ML20080C098

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Rev 1 to Effects of Intergranular Stress Corrosion Cracking on Operation of Grand Gulf Nuclear Station,Unit 1
ML20080C098
Person / Time
Site: Grand Gulf Entergy icon.png
Issue date: 08/16/1983
From: Adcock W, Angle C, Robert Lewis
MISSISSIPPI POWER & LIGHT CO.
To:
Shared Package
ML20080C095 List:
References
TAC-56304, NUDOCS 8308190073
Download: ML20080C098 (25)
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Text

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, OF  ;

INI'ERGRANUIAR SI'RESS CDRROSION CRACKING ON 'IEE OPERATION OF GEND GUIE NUCLEAR SIATION UNIT 1 Prepared By: .

h) M D [ zi

  • R. S. IAwis '

A. D. Watkins Material Science Engineer Supervisor, Material Science kE]0+st C. W. Ang]g Princi 1 Engineer, Operational Analysis i j

W. F. Adcock Principal Mechanical En r Approved By: / /

. Pinto ger of Nuclear Plant Engineering Initial Issue - August 13, 1983 Revision 1 -

August 16, 1983 B308190073 030817 PDR ADOCK 05000416 P pgg

1 CXNITNTS

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. IDENTIFICATION OF MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. NONOONPDfEING MATERIAL MITIGNTION OR q USED 'IO MINDiIZE IGSOC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 [
4. PRI%TRVICE AND INSERVICE INsm;nON . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. PIANNED FUIURE ACTION FDR MITIGATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6. WATER CHEMISTRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7. IEAK DE'rECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8. JUSTIFICATION EUR OPERATION .................................... 13 SIM ERY ........................................................ 15 APPDOIX "A" - INDIVIDUAL WEID IDENTIFICATION t

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l. INTPODUC'rIOth On July 27, 1983, Mississippi Power and Light Capany (MP&L) received a letter frczn the Nuclear Regulatory Cmmission (NBC) with respect to Intergranular Stress Corrosion Cracking (IGSOC) in the Recirculation and Residual Heat Bernoval Piping Systans (reference letter to J.P. McGaughy Jr.

- MP&L .frun D. G. Eisenhut - NDC, Docket No. 50-416) . 'Ihe NRC has concluded that BWR facilities with non-conforming (Service Sensitive per ,

NUREG-0313, Rev. 1) materials may be susceptible to IGSCC, which may be T unacceptable ~ for continued safe operation without stress mitigation, augmented inservice inspection, repair of affected pipe, and additional surveillance reqairements.

In considering actions relating to the need for the mitigation of stresses, replacement of susceptible piping and augmented inservice irspection, the NBC requested MP&L to subnit the following information:

a. Identify the materials used and special fabricaticm methods ertployed (both in the shcp and in the field) to minimize or mitigate IGSCC in piping systems which form the reactor coolant pressure boundary. Ebr non-conforming materials describe the piping systans, the actions taken or methods utilized (e.g., solution annealing, induction heat stress improvement program, etc.) to mitigate potential IGSOC in the reactor ccolant pressure boundary. If measures are planned to be responsive to this concern, provide a detailed schedule for the ccrrpletion of these actions. (NRC Question #1)
b. Provide a justification for operation with non-conforming materials in the reactor coolant pressure boundary. (NBC Question #2)
c. Describe what preservice inspections have been accmplished which would serve as the baseline for further identification of IGSOC. (NRC Question #3)
d. Describe what programs are to be implarented in water chenistry control to minimize or mitigate IGSOC. (NBC Question f4)

The purpose of this report is to provide a status and surrmary of the Grand Gulf Nuclear Station - Unit 1 (GGNS) reactor coolant pressure boundary with respect to intergranular stress corrosion cracking and to provide a response to each of the above questions. 'Ihe reactor coolant pressure boundary is defined in accordance with the guidelines set forth in the Code of Federal Regulations,10CFR 50.2(v) . In addition, the scope of this sturmary will be limited to circunfrential butt welds whose diameter exceeds or equal 2 inches.

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2. MATERIAL IDD7TIFICATION - (NIC CUESTION f1)

'Ihe GGNS - Unit I reactor coolant pressure boundary consists of the following material, as stated in the Final Safety Analysis Report (PSAR) .

Material variations and/or additions between this data and the Final Safety Analysis Report (FSAR) are indicated by a revisicri bar.

A. RBCIICUIATION SYSTm 'I

[ [ [ [ SPECIFICATION ]

[ omrotafr [ MIN [ MATERIAL [ (ASME/AS E) 1

[ [ [ [ ]

[ Pipe [ Welded [ Stainless [ SA 358, Gr. 304, 1

[ [ [ [ C1. I l

[ [ [ [ ]

[ Pipe [ Seamless [ Stainless [ SA-376, TP 304 1

[ [ [ [ ]

[ Elbow [ Fitting [ Stainless [ SA-403, Gr. WP304W cr ]

[ [ Plate [ Stainless [ SA-240 Gr. WP304IN 1

[ [ [ [ ]

[ Nozzle [ Fitting [ Stainless [ SA-403, Gr. WP 304 ]

[ [ Plate [ Stainless [ SA-240 l

[ [ [ [ ]

[ Flange [ Forging [ Stainless [ SA-182, Gr. F316 )

[ [ [ [ ]

[ Lug [ Plate [ Stainless [ SA-240, Gr. 304 1

[ [ [ [ ]

[ Bolt [ Bolting [ Im Alloy [ SA-193, Gr. B7 1

[ [ [ [ ]

[ Nut [ Bolting [ Im Alloy [ SA-194, Gr. 7, 2H ]

[ [ [ [ ]

[ Safe End [ Forging [ Stainless [ SA-182, Gr. 316L ] l

[ [ [ [ ]

[ [ [ [ ]

2

B. MIN SITAM PIPING

[ [ I I SPECIFICATION }

[ a n par e rr [ mfN [ MTERIAL [ (ASME/ASIM) }

[ _ [ [ I 1

[ Elbow [ Fitting [ Carbon Steel [ SA-420, Gr. WPBW, )

[ .

[ [ [ Code Case 1571 )

~

[ [ [ [ ]

[ Pipe , [ Welded [ Carbon Steel [ SA-155, Gr. KCF70, 1;

[

-[ [ [ Cl. 1 1'

[ [ [ [ A516, Gr. 70 1

[ [ [ [ }

[ Pipe [ Seamless [ Carbon Steel [ SA-106, Gr. B ]

[ [ [ [ ]

[ Elbow [ Fitting [ Carbcn Steel [ SA-234 Gr. WPBW ]

3

[ [ Plate [ Carbcn Steel [ A516 Gr. 70 )

[ [ [ [ Code Case 1571 ]

[ [ [ [ ]

[ Flange [ Forging [ Carbon Steel [ SA-105 )

[ [ [ [ ]

[ Nozzles [ Forging [ Carbcn Steel [ SA-105, Code Case ]

[ [ [ [ 1519 )

[ [ Forging [ Carbon Steel [ SA-181, Gr. II ]

[ [ [ [ ]

[ Ings [ Plate [ Carton Steel [ SA-516, Gr. 70 }

[ [ [ [ ]

[ Nozzles [ Forging [ Carbon Steel [ SA-350, Gr. LF2 )

[ [ [ [ ]

[ Safe End [ Forging [ Carbon Steel [ SA-508, Cl. 1 ]

[ [ [ [ ]

[ [ [ [ ]

3

C. FEEDATER (EW), IDW PRESSURE ODE SPRAY (LPCS), HIW PESSURE COE SPRAY (HPCS), RDCIOR CDRE ISOIATIN CDOLING (RCIC)

[ [ [ [ SPIIIFICATIN ]

[ cmPONENP [ FDfH [ MATERIAL [ (ASME/ASM) 1

[ [ [ [ ]

[ Pipe. [ Seamless [ Carbon Steel [ SA-106 Gr. C ]

[ [ [ [ } ,

[ Pipei ,[ Seamless [ Carbon Steel [ SA-106 Gr. B 1

[ [ [ [ ]

[ Fitting [ Welded [ Carbon Steel [ SA-234 Gr. WPCW l

[ [ [ [ }

[ Fitting [ Seamless [ Carbon Steel [ SA-234 Gr. WPC 1

[ [ [ [ ]

[ Fitting [ Welded [ Carbon Steel [ SA-234 Gr. WPB ]

[ [ [ [ ]

[ Fitting [ Ibrging [ Carbon Steel [ SA-105 1

[ [ [ [ ]

[ Safe Ends [ Forging [ Carbon Steel [ SA-508 Cl. 1 )

[ [ [ [ t

]

[ [ [ [ ]

.t NOTE: Safe Ends Apply to FW, LPCS, and HPCS ONLY.

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D. REACIOR WATER CLEAN UP (IHCU), RESIDtAL HEAT REMNAL (RHR)

[ [ [ [ SPECIFICATION ]

[ CCMPONDTP [ FORM [ MATERIAL [ (ASME/AS'IM) )

[ [ [ [ ]

[ Pipe . [ Seamless [ Stainless [ SA-132 TP304L 1

[ [ [ [ ]

[ Pipe,,' [ Seamless [ Carbon [ SA-106 Gr. C 1'

[ -[ [ [ ]

[ Pipe [ Seamless [ Carbon [ SA-106 Gr. B l I [ [ [ ]

[ Fitting [ Seamless [ Stainless [ SA-403 WP304L 1 I [ [ [ ]

[ Fitting [ Forging [ Stainless [ SA-182 F304L 1 I [ [ [ l

[ Fitting [ Welded [ Carbon [ SA-234 Gr. WPCW l

[ [ [ [ ]

[ Fittings [ Seamless [ Carbon [ SA-234-Gr. WPC 1 I [ [ [ ]

[ Fittings [ Seamless [ Carbon [ SA-234 Gr. WPB ]

[ [ [ [ ]

[ Fittings [ Forging [ Carbon [ SA-105 )

[ [ [ [ ]

[ Safe Ends [ Forging [ Carbon Steel [ SA-508 C1. I 1

[ I [ [ ]

[ [ [ [ ]

NorE: Stainless Steel portions are those small porticos that prwiG connection with the Recirculating Water System.

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3. NUN 00NPORtING 1%TERIAL MITIGATION OR M!' DEES UTILIZED BY GGNS 'IO MINIMIZE IGSOC - (NIC QUESTION 91)

A. Recirculating Water System

1. Mitigation practices employed by the manufacturer for the welding of spool assemblies consisted of:

/ (a) Solution annealing / quenching after welding.

(b) Application of weld inlay (corrosion resistant weld build up) on weld and preparations using Type 308L filler

' materials.

i (c) See Itan 2(c) (Regulatory Guide,1.44) for requirements inposed on the manufacturer by General Electric.

NOTE: See Appendix "A" of this Report for individual weld mitigation techniques.

2. During field fabrication the practices employed to mitigate or minimize IGSOC were:

(a) 'Ihe original Reactor Pressure Vessel (RPV) Safe Ends were I m oved and replaced with SA-182 F 316L with inconel and ER308L butter applied to the weld end preparations.

(b) Weld inlays were applied to the sweepolets on the ring header and RWCU nozzles located on the pe p suction spools.

'Ihe filler material used was Type 308L with ferrite measurements averaging 8.05 per cent miniman. Measurements were taken on deposited weld metal. (See Appendix A for specific weld location).

(c) Adherence to the " Final Safety Analysis Report" Appendix 3A, Regulatory Guides 1.31 Rev. I " Control of Stainless Steel Welding" and 1.44 " Control of the use of Sensitized Stainless Steel". In empliance with the positions taken to these Reg. Guides the following controls were inplanented:

For field fabrications, weld filler materials were required i to have a weld deposit ferrite content of eight (8) per cent miniman. ASME Section III allowable mininun is five (5) percent. All stainless steel welding was performed using low heat input welding processes. Preheat and interpass temperatures were controlled to a 350*F maximan. As an alternate to the testing specified in Reg. Guide 1.44, GE employed process controls to minimize severe sensitizaticm l (i.e., rwhwl weld heat input, control of cold work,

, control of interpass temperatures, and control of solution I

heat treatment) .

(d) Repair of field installed non1nitigated welds was not required. 'Iherefore, additional sensitization and stresses were not induced by redundant welding. Non-mitigated field welds were welded with 3/32 inch and 1/8 inch diameter filler materials.

. _ _ _ _ _ _ _ 9 , _ ____ _ _ _ --. . _ _ _ . _ . ._ . _ . . _ - - _

The welds were installed in the 2G and SG positions (Ref.

ASME Section IX) thus the welding parameters used would be on the lower end or allowable ranges to control weld puddle fluidity. By using the lower of the allowable range (i.e.,

volts and anps) the severity of the sensitization is reduced.

B. Feedwater System ,

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The original Feedwater RPV safe ends were renoved and replaced with SA 508 C1. I with Ni-Cr-Fe weld metal butter applied to the end preparations. Balance of feedwater by original design conforms to material selection requirernents of NUREG-0313 Revision 1. See Part 2(c) of this Report for material identification.

C. Control Rod Drive The Control Rod Drive Return has been removed aM capped at the vessel with Ni-Cr-Fe alloy (Inconel 600) . 'Ihe RPV safe end is SL 508 C1.1.

D. Other Systens The raterials used in the other systans satisfy the mlection requirestents of NUREn-0313 Revision 1. See Part two (2) of this Report for material identification by systen.

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4. PRESERVICE AND INSERVICE INSPECTIONS - (NBC QUESTION 43)

A. The baseline data for GGNS consist of Ultrascnic Examinations (ITT) using procedures meeting the requirerents of ASME Section XI. In addition to the Ur, the ASME Section III Radiographs for both field welds and shop welds are available for baseline data.

B. Etir our first refueling outage the following areas will be enhanced ary1/or developed: [  ;

1. Training of personnel for implementation of Inservice Inspection (ISI) contractor activities.
2. 'Ihe developnent of improved Ur s uce&res for use in the detection and characterization of IGSCE.
3. A program for the demonstration of 17r pwcedures and personnel to assure ability and proficiency in the detection and characterization of IGSOC. The basis for denonstration will be a sa:Tple containing IGSOC obtained frcm Nine Mile Point. The sanple will be characterized using an improved procedure with a proven capability in addition to other Nondestructive Examinations.
4. 'Ihe program for inservice inspection is being developed to include the requirements for augnente3 inspections as specified in NUREG-0313 Rev. 1.

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5. FIRMD FU1URE ACTION FDR MITIGATION - (hPC QUESTION #1)

For those welds not yet mitigated plans are being established that will  ;

initiate mitigation techniques at our first re-fueling outage. Techniques l under consideration are induction heating stress inprovement (IHSI) and last past heat sink welding (LMISW) with eriphasis on IHSI. MP&L has given General Electric approval to proceed with the manufacturer of IHSI coils for use on non-mitigated welds. Future enhancenent (i.e. , hydrogen ,

injection) to water chemistry is dependent on results of research now being perforned.

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6. )RTER QEMISTRY - (NBC CUESTION #4)

Conductivity, chloride and pH are monitored periodically in the primary coolant.

Limits are found in Section 3.4.4 of the GGNS Operating License Manual. 'Ihese limits are within ommonly accepted industry practices and Nuclear Regulatory Otmmission app m ed values.

'Ihe followin'g systes are periodically nonitored for contaminants to maintain the above required water quality of the primary coolant systems. [

Reactor Water Cleanup Systen Control Rod Drive Water Condensate Systm Condensate D mineralizer Effluent Feedwater Suppression Pool Condensate Storage Tank Refueling Water Storage Tank Oxygen concentration limits are not specified in BWR 'Ibchnical Specifications but are included at GCNS as procedural operational requirments for sme systems. In addition to the sanpling and monitoring programs, operational procedures provide Instructions that the feedwater heater drains should not be pmped to the feedwater system until the 02concentration is20-200 ppb.

'Ihe oxygen concentrations in the primary system during operation is expected to be approximately 0.2 ppn. This concentration was used in the GGNS crack growth evaluation (as presented in Section 8A) . Based on the predicted primary system water chemistry, the propensity for IGSOC to occur should be within the bounds of analyzed flaw growth characteristics. In addition, a large safety margin is available to cmpensate for any water chenistry variances that may be expected to occur during plant startup and operation.

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7. IEE DETECTICN - (NBC QUESTION #2) l Several methods of leak detection are used to monitor known and unknown leakage sources at (XNS. 'Ihe follow 2ng reactor coolant leakage systems are required to be operable during plant operation (

Reference:

Technical Specifications, Section 3.4.3.1) .

1) 'Ihe drywell atmosphere particulate radioactivity monitoring system. _

f

2) 'Ihe drywell floor and equipnent drain simp level and floor monitoring systen.
3) Either the drywell air coolers condensate flowrate nonitoring systen or the dryuell atrosphere gaseous radioactivity nonitoring system.

The purpose of the drywell leak detection subsystem is to nonitor various parameters in the drywell and to activate annunciators should the identified or unidentified leakage rates exceed the allowed limits.

(

Reference:

OGNS Safety Analysis Report 7.6.1.4.3.9, "Drywell Leak Detection Status").

The drywell leak detection subsysten consists of the following circuits to monitor unidentified leakage:

. Floor drain nonitoring subsysten. The monitoring subsystem activates annunciators when drain flow, simp level, or simp tatperature exceed predetermined values.

. Airborne radioactivity monitoring. 'Ihe drywell monitoring system activates annunciators when the airborne particulate, iodine, or gaseous activity exceeds predetermined values.

. Drywell air cooler condensate flow monitoring

. Drywell cooler inlet and outlet cooling water tatperature differen

, . Drywell air tstperature nonitoring

. Drywell pressure monitoring

'Ihe drywell leak detection system consists of the following circuits to monitor identified sources of leakage.

. Equipnent drain monitoring subsysten. The monitoring system activates annunciators when the drain flow, stmp level, or sump tatperatures exceed predetermined values.

. Valve sten packing leakoff monitoring

. Recirculation punp seal monitoring

. Reactor vessel head seal monitoring

. Safety / relief valve nonitoring l

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'Ihe Technical Specification Isakage Limits (Section 3.4.3.2) are given below:

(1) tb pressure boundary leakage (2) 5 GN unidentified leakage (3) 30, GH total leakage  ;

/

(4) 2 GH increase in unidentified leakage with any of hour period.

Several diverse means are provided to monitor leakage within the drywell.

Isakage in excess of the limits require controlled shutdown and identification of the source of leakage. Primary systm leakage locations can be identified by radiological means (pipe mears), aishne isotopic analysis, hydrostatic tests, ultrasonic inspection and visual inspection.

Any or all of these mans may be used to identify degradation of the primary systan boundary when leakage exceeds the technical specification limits.

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8. JUSTIFICATION FOR OPERATION - (NRC CUESTION #2)

A. Fracture Mechanics Evaluation of Flaws A preliminary fracture mechanics evaluation was performed by General Electric Ccmpany to conservatively estimate the maxinum expected crack griowth rate of the unmitigated GGNS welds assuming an initial ICBOC flaw existed at plant startup. (

Reference:

"A Fracture Mechanics  ;

Evaluation of Urrnitigated Recirculation Irop Welds in Grand Gulf '

Nuclear Power Station, Unit 1", RSFA #83-45, DRF #137-0010, HSM07,DA, August, 1983). It was further assumed that the postulated crack is circumferential and extends 360" around the ciremference of the pipe with an initial depth of 5% of the pipe wall thickness.

'Ibe purpose of the evaluaticn was to determine if an undetected pre-existing crack could grow to a critical flaw size within the time period between plant startup and the first scheduled refueling outage.

The evaluation was performed in accordance with the recently approved Appendix X to Section XI of the ASME Code, Paragraph IWB-4530,

" Acceptance Criteria for Flaws in Austenitic Stainless Steel Piping".

'Ihe expected crack growth until the next refueling outage ( 2 years) was conservatively based on an assmed 5% initial flaw size. 'Ihe final calculated size was then ecmpared to the allowable value.

'Ihe evaluation methodology used the worst-case stress and material properties information that was readily available frm the ASME Stress report for the twenty-two (22) unmitigated welds of the 034S recirculation piping systan. A review of the primary and sustained stresses at the subject weld locations indicated that the largest ccmbination of pressure, weight, and thermal expansicn occurred at the header-to-cross weld in the 16 inch diameter pipe. Residual axial welding stresses were characterized. Data for residual stresses were taken frm cmbined results of weld stress measurments on large diameter piping reported by G. E., Argonne National Laboratory and Southwest Research Institute.

In addition, crack growth data corresponding to furnace sensitized stainless-steel was used in the G. E. analysis for weld sensitized material in 0.2 ppm oxygenated water. This is a conservative asstoption since furnace sensitized material is worse than weld sensitized material under IGSOC. 'Ihis additional conservatism provides margin to account for fluctuations in water chemistry and l higher oxygen during startup.

l With the assmed initial flaw depth of 5% of wall thickness, the

calculated crack dept at the end of 16,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> ( 22 months l operations tine) is predicted to be 34% of the pipe wall thickness.

'Ihis calculated value of final flaw size is well below the ASME Section XI code allowable value of 63% of wall thickness.

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l B. Icak-before-Break Purther, the crack growth characteristics in BWR pipe, is "binodal" in nature either the cracks are short and deep or long and relatively ,

shallow (Ref.: EPRI Report R.P.1570-2, " Ultrasonic Sizing Capability of IGSOC and its Relation to Flaw Evaluation Procedures", dated August 4/1983). Welded joint flaws can be categorized into two types short, deep cracks that typically occur in snaller 4-12" diameter pipe, and '-

long shallow cracks that typically occur in larger size piping.

'Ihe stress distribution in large joints have a large cmpressive residual stress beginning about 20% through the wall frcra the inside surface and IGSCC growth rate will be significantly reduced in this ccrpressive region. Consequently, IGSCC progresses very slowly and may leak only after having been in service for several years, but the pipe will not break. Major weld repairs or other effects that perturb the stress field may alter the behavior pattern of the joints.

However the leak-before-break postulate for stainless steel pipe is supported by extensive field experience and analytical instability analysis. The evidence shows that crack growth is a stable phenmenon and guillotine rupture will not occur.

The umitigated recirculation piping welds at G@S are either 16 inch or 24 inch nminal dianeter. 'Ihe piping is expected to behave as a typical large joint assming major weld repair or other asymetrical perturbances were not introduced during the welding process. A review of the welding records of the recirculation piping welds shows that no weld repairs wem made to any of the unmitigated GGNS welds.

Therefore, based on this conservative evaluation, it can be concluded that the calculated crack growth for the 24 nonth period or until the next refueling outage is acceptable. 'Ihe flaw growth model assumed in the GGNS fracture mechanics evaluation is believed to be conservative and neither leaks nor breaks are expected to occur during the operating period to the next scheduled refueling outage.

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SLM ERY For all the systes that make up the Reactor Coolant Pressure Boundary (RCPB) only the Recirculating Water syst s contains materials which do not meet the selection requirments of NURDG 0313 Rev.1. Approximately 740 butt welds were used in the ,assably of the BCPB. 'Ihere are 128 welds in the IGSOC susceptible portions of the systern, of these only 22 are not mitigated. In omparison to ,

the overall ofCPB this represents 3 percent of the total welds. "

All 304 grade materials were solution annealed and quenched to eliminate furnace sensitization; all cast products meet the selection requirernents of NURD3 0313 Rev. 1; all weld filler materials used were either nickel base (for buttering) or Type 308L with ferrite in excess of 5 percent. '1he only areas within the recirculating water systs sureptible to IGSOC are the heat affected zones of the non-mitigated welds.

Mitigation techniques will be inplernented at the first refueling outage. Also at that time, the ISI program will include inproved Ur Procedures and the Aucynented Inspection Program.

It's evident frm the fracture mechanics evaluation that any IGSOC's induced during the operational period prior to first refueling outage will not create a safety concern. Sufficient leak detection has been provided to arrest any additional safety concerns towards undetected leakage due to IGSOC. Historical Data is still supporting leak before break. Grand Gulf will maintain water chmistry in accordance with GGNS Operating License Manual.

Based on the information presented in this report, MP&L concludes the following:

1) G@S is justified for operation until the first refueling outage.
2) After mitigation of the twenty-two (22) vulnerable welds, further problerns with IGSOC is not anticipated.

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f APPENDIX A IGSOC MITICATION bFtL1rIC JOINT INE0R%TICN l

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SPECIFIC JOINT INFOINATION i IOOP A W #1: This weld has had a mitigation technique applied.

. Safe-ehd - 316L SS,

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. Pipe / 304 SS, shop clad and solution annealed prior to welding. F W 42: This weld has had a mitigation technique applied.

. Pipe - 304 SS, shop clad and solutioned anrealed prior to welding.

W #4: This weld has had a mitigation techniuge applied.

. Elbow - 304 SS, shop clad and solution annealed prior to welding.

. Valve - SA351, CF8M, 0.06% C, Ferrite = 13.5%

W 45: Not Mitigated (SRI = 1.08)

. Valve - SA351, CF8M, 0.06% C, Ferrite = 13.5 %

. Pipe - 304 SS, 0.05% C, solution annealed prior to welding.

W #6: Not Mitigated (SRI = 1.15)

. Elbow - 304 SS, 0.05% C, solution annealed prior to welding.

. Punp - SA351, CF8M, 0.69% C, Ferrite = 16%

W #7: Not Mitigated (SRI = 1.00)

. Punp - SA351, CF8M, 0.069% C, Ferrite = 16%

. Pipe - 304 SS, 0.05% C, solution annealed prior to welding W #8: Not Mitigated (SRI = 1.00)

. Pipe 304 SS, 0.05% C, solution annealed prior to welding.

. Valve - SA351, CF8M, 0.05% C, Ferrite - 11.8%

W 49: 'Ihis weld has had a mitigation technique applied.

. Valve - SA351, CF8M, 0.05% C, Ferrite = 11.8%

. Pipe - 304 SS, shop clad and solution annealed prior to welding.

W #10: This weld has a mitigaticn technique applied.

l l . Pipe - 304 SS, shop clad and solution annealed prior to welding.

l

. Valve - SA351, CF8M, 0.06% C, Ferrite = 13.5%

Sheet 2 of 7

SPECIFIC JOINT INEGMATION I OCTP A (Cont'd) j W #11: Not Mitigated (SRI = 1.03) 1 I

. Valve.'- SA351, CF8M, 0.04% C, Ferrite = 12%

. Pipe f 304 SS, 0.052% C, solution annealed prior to welding. '

W #12: Not Mitigated (SRI = 1.15)

. Pipe - 304 SS, 0.051% C, solution annealed prior to welding.

. Reducing Cross - SA 403, 304 SS, 0.070% C, solution annealed prior to welding.

m #13: 'Ihese welds have had a mitigation technique applied.

. Sweepolet - 304 SS, field clad prior to welding.

. Riser Pipe - 304 SS, shop clad and solution annealed prior to welding.

N #14: These welds have had a mitigation technique applied.

. Riser Pipe - 304 SS, shop clad and solutico annealed prior to welding.

. Safe-end - 316L SS W #15: ' Itis weld has had a mitigation technique applied.

. Pipe - 304 SS, field clad prior to welding.

. Pipe - 304L SS SW #1: Not Mitigated (SRI = 1.13)

. Pipe - 304 SS, 0.055% C, solution annealed prior to welding.

. Cap - 304 SS, 0.048% C, solution annealed prior to welding, t

SW #2: Not Mitigated (SRI = 1.13)

{

l . Pipe - 304 SS 0.055% C, solution annealed prior to welding.

. Cap - 304 SS 0.048% C, solution annealed prior to welding.

SW #3 & SW #4: Not Mitigated (SRI = 1.20)

. Reducing Cross - SA403, 304 SS, 0.070% C, solution annealed prior to welding.

l -. Pipe - 304 SS, 0.055% C, solution annealed prior to welding.

Sheet 3 of 7

SPEXHFIC EINT INEGMATION IDOP A (Cont'd)

~

SW 45: Not Mitigated (SRI - 1.13)

. Reducihg Cross - SA403, 304 SS, 0.070%, solution annealed prior to

, welding.  ;

I t

. Cap - SA403', 304 SS, 0.070% C, solution annealed prior to welding.

I l

I I

Sheet 4 of 7

SPECIFIC JOINT INFORMATION (

IDOP B W #1: h is weld has had a mitigation technique applied.

. Safe-gxi - 316L SS

. Pipe /304 SS, shop clad and solution annealed prior to welding. d W #2: his weld has had a mitigatica technique applied.

. Pipe - 304 SS, shop clad and solutioned annealed prior to welding.

W #3: his weld has had a mitigatico technique applied.

. Pipe - 304L SS

. Tee - 304 SS, shop clad and solution annealed prior to welding.

m 44: h is weld has had a mitigation techniuge applied.

. Elbow - 304 SS, shop clad and solution annealed prior to welding.

. Valve - SA351, CF8M, 0.06% C, Ferrite = 14.5%

W #5: Not Mitigated (SRI = 1.08)

. Valve - SA351, CF8M, 0.06% C, Ferrite = 14.5 %

. Pipe - 304 SS, 0.052% C, solution annealed prior to welding.

W #6: Not Mitigated (SRI = 1.15)

. Elbow - 304 SS, 0.050% C, solution annealed prior to welding.

. Purtp - SA351, CF8M, 0.60% C, Ferrite = 16%

N #_7 : Not Mitigated (SRI = 1.00)

. Purip - SA351, CF8M, 0.060% C, Ferrite = 16%

. Pipe - 304 SS, 0.052% C, solution annealed prior to welding W #8: Not Mitigated (SRI = 1.00)

. Pipe 304 SS, 0.052% C, solution annealed prior to welding.

. Valve - SA351, CF8M, 0.050% C, Ferrite - 17%

N #9: W is weld has had a mitigation technique applied.

. Valve - SA351, CF8M, 0.050% C, Ferrite = 17%

. Pipe - 304 SS, shop clad and solution annealed prior to welding.

Sheet 5 of 7

SPECIFIC JOINT INFOIDRTION IDOP B (Cont'd)

N #10: ' Itis weld has a mitigation teqhnique applied.

. Pipe ,304 SS, shop clad and solution annealed prior to welding.

Valve g SA351, CF8M, 0.050% C, Ferrite = 11.5'a i N ell: Not Mitigated (SRI = 1.03)

. Valve - SA351, CF8M, 0.050% C, Ferrite = 11.5%

. Pipe - 304 SS, 0.051% C, solution annealed prior to welding.

W #12: Not Mitigated (SRI = 1.15) l . Pipe - 304 SS, 0.051% C, soluticn annealed prior to welding.

l l

. Reducing Cross - SA 403, 304 SS, 0.070% C, solution annealed prior to

, welding.

l N #13: h se welds have had a mitigation technique applied.

. Sweepolet - 304 SS, field clad prior to welding.

. Riser Pipe - 304 SS, shop clad and solution annealed prior to welding.

l N 014: hse welds have had a mitigation technique applied.

. Riser Pipe - 304 SS, shop clad and solution annealed prior to welding.

. Safe-end - 316L SS m 415: ' Itis weld has had a mitigation technique applied.

. Pipe - 304 SS, field clad prior to welding.

. Pipe - 304L SS SW #1 & SW #2: Not Mitigated (SRI = 1.13)

. Pipe - 304 SS, 0.055% C, soluticn annealed prior to welding.

. Cap - 304 SS, 0.048% C, solution annealed prior to welding.

SW 43 & SW 64: Not Mitigated (SRI = 1.20)~

. Reducing Cross - SA403, 304 SS, 0.070% C, solution annealed prior to welding.

. Pipe - 304 SS, 0.055% C, solution annealed prior to welding.

Sheet 6 of 7

SPECIFIC JOINF INFOft9CICE IOOP B (Cont'd)

SW #5: Not Mitigated (SRI - 1.13)

. Reducipg Cross - SM03, 304 SS, 0.070%, soluticm annealed prior to welding.

/

'SM03', 304 SS, 0.070% C, soluticn annealed prior to welding.

[

. Cap j

-i I

Sheet 7 of 7

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