IR 05000353/1987005
| ML20214V341 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/27/1987 |
| From: | Kaplan H, Strosnider J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20214V329 | List: |
| References | |
| 50-353-87-05, 50-353-87-5, NUDOCS 8706120058 | |
| Download: ML20214V341 (4) | |
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i U.S. NUCLEAR REGULATORY COMMISSION l
REGION I
Report No.
50-353/87-05
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Docket No.
50-353 l
License No. CPPR-107 Category A
Licensee:
Philadelphia Electric Company 2301 Market Street Philadelphia, PA 19101 Facility Name:
Limerick Nuclear Generating Station, Unit 2 Inspection At:
Limerick, Pennsylvania
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Inspection Conducted: April 27-30, 1987 Inspectors:
Id 9, D udh ib,T!F T H. ( Kaplah, Lead Reactor Engineer date I Materials & Process Section, EB, DRS Approved by:
5/' t7/87
. R. Strosnider, Chief, Materials &
date Process Section, EB, DRS Inspection Summary:
Inspection on April 27-30, 1987, (Report No. 50-353/87-05)
Areas Inspected: A routine, unannounced inspection was conducted of activities related to the installation of the Control Drive Rod (CRO) housings to Reactor Vessel (RV) stub tubes and the fabrication of the Feed Water (FW) thermal sleeve-sparger assemblies.
Welding and inspection of these items were being performed by General Electric personnel.
Results: No violations were identified.
0706120058 870601 PDR ADOCK 05000353 G
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DETAILS 1.
Persons Contacted 1.1 Philadelphia Electric Company D. A. DiPaolo, Quality Assurance Branch Head J. Pidgeon, Quality Assurance Engineer 1.2 General Electric S. S. Filippo, Quality Control Supervisor
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M. A. Quirin, Project Manager 1.3 Bechtel G. C. Kelly, LS QA Engineer 1.4 US Nuclear Regulatory Commission
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R. A. Gramm, Sr. Resident Inspector 2.
Inspection Purpose and Scope The purpose of this inspection was to review and observe the activities involving the installation of the control rod drive (CRO) housing into the reactor vessel (RV) and the fabrication of the RV feed water (FW) thermal sleeve-sparger assemblies.
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Control Rod Drive Housing to Reactor Vessel Head Stub Tube Installation The bottom head of the reactor vessel was required to conform to ASME Code Section III, Class I requirements. The stub tubes had been previously welded to the bottom head by Chicago Bridge and Iron, the vessel manu-facturer. The inspector reviewed typical certified test reports (CTRs)
for the housings and stub tubes and verified that the materials conformed to the designated SA materials specifications as required by engineering specifications.
For the housings, the materials conformed to SA312 GR.304 stainless pipe and SA182 GR304 fittings as specified in GE specification 22A2526 Rev. 1.
For the stub tubes, the material conformed to SB-167 Ni-Cr-Fe (Inconel) as specified in GE specification 21A9340.
The parts were assembled by inserting the CR0 housings through the stub tubes to their prop.er height above the 10 of the reactor vessel head and welding to the stub tubes.
The tubes were machined to provide for a "J" type reinforced fillet weld in accordance with GE drawing 197R626. Welding was performed in accordance with GE welding procedures LMI-WPS-8.43.1 Rev. I and LMI-WPS-8.43.2 Rev. 4 * which specified a combination of manual and automatic machine tungsten Inert Gas (TIG) welding processes; the former procedure for the root pass and the latter for the succeeding layers.
Rev. 3 was revised to delete a coated electrode designation to satisfy
an inspector's observation that only a bare wire designation (ER Ni Cr-3) is appropriate for the TIG process. A coated electrode was not and physically could not have been used in the automatic welding process.
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o The inspector witnessed portions of automatic welding of three housings to stub tubes using two machines at locations #2247, #2651 and #3055 in the RV head. The inspector confirmed that the welding parameters as registered at the ARC welding machine control panel during welding of housing assembly
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These included critical parameters such as amperage, voltage, excursion, and dwell times.
During the time (approximately h hour) the inspector observed the automatic
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welding of these three joints, two welding machines operated continuously without interruption except for setting the machines and checking alignment between layers. This interval allowed the weld to cool below 350*F, the maximum specified interpass temperature, prior to starting a new layer.
The inspector witnessed the alignment check during welding of one of the housings.
Lateral movement is determined by a surveyor's scope located on the core plate above the housings. After the magnitude and location of the misalignment is determined, the welder is instructed as to where to place the next bead, i.e. the side of the housing where the pull is desired.
Dimensional requirements are specified on GE drawing 166B8703.
The inspector visually examined portions of the automatic welds and found them free of visible surface defects.
The inspector witnessed liquid penetrant inspection and ultrasonic examination of the completed weld joint #2247 in accordance with Procedures 18XA2400-Rev. 1 and 18XA2500-Rev. 1, respectively.
No reportable indications were observed by either method.
In the case of UT examination the housing is filled with demineralized water and the examination is performed on the ID of the housing in the area coinciding with the fillet weld. The UT transducer is attached to the end of a rod which is inserted through the capped end of the housing, and manually manipulated around the circumference of the housing.
Prior to the examination of the housing, calibration of the instrument was established by the QC inspector using a mockup simulating the CRD housing-stub tube geometry.
The UT examination is not a Code requirement, but is required by GE installation specification 22A2673, Rev. 5.
The inspector reviewed the following records and documents pertaining to the CRD housing-stub tube welds.
These included weld procedure qualification record (PQR-23821), QC inspector certifications, base metal certifications (housing SA 312 GR 304 Ht. 58057 and SA 182 GR F304 and (Ht. 633023) stub tube SA 167 Ni-CR-Fe Ht. NX2698), filler metal certifications (ER NiCr-3-Hts.
97217 and 2362T382V) and Joint Process Control Sheet #2247. No deficiencies were noted in the review of these documents. As of May 1, 1987, GE had completed 164 of 185 housing to stub tube welds.
No violations or unacceptable conditions were identified.
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Fabrication of the Feedwater Thermal Sleeve to Sparger Assembly The inspector observed the welding of one (#270) of six feedwater thermal sleeve to sparger assemblies in the GE weld shop. Welding consisted of joining the fabricated type 316L stainless steel thermal sleeve to a type 316L stainless steel sparger. ASME iection III and IX requirements were
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specified in Section 4.5.2.1 of the FSAR for reactor vessel internals. The material (316L SS) and the joint geometry (full penetration joint) were specified in GE drawing 112D1782. The thermal sleeve was welded to an approximate 4" long reducing tee, extending from the midpoint of the sparger using the manual TIG process in accordance with GE Procedure LMI-WPS-8.8-3, Rev. 1.
The root pass was deposited by fusing an insert.
The inspector visually examined the back side of the root pass with a long handled mirror and intermediate and final layers and found no visible defects. The inspector requested that the weld reinforcement be measured since some portions in these areas appeared to be excessive. The rein-forcement was found to be <1/32" which conforms to ASME III requirements.
The inspector witnessed liquid penetrant inspection of the final layer in accordance with GE Procedure 18XAdOO, Rev. 1.
No penetrant indications were observed. Alignment of the thermal sleeve was checked between layers to allow for bead placement of succeeding layers to compensate for lateral movement.
This time interval allowed the weldment to cool below the maxi-mum specified interpass temperature of 350 F.
The precise placement of weld beads accounts for the uneven weld reinforcement.
The inspector reviewed records, certifications and documents relating to the subject weld. These included weld procedure qualification record (ISE-Q-44),
welder performance certifications and the QC inspector certification, base metal certifications (sparger ASTM A 403 GR. 316L-Ht.P11237 and thermal sleeve ASTM A 312 GR.316L Ht. 464851) and filler metal certification (308L-Ht. 464437).
No violations or unacceptable conditions were identified.
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Quality Assurance I
GE's Quality Assurance Department was found to have actively participated
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in the welding of the subject assemblies. A review of QA documents pertaining to the subject welds showed QC sign offs in the applicable Joint Process Control Steels at critical stages of welding. QC attributes inspected included cleanliness, fitup and liquid penetrant inspection.
The inspector also reviewed the NCRs generated to date; nine (9) for the
CRD housing-stub tube and two (2) for the thermal sleeves. Two of these eleven involved weld defects in the CRD housing welds; the remainder were dimensional. None of the conditions represented significant material deficiencies. Audit reports gene.ated by the licensee (4) and Bechtel (1)
were reviewed by the inspector.
The audit reports were found to be thorough and covered all phases of installation including welding, filler metal control, liquid penetrant inspection and ultrasonic examination.
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Exit Interview i
An exit interview was held on April 30, 1987 with members of the licensee's staff as denoted in Paragraph 1.
The inspector discussed the scope and findings of this inspection. At no time during this inspection was written material provided to the licensee by the inspector.
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