ML023120156

Conference Call to Discuss Quad Cities ISI Program CRD Welds

ML023120156
Person / Time
Site:	Quad Cities
Issue date:	11/06/2002
From:	Chan T, Jones, Kurth M, Lyon C, Raghavan L, Ring M, Wichman K Office of Nuclear Reactor Regulation, NRC/RGN-III
To:	Beck, Chrissotimos, Deboo, Gesior, Hiens D, Nicely, Simpson, Wojick Exelon Corp
References
Download: ML023120156 (13)

Text

11/6/02 10AM (EST)

Conference Call to Discuss Quad Cities ISI Program re: CRD Welds

Participants:

NRR: Chan, Wichman, Raghavan, Lyon Exelon: Simpson, Gesior, Deboo, Hien Do, Wojick, Nicely, Beck, Chrissotimos Region IIl: Ring, Jones, Kurth Status: Unit 1 began an RFO yesterday. Unit 2 completed its last RFO on 3/5/02. The 3rd ISI interval for Units 1 and 2 ends in February and March 2003, respectively. The 1989 Edition of the ASME Code is the applicable Code for the current ISI interval.

Before the call, the licensee provided design information that they felt supported their use of Section Xl, IWB-1220, to exempt the CRD housing welds from volumetric or surface examination (see attached pages). The welds have never been in the licensee's ISI program.

During the call, the staff stated that it had reviewed the information provided and concluded that Section XI, Table IWB-2500-1, Category B-O, Item B14.10 (Reactor Vessel - Welds in CRD Housing), applies to the Quad Cities CRD housing welds.

Therefore, the welds should be included in the ISI program.

The licensee stated that they agreed that Table IWB-2500-1 applied to the CRD welds, but their interpretation was that the exemption of IWB-1220 also applied. The staff stated that IWB-1220 does not apply, because the CRD housing is considered part of the reactor vessel. The staff has discussed the issue with members of the applicable Code committee. Also, the staff is aware that PWRs and at least some BWRs (e.g.,

Fermi) include the welds in their ISI programs. The licensee may, of course, pursue a Code interpretation.

The licensee stated that they understood the staff's position and would evaluate their options and let us know as soon as they decide a course of action.

QUAD CITIES CRD HOUSING WELDS CODE OF RECORD AND DESIGN SPECIFICATIONS ADDITIONAL INFORMATION 11/01/02

Purpose:

To provide design information to support use of ASME Section XI 1989 Edition, Subsection IWB-1 220 "Components Exempt from Examination" to exempt Category B-O CRD Housing welds from volumetric or surface examination.

Basis:

The design specifications for both: (1) the Quad Cities reactor vessel (i.e., General Electric Specification 21A1 113, Revision 1, dated September 20, 1966), and (2) the control rod drive housing (i.e., General Electric Control Rod Drive Housing Design Specification 919D260, dated December 9, 1969) were evaluated to determine the basis for exempting the CRD housing welds from volumetric or surface examination.

Specific details from the two design specifications are discussed below.

Reactor Vessel Desiqn Specification The design code of record for the Quad Cities Vessels is ASME Section III 1965 including Summer 1965 addendum as described in UFSAR section 5.3 Reactor Vessels.

The applicable Design Specification for the vessel is General Electric Specification 21A1113, revision 1, dated September 20, 1966, page 3 of 34 section 5.1.6 presents information on control rod drive penetration nozzles on drawing 886D485. Drawing 886D485 depicts the control rod drive penetration nozzle (stub tube) installation as being an integral part of the vessel. The vessel design specification does not include a glossary or definition section.

CRD Housing Design Specification General Electric Control Rod Drive Housing Design Specification 919D260, dated December 9, 1969 defines the functions, design requirements and operating conditions to provide a complete basis for design, construction and inspection in accordance with the ASME BPV Code Section II1. Section 5.2 page 5 of this specification provides the construction and inspection requirements of the control rod drive housings by referring to drawing 919D260.

Note' from drawing 919D260, for the control rod drive housing welds (this corresponds to the attached simplified drawing welds CRDH 3 and 4) require inspection in accordance with ASME BPV Section III 1965 Edition, Paragraph N-462.2(a) (i.e.,

Category B welds).

ASME Code,Section III, 1965 Edition Section N-460, "Design of Welded Construction," subsection N-461, "Welded Joint Category," paragraph (b) defines Category B as "Circumferential welded joints within the main shell, communicating chambers, nozzles, or transitions in diameter including joints between the transition and a cylinder at either the large or small end; circumferential welded joints connecting formed heads other than hemispherical to main shells, to transitions in diameter, to nozzles, or to communicating chambers.1" Footnote1 : Communicating chambers are defined as appurtenances to the vessel which intersect the shell or heads of a vessel and form an integral part of the pressure containing enclosure, e.g., sumps.

==

Conclusion:==

The control rod drive housing welds as described in the design specifications for inspection of welds are considered communicating chambers and are appurtenances to the vessel. Therefore, the welds are not part of the reactor vessel, and ASME Section XI 1989 Edition, Subsection IWB 1220 "Components Exempt from Examination" Category B-O Housing welds may be invoked.

Attachments:

1.

UFSAR Section 5.3.1 "Reactor Vessel Materials," page 5.3-1

2.

RPV design specification 21 1A1 113, Revision 1, dated September 20, 1966 (Table of Contents and page 3 of 34)

3.

CRD housing specification 919D260, dated December 9, 1969 (page 5)

4.

CRD Simplified Drawing entitled "CRD Penetration and CRD Housing"

5.

ASME Code,Section III, 1965 Edition (cover sheet and pages 46-47)

6.

Drawing 886D485 "Reactor Vessel" (NOTE: PDF is partial drawing)

7.

Drawing 919D260 "Control Rod Drive Housing" (NOTE: PDF is partial drawing)

QUAD CITIES -

UFSAR 5.3 REACTOR VESSELS This section presents pertinent data on the Quad Cities reactor pressure vessels (RPVs).

Unless otherwise noted, the information presented applies to both Unit 1 and Unit 2 RPVs.

5.3.1 Reactor Vessel Materials 5.3-1 The RPV materials and fabrication methods conform to the ASME Boiler and Pressure Vessel Code (ASME Code) 1965 Edition and the Summer 1965 Addendum as referenced in Section3.2.8.4. Inservice inspection (ISI) techniques conform to ASME Section XI with approved exceptions as' noted in Section 5.2.4.

5.3.1.1 Material Specifi'ations Reactor vessel material specifications are discussed in Section 5.2.3.1. Additional information on RPV Materials is contained in Section 5.3.3.2.

5.3.1.2 Special Processes Used for Manufacturing and Fabrication 5.3.2 The Quad Cities Unit 1 RPV was fabricated entirely in the United States by Babcock &

Wilcox (B&W). The Unit 2 RPV was fabricated by several different vendors, including one in Holland, as noted in the following paragraphs.

5.3-2a Fabrication work on the Unit 2 bottom head assembly and lower shell course was performed by the Rotterdam Dockyard Company (RDM) in Rotterdam, Holland. These two pieces were seam-welded together and returned to the United States as a fully completed subassembly including control rod drive (CRD) stub tubes, shroud support skirt, and vessel support skirt.

The CRD stub tube material is Inconel SB167, Code Case 1336, Paragraph 1. The stub tubes were joined to the vessel bottom by a weld on the Inconel-clad surface which makes a full penetration of the stub tube wall as specified in Figure N-462.4(e) of the ASME Code, 1965,Section III. The toe of this weld was removed by the finished counterbore.

All work on Unit 2 was performed and documented in accordance with ASME Section III.

The procedures required by the attachment to the National Board of Boiler and Pressure Vessel Inspectors' letter of July 24, 1968, were implemented by providing the Illinois State Board of Boiler Rules with the required documentation. This documentation included copies of all welder qualification test reports and performance test reports for each welder.

All other components of the Unit 2 core internals and primary system were of domestic manufacture. For example, B&W completed the circumferential seam weld which attached the upper shell course to the RPV flange.

5.3-1 Revision 6, October 2001

-U 0o "GENERAL m ELECTRIC ATU1C P=ZR EQUIPMENT V'r?.

P.). 9MX 254 171 CURTNER AVENUE im AN E. cAuw~ftR1 PROJECT' QUAD-CITIES SPECIFICATION AND REV. NO.

21AI113, Revision 1 9-22d6 DATE SPECpICATION TITLE REACTOR PRESSURE VESSEL TABLE OF CONTENTS SECTION TITLE PAGE 1.0 SCOPE 1

2.0 RESPON'SIBILITY 1

3.0 GENERAL DESCRIPTION 1

4.0 CODES 2

5.0 DESIGN REQUIREMENTS 3

6.0 DESIGN ANALYSIS 6

7.0 CONSTRUCTION 8

8.0 MATERIALS 12 9.0 FABRICATION 17 10.0 INSPECTION AND TEST 20 11.0

-PREPARATION FOR SHIPMENT 30 12.0 SUBMITTALS 31 ATTACIHENT A -

INSTRUCTION MANUAL, DRAWING & DATA REQUIREMENTS ATTAC101ENT B -

MATERIAL TESTS AND TEST SPECIMENS ISSUED BY PROD.UCTION.AND. S O':TROL ATPE-134 (9-62)

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D~wew1e TIT LI REACTOR PRESSURE VESSEL 5.0 DESIGN REOUIREENTS iI 5.1 Operating Conditions 5.1.1 Internal Pressure Design Pressure:

1250 puig at bottom of the reactor vessel Normal Operating Pressure:

1000 paig at top of reactor vessel 5.1.2, Temperat~ure Design Temperature:

5750F Normal Operating Temp.:

546"F 5.1.3 Reactor Core and Internal Weight The weight of the reactor core and internal structure, centers of gravity and distribution of loadings are shown on Drawing 8861)485.

5.1.4 Water Weight The weight of water contained in the vessel for various conditions of operation are presented on Drawing 88611485.

5.1.5 Pipe Reactions The Buyer shall provdp the Seller with the p-ipw reactions which the connecting piping will apply to all nozzles with a nominal size larger than the reactor vessel wall thickness and those nozzles which in addition are subjected to significant thermal cycling.

The reactions will be limited by the Buyer such that the combined stresses due to pipe reactions and design pressure in the vessel shell at the nozzle attachment will not exceed the design stress allowed by the ASME Code,Section III.

These pipe reactions shall be used in the detailed stress analysis required by the Code and performed by the Seller.

This analysis shall include the thin section of the nozzle in the vicinity of the weld preparation for connecting piping, any bi-metal weld and shall take into account the nozzle cladding.

5.1.6 Control Rod Drive Weight and Reaction The momentary reactions which are suddenly applied to each control Rod drive housing in the vessel bottom head are presented on Drawing 886D485.

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%CSWC SPYCIFICAUl-i 3.2 The eomstrwetlom &Ad ii~spection of the drive houstnts must to to accordeance with all of the i Zrejaeqfts xivrn by the brawtint 919?12&Q.O Q, Ml I or CA and associated drawings, *ptetticettons, processes, and Procedures.

5.0 rwSCaItIFzaC oRi PTCI The control rod drive housings are lastallod through vertical penetrattons Irn the lower bead of the 'reactor pressure vessel &n4 are welded to sltai tubes iNolte the v~sute.

The destgn, fabrication and Inspection requirements for the attac%

swat *ise covered by th, reactor vessel design specltflatlon for each p~.anr.

T1ý- portion of sac% koustng which Is above the wreld 1to-.b stub tub. £o pot coveted by the AS!C boiler and Pressure Vessel Code, state failure. could 04t release prtmary reactor water to the atmosphere siarowid~n the bous!ait.

The portion oft tie housi WSIch Is below she wreld to the stub tub* contains Ishe ivecber pzesspjrg and supports the me1Rh5 of the control sod drive sad tloe tontrol T&* cntrol "Id drives which ae"t Uhe reqVlrements of SzPeClflcgttcs 257XA33 ar. b'olt4 to tie fi~ame located at the lover ead of each hous Ij rte drive is sesled to t&U houstag bW setallic '0" rls* per Pro-do~g 3;;0h; P~1 WSaG

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"m~t be provided &t fAe Inside ileatter of %be dri-ve bouusig fi.sog. to e&1cv ror 04e usatafletiom of, %he key btach permits asiel mov~eat due %* thermal ehrpa&sio' ii fer~asee. bettvtee the hmsUua 0ad 0benmsI sleeve, bUt prevetst rotatios ir the tberssl sleeve vtich eoulJ "20-ch it tne the control rO4 "44lt tobe base.

noe r~yoae of the-thermal sleeve ts to reduce tbe spoperstar~e pt"isct L04 r-e.ILLrag UthrAI stresss perOAs the bo0sIj wall PertIczarel2 as tbe weld of the hevsim to the Bubk tube.

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IIO1IE AND PRIESSURIE VESSEL CO)EF SECTION Ill.

Rule~s for Constructioin. of'-

• NUCLEAQ VE70L 4

1965E Iiiion RlEPOR~T OF SUBCOMMITTEE OF BOILER AND PRESSURE VESSEL cO~It%=TEE 9.

THE. -AMERIICAN SOCIETY OF MECHANICAL ENGINEERIS UNITED) ENGINEERIING CENTER E4 AST' r-OITY-SE,'

E'-,NTIT STRIEE-T, NEW YORK.g N.Y. 10017

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L.Ld3a A SEE PAR.N-461

.FIG. N-461 ILLUSTRATION OF WELVED JOINT LOCATIONS TYPICAL OF CATEGORIES A,B, C, AND D N-460 DESIGN OF WELDED CONSTRUCTION N-461 glelded Joint Category - The term "Cat egory as used herein defines the location of a joint in. a vessel, but not the type of joint. The categories established by this paragraph are for use elsewherei--n this Section of the Code in specifying special equirements regarding joint type and degree of ihtspection for certain welded pressure-joints. Since ýhcse gpecial requirements, which are based on se~ice, material, an'd tMick ness, do not apply to. every welded joint, only those joints to i.hich spetial requirements apply are included in the categories. The special re quirements will apply to'joints of a'given cate gory only when specifically so stated. The joints included in each category' "are designated as joints of categories A, B, C, and D. Fig. N-461 illustrates typical joint locatiopA included in each category.

(a) Category A -

Longitudinal welded joints within the main shell, communicating chambers,'

transitions in diameter, or nozzles; any welded joint within a sphere,.ivithin a formed or flat head, or within the side plates 2 of a flat sided vessel; circumferential welded joirits connecting hemi spherical heads to main shells, to transitions in diameters, to nozzles, or to communicating chambers."

(b) Category B - Circumferential welded joints within the main shell, com'municating chambers, I nozzles, or transitions in diameter, including joints between the transition and a cylinder at Communicating chambers are defined as appurtenances to the vessel which intersect the shell or heads of a vessel nsd form an integral part of the pressure contsiniag en closure, e.g.. Pumps.

2 Side plates of a flat sided vessel are defined us any of the list plates forming un integral part of the pressure con taining enCloagure.

either the large? or small efd; circumferential welded joints connecting formed heads other than hemispherical to main shells, to transitions in di ameter, to nozzles, or to communicaiing chambers.',

(c) Category C.-- Welded joints connecting flanges, Van Stone laps,.tube sheets, or flat beads to main shell, to formed heaas, to transitions in diameter, to nozzles, or to communicating cham bers' ; any-Velded joint connecting one side plate - to another side plate of a flat sided vessel.

(d) Category D -

W'elded joints.connecting "communicating chambers, or nozzles to main shells, to spheres, to tra..sitions in diameter, to heads, or to flat sided vessels, and those joints connecting nozzles to communicating cbambers 1 (for nozzles at the small end of a transition in diameter, see Category B).

N-462 Permissible Types of Welded. Joints N-462.1 joints of CalegoryA-- All welded joints of f.ategory A as defined in N-461 shall be fully radiogra'phed in accordance with N-624 and shall be full penetration welds between plates or other elements that lie approximately in the same plane (double-welded butt joints). Joints made with consumable inserts. or gas backup or with metal backing strips that are later removed arenccept able as full-penetration-welded provided the back face of such joints r*eets the requirements of N-526.

N-462.2 joints o[ Category B -

All welded joints of Category B as defined in N-461 shall be in accordance with the following and shall be fully radiographed in accordance with N-624:

(a) Full penetration welded joints between plates or other elements that lie approximately in the same plane (doublc-%4cld,.t butt joints). Joints made with consurnable inserts or gas backup or with metal backing strips ihich are later removed 46

N-462. 2 -

N-462.4 are acceptable as full-penetration-wcldcd provided the back face of such joints meets the require ments of N-526.

(b) Full penetration welded joints in which the edges to be joined are prepared with opposing lips to form an integral backing strip, atid full penetration welded joints with metal bncking strips which aie not later removed are acceptable as full penetration-welded, except that the suit ability for cyclic operation must be analyzed by the method of N-415 using a fatigue-strength re duction factor of not less than 2.

M~hen used, backing strips shall be continuous and any splices shall be butt-welded.

(c) Full penetration-welded joints between plates or other elements that have an offset angle not greater than 30 deg, provided such %elded joints are rounded on both sides to a radius of not less than three times the base metal thickness, and provided the joint can be radiographed to the stasdards of N-624.

N'462.3 Joints of Category C -

All welded joints of Category C as defined in N-461 shall be in accordance with one of the following:

(a) Full penetration welds as defined in N-462.1 that are fully radiographed in accordance with N-624.

(1b) Full penetration corner welds similar to Fig. N-462.3, Sketches (1), (2) and (3) that are radiographically examined in accordance with N-624. The radiography of these details requires "special techniques',.-hich may require multiple exposures, and these techniques shall be accept able to the Inspector.

(c) Full penetration corner weld similar to Fig. N-462.3, Sketches (4), (5), and (6) that are radiographically examined in accordance with N-624. The radiography of these details requires special techniques 1, which may require multiple exposures, and these techniques shall be accept able to the Inspector. In addition, the fusion zone and the parent metal beneath the attachment sur face shall be ultrasonically inspected after weld ing in accordance with N-625 to verify freedom from lack of fusion and laminar defects.

N-462.4 Joints of Category D -

All welded joints of Category D as defined in N-461 shall be in accordance with one of the following:

(a) Butt gf elded Attachments-Nozzles may be attached by full penetration butt welds through the wall of either the vessel or the nozzle as shown in Fig. N-162.4(a). The butt weld shall be so located that it can be radiographically exam ined in accordance %%ith N-62t.

(b) Full Penetration Corner Welded Attach maents - Nozzles may be attached by full penctra-tion welds through the wall of either the vessel or the nozzle as shown in Fig. N-462.4(b).

(1) Nozzles attached in accordance with Fig..N-462.4(b), Sketch (6) shall be examined by radiography in accordance with N-624. The radio graphy of this detail requires special tech niques', %%hich may require multiple exposures, and these techniques shall be acceptable to the Inspector.

(2) Nozzles attached in accordance with Fig. N-462.4(b), Sketches (1), (2), (3), (4), (5) and (7) shall be examined by radiography in accord ance with N-621. The radiography of these details require special techniques I, which may require multiple exposures, and these techniques shall be acceptable to the Inspector. In addition, the weld, the fusion zone, and the parent metal beneath the attachment surface shall be ultrasonically in spected after welding in accordance with N-625 to assure freedom from lack of fusion and laminar defects.

(c) Attachment of Connections Using Deposited Weld bletal as Compensation.

(1)

Built-up weld deposits may be applied to either the vessel or the nozzle wall provided:

(a) the deposited weld is radiographically examined before assembly in accordance with N-624, (b) the deposit satisfies the impact re quirements of Table N-332, and (c) the.coefficients of thermal expansion of the base metal, the weld metal, and the connec tion do not differ by more than 15 per cent of the lowest coefficient involved.

Nozzles may then be attached by full penetra tion welds through the wall of either the vessel or the nozzle as shown in Fig. N-462.4(c). This weld attachment shall be so located that it can be examined by radiography in accordance with N-624. Prior to fabricating the vessel, the manu facturer shall demonstrate to the satisfaction of the Inspector the adequacy of the radiographic technique' which is to be used in fabrication.

Ihenever a weld is attached to a plate surface as in Fig. N-462.4(c), the weld, the fusion zone, and the parent metal beneath the attachmcnt sur face shall be ultrasonically ixnmined after Step 1 in Fig. N-462.4(c) in hccordance with N-625 to insure freedom from lack of fusion and laminar defects.

(2) The inner corners of finished openings in

%hich the nozzle necks do not extend beyond the inner surface of the part penetrated, shall be rounded to a radius of 1,4 the required thickness of See ASTM Specification E94-62T. Recommended Practice for Radiographic Testing.

47 ARTICLE 4 DESIGN

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