ML20244E556
| ML20244E556 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 06/08/1989 |
| From: | Chaudhary S, Winters R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20244E545 | List: |
| References | |
| 50-318-89-15, NUDOCS 8906200390 | |
| Download: ML20244E556 (8) | |
See also: IR 05000318/1989015
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
-50-318/89-15
, Docket Nos.
50-318
License No.
Licensee:
Baltimore Gas and Electric Company
Charles Center
P. 0. Box 1475
Baltimore, Maryland ~21203
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Facility Name: Calvert Cliffs Nuclear Power Plant Unit 2
Inspection At: 'Lusby, Maryland
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Inspection Dates: May 8- 12, 1989
Inspector:
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R. W. Winters, Reattor Engineer, MPS, EB,_
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DRS,. Region I
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Approved by:
in/'
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S. Chaudhary, Chief, Materials & Processes
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Section, Engineering Branch, DRS, RI
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Inspection Summary: Routine unannounced inspection on May 8-12, 1989 Report
No. 50-318/89-15)
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Areas Inspected: The inservice inspection program, including the ten year
plan, steam generator eddy current testing, primary and secondary water
chemistry results, and the erosion corrosion control program was reviewed.
Results: One violation concerning the certification of the licensee's
nondestructive examination personnel was identified.
No other deviations
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or violations were found in the areas inspected.
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DETAILS
1.0 ' Persons Contacted
Baltimore Gas and Electric Company
H. Brust', Nuclear Materials Engineering
S. Buxbaum, Supervisor, Nondestructive Examination
P. Ca11anan, Quality Assurance Auditor
- P. Crinigan, General Supervisor, Chemistry
- C. Cruse, Manager, Nuclear Engineering
L. Decker, Nuclear Materials Engineering
- K. Hoffman, Nuclear Materials Engineering
- W. Lippold, General Supervisor, Technical Services Engineering
- A. Reed, Engineer, Metals Laboratory
L. Russell, Manager Calvert Cliffs
- B. Rudell, Supervisor, Nuclear. Materials Engineering
- D. Shaw, Licensing Engineer
- D. Van Petten, Nuclear Materials Engineering
Zetec Incorporated
W. Gray, Supervisor, Eddy Current Testing
NDE Technologies Corporation
T. Beiers, Lead Engineer, Eddy Current Evaluation
United States Nuclear Regulatory Commission
- V. Pritchett, Resident Inspector
- Denotes those attending the exit meeting.
The inspector also contacted other administrative and technical
personnel during the inspection.
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2.0 Scope
The scope of this ir.spection was the review and observation of
activities in the following areas:
steam generator eddy current examination
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the ten year inservice inspection (ISI) program
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the erosion corrosion control program
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NDE examiner certification program
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primary and secondary water chemistry results
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"3 0 ' Steam Generator Eddy Current Examination Review
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Eddy Current Examination
The ISI.ofLthe steam generator tubes is conducted in accordance with
the unit's Technical Specifications.
It is-not:part..of the ISI
program for the' balance of plant equipment and components.
In
accordance with'the Technical. Specifications the' minimum number of
tubes required for the inspection was 6% of the active tubes in either
steam generator. This amounted to 508 tubes in steam generator 21 or
510 tubes in. steam generator 22.
The' licensee, however, opted to perform a 100% inspection of.the 8456
. active tubes in steam generator 21 and of the 8491 active' tubes in
' steam generator 22 using the standard bobbin coil EC technique.
As a result of this examination, six defectise and five' degraded tubes
were identified in steam generator 21, and.five defective and three
- degraded tubes were. identified in steam generator 22. These tubes
were scheduled for plugging' These defective and degraded tubes placed
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'the steam generators 'in Category C-2.
Category C-2 is defined as
follows:
One or more tubes, but not more than 1% of the total. tubes
inspected are defective, or between 5% and 10% of the total tubes
inspected are degraded tubes.
Of the six tubes-found defective in steam generator 21, all were.
suspected intergranular attack in the sludge pile region. Of the five
defective tubes in steam generator 22 two were suspected wear at the
vertical' middle support plate-(antivibration bar) and three were
suspected .intergranular attack in the sludge pile region.
In addition to the above testing, the licensee elected to perform
motorized rotating pancake coil (MRPC) inspections of selected tubes
in each of the steam generators.
This technique was used both in the
U-bend region and from the first support plate into the tubesheet.
The NRC inspector cbserved selection of the tubes to determine-if
primary side intergranular. cracking was present at the top of the
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tubesheet as reported by another licensee. These tubes were selected
based on areas in the steam generator that indicated active areas of
degradation, i.e. areas of previously plugged tubes due to IGA at the
top cf the tubesheet.
The inspector also observed the testing of
selected tubes using the MRPC.
Data Analysis
The inspector observed the analysis of the eddy current data and
interviewed the Level III analysts of the responsible organizations to
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determine the~ adequacy of the method. The eddy current data were
analyzed using a three step process as follows:
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Primary analysis-by individuals ' certified as at least a Level II
analyst in eddy current testing.
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A' screening.of the data by' computer using more. stringent
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acceptance standards than those used by the, primary analyst.
Secondary manual analysis by. individuals certified as, at least a
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Level II enalyst in eddy current testing. The secondary analysis-
was performed by a company independent of.the company retained
for data acquisition and primary analysis.
.Following.these analyses, resolution of differences was accomplished
by a certified Level III analyst in eddy current examination'.
- Concl usi on_s
Based'on the' inspector's review of the steam generator eddy current
testing program and observation of the testing and data. analysis, the
inspector concluded that the licensee had performed testing and
evaluation-in' excess of the Technical Specification requirements.
Nineteen of the 9336 active tubes were plugged (8.as a preventive
measure). ' Use of the MRPC in tho U-bend regions and from the first
support plate into the'tubesheet indicate the' licensee's concerns for
defects found by other facilities.
4.0 Erosion / Corrosion Control Program
The licensee initiated an informal erosion / corrosion (E/C) program in
1979 to identify carbon steel systems where E/C existed, quantify the
extent of E/C, and to establish a decision making process for
inspecting or replacing components. The present formal program was
established in 1984.
The program is administered by the licensee's ISI group. These
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-engineers have classified various components in accordance with a
priority system based on steam moisture content or' flashing conditions
within the. system and fluid velocity, component geometry, operating
conditions, temperature / pressure, and plant and industry experience.
The total number of components in all three priorities (' A',
'B', or
'C') is approximately 3000 in Unit 2.
During normal outages
approximately 250 components are inspected. Of these 250 components,
approximately 4094 are reinspection of components previously
identified as " Red Alert". A four step system is used to classify
inspected components as follows:
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Unacceptable - these components.have reached minimum wall
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thickness or it is expected that they will reach minimum wall
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thickness during the next refueling cycle. Unacceptable
components are replaced except when detailed engineering
evaluation indicates that they will not reach minimum wall
thickness during the next operating cycle.
. Red Alert - it is predicted that these components will last for
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one, refueling outage-and will need-to be replaced during the next
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outage.
Red alert components are scheduled for replacement.
during the'next refueling outage. However, prior to replacement
they.are-reinspected and a detailed evaluation prepared by
engineering.
~ Yellow Alert
it_is predicted that_these components will last
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for two refueling' outages before requiring' replacement. Yellow
alert components are scheduled for reinspection during the second
outage after falling into the Yellow alert category.
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Acceptable - it is predicted that these' components.will not
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require replacement until the~ third. outage as a mi_nimum. The
condition.of these components is recorded and inspection'
rescheduled as required.
-The licensee experienced a leak in the blowdown line from steam-
generator!22. The inspector noted that this blowdown line was in the
.E/C program ~where several areas had been inspected and identified as
having wall loss.significantly less than that of the failed piping.
The leak location was scheduled for inspection during the current
outage. The actual failure was at an area of acceptable undercut on
the pipe adjacent to the socket weld of the elbow. This undercut was
located in the area of most severe / erosion. A leak occurred when the
erosion met the undercut.
Conclusions
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The licensee's program for E/C is comprehensive and has been in
operation long enough to provide meaningful data on the
characteristics of the plant components. The failure of the program
to identify the steam generator blowdown line was traced to a welding
defect, not_to a breakdown in the E/C program.
This particular
section of piping was scheduled for examination during the present
outage and presumably, this thin section in the piping would have been
identified and replaced. Additional information regarding this steam
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leak is covered in NRC IR No. 50-318/89-14.
5.0 Inservice Inspection Program Review
Calvert Cliffs Units 1 and 2 are in the first period of the second 10
year inspection interval at this time.
The ISI program is based on
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the ASME Code,Section XI, 1983 Edition, Summer 1983 Addenda.
The
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initial interval was adjusted so that the ISI program for each unit
would be coincident.
This adjustment was approved by the NRC.
The inspector discussed the ISI program with the responsible engineer
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and determined that the required inspections for the first period of
the second interval had been completed except for those components
that were dependent on other plant activities being completed, e.g.
the fuel moves being completed.
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6.0 NDE Examiner Certification Program
1.
In addition to the licensee's staff, contractors are used for varicus
types of NDE associated with ASME Section XI, the E/C program and
steam generator eddy current inspections. The licensee's staff was
technically capable of performing their assigned duties, and the staff
size appeared adequate to meet the scheduled work load.
The inspector
selected staff NDE personnel qualification - certification records,
and records related to contractor NDE personnel. The records of
contractor personnel who had performed examinations at the site were
reviewed and it was verified that these individuals were properly
qualified and certified in accordance with the applicable requirements
of ASME Section XI and SNT-TC-1A. The inspector reviewed the
qualifications - certifications for a representative sample of the
indiv % als involved in the data analysis of the testing done on the
These individuals were highly qualified and
properly certified.
. Licensee personnel were certified in the visual, liquid penetrant,
magnetic particle, and ultrasonic examination methods.
Records of
selected individuals reviewed by the inspector to determine that their
certifications was in accordance with the requirements of ASME Section
XI, ANSI N45.5.6 - 1978, SNT-TC-1A, and the licensee's program.
The
record packages were found to contain documentation of current visual
acuity, education, resumes, and various training records. However,
these records did not clearly show that the qualification, experience,
and training requirements were met prior to certification. Also, the
records did not indicate that the requirements for visual examiner
types VT-1, VT-2, VT-3 and VT-4 had been addressed. The licensee's
written program for certification did not address these visual
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requirements.
In addition, the annual training requirements of the
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licensee's program had not been met. The inspector noted that in one
case the certification for a visual examiner had expired. The
inspector discussed this with the individual and was informed that the
individual was not aware of his certification having expired since the
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licensee had discontinued the procedurally required practice of
issuing NDE examiner identification cards.
The licensee issued a
nonconformance report to require investigation of the inspections
performed by this individual during the period his certification was
expired. These deficiencies are a violation of 10 CFR 50, Appendix B,
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Criterion IX, and the licensee's written procedure requiring
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compliance to the ASME Code and SNT-TC-1A (89-15-01).
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Conclusions
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The licensee maintains acceptable control of their NDE contractors and
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their certifications.
However, certification records of the
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licensee's staff were found incomplete and lacking in organization.
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.7.0
Primary and Secondary Water Chemistry
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-Water chemistry data were reviewed as part of this inspection. The
methods of collecting and verifying the accuracy of these data were
not included in the scope of the inspection.
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The inspector reviewed the primary water chemistry results for the
period from January, 1988 through March 1989 and observed that the
Boron / Lithium ratio was significantly above the licensee's
specification (CP-204) for 8 of the 14 months of full power operation.
This ratio is varied to maintain the pH in the required range of
6.8-7.5.
During this period the pH was maintained within
specification except for short periods of time.
The Iodine Dose
Equivalent was maintained at less than 0.1 uCi/gm which is
significantly below the Technical Specification limit of 5.0 uCi/gm.
In reviewing the secondary water chemistry results for the three
months preceding the shutdown for the present refueling outage the
inspector observed that the licensee was achieving water quality
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results superior to the EPRI Guidelines. lypical results for this
period are shown in Table 1.
TABLE 1
Secondary Water Chemistry History
Blowdown Sample
Parameter
Calvert Cliffs
EPRI Guide
Results
Cation Cond., uS/cm
0.11
0.8
Chloride, ppb
2
20
Sodium, ppb
5
20
Sulfate, ppb
2
8.0 Pressurizer Heaters
The licensee reported that 22 of the 120 heater assemblies in the
pressurizer in Unit 2 showed evidence of leakage.
This evidence was
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indicated by boron buildup on the.outside of the heater assembly. The
assemblies consist of an inconel sleeve 1.158 inch 0.D._and
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approximately 0.875 inch I.D. welded into the bottom head of the
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pressurizer on the inside with a partial penetration fillet weld. The
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heater assembly is welded to the outside of the sleeve to provide a
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removable seal for heater replacement.
Heaters showing evidence of
leakage are identified as shown in Table 2.
TABLE 2
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HEATER LOCATIONS SHOWING EVIDENCE OF LEAKAGE
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H3
F3
D3
E2
M2
C2
C1
H1
F2
D2
B2
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B1
D1
F1
K1
J2
G2
El
G1
Z1
BB1
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In addition to the evidence of leakage found around the above heater
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penetrations, other evidence of leakage was observed near the top of
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the pressurizer at the pressure tap located 7 1/2 from 0 toward 90 .
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At-the time of the inspection the pressurizer had not been opened to
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allow internal examination of these areas.
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Failure Analysis
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The inspector discussed the heater leaks with one of the plant
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metallurgists and was informed that the licensee had provided samples
to the mobile metallurgical laboratory installed in a van to perform
analysis of these and other failures as required. The inspector
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toured this facility and noted that it contained all of the equipment
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necessary for performing metallographic analysis including high and
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low power optical microscopes with photographic capability.
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metallographic sample preparation facilities, and a data link with the
main laboratory. This facility allows the licensee to perform
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controlled and timely failure analysis.
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9.0 Management Meetings
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Licensee management was informed of the scope and purpose of the
inspection at the entrance interview on May 8, 1989.
The findings of
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the inspection were discussed with licensee representatives during the
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course of the inspection and presented to licensee management at the
May 12, 1989 exit interview (see paragraph I for attendees).
At no time during the inspection was written material provided to the
licensee by the inspector.
The licensee did not indicate that
proprietary information was involved within the scope of this
inspection.
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