Systems Engineering Supervisor
- K. Bartes, SQV Supervisor
- D. Christiana, Station Support Engineering
- J. LeWand, Regulatory Assurance
- C.
Barrett, ISI Coordinator
- M. Sears, ISI Group Leader
- A. Haeger, Regulatory Assurance Supervisor U. S. Nuclear Reaulatory Commission (NRC)
S. DuPont, Senior Resident Inspector
- R. Roton, Resident Inspector Illinois Department of Nuclear Safety (IDNS)
- L, Sage, Head, Code Compliance Section Westinghouse Electric Corocration (WEC)
J. Graw, Site Supervisor D. Obuzenu, level III ET EBASCO Services (EBASCO)
J. Sengenberger, NDE Supervisor, Level III Hartford Steam Boiler Inspection and Insurance Company (HSB)
L. Malbana, ANII A. Hamanes, ANII Supervisor
- Denotes those present at the exit interview on April 20, 1993.
The inspectors also contacted and interviewed other licensee and
.
contractor personnel.
2.
Inservice Inspection (ISI)
a.
Proaram Review (730SI)
Personnel from EBASCO, WEC and Ceco performed the ISI in accordance with ASME Code Section XI, 1983 Edition, Summer 1983 Addenda. Where ASME requirements were determined to be impractical, specific relief requests were submitted to the Office
=
-
,
t
.
i of Nuclear Reactor Regulation (NRR) in writing.
The NRC inspector reviewed the specific relief requests including the related correspondence between the licensee and.the NRC. The inspectors verified that the ISI activities were being conducted in accordance with the ISI program. Overall organizational staffing
'
for the ISI program was found to be acceptable.
b.
Procedure Review (73052)
]
'
All applicable ISI procedures were approved by the Authorized
.
Nuclear Inservice Inspector (ANII) and were found to be acceptable and in accordance with ASME Sections XI and V,1983 Edition, i
Summer 1983 Addenda.
>
The NRC inspector reviewed the.ISI procedures utilized during the observations of nondestructive examinations (NDE), the eddy current examination (ET) data analysis guidelines, and _ Technical
,
Specification requirements for examination of the steam generator i
tubes. NDE procedures were in compliance with the applicable Code requirements and the data analysis guidelines provided the necessary information for the analyst to perform the analysis of the ET data. The guidelines adequately described specific anomalies (with examples) found in previous examinations of similarly designed steam generators.
,
The IDNS inspector reviewed the following. procedures-Procedure By Title BC-MT-583-1, R0 EBASCO Magnetic Particle Examination of Welds and Bolting
'
BC-PT-583-1, R0 EBASCO Liquid Penetrant Examination BC-UT-CP-2, R0 EBASCO Procedure for Inspection System Performance Checks
)
'
BC-UT-S83-1, R0 EBASCO
' Ultrasonic Examination of Classes 1 and 2 Piping Joining Similar and Dissimilar Materials i
BC-UT-583-2, R0, Al EBASCO Ultrasonic E.xamination of Classes 1 and 2 Vessel Welds Incluling Reactor Pressure Vessel Welds BC-UT-S83-4, R0 EBASCO Ultrasonic Examination of Classes 1 and 2 Vessel Welds Less Than or Equal to 2 Inches
.
-
l
'
l
,
'
BC-UT-S83-7, R0 EBASCO Ultrasonic Straight Beam i
j Examination of Piping Wolds NDT-C-2, R19, A4 Ceco Ultrasonic Inspection of Similar and Dissimilar Metal Pipe Welds at Nuclear Power Stations NDT-C-45, R1 CECO Ultrasonic Inspection of Piping Base Material and Butt Welds at Nuclear Power Stations for Piping Diameters i
from 1%" up to, but not Including 4" Nominal Diameter All applicable ISI procedures were approved by the ANII. The ISI procedures were found to be in accordance with the applicable editions and addenda of ASME Sections V and XI.
c.
Observations of ISI Work Activities (73753)
The NRC inspector observed work activities and had discussions l
with personnel during the ISI activities. These observations included the following:
Eddy current examination of the steam generator tubes.
l
!
Ultrasonic examination (UT) of main steam piping, steam i
generator "C" transition girth weld, and residual heat j
exchanger (RHR) nozzle to shell welds. The RHR nozzle to
'
shell examinations were performed using the "P-scan" UT l
method and equipment.
This method provides optimum data and repeatability for examining previously identified (reference NRC inspection report number 50-456/92021(DRS)) indications.
This provides an advantage for analysis and monitoring for change or growth.
The NRC inspector reviewed the P-scan data and confirmed the indications recorded were bounded by the flaw evaluation WCAP-13454 dated March 1992. The P-scan UT recorded 22 indications which exceeded 100 percent of the Distance Amplitude Curve with thru wall measurements ranging from 5 to 52 percent and lengths from.3 to 5.5 inches.
These welds will be examined during future outages in accordance with ASME Section XI Code requirements, to assure the flaws are stable and exhibit no growth.
,
Magnetic particle examination (MT) of main steam piping
!
Visual examination (VT) of reactor vessel and reactor vessel head interior surfaces.
.
_.
_
_
_
_
__
__
_
..
.
.
.
'
The inspectors reviewed the qualifications and certifications of all inspection personnel performing ISI to ensure compliance with
,
SNT-TC-1A requirements.
l
!
No violations or deviations were identified.
d.
'ISI Data Review (73755)
.
The inspectors reviewed ISI documents. relating to the. following:
i
NDE data sheets for UT, MT, ET, VT, and. liquid penetrant
<
examinations.
,
NDE equipment certifications and calibration reports.
o The examination data complied with the requirements of the ASME
'
Code and applicable procedures, all indications were appropriately
.
dispositioned.
'
3.
Eddy Current Examination of the Steam Generator Tubes The licensee employed the services of Westinghouse Electric Corporation (WEC)-to perform the ET,0f the Unit 2 SG's.
A multifrequency ET was performed using four data stations in parallel, probing from the hot and cold legs of the SG's.
Fifty percent of the~ tubes in all four SG's were
,
inspected with the bobbin coil through the U-bends from the hot leg of the SG's.
The remainder of the tubes were inspected full _ length. The
bobbin probe ET was conducted in accordance with WEC procedure MRS 2.4.2 GEN 35,. Revision 1. ' All distorted roll indications '(DRIs) and
nonquantifiable indications found during the bobbin inspection were inspected with the rotating pancake coil.(RPC). A sample of
.
-
manufacturing buff marks with flaw like characteristics were also examined with RPC. These indications were classified as' manufacturing anomaly marks (MAM), a new designation for this type of ET indication.
MAMs are similar to manufacturing buff mark (MBM) signals; however, are usually caused when the tubes contact the support plate 'during the tube insertion process. This creates anomalies that can present flaw-like l
signals.
WEC performed a primary and secondary evaluation of all ET data. The two major type of indications found thi.s inspection were MBM's and MAM's. Sixteen tubes with indications in excess of the plugging limit were identified. These defects were anti-vibration bar (AVB) wear.
All sixteen defective tubes were plugged using WEC mechanical Inconel 690 tapered plugs. All MAM's reported were re-evaluated from the. 1990/1991 data to determine whether the indications were service induced discontinuities or inherent anomalies. The data. review concluded that
!
the MAM's were present in the previous 1990/1991 data and no growth was
'
apparent,.the re-analysis showed no change in the indications. The reason most of these indications were not classified previously is due to the signal amplitude being very low. Most of these type. indications were classified as "no defect detected" due to the. signal amplitude.
A
i
!
-
_
_,
-
_
,..
t l
-
l
.
recent tube rupture at another plant in SG free span tubing has increased the sensitivity of the ET examiners to look closer at these types of indications. Although the number of MBM's and MAM's identified was extremely high, the increased number of these type of indications reported this outage does not represent an increase in degradation of the SG's tubes. The identification and recording of these indications represents a conservative approach of reviewing the ET data and preserving the data for future analysis and comparison. This will provide additional assurance that the MBM and MAM type indications are monitored for degradation during future examinations.
ET Indication Summary Indication SG-A SG-B SG-C SG-D AVB 173
127
MAM 204 479 369 205 MBM 1256 1005 1226 1482 DRI
0
2 The NRC inspector observed the ET in progress and reviewed the following documents:
CECO Byron /Braidwood Station Eddy Current Data Guidelines.
Steam Generator ET report.
l Braidwood Technical Specifications.
WEC procedure 2.4.2 GEN 35, Revision 1.
ET graphics and data reports.
The licensee's SG inspection program is conservative and corrective actions were implemented as required. The IDNS inspector observed RPC examination of SG-A and mechanical tube plugging of SG-C.
No violations or deviations were identified.
4.
Erosion / Corrosion Proaram (49001)
The NRC inspector reviewed the Braidwood Station Erosion / Corrosion Program BWVP 200-20, Revision 0.
The program provides for the conservative calculation of estimated wear rates based on measured i
thickness changes, material, chemical, temperature, flow phase / rate, l
pressure, and pH.
The program includes the use of EPRI CHECMATE and the
!
CECO, CEECALC 4.02 programs and provides for the selection of additional components based on industry experience, NRC information notices, IMPELL recommendations, and plant specific experience.
. _.
.
.
.
__
'
'
.
-
\\
-
The NRC inspector interviewed the Braidwood Station coordinator regarding implementation of the program, and observed the ultrasonic examination data gathering, data processing and removal and replacement activities of one extraction steam pipe elbow. The licensee and contractor employees complied with the referenced procedure j
requirements. During this outage 52 components were examined, three pipe spools were removed and replaced and one component was repaired.
'
The licensee's erosion / corrosion program appears to be conservative and adequate to prevent catastrophic failure of piping components susceptible to this type of degradation.
I No violations or deviations were identified.
!
5.
Exit Interview (30703)
!
-
"
l The inspectors met with licensee representatives (denoted in Paragraph l
1) at the conclusion of the inspection on April 20, 1993, and summarized the scope and findings of the inspection noted in this report. The NRC
'
s inspector also discussed the likely informational content of the
'
inspection report with regard to documents or processes reviewed by the inspector during the inspection. The licensee did not identify any such documents / processes as proprietary.
,
'
i
!
l I
l
!
l l
l l
l l