ML20078D853
| ML20078D853 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 01/07/1995 |
| From: | Potter M GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19311B683 | List: |
| References | |
| 25A5615, 25A5615-R, 25A5615-R00, NUDOCS 9501310023 | |
| Download: ML20078D853 (15) | |
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EIS IDENT:
9' 25A5615 SH NO.1 GENuclearEneryy Revs REVISION STATUS SHEET DOC TITLE SHROUD STABILIZER LEGEND OR DESCRIPTION OF GROUPS TYPE: INSTALLATION SPEC FMF: QUAD CITYI AND II hlPL NO: PRODUCT SUh1MARYSEC. 7 THIS ITEM IS OR CONTAINS A SAFETY RELNIID ITEM YES DC NO O EOUIP CIASS CODE P REVISION C
0 RM41766 JAN 0 7 995 PRINTS TO MADE BY fjg/cff APPROVALS 9y GENERAL ELECTRIC COhfPANY 175 CURTNER AVENUE hf.D. POTTER M.D. POTTER SANJOSE, CALIFORNIA 95125 CHK BY ISSUED R. LOVELL R.J. AHMAN Y1995 CONT ON SHEET 2 9501310023 950116 PDR ADOCK 05000254 Q
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- 1. SCOPE 1.1 Purnose. This specification provides the engineering requirements for installing shroud stabilizers which replace the H1 through H7 horizontal shroud welds in the Quad Cities reactor j
assembiv.
l 1.2 If any conflict exists between this document and any other document referenced herein, this document shall govern.
1.3 This document, along with the reactor modification and installation drawing, defines all the l
engineering requirements for installation of the shroud stabilizers.
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1.4 As used herein, the term " Installer" refers to the company or personnel contracted by the l
Plant Owner to install the shroud stabilizers.
- 2. APPLICAllLE DOCUMENTS 2.1 General Electric Documents. The following documents form a part of this specification to i
the extent specified herein.
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2.1.1 Sunnortine Documents 25A5669, Shroud Stabilizers Design Specification a.
b.
107E5487, Reactor (Modification & Installation) l I
c.
21 A2040, Cleaning and Cleanliness Control d.
D50YP5, Nickel-Graphite Thread Lubricant c.
Il2D6539, Contact, Lower l
f.
112D6506, Lower Stabilizer (lower contact assembly) g.
I12D6537, Contact, Upper h.
I12D6511, Upper Stabilizer Assembly (upper spring assembly) i.
Il2D6509, Tie Rod Assembly j.
I12D6543, Spring, Lower k.
I12D6597, Nut, Lock 1.
I12D6545, Tie Rod-Spring Assembly
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's 25A5615 SH NO. 3 O
GENuclearEneryy nev. 0 2.1.1 (Continued)
Il2D6612, Support, Mid-Shroud m.
112D6607, Mid Support Assembly n.
112D6535, Support, Lower o.
p.
112D6508, Toggle Bolt Assembly q.
112D6532, Washer, Toggle Bolt 112D6531, Nut, Toggle Bolt r.
s.
I12D6523, Pin, Clevis 112D6510, Stabilizer Support Assembly t.
112D5256, Bracket Yoke Assembly u.
I12D6510, Stabilizer Support Assembly v.
112D6524, Alignment Bracket w.
2.1.2 Suoniemental Documents NEDC-31735P GE BWR Operator's Manual - Materials and Processes a.
- 3. DESCRIPTION
.3.1 The purpose of the stabilizer installation is to structurally replace horizontal girth welds H1 through H7 in the shroud; weld designations and the design requirements for the stabilizers are defined in the Design Specification, Paragraph 2.1.la. The installation of the shroud stabilizers involves electric discharge machining (EDM) of some slots and holes in the existing structure, assembling the stabilizer hardware in the reactor, and preloading the threaded fasteners. No structural welding or defect removal by machining are involved.
- 4. RESPONSIBILITIES 4.1 The Installer shall accept full responsibility for his work. The Installer shall comply with the requirements of this document and the supporting documents listed herein.
4.2 The Installer shall take the responsibility for coordination of his work with the work of others l
including the coordination of work planning and radiation monitoring with the Plant Owner, l
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25A5G15 SH NO. 4 ED REV. 0 4.3 The Installer shall be responsible for providing all specialized handling, alignment, and installation equipment, as may be necessary to perform this work, except as otherwise agreed to by the Plant Owner.
4.4 The Installer, except as otherwise agreed to by the Plant Owner, shall be responsible for machining as specified and limited by the applicable modification drawing.
4.5 The Installer shall supply adequately qualified personnel for supervision and for performing the tasks required to complete the stabilizer installation.
- 5. REQUIREMENTS 5.1 General 5.1.1 During installation, the installer, except as otherwise agreed to by the Plant Owner, shall complete data sheets and quality control checksheets as required by the specifications and instructions listed in this document. The Installer shall also keep log notes, records, etc., for future reference. Video tapes shall be taken of the completed repair. Tabular data entries designated for as-built measurements on the installation drawing shall be recorded.
5.1.2 Procedures and installation equipment shall be developed and designed to minimize the potential ofloose parts within the RPV.
5.1.3 Following completion of the installation of the stabilizers, verification, inspection and signoff shall be performed to ensure that all objects have been removed from the RPV.
5.1.4 All uncontaminated tools shall be stored in an uncontaminated controlled area and l
brought to the work area only as needed for fit-up and installation.
5.1.5 Refer to Paragraph 2.1.2.a for miscellaneous consumahles approved for use in the reactor i
vessel.
5.2 Personnel Safety l
5.2.1 Radiation Control 5.2.1.1 All work shall be done with the concurrence of au aer the instructions of the authorized site Health Physics Personnel. At no time shall their requh.ments for dosimeter monitors, j
protective clothing or devices, time limits, exposure limits, etc., be violated.
5.2.1.2 Machining on contaminated surfaces, as required, shall be done in accordance with Health Physics and Safety Personnel requirements.
5.2.1.3 Radiation control practices shall be used to reduce exposure to workers to levels which are as low as reasonably achievable (ALARA).
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25A5615 SH NO. 5
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l 5.2.2 Safety Precautions l
5.2.2.1 Concern for personnel safety shall govern all work operations. All personnel working in hazmdous locations shall be under constant surveillance by other personnel. All electric equipment shall be grounded or double insulated. Welding cables and leads shall be in good condition.
l 5.2.2.2 All work areas shall be kept neat and orderly. Protective measures and devices shall be l
used to keep all tools, equipment, and materials from inadvertently dropping into the RPV.
5.2.2.3 Care shall be exercised to keep contamination of articles which must enter and leave contamination zones to a minimum. In all cases, site radiation control requirements shall be met.
5.3 Cleanine and Cleanliness Control 5.3.1 During this stabilizer installation program, cleaning and cleanliness control shall be in accordance with the document listed in paragraph 2.1.1.c. In addition, no graphite lead pencils are allowed to contact stainless steel and nickel alloys.
5.4 Prereouisites j
5.4.1 Jet Pump Throat Covers. Prior to the shroud stabilizer installationjet pump throat covers shall be installed as required.
5.4.2 Reactor Temperature. The reactor water temperature shall be less than 100*F, however the l
RHR shutdown cooling flow must be off whenever the installadon activity in progress involves l
critical remote underwater handling in the annulus area.
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- 6. INSTALIATION REQUIREhfENTS 6.1 The installation sequence described below is not itself mandatog, so long as all specified installation requirements are accomplished. To assist in evaluating alternative sequences, the intent of some requirements, which are not self evident, are summarized in the step description.
l 6.2 Install protective shielding for the feedwater sparger and core spray line.
NOTE: The below step is a contingency, which will only be performed if there is insuflicient clearance to complete the installation.
6.3 Go-gage checks shall be performed to ensure there are no weld fillets that interfere with the inspection of the lower spring.
6.4 Using go, no-go gage, assure that there is at least 0.6 inches of clearance between the shroud and each of the ten (10) jet pump riser braces. If there is less than 0.6 inches clearance, measure the clearance and report it to GENE Engineering for disposition prior to installation.
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GENuclearEnergy nev. 0
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6.5 hicasure and record the annulus width at the top guide support ring and at the core support ring elevations as shown on the 107E5487 modification and installation drawing. Examine the RPV and shroud contact areas to assure that there are no abrupt discontinuities; if so, EDhi spctface these areas flush. The vessel and shroud contact locations of the final stabilizer parts shall be simulated in taking these measurements.
l CAUTION: Several piece parts are to be machined based on in-reactor l
measurements at a specific reactor azimuth. These parts shall then be i
designated by specific serial number, as recorded on the as-built data table l
on drawing 107E5487, for that specific azimuth.
6.6 Based on the in-reactor measurements, machine the RPV contact surface of the lower contact, drawing 112D6539 as shown on the 107E5487 modification and installation drawing.
Assemble the lower contact as shown on the lower stabilizer assembly, drawing 112D6506.
6.7 Based on the in-reactor measurements, machine the RPV contact surface of the upper l
contact, drawing 112D6537, as shown on the 107E5487 modification and installation drawing.
l Assemble the upper contact as shown on the upper stabilizer assembly, drawing 112D6511.
6.8 Working in the equipment pool, locate the proper datum on the shroud as shown on the 107E5487 modification and installation drawing, hiachine (EDht) slots in the shroud as specified on the 107E5487 modification and installation drawing.
6.9 In accordance with the 107E5487 modification and installation drawing, machine (EDhi) two holes in shroud support plate. EDhi swarf shall be captured to the maximum extent practical.
6.10 Hone the holes in the shroud support plate. To assure the removal of microfissures from the EDh1 hole in the shroud support plate, the hone operation shall remove a minimum of 0.005 inch from the inside surface of the hole while meeting the final hole size requirement on the 107E5487 modification and installation drawing.
6.11 Installlower support,112D6535, over the two shroud support plate holes using two toggle bolt assemblies,112D6508, and two toggle bolt washers,112D6532, and two toggle bolt nuts, 112D6531, and the two lock nuts,112D6597, as shown on the 107E5487 modification and installation drawing. Lubricant (D50YP5B) shall be applied to the threaded surfaces. Tension the two toggle bolts to the specified load, tighten the toggle bolt nuts and Jghten the lock nuts.
Inspect to verify the installation of the lower support. Crimp the toggle bolt lock nuts, and inspect for proper crimping of the retainers.
6.12 Install the clevis pin,112D6523,in the mating hole of the lower support in accordance with the requirements of the 107E5487 modification and installation drawing.
N 25A5615 SH NO. 7 W
GENuclearEnergy nev. 0 6.13 Complete the tic rod-spring assembly. Assemble the tie rod, assembly drawing 112D6509, with the lower spring, drawing 112D6543 (drill pin hole and install lock pin), and the lower l
stabilizer, drawing 112D6506 as shown on the tie-rod spring assembly drawing 112D6545 (lower l
stabilizer is rotated 180 from that shown on drawing). Lubricant (D50YP5B) shall be applied to the threaded surfaces.
6.14 Temporarily protect the exposed tie rod thread from damage.
CAUTION: Maneuvering of the tie rod-spring assembly must be done with l
extreme care to tvoid damaging reactor hardware such as thejet pump sensing lines.
6.15 Install the tie rod-spring assembly,112D6545,in accordance with the requirements of the 107E5487 moa..ication and installation drawing. Maneuver lower spring clevis over clevis pin and support vertically.
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l 6.16 Rotate and position the lower stabilizer assembly, '12D6506, as shown on the 107E5487 l
modification and installation drawing. Verify that the lower stabilizer assembly latch is engaged I
in the tie rod slot.
6.17 Position the bracket yoke assembly, ll2D5256,in the reactor vessel at the proper elevation above the tie-rod thread protector. Position the tie-rod to allow passage of the yoke over the end of the tie rod. The yoke is to be suspended at the proper elevation to facilitate assembly with the upper support assembly.
6.18 Position the right-hand and left-hand stabilizer support assemblies, ll2D6510P001 and P002,in the shroud flange holes and install the right-hand and left-hand ends of the yoke,in accordance with the requirements of the 107E5487 modification and installation drawing.
6.19 Remove the temporary thread protection from the tie-rod. While forcing the upper end of the tie rod radially inward, taking up clearance in the bracket yoke's clearance hole, measure the radial gap from the tie rod to the vessel wall at tne mid support elevation. The de rod itself should not be bowed while taking this measurement. The vessel contact locations of'he mid support shall be simulated in taking these measurements. Based on this in-reactor measurement, i
l machine the contact surfaces of the midsupport, drawing ll2D6612,in accordance with the requirements of the 107E5487 modification and installation drawing.
6.20 Install the tie rod nut and torque in accordance with the requirements of the 107E5487 i
modification and installation drawing; continue to force the upper end of the tie rod radially inward during tensioning. Verify that the tie rod nut is properly locked by its retainers.
Lubricant (D50YP5B) shall be applied to the nut threaded surfaces.
6.21 Install the mid support assembly,112D6607,in accordance with the requirements of the l
107E5487 modification and installation drawing. Verify that the mid support latch is enraged in the tie rod slot.
25A5615 SH NO. 8
@MM REV. 0 6.22 Install upper stabilizer (spring) assemblies,112D6511,in accordance with the requirements of the reactor modification drawing. Lubricant (D50YP5B) shall be applied to the 0.50 inch slot areas and thejacking bolt (threaded and moving surfaces). Engage with stabilizer support assembly and adjust thejacking bolt as specified on the 107E5487 modification and installation j
drawing to preload the upper spring. Check that the spring retainers are properly engaged to j
lock thejacking bolt.
6.23 Remove the protective shielding for the feedwater sparger and core spray line.
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6.24 Repeat steps 6.2 through 6.23 for the installation of stabilizer hardware at the remaining azimuth locations.
- 7. EXAMINATION AND TESTING 7.1 Visual Examination. Visually examine the stabilizer iastallation preparations to verify that all of the required holes have been machined in the proper locations and that all debris has been
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removed from the area. Visually examine the installed stabilizers to verify compliance with the 107E5487 modification and installation drawing.
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- 8. RECORDS AND SUBMITTALS l
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8.1 Prior to implementation of this stabilizer installation program, the following procedures shall I
be submitted by the Installer and approved by the Owner.
Installation and inspection procedures including sequence data sheets, measurement data a.
sheets, quality control checksheets, drawings, sketches, instructions, etc..
b.
Cleaning and cleanliness control procedures.
c.
Machining procedures as applicable.
d.
As-built drawing (data required by 107E5487).
8.2 Af ter implementation of this stabilizer installation program, all recorded data records, photographs, video tapes, logs, etc., shall be submitted by the Installer to the Owner for file and information within 30 days. The 107E5487 modification and installation drawing shall be updated to incorporate the in-reactor as-built measurements, and the as-built measurements with corresponding serial numbers of the parts machined as part of the installation process. One copy shall be submitted to GENE within 30 days.
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l EhM 25A5615 SH NO. 9 REV.O FINAL
- 9. DEVIATIONS AND SUBSTITUTIONS i
9.1 All deviations, as a result of damaged equipment, nonconforming conditions', or any proposal by the Installer for substitutions, modifications, or relaxation of the specified materials, procedures or design shall be submitted to the Owner for consideration and j
approval.
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ATTACHMENT B Quad Cities Station Unit 2 Core Shroud Inspection Plan
References:
- 1. NRC Generic Letter 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors" 1
- 2. BWRVIP document GENE-523-113-0894, BWR Core Shroud Inspection and Evaluation Guidelines, dated September 1994.
4.
USNRC Safety Evaluation Report on Boiling Water Reactor (BWR) Core Shroud Repair Design Criteria, dated September 29,1994.
i Commonwealth Edison (Comed) is submitting Quad Cities Station's Core Shroud Inspection Plan for Unit 2 per the requirements of Reference 1. Comed is committed to comply with the additional reporting requirements of GL 94-03 Items 2 (a) and (b), as those items apply to Quad Cities Unit 2.
l The format of this attachment retains the numbering sequence of Generic Letter 94-03.
As stated in the Generic Letter, the NRC has encouraged licensees to follow the guidance developed for this issue by the BWROG (and subsequently the BWR Vessel Internals Project, BWR-VIP).
t Comed is committed to the BWR-VIP. Comed has been and will continue to be an integral part of the BWR-VIP. Quad Cities Station will continue to follow the guidance provided with respect to inspections, flaw assessment, evaluations, and repair options as this guidance is provided. This response provides reference to these documents where applicable. In referencing these items, it is not intended that they supersede the design basis analysis of record at the Station.
Comed has reviewed the BWR-VIP "BWR Core Shroud Inspection and Flaw Evaluation Guidelines" l
(Reference 2) and has concluded that Quad Cities Unit 2 is a Category C plant. As such, a comprehensive inspection of shroud welds 111 through 117 is required. However, Comed will be installing a core shroud repair that structurally replaces the core shroud horizontal circumferential welds til through 117 and accounts for cracking of the 118 weld. The design has been developed considering through wall 360 degree circumferential cracks at the 111 through 118 welds. Quad Cities Unit 2 is presently planning to install the core shroud repair hardware during the upcoming Q2R13 refueling outage. Therefore, the inspection plan has been developed to interface with the shroud repair to assure that structural integrity of the core shroud is maintained.
Reportino Reauirements 2.
No later than 3 months prior to performing the Core Shroud inspections, provide the following information:
2.(a)
The inspection plan requested in item 3 of the Requested Actions.
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ATTACHMENT B (cont.)
" Item 3 of the Requested Actions section of the Generic Letter mquires the development of an inspection plan which addresses:
(a)
All shroud welds (from attaciunents to the vessel to the top of the Shroud) i and/or, provides a justification for the elimination of particular welds from consideration; and (b) examination methods..."
The inspection plan will be implemented during the thirteenth refuel outage for Quad Cities Unit 2 currently scheduled to begin in of March 1995. The shroud inspection will be performed in conjunction with the comprehensive repair of the co'- shroud. The plan has been developed to comply with the Reference 2 guidelines with consideration of implementing the core shroud repair.
The horizontal welds H1 through H7 will not be inspected as the shroud repair design has been developed considering through wall 360 degree circumferential cracks at these locations. The areas of the shroud utilized as anchorage points for the repair will be visually examined (enhanced VT-1) to the extent practical, prior to installation of the repair hardware. This will include portions of the H9 weld adjacent to the shroud support ledge (Reference 3 and 4).
The ring segment welds and the vertical welds will be inspected to the extent necessary to satisfy i
the core shroud repair design requirements. The extent of these weld inspections is based upon the stresses that were established as part of the modification design (Reference 5). See Table 1 for a description of the scope of the core shroud inspections of the design reliant hardware.
The core shroud weld inspections will be accomplished using either enhanced visual examination (VT-1) or ultrasonic examination (UT) techniques or a combination. Where the enhanced VT-1 is solely utilized (with the exceptions as noted in Table 1), both surfaces of the area of interest (ID and OD) will be examined. Where UT techniques are utilized, they may consist of 45 degree shear and 60 degree RL wave to examine the far surface and the " creeping wave" UT or enhanced t
VT-1 method to examine the near surface. The " creeping wave" UT will be used in lieu of eddy current (ET) testing due to lack of a qualified technique at this time.
l The preferred inspection method is UT. However, the extent and type of inspections may be affected by accessibility and core shroud geometry. The best available technologies and techniques will be utilized to ensure that the design requirements of the core shroud repair are met with respect to the shroud welds.
Justification for deferring the inspection of the remaining shroud welds, including attachment welds (i.e., shroud to support leg and support leg to bottom head) is provided in Reference 2 guidelines.
2.(b)
Plans for evaluation or repair of the Core Shroud based on the inspection results.
Quad Cities Unit 2 Core Shroud will be repaired by implementing a comprehensive repair as discussed in Attachment A during the upcoming refuel outage (Q2R13). If evaluation of the inspection results is warranted, they will be performed in accordance with the Reference 2 guidelines as well as the repair modification design criteria.
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ATTACIIMENT B (cont.)
Within thirty days from the completion of the shroud inspections, the results will be provided to the NRC staff.
Please note the Quad Cities Unit 1 Shroud Inspection Plan will be submitted at a later date to support the fourteenth refuel outage (QlR14), which is currently scheduled for the Spring of
- 1996, l
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TABl11: Owul Gties Unit 2 Scone of Core Shmud Imnectiom forO2R13 MFU)(note 1)
DESCRII'IlON DESIGN RFBANT INSPFCI1ON ASSIXSMIST FUNCI1ON Shrotrillead 4 segment welds to Tmnsfer of vertical hg is connected by 48 shroud Flange hg form ring loads and resist head bolts to shroud head.12 Segment Welds differential pmssures.
bolts per segment. Visually (VI-V4) hg provides latemt inspect one side of the ring support for shroud.
segment welds (note 2).
Shroud llead Area of notches for Tmnsfer of venical Visual inspection of ama of Flange %g venical connection loads.
attachments.
of repair hardware Venical Welds 3 venical welds Resist differential Design reliant portion of welds between 111-112 fonn shell course pressures. Proside will be inspected.
(V5-V7) lateral stability.
Top Guide 6 segment welds to Transfer of vertical Design reliant portion of welds Suppon Ring form ring loads and resist will be inspected (note 2).
Segment Welds difTerential pressures.
(V8-V13)
Ring provides lateml suppon for shroud.
Venical Welds 3 venical wekis Resist differential Design reliant ponion of welds between 113-115 form each shell pressums. Provide will be inspected.
(V14-V19) course lateral stability.
Core Plate 6 segment welds to Tmnsfer of vertical Ring is connected to core plate Support bg form ring loads and resist via 42 bolts and 4 alignment Segment Welds differential pn:ssures.
pins, ~7 bolts per segment. No (V20-V25)
%g provides lateral inspection of these welds is suppon for shmud.
planned (note 2).
Venical Welds 3 venical welds Resist difTerential Design reliant ponion of welds between 116-117 form shell course precsures. Proside will be inspected.
(V26-V28) lateral stability.
l 1Iorizontal Weld Shmud support Transfer of frictional Inspect weld at four locations to 118 ledge weld to resistance acmss weld verify no separation ofjoint.
l shroud support joint.
cylinder Shroud Suppon Repair hardware Shroud repair Visual inspection of the area of Irdge anchorage anchorage at 4 the attachments.
locations.
Ilorizontal Weld Shroud support Transfer of venical Design reliant portion of weld 119 ledge weld to RPV and horizontal loads to will be visually inspected fmm shell the RPV.
the top side.
Note 1: Reference GE Drawing 105El415B Revision 0 for QC2 Shroud Fabrication Iktails.
Note 2: Analysis is being performed to determine the amount of weld required to resist the applied loads.
The affect of the connected elements (e.g. bolts and pads) will be considered in the evaluation.
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l ATTACHMENT D Quad Cities Station Unit I and Unit 2 Selected Core Shroud Repuir Design Documents Non-Proprietary Version GENE-771-71-1094, Revision 1
" Quad Cities Units 1 & 2 - Shroud Repair Seismic Analysis" Color Picture of Computer Model of Core Shroud Repair at Quad Cities Station l
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GENE-771-71-1094, Revision 1
" Quad Cities Units 1 & 2 - Shroud Repair Seismic Analysis" Non-Proprietary Version l
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