IR 05000261/1990021
| ML14178A050 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 10/16/1990 |
| From: | Blake J, Coley J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML14178A049 | List: |
| References | |
| 50-261-90-21, NUDOCS 9011080308 | |
| Download: ML14178A050 (8) | |
Text
pj% REG&o UNITED STATES o
NUCLEAR REGULATORY COMMISSION REGION 11 101 MARIETTA STREET, ATLANTA, GEORGIA 30323 Report Nos.: 50-261/90-21 Licensee: Carolina Power and Light P. 0. Box 1551 Raleigh, NC 27602 Docket No.: 50-261 License No.: DPR-23 Facility name:
H. B. Robinson Inspection Conducted: October 1-5, 1990 Inspector:
/ C ey Date Signed Approved by:1
/6 X
J..
ake, Chief ate Signed M e als and Processes Section E g' eering Branch ivision of Reactor Safety SUMMARY Scope:
This routine, unannounced inspection was conducted in the areas of observation of inservice inspection and work activities (73753).
Results:
The licensee's inservice inspection work and work activities were proceeding effectivel During the inspection the inspector held discussions with cognizant licensee personnel concerning a crack discovered in a level indicator nozzle on the "C" accumulator; reviewed base-line radiographs for the new service water piping welds; observed ultrasonic re-evaluation examinations of indications on Steam Generator B, Weld 5; and observed other ultrasonic and liquid penetrant examinations on piping and component One unresolved item was identified 50-261/90-21-01
"Welds not Identified on Inservice Inspection (ISI) Isometric (ISO)
Sketches", paragraph 2 b, and one concern was identified to senior management involving a welding machine incorrectly grounded to a stainless steel pip In the areas inspected, violations or deviations were not identifie PDR ADOCK 05000261
PNU
REPORT DETAILS 1. Persons Contacted Licensee Employees
- W. M. Biggs, Manager, Nuclear Engineering Department
- S. A. Billings, Technical Aide, Regulatory Compliance E. Black, Supervisor, Site QA/QC
- R. D. Crook, Senior Specialist, Regulatory Compliance
- C. R. Dietz, Site Project Manager, Robinson Nuclear Power Division
- S. W. Farmer, Engineering Supervisor, Programs
- E. M. Harris, Jr., Manager, On-site Nuclear Safety
- R. E. Morgan, Assistant To Project Manager
- M. F. Page, Manager, Technical Support
- W. J. Powell, Senior Specialist, Nuclear Engineering Department
- J. J. Sheppard, Plant General Manager
- R. M. Smith, Manager, Maintenance
- H. G. Young, Manager, QA/QC
- A. R. Wallace, Operations Coordinator D. Weber, ISI Engineer Other licensee employees contacted during this inspection included engineers, technicians, and administrative personne Other Organizations J. B. Campbell, Supervisor, Westinghouse G. Healey, Test Engineer, Gilbert and Associates B. Pelzer, Test Engineer, Gilbert and Associates NRC Resident Inspectors
- L. Garner, Senior Resident Inspector
- K. Jury, Resident Inspector
- Attended exit interview on October 5, 1990 2. Inservice Inspection (73753) Unit 2 The inspector observed inservice inspection (ISI)
work and work activities to ascertain whether examination, repair, and replacement activities associated with ASME Class 1, 2, and 3 components were performed in accordance with Technical Specifications, the applicable section and revision of the ASME Code, correspondence between NRR and the licensee concerning relief requests, and requirements imposed by NRC/industry initiative H. B. Robinson is presently in the fifth and last outage of the second inspection interva The applicable Code for this interval is the ASME B&PV Code,Section XI, 1977 Edition, with addenda through Summer 197 a. Volumetric Examination of Welds using the Manual (A -
scan)
Ultrasonic Technique The inspector observed ultrasonic examinations performed on the following welds:
Weld Joint N ISO Sketch N System/Component
CPL-237 10" Diameter Line N Stainless Steel 10-SI-55 Weld on Loop C Accumulator Discharge
CPL-205A Steam Generator "B" Girth Weld Ultrasonic inspection of the safety injection weld (N ) was performed by Westinghouse examiners in accordance with CP&L procedure N CP&L-ISI-206, Revision 0. No recordable indications were observed during the examination of this wel However, the inspector noted nearby unsatisfactory conditions in the regenerative heat exchanger room during this inspection in that a cyclomatic weld machine had been grounded to a 1" diameter stainless steel pipe which ran across the room and branched down to valve CVC 389 (excess letdown heat exchanger to seal water return).
Follow-on inspection using a flashlight by the inspector and a Westinghouse examiner established that the clamp for the ground lead had created a vee groove in the pipe approximately 2 1/2" long and 0.005" to 0.010" dee This condition was reported to CP&L management and a liquid penetrant examination was performed on the pip However, licensee personnel stated that the examined area did not exhibit a groov Therefore, either the liquid penetrant examination was performed on the wrong area of the pipe or the groove was removed by unauthorized grinding after removal of the ground lead and prior to the penetrant examinatio During the exit the inspector addressed the unacceptable practice of attaching ground leads which can create arc strikes on plant piping system The site project manager stated that all welders on site would be notified that the practice of attaching ground leads to plant piping was unacceptable and not allowe The engineering supervisor for programs stated that further investigation would be conducted as to whether the correct area of the pipe had been examine Adequate resolution of this item will be verified during a subsequent inspection to be completed during the current outag The ultrasonic examinations performed on Weld No. 5 of SG - B were conducted on 3 indications that had been detected during the second interval examinations completed earlier in the current outag The evaluation and sizing of the discontinuities was performed by a CP&L
examiner with assistance from Westinghous The 3 indications were all below the 50% DAC level and had not been detected during the first interval examination CP&L's technical staff expressed concerns that these discontinuities may be indicative of problems experienced at Indian Point, Surry and Zion where cold water (apparently from the feedwater header)
had created significant cracking adjacent to this weld. Therefore accurate sizing data was collected for comparison to examination data to be taken at a later dat Evaluation of the present data indicated that problems similar to those at Indian Point do not presently exist for this steam generator girth weld at H. B. Robinso b. Surface Examination of Welds using the Liquid Penetrant Technique The inspector observed Westinghouse examiners conduct liquid penetrant examinations on Weld N and Weld N of the seal water heat exchanger (CP&L Sketch 211, Revision 0).
Only one third (1/3) of each weld was required to be examined this interva The examiners conducted the inspection in accordance with CP&L Special Procedure SP-930 and both welds were determined to be satisfactor In addition to the above examination, the inspector accompanied Westinghouse examiners during their attempt to perform liquid penetrant examinations on the following weld The examiners were unable to perform the examinations for the reasons liste Reason test Weld ID CP&L Sketch N Diameter/System Not Performed No. 29 CPL-220 6" Diameter Pipe Too Hot Safety Injection Nos. 2,3,4 CPL-234B 8" Diameter Welds Not Containment Spray Adequately Cleaned During the Westinghouse examiners' search for the weld joints listed on sketch CPL-234B the inspector noted that the weld configurations depicted in the sketch did not agree with actual field condition The actual as-built piping run from the containment penetration (P 44) to the first weld on the elbow includes 13 weld However the sketch identifies the first weld on the elbow as No. 10 rather than 1 The inspector held discussions with the licensee's Inservice Inspection (ISI)
Engineer concerning the inaccuracy of the ISI sketch and noted that this finding could indicate an incorrect total weld population included in the ISI progra Also that sketches which do not correctly depict the weld configuration could very likely cause an examiner to perform the required examination on the wrong wel The ISI engineer stated that some of the sketches had been found inaccurate and updated and any others would be updated when found to be incorrec Further that extra welds have been added to the program sample to offset the adverse impact of those
not depicted on the sketche In the case of the three additional welds discovered on sketch CPL-234B one was added for examinatio However, all three welds were on "pup" pieces and were not classed as structural discontinuitie Therefore the examination was not required under the applicable Code for these Class 2 pipe weld The inspector informed the plant manager that the failure of H. Robinson inservice ISO sketches to accurately identify welds in the piping involved was of concern due to the reasons given abov Also that this matter would be discussed with NRC's Office of Nuclear Reactor Regulation (NRR)
regarding potential adverse impact on the NRR approved current ISI program as well as the Third Inspection Interval program which CP&L is presently preparing to submit to NRR for approva Senior plant management assured the inspector that CP&L would complete additional assessment of this matter to determine how these sketches can be corrected to accurately reflect actual pipe/weld joint configurations. This item was identified as Unresolved Item 50-261/90-21-01, "Welds not Identified on Inservice Inspection ISO Sketches".
c. Repair and Replacement Activities During performance of a hydrostatic test on the SI accumulator "C",
a leak was detected in the stainless steel nozzle coupling for one of the upper level transmitter instrument line The Material Engineering Unit of the CP&L Nuclear Engineering Department (NED) is providing technical support and will coordinate the evaluation activities for this projec Preliminary failure analysis results indicate that the cause of the leak was from an intergranular stress corrosion crack (IGSCC)
in the nozzle couplin A computerized search by the licensee on the Nuclear Plant Reliability Data System (NPRDS)
revealed that a similar problem may have been experienced on one of Prairie Island's SI accumulator This is a recent failure and evaluation of the defective condition, its root cause, and plans for repair are not yet complet However, the following goals have been established by NED and work is proceeding to meet these goals:
Complete the failure analysi *
Acquire available information from Westinghouse on design and manufacture of SI accumulator *
Obtain specific information from Prairie Island personnel on their past accumulator problem *
Develop a Code acceptable repair method to be used in repairing this failed coupling with the assistance of Structural Integrity Associates. An engineering evaluation and any necessary special procedures would be developed prior to repair implementatio *
Evaluate the susceptibility of the other stainless nozzles on the accumulators to IGSCC by determining if they are manufactured from low carbon grade of stainless (use of Westinghouse records and/or carbon analysis of filings obtained from nozzles).
- Develop and implement a plan for the inspection and possible future reinspection of other accumulator nozzles if analyses show that these are manufactured from stainless other than low carbon (less than 0.03% carbon)
grad Inspection might include liquid penetrant examination and ultrasonic examination techniques to determine if nozzles contain IGSCC in that portion of the nozzles which extends outside the accumulator shell O *
Prepare a final report on the evaluation and repai From work accomplished by the licensee to achieve the above goals the inspector was able to establish the following specifics concerning this failure:
Vessel thickness: 2 3/8"
Pipe size:
2" Diameter stainless steel
Materials:
SA-182-304 (304 ELC)
Pressure:
600 psi minimum 700 psi maximum
Temperature Range: approximately 115 degrees F operational 300 degrees F design
Defect length:
Defect extends from coupling socket crevice area to the accumulator ID
Crack resistance:
Coupling and nozzle were sensitized during initial manufactur *
Ongoing examinations:
CP&L is performing UT & PT examinations on the remaining 23 nozzles on the three accumulators at H. B. Robinso *
Carbon content for failed nozzle:
0.062%
Accumulator manufacturer: Delta Southern Company of Baton Rouge, Louisian *
Hoop Stress:
No significant hoop stress detecte *
Chemical analysis:
Chemical analyses not completed to dat Electric Power Research Institute (EPRI)
contracted to perform necessary evaluatio Since resolution of this item may have generic implications the inspector will complete further evaluations during a subsequent inspection scheduled to be completed during the current outag In addition to the evaluation and repair activity discussed above, the licensee is presently fabricating and installing new service water piping spool pieces to replace the plant piping which has been attacked by microbiologically induced corrosion (MIC).
The new piping has been filled with water and the licensee is radiographing each circumferential weld in order to produce a base-line for future MIC inspections even though radiographic inspection of these welds is not required by the applicable Code. The inspector reviewed the radiographs taken to date to determine workmanship of the licensee's welders on Code welding applications not normally requiring radiography. The quality of the welds and radiographs reviewed was excellen d. Review of ISI Plan, Procedures, Qualifications, Certifications, and Completed Examination Records The inspector reviewed the licensee's ISI plan as well as all material and equipment certifications; examiners'
qualifications, certifications, and eye tests; records of examinations completed to date; and examination proceedure The following Westinghouse examiner certifications and procedures were also verified as satisfactory:
Westinghouse NDE Examiner UT PT VT MT KMA I
II II II KHB II II II II JBC II II III II RWC II II II II BD I
II II II GAJ I
II II GAM II II II II MWR III III III III Examination Procedures Reviewed CPL-SP-932, Rev. 0, Visual Examination CPL-SP-927, Rev. 0, Qualification of UT Manual Equipment CPL-SP-930, Rev. 0, Liquid Penetrant Examination CPL-SP-933, Rev. 0, Manual UT Examination of Bolting CPL-SP-931, Rev. 0, Manual UT Examination of Welds in Vessels CPL-SP-928, Rev. 0, Magnetic Particle Examinations CPL-SP-935, Rev. 0, Underwater Remote Vessel Examination CPL-SP-924, Rev. 0, Thickness and Beam Angle by Ultrasonics CPL-SP-925, Rev. 0, Preservice and Inservice Examination Documentatiion CPL-SP-929, Rev. 0, Manual Ultrasonic Testing of Welds Within the areas examined, no violations or deviations were eidentifie. Exit Interview The inspection scope and findings were summarized on October 5, 1990, with those persons indicated in paragraph 1 abov The inspector described the areas inspected and discussed in detail the inspection finding Dissenting comments were not received from the license Proprietary information is not contained in this repor Unresolved Item 50-261/90-21-01,
"Welds not Identified on Inservice Inspection ISO Sketches", paragraph 2 b.