ML16139B074
| ML16139B074 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 02/10/1994 |
| From: | Gray E, Harris R, Peterson P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML16139B075 | List: |
| References | |
| 50-287-94-400, NUDOCS 9404110139 | |
| Download: ML16139B074 (10) | |
See also: IR 05000287/1994400
Text
U.S. NUCLEAR REGULATORY COMMISSION
REGION I
DOCKET/REPORT NOS.
50-287/94-400
LICENSE NO.
LICENSEE:
Duke Power
422 South Church Street
Charlotte, NC 28242
FACILITY NAME:
Oconee Nuclear Power Station, Unit 3
INSPECTION AT:
Seneca, South Carolina
INSPECTION DATES:
January 18-28, 1994
CONTRACTORS:
William Mingus, TET,Inc., Mobile, AL
David Payne Jr., TET, Inc., Mobile AL
INSPECTORS:
'chard
.
arns, NDE Technician
Date
Mobile NDE Laboratory, EB, DRS
Patrick M. eson, NDE Technician
Date
Mobile NDE Laboratory, EB, DRS
APPROVED:
r__//-_
___
Edwin H. Gray, Chief
Date
Mobile NDE Laboratory, EB, DRS
9404110139 940310
PDR ADOCK 05000287
Q
2
Inspection Summary: An announced inspection was conducted at Oconee Nuclear Power
Station during the period January 18, through January 28, 1994, using the Nuclear
Regulatory Commission (NRC) Mobile Nondestructive Examination (NDE) Laboratory,
(Report No. 50-287/94-400). The purpose of the Mobile NDE Laboratory is to perform
independent nondestructive examinations, evaluations of components, systems and weldments
to assure that examinations performed by the licensee are in compliance with codes,
standards and regulatory requirements.
Areas Inspected: Areas examined during this inspection included a review of the licensee's
inservice inspection (ISI) program and nondestructive examinations of safety-related
weldments, selected from the high pressure injection (HPI), reactor coolant (RC), low
pressure injection (LPI), pressurizer (PZR), core flood tank (CFT) and auxiliary feedwater
(AFW) systems. Also included in this inspection, was a review of the erosion/corrosion
(E/C) program.
Results: Within the expected normal variations in examination techniques, the results of the
NDE evaluations performed by the NRC essentially agreed with the results obtained by the
licensee. The inspection team concluded, on the basis of items sampled, that the ISI program
and related NDE meets the ASME Code requirements and that the E/C program as
implemented provides reasonable assurance of identifying components with significant E/C
degradation.
During the inspection, weaknesses were noted. A weakness is a condition that without
attention could develop into a safety problem or regulatory issue. Weaknesses are identified
for licensee review and corrective action as appropriate. The weaknesses identified include:
the licensee technical review of UT data sheets are usually limited to those with indications
that require evaluation by the NDE Level Ill UT, profile/plot data sheets for UT were
difficult to interpret, the designation of mode conversion and beam redirection were not
consistently applied, and the plot of UT indications was not accurate or realistic for
geometric indications. Ultrasonic signals associated with geometry were in some cases
plotted as indications in the weld or in the base material. Another weakness identified was
excessive artifacts on radiographs of welding on recent pipe modifications.
DETAILS
1.0
INDEPENDENT MEASUREMENTS - NRC NONDESTRUCTIVE
EXAMINATION AND QUALITY RECORDS REVIEW OF SAFETY-RELATED
SYSTEMS (73753)
During the period of January 18 through January 28, 1994, an onsite independent inspection
was conducted at Oconee Nuclear Power Station. The inspection was conducted by NRC
inspectors and contractors. The objectives of this inspection were to assess the adequacy of
the licensee's inservice inspection (ISI), nondestructive examination (NDE) and quality
control programs, and the licensee's actions regarding the implementation of the
erosion/corrosion (E/C) program. This was accomplished by duplicating those examinations
performed by the licensee, as required by regulations and codes, evaluating the results, and
performing a review of the ISI program, E/C program and NDE procedures used to
implement these programs. Section 4.0 of this report contains a listing of the specific welds
inspected.
The Code of Federal Regulations (CFR), Title 10, Part 50.55a (10 CFR 50.55a), requires ISI
of safety-related equipment to identify system degradation. The required inspections are
detailed in the American Society of Mechanical Engineers (ASME) Boiler and Pressure
Vessel Code,Section XI, for Inservice Inspection as stated in 10 CFR 50.55a (b). The NRC
inspection described in this report was made using the Mobile Nondestructive Examination
(NDE) Laboratory. The Mobile NDE Laboratory is capable of independently performing the
examinations required of the licensee. This capability provides the NRC with unique insights
into the licensee's inservice inspection program and on a sampling basis, the adequacy and
accuracy of the licensee's specific NDE inspections.
The scope of this inspection was to perform NDE on components of systems that were
available and to review portions of the ISI program.
Results: The licensee's ISI and NDE programs as implemented were found to meet the
ASME Code and regulatory requirements, although weaknesses were noted. Weaknesses are
identified for licensee review and corrective action as appropriate and are discussed under the
relevant section of this report.
1.1
Nondestructive Examination (NDE)
Visual Examination (57050)
Thirty seven (37) safety-related pipe weldments and adjacent base material (1/2 inch on
either side of the weld) were visually examined in accordance with NRC Procedure NDE-10,
Rev. 0, Appendix A, and associated quality control documents, isometrics and as-built
drawings. Examined during this inspection were ASME Class 1 and 2 pipe weldments
selected from the high pressure injection (HPI), low pressure injection (LPI), reactor coolant
(RC), pressurizer (PZR) and auxiliary feedwater (AFW) systems. Inspections were
4
performed specifically to identify any cracks or linear indications, gouges, leakage, arc
strikes with craters, or corrosion, which may infringe upon the minimum pipe wall thickness
and modifications to piping or components. Mirrors, flash lights and weld gauges were used
to aid in the inspection and evaluation.
Results: The welds examined were ground for inservice inspection prior to surface and
volumetric examinations. The welding and overall workmanship inspected was acceptable.
The inspection reports of the licensee reflected the as-found conditions. No deviations were
identified.
Liquid Penetrant Examination (57060)
Nineteen (19) safety-related pipe weldments and adjacent base material (1/2 inch on either
side of the weld) were examined using the visible dye, solvent removable method per NRC
Procedure NDE-9, Rev. 1, in conjunction with Oconee Site Procedure NDE-35, Revision 14.
Included in this inspection were ASME Class 1 and 2 stainless steel pipe weldments selected
from the RC, PZR, HPI and LPI systems.
Results: The surface areas examined were adequately prepared for the examination. The
licensee recorded the same relevant indications noted by the NRC. No rejectable indications
were identified, and no deviations noted.
Magnetic Particle Examination (57070)
Thirteen (13) safety-related pipe weldments were examined with the magnetic particle method
using NRC Procedure NDE-6, Rev. 1, Oconee Site Procedures NDE-25, Revision 15, and
associated isometric drawings. Included in this examination were ASME Class 2 pipe
weldments selected from the AFW systems.
Results: The surface areas examined were adequately prepared for the examinations. There
were no recordable indications found by the NRC.
Ultrasonic Examination (57080)
Twelve (12) safety-related pipe weldments were ultrasonically examined using NRC
Procedure NDE-1, Rev. 1, in conjunction with Oconee Site Procedure NDE-600, Revision 1,
and associated isometric drawings and ultrasonic inspection reports. Included in this
examination were ASME Class 1 and 2 pipe weldments selected from the RC, HPI, LPI and
PZR systems. To obtain the greatest possible repeatability in performing the NRC
independent evaluations, the examinations were performed using ultrasonic units, transducers
and cables that matched, as closely as possible, those used by the licensee. A distance
amplitude correction (DAC) curve was established utilizing Oconee calibration standards.
5
Weld volume coverage limitations for the extent of UT examinations were noted on some
weldments. The data sheets indicated that it may be necessary to ask for a relief request on
the examination coverage on specific welds due to the joint configuration and restrictions.
ASME Code Case N-460 is applicable for defining the extent of weld volume coverage for
the examination to meet the ASME Code.
Results: The ultrasonic examinations performed by the NRC closely matched, within
expected variations for this method, those of the licensee. However, two weaknesses were
noted. The indications plotted by the licensee per Procedure NDE 600, Revision 2,
paragraph 10.1.2 were not plotted accurately. In some cases the sound path terminated
within the weld metal or the base metal, showing no evidence of a geometric reflector.
Some of the UT signals were evaluated as beam redirection and other signals of the same
type were evaluated as mode conversion. Further evaluation was not performed to determine
if either beam redirection or mode conversion existed. This inaccuracy can result in
misinterpretation of the ultrasonic signal. The weakness with UT plots was discussed with
Duke Power's UT Level Ill. Training to improve the plots had been initiated after the 1992
outage but review of the 1994 UT data sheets did not show a significant improvement. The
licensee submitted a generic relief request, dated December 2, 1993, for the UT examination
volume issue and the above data sheets were found to be consistent with that relief request.
Radiography (57090)
Fourteen (14) sets of radiographs of welds made as part of the current piping modifications
were reviewed and two (2) welds were independently radiographed by the NRC to determine
if the overall weld and radiographic quality was in accordance with the applicable procedure
and ASME Code requirements.
The radiographs were reviewed for the weld quality with respect to the Code radiographic
standards, penetrameter placement, film density, density variation, film identification, weld
coverage and film quality.
Results: The results of the NRC closely matched those of the license. The requirements
were met, and no rejectable discontinuities were observed on the radiographs. However, the
film quality of the radiographs is a weakness. An excessive number of the radiographs
contained artifacts. Two radiographic film are used for each exposure. Often both film had
to be reviewed to provide the required area of interest and weld acceptability. One weld,
'3-51A-121-14, view 2-3, contained roller marks from the film processor on both film in the
same area on that radiograph set. The Duke Power RT Level III confirmed the artifacts
were acceptable but not desirable. The basis used for this acceptance was the ASME Code,
Section V and the Procedure NDE-10, Revision 18, "General Radiography Procedure
(Nuclear Stations)," dated 5/20/93, "all radiographs shall be free from mechanical, chemical,
or other blemishes to the extent that the blemishes cannot mask or be confused with the
.
image of any discontinuity in the object being radiographed." The Oconee NDE staff
acknowledged the weakness.
6
Erosion/Corrosion (49001)
Concerns regarding erosion/corrosion (E/C) in balance of plant piping systems have
heightened as a result of the December 9, 1986, feedwater piping line rupture which
occurred at the Surry Plant. This event was the subject of NRC Information Notice 86-106,
issued December 16, 1986, and its supplement issued on February 13, 1987.
The actions by the Oconee plant staff with regard to the detection of erosion/corrosion in
plant components were reviewed with respect to NUREG-1344, "Erosion/Corrosion Induced
Pipe Wall Thinning in U. S. Nuclear Power Plants," dated April 1989, Generic Letter 89-08
issued May 2, 1989, and NUMARC Technical Subcommittee Working Group on Piping and
Erosion/Corrosion Summary Report, dated June 11, 1987.
The E/C program includes an overall Pipe Erosion Control Program with input from the
NP-3944 EPRI Report, and a Unit specific Erosion Control program. The current E/C
program at Oconee Unit 3 tracks 572 components (points) of which 89 were scheduled for
measurement during the present outage. Examination of a component, such as a piping elbow
includes a section of pipe on both sides of the elbow. While the E/C program is primarily
engineering judgement and experience based, the recent application of the EPRI Checmate
E/C analysis to Units 2 and 3 has confirmed the previous component selections for
examination or replacement to be those of higher susceptibility to E/C.
.
Results: Oconee Nuclear Power Station has an E/C program that includes application of
NRC and EPRI guidance and industry experiences. The methods used by Oconee personnel
to select and evaluate components provide reasonable assurance of identifying components
with significant E/C degradation. The four (4) components examined by the NRC closely
matched those of the licensee.
2.0
REVIEW OF SITE NDE PROCEDURES AND MANUALS (73052)
The required inspections are detailed in the American Society of Mechanical Engineers
(ASME) Boiler and Pressure Vessel Code,Section XI, for Inservice Inspection (ISI) as noted
in 10 CFR 50.55a (b). For the inspection program, the Code edition and addenda used is
determined in accordance with the requirements of 10 CFR 50.55a (g).
Oconee Nuclear Power Station, Unit 3 submitted their second (ten year) interval inservice
inspection program to the NRC prior to the interval start date of March 1, 1984. The items.
and areas planned to be examined in this program are based on the 1980 Edition of
Section XI of the ASME Code up to and including the Winter, 1980 (80W80) Addenda
which is the applicable Code edition.
The following licensee procedures were reviewed for compliance to the applicable codes,
.
standards and specifications.
7
Procedure Title
Number/Revision
Date
General Radiography Procedure
NDE-12
12/10/92
for Preservice and Inservice Inspection
Revision 8
Magnetic Particle Examination
NDE-25
09/07/93
Procedure and Techniques
Revision 15
Liquid Penetrant Examination
NDE-35
09/15/93
Revision 14
Ultrasonic Examination of Studs and Bolts
NDE-44
02/08/92
Revision 9
Reference System for Identification
NDE-90
02/27/92
Layout of Welds and Systems Components
Revision 0
Ultrasonic Examination of Similar Metal
NDE-600
02/08/93
Revision 2
Ultrasonic Examination of Welds Using
NDE-610
07/06/93
Refracted Longitudinal Waves
Revision 1
Ultrasonic Examination of Welds in
NDE-620
08/19/92
Ferritic Pressure Vessels Greater than
Revision 1
2 Inches in Thickness
Straight Beam Ultrasonic Examination of
NDE-640
01/16/92
Welds and Base Material in Pressure
Revision 1
Vessels and Pipe
Ultrasonic Examination of Reactor Vessel
NDE-650
12/15/92
Flange-to-Shell Welds
Revision 0
Ultrasonic Sizing of Planar Flaws in
NDE-670
01/23/92
Ferritic and Austenitic Steel
Revision 0
Ultrasonic Examination of Nozzle Inner
NDE-680
02/16/93
Radii in Ferritic Pressure Vessels
Revision 0
8
Procedure Title
Number/Revision
Date
Examination of Similar Metal in Wrought
NDE-1001
03/17/93
Ferritic and Austenitic Piping
Revision 0
P-Scan Ultrasonic Examination of Similar
NDE-1002
10/28/93
Metal Welds in Wrought Ferritic Pressure
Revision 0
Vessels Greater Than 2.0 In. in Thickness
Results: No violations were noted. The licensee was noted to have been making systematic
progress in completing examinations during the progress of the second 10 year interval such
that by the last outage in the interval for Unit 3, the remaining required inspections were
readily scheduled for completion.
3.0
MANAGEMENT MEETINGS
Licensee management was informed of the scope and purpose of the inspection at the
entrance meeting on January 19, 1994. The findings of the inspection were discussed with
the licensee representatives during the course of the inspection and presented to licensee
management at the exit meeting January 27, 1994. The licensee did not indicate that
proprietary information was involved within the scope of this inspection, nor did the licensee
object to any of the findings of the inspection. The following individuals were contacted:
Duke Power Company
- D. Dalton
Regulatory Compliance
- T. Coleman
ISI Engineer
- T. Tucker
NDE Level III
- C. Freeman
NDE Level III
- T. Royal
Engineering Supervisor
- G. Moss
NDE Outage Support
- D. Cabe
NDE Tech Support
- R. Pettit
NDE Outage Support
- A. Richmond
BWNT NDE Services
- J. Warren
Mechanical Maintenance
J. McArdle
UT Level III (Phone Conf)
E. Few
Plant E/C Coordinator
M. Pyne
Site E/C Engineer
9
U.S. Nuclear Regulatory Commission
- C. Beardslee
RI, DRS Inspector
- P. Harmon
RI, Oconee Senior Resident Inspector
- J. Blake
RII, Section Chief, DRS
- J. Coley
RII, Reactor Inspector, DRS
- K. Kavanagh
NRR, Intern
- Denotes those attending the exit meeting.
The inspectors also contacted other administrative and technical personnel during the
inspection.
4.0
TABLE OF COMPONENTS INSPECTED
This is a table listing the components examined by the NRC Mobile NDE Laboratory during
its inspection of Oconee Nuclear Power Station.
NRC NDE MOBILE LABORATORY
TABLE No. 1
WELD ID. No.
SYS
NONDESTRUCTIVE TEST
F
SHTJ 1
V Rh
r
I'
i
b
ISOIDRAWING
LIN
CL
PT_
ACC
J
PZR
I
X
X
X
X
PZR
1
X
X
X
X
PZR
1
X
X
X
X
PZR
I
X
X
X
X
PZR
1
X
X
X
X
3-53A-17-17
2
X
X
X
3-53A-16-05
2
X
X
X
3-53A-17-02
2
X
X
X
X
3-53A-17-04
2
X
X
X
X
3-53A-17-08
2
X
X
X
X
3-53A-17-12
2
X
X
X
X
3-54B-8-43
2
X
X
X
3-54B-6-23A
2
X
X
X
3-54B-6-23
2
X
X
X
3-03A-147-10
2
X
X
X
3-03A-147-4
2
X
X
X
10
NRC NDE MOBILE LABORATORY
TABLE No. 1
WELD ID. No.
SYS
NONDESTRUCTIVE TEST
SHTJ 1
jOR
ISO/DRAWING
LIN
CL
ACC
RFJ
3-03A-147-12
2
X
X
X
3-03A-147-SVEN
2
X
X
X
3-03A-147-14
2
X
X
X
3-03A-147-6
2
X
X
X
3-03A-147-4VEN
2
X
X
X
3-51A-63-30
1
X
X
X
3-50-152-05
RC
I
X
X
X
3-50-152-07
RC
I
X
X
X
3-LP-18-76
1
X
X
X
3-LP-18-39
1
X
X
X
NRC NDE MOBILE LABORATORY
TABLE No. 1
WELD ID. No.
SYS
NONDESTRUCTIVE TEST
SHTJ 2
__
_
ISO/DRAWING
LIN
CL
PTJMT
ACC
REJ
3-53A-17-4
I
X
X
X
3-53A-17-2
1
X
X
X
3-50-152-7
RC
2
X
X
X
3-50-152-5
RC
2
X
X
X
3-CFTA-UH-SHL
cFr
2
X
X
X
3-03-147-10
2
X
X
X
3-03-147-6VEN
2
X
X
X
3-03-147-7VEN
2
X
X
X
3-03-147-8
2
X
X
X
3-03-147-8VEN
2
X
X
X
3-03-147-9
2
X
X
X