IR 05000311/1991032
| ML18096A487 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 01/14/1992 |
| From: | Gray E, Patnaik P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML18096A486 | List: |
| References | |
| 50-311-91-32, NUDOCS 9202030011 | |
| Download: ML18096A487 (6) | |
Text
Report N Docket N U. S. NUCLEAR REGULATORY COMMISSION
REGION I
License No. * DPR-75 Licensee:
Public Service Electnc and Gas Company Facility Name:
Salem Nuclear Generating Station. Unit 2 Inspection At:
Hancocks Bridge. NJ Inspection Conducted:
- December 17 through December 20. 1991 Inspector:
P. Patnaik, Reactor Engineer, Materials Section, Engineering Branch, DRS
- Approved by: -*--=-?t_,_/_/_,__~-~-, ~'-------
E. Harold Gray, Cfaef, Materials Section, Engineering Branch, DRS date date Areas Inspected: Review of a sampl~ of inspection data on the December 1991 eddy current examination of steam generator tubes and the inservice inspection of the steam generator vessel. The inservice inspection plari for the sixth refueling outage of Salem Unit 2 was reviewed for compliance to the applicable codes and the regulatory requirement. The eddy current examination activities in progress were observed to verify proper implementation of the eddy current progra Results: The inservice inspection program and the eddy current inspection program reviewed for the sixth refueling outage of Salem Unit 2 complied with the applicable code and the regulatory requirements. The licensee demonstrated acoustic similarity between materials of
_the calibration block and the steam generator vessel, during the inspectio *1 920122 PDR ADOCK 05000311
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- -* *
Steam Generator Eddy Current Examination (73753, 73755).2
. The steam generator.eddy current examination of Salem Unit 2 was conducted during the sixth refueling outage in December 1991. Salem Unit 2 is a four loop Westinghouse pressurized water reactor having model 51 steam generators with 3388 U-tubes in each.* The licensee examined a total of 50%
of the tubes in each of two steam generators using a bobbin coil and a rotating pancake coil. The Westinghouse recommendation for model 51 steam generators having explosive tube expansion has been to examine 20 % of tubes in each steam generator for all four generators during each outage. However,*
both inspection guidelines exceed the Technical Specification requirement. In the licensee's evaluation, the bases for examining 50% of tubes in two steam generators as opposed to examining 20 % of tubes in all four generators were the benefits of reduced man-rem exposure, early completion of 100 % tube examination and a reduced outage schedule with no impact on evaluation of steam generator tube integrity. Hence, the licensee's inspection approach of examining 50 % of tubes in two steam generators was considered by the NRC to be a reasonable variation from the Westinghouse guideline The licensee identified eight tubes that are susceptible to fatigue cracking and consequent tube rupture, such as that of North Anna, due to flow induced vibration and presumably lack of support from anti-vibration bars. These tubes were removed from service by" installing a cable type dampener in each tube and plugging the hot leg and the cold leg ends. The cold leg plug, called the sentinel plug, has a small hole which will allow a controlled leakage from primary to secondary in the event of a tube rupture. The cable type tube dampener extended from the hot leg of the tube sheet over the U-bend up to the seventh support plat Findings The licensee performed an eddy current examination of 204 randomly selected tubes in #21 steam generator using a bobbin coil to satisfy the Technical Specification. There was no defective or degraded tubes found in the sample of tubes examined. Hence, a scope expansion was not required. The licensee, however, examined forty-five tubes with previous indications and 1490 additional tubes to bring the total number of tubes examined to 50 % in #21
~----
sre,am generator and a corresponding number of tubes in #23 steam generator using* a bobbin coil* and a rotating pancake coil. The result of this second sample examination indicated eight degraded tubes in #21 steam generator and no degraded tube in #23 steam generato Two tube dampeners in #21 steam generator, five in #22 steam generator and one in #23 _steam generator were installed and, hence, the affected tubes were removed from servic As a result of eddy current indications, eight degraded tubes were preventively plugged in #21 steam generator. Two cold leg plugs in #24 steam generator were replaced by sentinel plugs since both tubes had tube stabilizers installed previously. The following is the scope* Of tube plugging during the. outag Tubes Plugged due Tubes Plugged due to Total Steam Generator to eddy current due to dampener tubes N indication installation plugged
8
10
5
23
1
- 2
- Two existing cold leg plugs were replaced.with sentinel plug The plugging of tubes and the installation of dampeners were approved by the engineering department. The plug removal and installation complied with the licensee's procedure MRS 2.3.2 PSEG-13, Rev. 0, "Mechanical Plugging of Steam Generator Tubes for Salem Nuclear Power Plant." The inspector reviewed the process data sheets for manual and robotic plug installation to verify the applied pressure and the distance measurement on plugs to determine acceptance of installation. The data met the acceptance criteria established during system calibratio The inspector reviewed the eddy current examination procedure MRS 2.4.2 GEN-35 to determine compliance with the ASME Codes,Section XI and V and reviewed the data analysis guideline (DAT-GYD-001).
There was no discrepancy noted within the scope of review. However, the data analysis guideline was a generic document for all Westinghouse plant Hence, the data review may not be uniform for Salem steam generators. The preparation of a Salem plant specific data analysis guideline would identify for the eddy current technician the specific plant needs for evaluation of data including the types of typical eddy current indications, operator training needs and steam generator operating histor ~-
- Certifieations for eddy current technicians, mechanical plug operators and cable dampener ins~lers were reviewed. These certifications met the personnel training and qualification requirement -of the applicable procedur Conclusion For those areas inspected, the eddy current examination program, the plugging of tubes and the installation of tube dampeners met the industry standards and the regulatory requirements. A plant specific data analysis-guideline would ensure uniform data reviews of Salem steam generators and provide quality control during data analysi.0 Inservice Inspection CISI) (73753, 73755).2 During this inspection, the inservice inspection plan for the third period of the first interval was reviewed to ascertain if the requirements of the ASME Code,Section XI and the Technical Specifications were met. Limited data on inservice inspections conducted in,the early phase of inspection activity were reviewe Findings The licensee conducted an inservice inspection in the third period of the first inspection interval during the sixth refueling outage of the unit. The applicable code for inservice inspection was the ASME Code,Section XI, the 1974 Edition with Summer 1975 addenda. The inspector reviewed portions of ultrasonic examination data on welds in the secondary side of #21 steam generator. Two of the welds selected were the shell "D" to the upper-head and the shell "C" to the transition cone. The data were complete and the findings were cl~ly documente The licensee's contracted personnel for ultrasonic examination were certified to appropriate ASNT levels to perform examinations. The contractor's procedure for ultrasonic examination was in compliance with ASME Codes and was approved by the license The calibration block used to examine-* the referenced welds was made of material conforming to SA 302, Gr B, whereas the material of the vessel conformed to SA 533, Gr B. Since the materials were of different ASME specifications, the licensee conducted an attenuation measurement during the inspection, to estabiish acoustic similarity between the calibration block and the steam generator material. The block material was found to be acoustically
. similar to the vessel material. *However, for the second ten year interval the licensee requires relief from the NRC on the 1986 code requirement that the calibration _block be made of the same material spee!fication as* that of the componen The quality assurance coverage of the licensee's inservice inspection activities was considered to be adequat * *
- Conclusion For those areas inspected, the licensee's ISi program complies with the regulatory and the ASME Code *requirement. The licensee demonstrated acoustic similarity between materials of the calibration. block and the steam generator vessel during the inspection.*
. Entrance and Exit Meetings Members of the licensee's management, engineering arid technical staff were informed of the scope and the purpose of the inspection at the.entrance meeting which *took place on December 17, 1991. The findings of the inspection were presented to and discussed with members of the licensee's management at the conclusion* of the *
inspection on December 20, 1991. A list of exit meeting attendees is appended to this report as Attachment I*
!
. ATTACHMENT I Public Service Electric & Gas M. Morroni E. H. Villar J. R. Wray W. R. Schultz P. P. J. O'Donnell D. Poucks
- M. Prystupa
. M. Shedlock C. J. Conner E. Krufka P. J. Duca C. A. Vondra
- Title/Organization Salem Tech. Dept. Manager I PSE&G Station Licensing Enginee.
Radiation Protection Engineer I PSE&G Manager - Station QA I PSE&G.
Salem Operation Engineer I PSE&G Principal Training Superyisor I PSE&G RPE I Hope Creek Salem Maintenance Manager. *
Sr. ISI Supervisor I Site Services*
Salem Site E.ep. I Atlanta Electric Salem Site Rep. I Delmarva Power General Manager Salem Operations U.S. Nuclear Reguiatory Commission R. L. Nimitz P. Patnaik S. M. Pindale Sr. Radiation Specialist l NRC Reactor Engineer I NRC Resident Inspector I NRC