ML20035H087
| ML20035H087 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 04/14/1993 |
| From: | Gray E, Mcbreaty R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20035H079 | List: |
| References | |
| 50-317-93-08, 50-317-93-8, 50-318-93-08, 50-318-93-8, NUDOCS 9305030101 | |
| Download: ML20035H087 (6) | |
See also: IR 05000317/1993008
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
50-317/93-08
REPORT NOS.
50-318/93-08
50-317
DOCKET NOS.
50-318
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LICENSE NOS.
LICENSEE:
Baltimore Gas & Electric Company
MD Rts 2 and 4, P.O. Box 1535
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Lusby, Maryland 20657
FACILITY NAME:
Calvert Cliffs Nuclear Power Plant
INSPECTION AT:
Lusby, Maryland
INSPECTION CONDUCTED:
March 15-19,1993
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INSPECTOR: (
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-MR. A. McBrearty, Reactor Engineer
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Materials Section, EB, DRS
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APPROVED BY:
E. H. Gray, Chief, fiaterials Section
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Engineering Branch, DRS
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9305030101 930423
ADOCK 05000317
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Areas inspected: An announced inspection was conducted of the licensee's inservice
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inspection (ISI) program and r: lated activities. The inspection was conducted to ascertain
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whether the program conformed to code and regulatory requirements, and whether the
activities were performed in a way that confirms the plant's acceptability to continue
operation.
Results: The ISI program conforms to code and regulatory requirements regard.ing code
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edition and administrative controls of the program. Program implementation generally
confirms the plant's acceptability for continued operation. Portions of the implementation
activities demonstrate a need for improved licensee oversight of its ISI vendor, and a more
complete review of vendor nondestructive examination personnel qualification / certification
records. One violation was identified regarding the use of an inappropriate ultrasonic
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examination procedure to evaluate rejectable magnetic particle examination indications.
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DETAILS
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INSERVICE INSPECTION (ISI) ACTIVITIES (IP73753)
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Calvert Cliffs Unit 2 is in its second inspection interval and the current outage is the first
refueling outage of the interval's second period. The applicable code edition for the interval
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is the 1983 Edition through Summer 1983 Addenda of ASME Section XI.
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A portion of the ultrasonic examination of reactor coolant pump stud No. RS-50651-35 and
the magnetic particle examination of a portion of main steam system weld 36-MS-2001
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weld 3 were observed. The observations were to ascertain that the examinations were
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performed in compliance with ASME code and regulatory requirements, and that the
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examiners were qualified to perform those examinations.
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In each case the examiner demonstrated his expertise using the particular examination
method. The appropriate procedure was available and the equipment was properly calibrated
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as required by procedural and code provisions. The stud examination was halted by the
examiner when it became apparent that it could not be performed as required due to an
obstruction that required additional cleaning of the bore area.
The magnetic particle examination of weld 3 was completed prior to this inspection and
detected a rejectable surface indication which was reported. The inspector requested that a
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portion of the examination be re-performed in his presence to assess the severity of the
condition. The examination revealed a linear indication, 3/8" long which was determined to
be rejectable per ASME Code Section XI, IWB-3514.7 and Table IWB-3514.4. A similar
rejectable indication was detected on the 34" diameter weld No. 6 of the main steam system.
However, where indications on the outer surface of piping as detected by the surface
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examination method during an inservice examination exceed the allowable standards of IWB-
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3514.7, IWB-3514.2(b) permits indications to be examined by the ultrasonic method. The
acceptance of these indications shall be governed by the allowable indication standards for
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the volumetric examination method in Table IWB-3514-1. Further, ASME Section XI, IWB-
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3420, requires that each flaw indication shall be characterized by the rules of IWA-3300 to
establish the dimensions of the indications. Also, IWB-3420 requires that these dimensions
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shall be used in conjunction with the acceptance of Table IWB-3514-1.
In the above cases, the ultrasonic evaluation of the surface indications was performed using a
technique that incorporated a 45 full Vee shear wave calibrated on ID and OD notches
0.182" and 0.100" deep for weld three and six, respectively. Those notches are
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approximately 10% of wall thickness in depth. The examination and calibration technique is
intended for the routine Section XI examination of the lower third of the weld. Further, the
's a lique was demonstrated at another nuclear facility to not reliably detect cracks emanating
ir the outside surface of a pipe. In that demonstration, seven cracks were known to be
present and only two of the deepest cracks were detected using the 45 shear wave full Vee
technique. The demonstration agrees with the results of studies performed at the Pacific
Northwest Laboratory of Battelle Memorial Institute at Richland, Washington, which
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examined the probability of detection of cracks at various depths.
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Based on the use of the 45 shear wave ultrasonic examination technique, the welds were
accepted by the licensee. The licensee's use of the ultrasonic examination method was to
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preclude having to expand its magnetic particle examination sample. Although the ultrasonic
results were evaluated as acceptable, the licensee prepared two Issue Reports (IR5-008-678
and -679) to remove the arc strikes that caused the magnetic particle indications. Those
reports were issued by the licensee prior to this inspection.
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As stated above, the ultrasonic method selected to evaluate the magnetic particle surface
indications was not appropriate for its application in that it was not demonstrated to be
capable of detecting or sizing the known surface indications. Additionally, no documentation
was available to confirm that the indication dimensions were established and used in
conjunction with the acceptance of Table IWB-3514-1. This is considered to be a violation
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(50-318/93-08-01).
The inspector's discussions with cognizant licensee and ISI vendor personnel regarding the
matter resulted in the licensee's decision to have the appropriate ultrasonic equipment (search
units and calibration blocks) brought to the site so that a second ultrasonic examination could
be performed of the two welds using a technique appropriate for the detection of cracks
initiating at the OD surface. The examination was not yet performed at the conclusion of
this inspection.
Personnel Oualification/ Certification Records
Qualification / Certification records of personnel responsible for performing the examinations
observed by the inspector, and others responsible for performing inservice inspection at the
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site during the ongoing refueling outage were reviewed.
Records of Southwest Research Institute (SWRI) personnel were generally complete and
verified that each individual was qualified and certified to the level of competence
commensurate with his assigned duties.
Records of Sonic Systems International, Ir .. were incomplete and did not confirm that each
individual was properly qualified to perform ISI at the Calvert Cliffs Nuclear Power Plant.
The records failed to include written and practical examination dates, length of experience or
the amount of training provided to each individual prior to certification. The certification
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expiration date was identified on each record, but could not be verified in the absence of the
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qualifying examination dates. At the inspector's request the licensee contacted Sonic Systems
International and obtained the missing information which was provided to the inspector at the
exit meeting.
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Inservice Inspection Data
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Ultrasonic examination data associated with safety injection system weld 6-ISI-2202-10, a 6"
diameter, stainless steel valve to pipe weld, was selected for inspection to ascertain that the
examination was performed by qualified examiners, and that the data were properly recorded
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and evaluated.
Examination access was limited to the pipe side because of the valve configuration. The
SWRI Profile and Thickness Information Record Sheet No. 135002, dated
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February 26,1993, was prepared to show the amount of coverage accomplished by the one
side examination. The transducers were placed on the pipe side of the weld with sound
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transmission toward the valve side using the shear mode and entry angles of 45* and 60 . A
note on the profile sheet stated that "100% two directional coverage obtained from pipe
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side," however, the inside surface contour of the weld suggests that complete coverage of the
weld was unlikely from only one side. A plot of the coverage constructed by the SWRI
examiner appeared to confirm the coverage claimed by the note. A subsequent attempt by
the NRC to confirm the claimed coverage using the EPRI developed RAYTRACE computer
software suggested that portions of the required weld examination volume were not covered
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by the ultrasound and that 100% coverage was not attained. The matter was discussed with
cognizant licensee personnel. Ifit is found that less than 90% of the required volume can be
examined, a request for relief from the code requirement will be submitted to the NRC.
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Conclusion
The Baltimore Gas & Electric Company (BG&E) oversight of ISI vendor activities shows a
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need for improvement as exemplified by the selection, by the vendor, of an inappropriate
ultrasonic examination technique to evaluate defects originally detected by the magnetic
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particle method. A second example is the claim of 100% examination coverage of safety
injection weld 6-SI-2202-10 by the vendor and accepted by BG&E. The weld profile
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suggests that complete coverage was unlikely and an NRC attempt using the EPRI developed
RAYTRACE computer software to confirm that 100% coverage was attained showed that a
portion of the required examination volume was not examined by the pipe side examination
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documented by the ISI vendor. Further evidence of the need for improved BG&E
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involvement in vendor inservice inspection activities is the acceptance of incomplete
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qualification / certification records of vendor nondestructive examination personnel who were
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responsible for performing inservice inspection at Calvert Cliffs.
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EXIT MEETING
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The inspector met with licensee representatives, denoted in Attachment 1, at the conclusion
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of the inspection on March 19, 1993. The inspector summarized the scope and findings of
the inspection.
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ATTACIIMENT 1
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Exit Meeting Attendance - 3/19/93
Calvert Cliffs Nuclear Power Plant (BG&E)
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Name
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K. Hoffman
Principal Engineer NISU
D. Muth
Compliance Engineer
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D. Song
ISI Engineer NISU
D. Vincent
Plant Engineering
B. Watson
Gen. Supervisor - Radiation Safety
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U.S. Nuclear Regulatory Commission
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S. Flanders
Reactor Engineer
R. McBrearty
Reactor Engineer
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