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{{#Wiki_filter:}} | {{#Wiki_filter:Dominion Energy Nuclear Connecticut, Inc. | ||
5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion Dominion Energy.com November 17, 2021 Energy U.S. Nuclear Regulatory Commission Serial No. 21-292 Attention: Document Control Desk NRA/SS RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
MILLSTONE POWER STATION UNIT 3 ALTERNATIVE REQUEST IR-4-09 FOR USE OF AN ALTERNATIVE BRAZED JOINT ASSESSMENT METHODOLOGY TO DEMONSTRATE STRUCTURAL INTEGRITY OF CLASS 3 MODERATE-ENERGY PIPING Pursuant to 10 CFR 50.55a(z)(2), Dominion Energy Nuclear Connecticut, Inc. (DENC) requests Nuclear Regulatory Commission (NRC) approval to use an alternative to the requirements of IWD 3132.3(b) of the American Society of Mechanical Engineers (ASME) Code, Section XI, 2013 Edition. The proposed alternative evaluation method would allow for temporary acceptance of brazed joint leakage in moderate energy, copper-nickel and nickel-copper, Class 3, service water piping with cast bronze fittings. | |||
Temporary acceptance is based on determining the degree of remaining bonding through ultrasonic (UT) examination of the affected brazed joint (similar to the approach given in ASME Code Case N-874), in combination with performing a structural integrity assessment (utilizing the guidance of ASME Code Case N-513-4). Final repair of a leaking brazed joint would be performed during the next refueling outage following leakage identification. Until a repair is completed, periodic monitoring of a leaking joint would be performed to verify that the assumptions of the structural evaluation remain valid. With this approach, leaking brazed joints can be replaced in a systematic and planned manner, without unnecessary unavailability of safety related systems or components or unnecessary plant shutdowns. provides Relief Request IR-4-09. Attachments 2 and 3 provide applicable figures, and applicable brazed joint configurations and materials, respectively. provides a summary of previous applications of the approved brazed joint assessment methodology and a technical evaluation example. Attachment 5 describes the mechanical testing performed for MPS3. Attachment 6 provides a UT procedure for reference only (which is subject to change). Attachment 7 provides additional technical basis information related to braze shear stress. | |||
Serial No. 21-292 Docket No. 50-423 Page 2 of 3 If you have any questions regarding this submittal, please contact Shayan Sinha at (804) 273-4687. | |||
Sincerely, Mark D. Sartain Vice President Nuclear Engineering & Fleet Support Attachments: | |||
: 1. Alternative Request IR-4-09, Use of an Alternative Brazed Joint Assessment Methodology to Demonstrate Structural Integrity of Class 3 Moderate-Energy Piping | |||
: 2. Applicable Figures | |||
: 3. Applicable Brazed Joint Configuration and Materials | |||
: 4. Summary of Previous Methodology Applications and Technical Evaluation Example | |||
: 5. Mechanical Tests | |||
: 6. Ultrasonic Test Procedure | |||
: 7. Additional Basis for Braze Shear Stress Commitments made in this letter: None | |||
Serial No. 21-292 Docket No. 50-423 Page 3 of 3 cc: U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 R. V. Guzman Senior Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 C2 Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 1 ALTERNATIVE REQUEST IR-4-09 1 USE OF AN ALTERNATIVE BRAZED JOINT ASSESSMENT METHODOLOGY TO DEMONSTRATE STRUCTURAL INTEGRITY OF CLASS 3 MODERATE-ENERGY PIPING MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. (DENC) | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 1 of 12 Alternative Request IR-4-09 In Accordance with 10 CFR 50.55a(z)(2) | |||
Hardship Without a Compensating Increase in Quality and Safety | |||
: 1. ASME Code Component(s) Affected ASME Code Class: Code Class 3 | |||
==References:== | |||
ASME Section XI, IWD-3132.3(b) | |||
Examination Category: N/A Item Number: N/A | |||
== Description:== | |||
Alternative Brazed Joint Assessment Methodology Components: Service Water System Brazed Piping Joints, Three Inches Nominal Size and Smaller Figure 1 in Attachment 2 shows a typical brazed joint. Attachment 3 provides additional details concerning applicable brazed joint materials, configuration, and brazing. | |||
===2. Applicable Code Edition and Addenda=== | |||
ASME Section XI, 2013 Edition (No Addenda) | |||
===3. Applicable Code Requirement=== | |||
IWD-3132.3 Acceptance bv Evaluation A component containing relevant conditions is acceptable for continued service if an evaluation demonstrates the component's acceptability in accordance with (a) or (b) below. | |||
(b) Temporary acceptance of flaws in moderate energy piping may be performed in accordance with Nonmandatory Appendix U, Supplement U-S1, and temporary acceptance of degradation in moderate energy vessels and tanks may be performed in accordance with Nonmandatory Appendix U, Supplement U-S2. | |||
The ASME Section XI Nonmandatory Appendix U requirements do not provide guidance specific to evaluation and temporary acceptance of brazed joint leakage. | |||
As such, leakage from an unisolable brazed joint could require removal of the unit from service to support isolation and draining of the associated service water train. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 2 of 12 DENG is proposing to use an alternative evaluation method that would allow for temporary acceptance of brazed joint leakage in moderate energy, copper-nickel and nickel-copper, service water piping with cast bronze fittings. The proposed alternative evaluation method is similar to the guidance of ASME Code Case N-874, which is expected to be designated an acceptable code case for use in the upcoming Revision 20 of Regulatory Guide 1.147 (ADAMS Accession No. ML20120A631). One difference between this proposed alternative and Code Case N-874 is that additional provisions for acceptance when <60% bond is detectable are also included in the proposed alternative. Any brazed joint leakage that is detected and temporarily accepted using the proposed alternative evaluation criteria would be subject to ongoing monitoring and would be repaired in accordance with ASME Section XI Article IWA-4000 no later than the next refueling outage. The proposed alternative evaluation is also consistent with aspects of ASME Code Case N-513-4, which is listed by the NRG as an acceptable code case for use in the currently approved Revision 19 of Regulatory Guide 1.147. | |||
===4. Reason for Request=== | |||
During the course of plant operation, minor leakage of brazed joints is sometimes observed through a defect in the braze bond between the pipe and fitting. Leakage is considered to be minor when it is at a rate of drops per minute, or if only moisture or salt deposits are visible. | |||
Section XI and Section Ill of the ASME Code do not have guidance applicable to evaluation of minor leakage through brazed joints caused by defects in braze bonding between piping and fittings. Section XI, IWD-3000, has no requirements pertaining to brazed joints. Therefore, Section XI does not have rules specific to examination and acceptance of relevant conditions observed in brazed joints. | |||
Lacking such guidance, the leaking joint must be repaired in accordance with IWD-3132.2. | |||
A safe alternative to the requirement to immediately repair a brazed joint with minor leakage can include a deferred, but planned, repair/replacement activity that permits continued plant operation based on an evaluation of continued acceptable integrity and functionality of the brazed joint. With this approach, leaking brazed joints can be replaced in a systematic and planned manner, without requiring unnecessary unavailability of safety related systems or components or the potential for unnecessary plant shutdowns. | |||
In some cases, performing an ASME Code repair on a degraded brazed joint might render certain safety-related systems or components inoperable, thereby potentially requiring a plant shutdown to comply with Technical Specification requirements. A plant shutdown would unnecessarily cycle plant components, which is not desirable in maintaining the structural integrity of the safety-related components. Additionally, the need to shut down the plant for implementing an ASME Code repair of a brazed | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 3 of 12 joint with minor leakage would result in hardship without a compensating increase in the level of quality and safety when the structural integrity of the degraded joint and associated system functionality can be ensured by appropriate evaluation. | |||
: 5. Proposed Alternative and Basis for Use In lieu of the immediate repair requirement of IWD 3132.2, DENG proposes to perform a supplemental ultrasonic (UT) examination and comparison with alternative acceptance criteria. The UT examination will establish the extent of braze bond within the joint. The UT results will be compared with pre-established brazed joint bond levels required for structural integrity of the specific piping under consideration that accounts for the design basis loadings applicable to the condition. This method will establish the basis for determining joint integrity to the extent required for system operability. | |||
The proposed methodology provides for continued monitoring until the nonconforming condition (e.g., minor leakage) is resolved through repair/replacement activities. Periodic monitoring of the joint and its leakage verifies that the assumptions used for the assessment remain valid. The overall methodology has been validated by performance of physical testing on an array of simulated bond configurations, and several brazed joints salvaged from MPS3 piping. | |||
5.1 SCOPE The alternative is limited to brazed, Class 3, service water piping (typically constructed of copper-nickel or nickel-copper piping and cast bronze fittings) or on-skid equipment piping that has a design pressure of 150 psig or less and a design temperature of 150 degrees Fahrenheit or less. The piping nominal size is limited to three inches maximum. | |||
Basis: | |||
The limitation of pipe sizes to three inches or less ensures that the alternative is applied to piping for which it was intended and is comparable to the range of pipe sizes (two and three inches) included in the physical testing described in Attachment 5. The limitation to service water systems ensures that the operating pressure and temperature are well within the moderate energy range. The fluid contents of the piping are comparable to those examined for potential corrosion effects. | |||
5.2 EXAMINATION As permitted by IWD-3200, "Supplemental Examinations," the brazed joint will be examined by UT using a straight beam technique that monitors the relative strengths of signals returned from the internal diameter (ID) of the pipe and the | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 4 of 12 fitting. This technique was derived from, and is consistent with, a technique standardized by the U.S. Navy for use on brazed shipboard piping. 1 The UT procedure in Attachment 6 is provided for reference only and is subject to change. The UT procedure will require that technicians be certified in accordance with ANSI/ ASNT CP-189, 1995 Edition. Only Level II or Ill certified technicians may perform or review the brazed joint UT results, and they must be familiar with brazed joint geometry and signal response characteristics. As a prerequisite, the examination surface must be suitably prepared to obtain satisfactory sound transmission. The joint circumference is marked at a number of locations such that they are spaced no greater than one inch apart. A straight beam longitudinal wave signal is required for the actual examination. At each marked location, the percent bond is recorded based on the relative strengths of signals received from the pipe ID and fitting ID. The procedure provides instructions to distinguish between fittings of the "face fed" and "insert" type, the latter of which have an internal groove in which a ring of braze filler material is inserted before brazing. | |||
The MPS3 UT procedure will provide suitable data sheets for documenting the braze bond readings and calibration data. The data sheets are reviewed by a certified Level II or Ill reviewer. The data sheets are then forwarded to Engineering for assessment. | |||
Basis for Nondestructive Examination Technique: | |||
The alternative UT examination is based on requirements for UT examination contained in the U.S. Navy standard for fabrication and inspection of brazed piping. It uses basic straight beam UT technology, and was utilized to confirm the quality of critical piping systems in the submarine fleet of the U.S. Navy. A brazed joint is considered acceptable without further evaluation by the standard if the average measured bond reading is 60 percent or more. | |||
Consistent with the referenced standard, the MPS3 procedure will require this work to be performed by certified UT technicians, using calibrated equipment and approved couplants. It will require examination at multiple locations around the circumference of the fitting. It will require review of the data by a Level II or Ill technician. The UT procedure has been reviewed and approved by a Level Ill technician in accordance with DENC's quality requirements. | |||
Previous trial demonstrations show that individual bond readings at a location on the fitting may vary, but the average reading is consistent among qualified examiners. | |||
1 NAVSEA 0900-LP-001-7000, "Fabrication and Inspection of Brazed Piping Systems", dated January 1, 1973. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 5 of 12 5.3 ASSESSMENT An assessment of the joint using this methodology includes the following considerations: | |||
* System performance and indirect effects assessments, | |||
* Adjustment of bond readings to account for uncertainties, | |||
* A review of the design basis stress analysis of the piping to determine required joint strength, and | |||
* Comparison of the adjusted bond readings with the prequalified bond levels that have been shown empirically by physical testing to assure structural integrity. | |||
5.3.1 SYSTEM EFFECTS As a prerequisite to structural assessment, knowledgeable engineering personnel assess the effect of the leak on the system and other nearby equipment. Typically, a brazed joint with a defect in the braze material bonding will leak only drops per minute. The actual leak rate will be estimated and compared to service water system margins for loss or diversion of flow. In addition, a walkdown will be performed to identify any nearby equipment that may be affected by dripping or impingement spray from the leak. If required, a drip collection device or spray shield will be installed and maintained for the duration that the leak continues. | |||
Basis: | |||
ASME Code, Section XI Code Cases, such as N-513-4, permit continued operation of moderate energy systems with minor leakage when justified by evaluation of system performance. Similarly, the proposed alternative permits continued operation provided that the leakage rate will not . | |||
adversely affect required flows, and the leakage or spray will not adversely affect safety-related equipment. Typical flow from a brazed joint experiencing minor leakage is in terms of drops per minute. Even in a theoretical worst case of a joint having a total lack of braze material, the close tolerance between the pipe and fitting prevents significant flow. The total diametric clearance of a braze joint is about 0.005 inches. For a three-inch pipe, the maximum possible flow area would be nominally 0.027 square inches (e.g., 3.14 x 3.5 x 0.0025) through which the upper bound flow rate at 100 psig would be about 6 gpm, a very small flow rate in comparison to service water pump capacity. More realistic estimates and actual leak rates would be much lower. Therefore, the maximum potential braze joint leakage is very small. In addition, the proposed alternative requires a specific evaluation to assure that leakage does not unacceptably reduce system margins. Therefore, the system will meet all | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 6 of 12 functional requirements and maintain an equivalent level of quality and safety. | |||
5.3.2 ACCEPTANCE THRESHOLD AND ADJUSTMENT OF BOND READINGS If the average measured bond reading is 60 percent or more, then no further assessment is required since the bond strength exceeds piping strength. If the average is less than 60 percent, then the bond readings as documented in the UT procedure are adjusted downwards on a sliding scale. The adjustments would be made such that all readings at 10 percent and below are assumed to be zero, and readings above 10 percent are adjusted using the following formula: | |||
bactj = 100 x (reading -10)/(100 -10) units of percent For example, a 50 percent UT reading would be adjusted to 44 percent bond level for assessment purposes. For simplicity, the adjustment may be applied to the average of the UT readings, or alternatively to each of the UT readings prior to averaging. The average of the adjusted readings is then used for assessment purposes. For bond readings that are significantly non-uniform around the circumference of the braze, an effective (lower) bond is computed based on the equivalent moment of the adjusted bond areas. | |||
If the average adjusted bond reading is above 55 percent, then the joint strength is considered equal to or better than the piping, and steps 5.3.3 and 5.3.4 below are not performed. | |||
Basis for acceptance threshold and adjustments of readings: | |||
Acceptance of average UT bond readings of 60 percent or more is the same as the acceptance criteria in the U.S. Navy standard that has been used for critical shipboard piping systems. The U. S. Navy criteria are applicable to systems rated 300 psig and greater. The 60 percent threshold criterion is therefore conservative for systems with design conditions of 150 psig or less. For further confirmation of the 60 percent threshold, testing has shown that if true bond in the joint exceeds 30 percent, then the piping collapse load occurs before any bond failure. The testing performed for MPS3 is described in Attachment 5. There is no braze bond failure mode because the piping deforms plastically to relieve the imposed load, and this occurs at loads greater than the maximum load permitted by the licensing basis analysis of the piping. The downward adjustment of bond readings beyond what is required by the U.S. Navy | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 7 of 12 standard is an introduced conservatism used to help correlate the data from actual piping samples, and accounts for uncertainties in bond readings. | |||
5.3.3 CONSTRUCTION CODE QUALIFICATION STRESS ANALYSIS REVIEW The Construction Code qualification stress analysis of record is reviewed to determine design basis loadings at the subject brazed joint. Pressure, deadweight, and safe shutdown earthquake (SSE) loadings are included. | |||
The loads are either used directly or expressed in terms of equivalent pipe stress, so that stress analysis outputs may be used directly. The stress intensification factor (SIF) that may have been applied in Construction Code stress analysis is not required to be included in the summation of nominal stresses used for assessment. | |||
Basis for Stress Analysis Review: | |||
The review of stress analysis required by this proposal is a data gathering activity required to determine the primary loads imposed on the brazed joint. The primary loads consist of maximum operating pressure, deadweight, SSE seismic, and any transient dynamic loads that have been defined for the piping. Since the stress analysis is the calculation of record for qualifying the piping in accordance with licensing basis requirements, it is an acceptable source of input for assessing the structural integrity of brazed joints. | |||
The use of Construction Code stress values implicitly treats piping torsion loads as equivalent to bending moments. This is conservative because in the bonded joint, the torsional shear is half that calculated on an equivalent pipe stress basis. | |||
5.3.4 COMPARISON OF ADJUSTED BOND TO REQUIRED BOND Equation 3 in Figure 2 of Attachment 2 was developed to give the allowable loading for an equivalent bond level. The equation is used for a comparison that is needed only when the average bond is less than 60 percent. When an equivalent adjusted bond of a brazed joint is determined, as described in Section 5.3.2, an allowable loading (Smax(badj)) can be obtained from the equation. This is the safe loading level that the joint can withstand. If the joint load demand that has been determined in Section 5.3.3, multiplied by a factor of safety (FS) of 1.5, is less than the allowable (1.5 Seq < Smax(badj)), then the brazed joint is concluded to have adequate structural integrity for continued service. The comparison is quantified as shown in Figure 2. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 8 of 12 An example of a structural assessment performed for an actual leaking brazed joint is included in Attachment 4. One joint in the example is SWP95-FW-38, which was observed to have a 42 percent average measured bond. The measured bond values were adjusted as described above, and this effective bond level results in a joint load capability of 7.015 ksi nominal pipe stress. The 7.015 ksi load capability is adequate for the design basis loads of this example, since the joint load demand, including an FS of 1.5, is 6.308 ksi. Therefore, the example structural assessment concludes the joint can be left in service provided it is monitored until its permanent repair/replacement activity is completed. | |||
If a joint does not have adequate bond by this assessment, the comparison for determining the adequacy of structural integrity of the joint is not applicable. Prompt repair/replacement of the joint, or temporary non-Code repairs subject to NRC review and approval may be options for the resolution of nonconforming conditions, consistent with considerations in Inspection Manual Chapter (IMC) 0326, "Operability Determinations," | |||
dated 10/01/2019. | |||
Basis for Comparison of an Adjusted to Required Bonding: | |||
Brazed joints with reduced bond levels can retain a significant strength that is adequate for the structural integrity of the joint. DENG sponsored tests at an independent testing facility to demonstrate the correlation between reduced bond levels and joint strength. The tests and their results are described in Attachment 5. | |||
The correlation developed by the testing conservatively determined a required bond level for a given intensity of joint loading. The results of these tests support the use of the comparison shown in Figure 2 of for the structural integrity analysis. | |||
The estimated joint strength obtained using Equation 3 in Figure 2 is confirmed conservative by test results. Each of the tested joints achieved a collapse load above the load which would be predicted for a 7.5 ksi braze shear strength. This also confirms the acceptability of the 7.5 ksi maximum braze shear stress assumption that is used as an input to the Equation 3, shown in Figure 2. Additional basis for acceptability of this value is contained in Attachment 7. | |||
The evaluation of the test results considers the adjustment of bond readings imposed by this methodology, a joint load capacity that is based on a 7.5 ksi shear stress, and an imposed FS of 1.5 on loads and pressure. With all these considerations, the tests demonstrate that a margin of greater than 1.5 exists between test results and estimated | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 9 of 12 allowable joint load capacity from the actual piping removed from plant service. This margin provides an FS equivalent to what is provided by the ASME Code, Sections Ill and XI as discussed below. | |||
The ASME Code, Section Ill, Appendix F has been referenced by the NRG for evaluation of degraded conditions. 1 Appendix F, paragraph F-1331.1 (a) permits primary stress at levels up to 0.?Su (code specified ultimate tensile strength) and in paragraph (c), it permits primary membrane plus bending stress at levels up to (1.5)(0.?Su) = 1.05Su. The maximum FS resulting from these comparisons is 1.4 relative to ultimate strength. For shear across a section, paragraph F-1331.1 (d) limits shear to 0.42Su for an FS of 1.37 relative to (1 / 3)Su. The 7.5 ksi shear limit used at the braze bond is well below this Appendix F limit of 0.42Su for the pipe and fitting materials. | |||
The ASME Code, Section XI permits acceptance of planar flaws for which Appendix C requires an FS of 1.4 for circumferential flaws (paragraph C-2621) and requires an FS of 1.3 for axial flaws for faulted loads (paragraph C-2622). These FSs from Appendix C are also incorporated by reference in Code Case N-513-4. | |||
Considering the ASME Code references described above, an FS of 1.5 for design basis loadings in ductile materials provides an equivalent and acceptable level of safety as compared to the plant design basis and permitted methodologies for evaluation of flaws. | |||
5.4 MONITORING The proposed alternative assessment methodology requires periodic monitoring to assure that the assumptions of the assessment remain valid. This monitoring will be in addition to the normal daily plant operator rounds, during which personnel observe for signs of leakage. The monitoring will be by visual observation of the appearance of the joint and its leak rate, plus re-examination of the joint by UT to reconfirm the percent bonding. The frequency of the monitoring will be approximately once every three months. The monitoring will continue as described until the joint is repaired or replaced. If there are changes in the nonconforming condition of an evaluated brazed joint with minor leakage that may impact its assessment for adequate structural integrity or its functionality, a Condition Report will be generated in accordance with the Millstone Power Station Corrective Action Program. The UT readings on the joint will also be repeated and reassessed. | |||
1 NRC Inspection Manual, Inspection Manual Chapter 0326, "Operability Determinations," October 1, 2019. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 10 of 12 Monitoring Basis: | |||
The degree and frequency of periodic monitoring is conservative because the braze defect that permits this form of leakage stems from original construction or | |||
* fabrication and is not the result of a progressive degradation mechanism. | |||
Conditions that are applicable to the use of this methodology arise from defects in braze material inside a socket joint and will have a very low leak rate. | |||
At MPS3, there have been no conditions where the piping has disengaged from brazed fitting sockets. Consequently, no conditions have been observed that would have impacted the ability to maintain adequate system flow. This positive operating experience is due to the inherent structural integrity of brazed joints in service water systems. | |||
To further address the potential for degradation, a search and review of external operating experience was performed. Braze failures in closed loop and electrical cooling systems such as generator stator cooling have been attributed to corrosion. However, there was no operating experience indicating progressive failure for open loop seawater systems. To confirm the conclusion that no progressive failure mechanism applies, DENG disassembled and examined two specimens that had already been removed from Millstone Power Station seawater service, and that were reported to have low bonding. The surface examination of the separated fitting and pipe surfaces did not reveal evidence of braze metal corrosion product. Since these examined joints are typical of plant construction and had seen nearly 20 years of service with no degradation of the bond, it is concluded that periodic visual monitoring of leak rate for this condition is acceptable, and monitoring may be scheduled on a quarterly basis. The periodic visual monitoring of leak rate will ensure that degradation to system functional margins does not occur. | |||
5.5 REPAIR/ REPLACEMENT If the assessment concludes that a brazed joint with leakage retains adequate structural integrity and functionality, an operability determination can be used to document an 'operable but not fully qualified' status. A timely repair/replacement activity can be planned in accordance with 10 CFR Part 50, Appendix B. | |||
Consistent with the Millstone Power Station Corrective Action Program, the permanent Code repair/replacement for this type of nonconforming condition will be considered timely if completed during the next cold shutdown of sufficient duration, or the next refueling outage, whichever comes first. | |||
If a joint does not have adequate bond by this assessment, the methodology for determining the adequacy of structural integrity of the joint is not applicable. | |||
Prompt repair/replacement of the joint, or temporary non-Code repairs subject to | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 11 of 12 NRC review and approval may be options for the resolution of nonconforming conditions, consistent with considerations in IMC 0326. | |||
Basis: | |||
The bases for continued operation prior to repair of the joint are that system functionality is maintained as justified in Section 5.3.1 above, structural integrity of the joint is maintained as justified in Section 5.3.4, and there is no progressive braze bond failure mechanism that would alter these conclusions over time. | |||
Compensatory actions for the condition are administratively controlled under the Millstone Power Station Corrective Action Program. These include, but are not limited to, the periodic monitoring of leakage for the condition or housekeeping measures to contain minor leakage from affected piping. The application of this methodology will be consistent with considerations of IMC 0326 for the resolution of nonconforming conditions. The permanent repair/replacement of the brazed joint assessed using this methodology will be in accordance with ASME Code, Section XI, IWA-4000. | |||
5.6 AUGMENTED EXAMINATION: | |||
If minor leakage is observed at a brazed joint, five similar brazed joints will be selected for augmented leakage examination. The additional joints will be selected based on consideration of adjacency, train, fitting type, or other factors that may be evident from the specific condition. Selected joints for augmented examination will be consistent with ASME Code Case N-513-4. If leakage is observed in similar joints, the resolution of each nonconforming condition will be evaluated in accordance with the Millstone Power Station Corrective Action Program, and the extent of condition will be documented and addressed. | |||
Basis: | |||
The examination of the additional joints is consistent with current practice for the resolution of nonconforming conditions, (e.g., application of ASME Code Case N-513-4). Augmented examinations provide information regarding the extent of condition being evaluated and are consistent with current Millstone Power Station procedures for responding to leakage in service water piping. | |||
==5.7 CONCLUSION== | |||
It is proposed that in lieu of the immediate repair requirement of IWA-3132.2, DENC will perform a supplemental UT examination and comparison with alternative acceptance criteria. As justified above, DENC concludes that the proposed brazed joint assessment methodology, as an alternative to immediate ASME Code repair or replacement, provides reasonable assurance of structural integrity of degraded brazed joints. Therefore, pursuant to 10 CFR 50.55a(z)(2), | |||
the proposed alternative concludes that performance of an immediate ASME | |||
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 12 of 12 Code repair or replacement of MPS3 degraded brazed joints that are considered to be acceptable using the proposed methodology would result in hardship without a compensating increase in the level of quality and safety. | |||
: 6. Duration of Proposed Alternative This proposal requests approval for the use of an alternative brazed joint assessment methodology for the duration of MPS3's fourth 10-year lnservice Inspection (ISi) interval, which began on February 23, 2019, and ends on February 22, 2029. | |||
: 7. Precedents A similar request for alternative was granted for the second ISi interval (Relief Request IR-2-38) per {{letter dated|date=February 28, 2007|text=letter dated February 28, 2007}} (ADAMS Accession No. ML070580514), and for the third ISi interval (Relief Request IR-3-04) per {{letter dated|date=November 30, 2009|text=letter dated November 30, 2009}} (ADAMS Accession No. ML093221042). | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 2 APPLICABLE FIGURES MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 1 of 9 TABLE OF CONTENTS Figure 1: Typical Brazed Joint Configuration 2 Figure 2: Equations for Brazed Joint Assessment 3 Comparison of Brazed Joint Load vs. Capacity Figure 3: Two Inch Couplings: Fabricated Samples at (a) 30% (above) and (b) 60% bond 4 Figure 4: Two Inch Joints: Two Fabricated Samples with 12% Bond 5 Figure 5: Arc Segment Disbandment, (a) 90 (above) and 6 (b) 126 Degrees Arc Figure 6: Two Inch Braze Field Sample Test Curve 7 Figure 7: Three Inch Braze Field Sample Test Curve 8 Figure 8: Test Results for Specially Fabricated Joints 9 Figure 9: Test Results for Joints Removed From Service 10 | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 2 of 9 Weepage location 7A bondlny Braze ftller motel Pipe pipe and fitting | |||
-+- ....... | |||
-+- ....... | |||
t t t t t t t t t t t t Internal Fluid Pressure jA Figure 1: Typical Brazed Joint Configuration | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 3 of 9 | |||
( 1) | |||
(2) | |||
S Ip = longitudinal pressure stress Unintensified pipe stresses from Code S di = deadload stress qualification analysis Ssse = SSE seismic stress S dyn = dynamic stress (if defined) 2 n D *Lins *tmax (3) | |||
Smax(badj) = - * - - - - - | |||
* b a d j 4 zpipe D = pipe outside diameter Lins = depth of fitting socket excluding any insert groove Zpipe = piping section modulus | |||
'tmax = 7500 psi (maximum braze shear stress) b adj = adjusted effective bond Figure 2: Equations for Brazed Joint Assessment Comparison of Brazed Joint Load vs. Capacity | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 4 of 9 5000 l!i**l!liiill!!* Raw 450<.l | |||
-Corre,c.ted 4000 3500 | |||
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i 2500 | |||
..5 .:moo 1500 | |||
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I 500 I f | |||
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4000 . - r orrccted J.500 | |||
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0 O ~5 0.5 0.75 l25 15 1.75 " | |||
015pla~mcnt (111} | |||
Figure 3: Two Inch Couplings: Fabricated Samples at (a) 30% (above) and (b) 60% bond | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 5 of 9 5000 4500 | |||
-Corrected 4000 | |||
]500 | |||
..... 3000 | |||
.:::i e | |||
-a0 250{) | |||
....I 200{1 1500 1000 500 u | |||
0 O 25 0.5 0.75 1.25 I5 1.75 .., | |||
DLc;pJacement (in; 5ll00 4500 4000 | |||
.,soo JOOIJ | |||
.r;;;. | |||
"'Cl | |||
*~ 150(1, | |||
.2lll'IIJ 1500 I fl{10 500 0 | |||
0 <J 15 0.5 O 75 I 25 I5 I 7.5 "' | |||
Dtiplarctnert (in) | |||
Figure 4: Two Inch Joints: Two Fabricated Samples with 12% Bond | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 6 of 9 5000 | |||
....... , Ra\\t 4500 | |||
-Co~ted 4000 3500 | |||
-6 | |||
~ | |||
3000 | |||
'1j 2500 3 :woo 1500 I 0()0 . | |||
~ | |||
500 ' | |||
0 0 0.25 0.5 0 75 l.25 1..5 l 75 D?-iplncement (in) 5000 | |||
**** ... Rn\\' | |||
45UO | |||
- - ( 'orrect-cd 40UO J.500 | |||
:,(}\.Ii) | |||
-:E:. | |||
";',l | |||
~ | |||
25{10 | |||
~ | |||
.::ooo 1500 IOI.JO 500 I 0 | |||
u 015 05 O75 1.15 J.5 l.75 "' | |||
Ol,i).11Jac~menl (in) | |||
Figure 5: Arc Segment Disbondment, (a) 90 (above) and (b) 126 Degrees Arc | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 7 of 9 40 No bond failure 2" Coupling | |||
-Stress,136 Joint 36, 65% bond l!1l QI | |||
.:I ti) 30 | |||
\ 2" Coupling | |||
-Stre.'is,137 | |||
-Stress,139 (Unadjusted bc,nd rea_d_ing_s) | |||
Joint 39, 55% bond | |||
: 8. 20 | |||
~ Partial bond failure | |||
*a | |||
~ | |||
10 2" Coupling Joint 37, 27% bond 0 0.25 0.5 0.75 l.25 1.5 I.75 2 2" FieldSamples Disiincement (in) | |||
Figure 6: Two Inch Braze Field Sample Test Curve 40 C 30 g ,-? 2 ~~==...-:=----4A --~~-- | |||
...~ 3 - ~ - 3 IA ti) t 20 | |||
~ | |||
~_,,_-"""-\---- | |||
----~ | |||
it 9 | |||
-J2,45% | |||
*5 -J3,47% | |||
rJ -J4A, 15% | |||
IO | |||
---J9,38% | |||
-J9J,48% Unadjusted bond readings | |||
-J31A,21% | |||
0 0.1 0.2 0.3 0.4 0.5 3" Field Samples DJs placement (in) | |||
Figure 7: Three Inch Braze Field Sample Test Curve | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 8 of 9 | |||
~ 45 U) 0 40 ~ | |||
I | |||
-~~ | |||
C: 35 30 No bond failure, pipe collapse governs F | |||
2" test 25 3" test | |||
= | |||
ln e 20 I-' - - - -1 .A .- -- ,- _,. -- ~ . . | |||
- _. - - 2.4 Sh Limit Cl) 15 ,.;" | |||
~,.,. | |||
,..,,,. - . - .. - .. 2 11 Shear Limit | |||
.,~ ........... | |||
.S, 10 - ~ t,.:,,~' | |||
a: .>,:,~.. - ~ - . -3" Shear Limit 5 ... ,- | |||
s D _., | |||
~~ | |||
l iB" 0 .... I I I I 0% 20% 40% 60% 80% 100o/o Percent True Bond Figure 8: Test Results for Specially Fabricated Joints | |||
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 9 of 9 | |||
. No bond failure, pipe_ ll. 2 11 Field Samples collapse governs 0 | |||
,,,. o 3" Field Samples cP | |||
~ | |||
0 | |||
-- 0 | |||
.u. | |||
: 6. ..... | |||
fill",..._ | |||
- . .... .. .. ,,. .. 2" Shear Limit | |||
. . .,,,,,."" - * - 3" Shear Limit D.. 0 ... , | |||
,, 'ff | |||
~,,, - .. | |||
* 2.4 Sh Limit I | |||
' I I 0% 20% 40% 60% 80% 100% | |||
Adjusted Percent Bond Figure 9 .. Test Results for Joints Removed From Service | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 3 APPLICABLE BRAZED JOINT CONFIGURATION AND MATERIALS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 3, Page 1 of 2 1.0 MATERIALS Typical materials of construction for brazed piping are copper-nickel (SB-466) or nickel alloy (SB-165) annealed piping, and cast bronze fittings and valves (SB-61 or SB-62) dimensioned to MIL-F-1183. The brazing alloy is SFA 5.8 BAg-1, BAS-1a, or BAg-7. ASME, Section Ill Code minimum properties of the piping and fitting materials are: | |||
Yield, Ultimate, Material Item Sh, ksi ksi ksi SB466 Pipe 8.7 13 38 CDA706 SB-165 Pipe 17.5 28 70 SB-61 fitting 8.5 16 34 SB-62 fitting 7.5 14 30 2.0 CONFIGURATION As shown in Figure 1 of Attachment 2, a typical brazed joint fitting has a deep socket for inserting the pipe. Although it appears similar to a socket welded joint, the fabrication and structural behavior are quite different. Whereas the socket weld achieves its joint strength by a fillet weld, resulting in fusion of similar material between the pipe and the outer face of the fitting, the braze achieves its strength by surface bonding of the outside of the pipe to the inside of the fitting socket using a dissimilar metal braze filler of silver alloy. The resulting braze filler metal is very thin (approximately 1 to 5 mils). The load transfer between pipe and fitting is thus primarily by shear through the braze filler. It is noted that there is no inherent stress concentration factor like that normally applicable to socket welds because there is no significant pipe wall bending induced by the shear load transfer over a length that is several wall thicknesses long. | |||
The following has been excerpted from a standard piping handbook. 1 The length of lap in a joint, the shear strength of the brazing alloy, and the average percentage of the brazing surface area that normally bonds are the principal factors determining the strength of brazed joints. The shear strength may be calculated by multiplying the width by the length of lap by the percentages of bond area and by taking into consideration the shear strength of the alloy used. | |||
For the standard braze joint fittings used at MPS3, the joint overlap is about four to one. The smallest overlap occurs in a three-inch joint, with an overlap length of 3.6 times pipe wall thickness. | |||
1 Crocker and King, Piping Handbook, 5th Edition, McGraw-Hill Book Company, page 7-212 | |||
Serial No. 21-292 Docket No. 50-423 Attachment 3, Page 2 of 2 3.0 BRAZED JOINT FUNCTIONAL CHARACTERISTICS Since the piping loads causing longitudinal stress in the pipe are all transferred by shear stress through the brazed bond, the shear stress in the brazed bond is directly related to longitudinal pipe stress divided by a factor equal to the overlap ratio. Thus, for a fully bonded brazed joint, the shear stress is about one fourth of the piping longitudinal stress. If the bond is only 50 percent of maximum, then the bond shear stress will be about half the piping longitudinal stress. Given that piping and brazing filler metals have similar strength, a brazed joint has more than enough residual strength to tolerate moderate bond imperfections. Consequently, the joint is not the weak link in the piping assembly. | |||
Consistent with this inherent over-design of brazed joints, the Construction Codes, such as Section Ill of the ASME Code and ANSI B31.1, require only visual inspection of the resulting bond. ND-5360, Visual Acceptance Standards for Brazed Joints, states "Brazing metal shall give evidence of having flowed uniformly through a joint by the appearance of an uninterrupted, narrow, visible line of brazing alloy at the joint." Surface exams such as by liquid penetrant are not required. Volumetric exams are not specified or even defined for brazed joints. | |||
If the lack of bond is severe, then the brazed joint becomes the weak link in the piping assembly. It fails by shear failure of the brazed bond. Brazing with a lower level of bond may however be acceptable if the piping design basis loads are low enough. A brazing material defect with minor leakage is not the result of a flaw in the pipe or fitting pressure boundary. The pressure-retaining boundary retains its structural integrity. Although the shear load transfer between the pipe and fitting is clearly a pressure boundary function, the brazing material functions more as a sealant between the connected components and less like a pressure boundary. | |||
With regard to structural integrity, imperfections in the sealant function of the braze material are permissible, provided its load transfer function retains adequate margin. | |||
Thus, because there is no direct degradation of the pressure boundary, the available flaw evaluation methodologies such as in ASME Code Case N-513-4 or Generic Letter 90-05, are not directly applicable. In addition, the characterization of braze imperfections is very different from the planar flaws or loss of wall thickness that are addressed in ASME Code, Section Ill, IWA-3000. | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 4 | |||
==SUMMARY== | |||
OF PREVIOUS METHODOLOGY APPLICATIONS AND TECHINCAL EVALUATION EXAMPLE MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 4, Page 1 of 24 Summary of Previous Methodology Applications During the second MPS3 inservice inspection (ISi) interval, the brazed joint methodology, as approved, was employed in three instances (under IR-2-38). In two of the instances, the leaking joints were repaired within 90 days of discovery and in the third instance, the repair was performed at the next refueling outage. For the third instance, this attachment provides a summary of the original assessment, subsequent UT monitoring, and final repair. | |||
During the third MPS3 ISi interval, there were no instances which required use of the brazed joint methodology as approved by the NRC under alternative request IR-3-04. | |||
Example of Methodology Application This example relates to a brazed joint that was discovered to be leaking on March 4, 2008. The following activities were then performed. | |||
Date Activity Document Remarks 3/11/2008 UT Examination AWO M30802596 Attached to Technical Evaluation 3/13/2008 Engineering Technical Evaluation Included with this Assessment M2-EV-=08-0006 attachment. | |||
5/29/2008 UT Re-examination AWO M30804182 Inspection sheet included with this attachment. | |||
8/26/2008 UT Re-examination AWO M30804183 Inspection sheet included with this attachment. | |||
10/8/2008 Begin MPS3 refueling NA outage 11/2/2008 Brazed Joint Repair AWOM30802598, per .Brazed joints replaced DM3-00-0192-08 with butt welds and socket welds The table shows the 90-day reinspection frequency requirement of the methodology was satisfied. | |||
Note: The first examination and technical evaluation addressed nearby brazed joints that were not leaking and therefore met construction code requirements. These additional examinations were done for information only. Subsequent examinations addressed the leaking joint only. | |||
Serial No. 21-292 * . ... -**. __ | |||
- ... -*-- -BockefNo. s6~423* ..... | |||
Attachment 4, Page 2 of 24 QA Non-QA | |||
~ | |||
DB or LB document change required? yes D no ~ | |||
TECHNICAL EVALUATION for Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 Millstone Unit 3 M3-EV-08-0006 Rev.00 3/13/2008 . | |||
u' 1'11\IZ ~lr1\o~ | |||
/" pages 11 3/IJ/or Preparer - Glenn Gardner Date 3/{3/oe Independent Reviewer - Thomas Steahr Date Engineering Approver - Martin Van Haltern Date | |||
*Page I of 19 | |||
-p-****u-H-~ .,, | |||
' *I _,. | |||
Technical Evaluation No. M3-EV-08-0006, Rev. 00, page 2 of 19 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 Section ~ | |||
Table of Contents 2 1.o*puRPOSE 3 | |||
==2.0 BACKGROUND== | |||
3 | |||
==3.0 REFERENCES== | |||
3 4.0 DISCUSSION 4 5.0 SAFETY-SIGNIFICANCE 9 | |||
==6.0 CONCLUSION== | |||
S 9 7.0 LIST OF ATTACHMENTS 9 Pages in body 9 Pages in attachments 10 Total pages 19 2 | |||
P~ge 2 of 19 | |||
.....,.__ . -~-.-----Serial No .. 21-2~2 Docket No. 50-423 Attachment 4, Page 4 of 24 Technical Evaluation No. M3-EV-08-0006, Rev. 00, page 3 of19 Evaluation ofUnit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 1.0 PURPOSE The purpose of thi.s evaluation is to deterrnine the structural integrity of a leaking brazed joint in service water instrumentation piping to flow indicator FT-43B, upstream of root valve 3SWP*V222. This3/4" piping branches off line 3SWP-030-09S-3. The brazed joint was identified as having evidence of leakage in CR-08-02368. A subsequent UT exam characterized the extent ofbrazedjoint bond (Reference 3.3). This document provides a structural evaluation to support continued operation pending repair and summarizes requirements to monitor its condition. * | |||
==2.0 BACKGROUND== | |||
* A method for evaluating the structural integrity of degraded brazed joint was developed in Reference 3.4 and accepted by the NRC in Reference 3.S. The Reference 3.4 Technical Evaluation provides a spreadsheet based evaluation tool to assess the structural acceptability of degraded (including leaking) brazed joints. This Technical Evaluation, in conjunction with the | |||
* UT procedure (Reference 3.6), provides the basis and specific instructions for examination, structural evalµation and reinspection requirements for degraded brazed joints in Millstone Unit 3 service water piping. Procedure MP-24-ENG-FAP947 (Reference 3.8) summarizes all requirements for responding to service water leaks. | |||
The spreadsheet documented in the Reference 3.4 Technical Evaluation implements the approved methodology for evaluating brazed joint integrity. Its data inputs include calculated piping stress levels and the ur bond readings for the joint. The sheet is self documenting and provides a conclusion on whether the joint is acceptable for design basis loading. Specific directions for use of the spreadsheet are contained in Reference 3.4 and are not repeated here. | |||
==3.0 REFERENCES== | |||
3.1 CR-08-02092, Unplanned TRM for Minor Seepage From A SWP Strainer Backwash Line 3~SWP-003-021-3 Brazed Joint, dated 3/04/2008. | |||
3.2 . Drawing No. 25212-21001 sheet 21, Rev. 9 ./ | |||
3.3 Ultrasonic Examination Straight Beam Measurements, AWO Number M3-08-02596, dated 03/11/2008 (Attachment 1). | |||
3.4 Technical Evaluation M3-EV-05-0002 "Examination and Structural Assessment of Brazed Joints" Revision O1 dated 7/l 7/07. | |||
3.5 "Safety Evaluation by the Office of Nuclear Reactor Regulation, relief Request IR-2-38", | |||
US NRC, Transmitted by the {{letter dated|date=February 28, 2007|text=letter dated February 28, 2007}}, Dominion licensing file 07~ | |||
0153. | |||
3 Page 3 of 19 | |||
_, ....,------ . **-- _,, ___ *--***-****-* ......,.......-,. _____ Serial Np. 21-292 . | |||
Docket No. 50-423 **-* * - - | |||
Attachment 4, Page 5 of 24 Technical Evaluation No. M3-EV-08-0006, Rev. 00, page 4 of 19 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 3.6 Procedure MP-UT-45 Rev 00-01 "Ultrasonic Examination Procedure for Examination of Brazed Joints- Millstone Unit 3 Service Water Piping". | |||
3.7 Calculation No. NP-SWP-95-V222, Rev. 2 Change 0, "Root Valve Piping: Support Requirement Verification". / | |||
3.8 Procedure MP-24-ENG-FAP947, Rev. 001-01, "Non-Code Repairs in Safety Class 3 Piping", dated 9/24/2007 4.0 DISCUSSION The UT was obtained on three brazed joints, FW-37, FW-38 and FW-8. Only FW-38 was leaking arid that degraded condition is the one specifically evaluated here, FW-3 7 was not leaking and had greater braze bond than FW-38. FW-8 was at a flange that had interfering studs so only a partial set of readings was obtained on it; however it had readings comparable to FW- | |||
: 38. As discussed in Reference 3.4 the ASME Code does not have a requirement for minimum braze bond. Thus there is no degraded or non~conforming condition for either FW-37 and FW-8 and they are not considered to be a structural integrity concern requiring detailed evaluation. | |||
For information only the braze bond readings and evaluation summary for FW-37 are attached. | |||
The formal evaluation of the leaking braze joint FW"38 is documented on the following spreadsheet pages. The braze bond UT readings are transcribed directly into the 'UT Readings' sheet. To account for 12 data points, the data input range for the average bond was modified to only consider the 12 data points, and zero percent bond readings were input for the other eight data point inputs that were not needed. A similar change was made on the 'Bond Cales' sheet for the "BPress" on lines 29 and 65. Finally, on the summary sheet, the plot range was changed in order to show only the relevant 12 data points. Note that the methodology does specify a minimum number of UT data points and 12 points on the approximately 1.5" OD of th~ elbow | |||
* fitting give a data point spacing of about 0.4 inches which is comparable with the UT probe size. | |||
4 Page4 of 19 * | |||
. Serial No. 21-292 t, * * * . . | |||
DockeCNo. so'.423 -***-*- ..... *****- | |||
Attachment 4, Page 6 of 24 M3-EV-08-0006 Page 5 Sheet 1 of 4 Braze Bond Structural Assessment Joint SWP95-FW-38 Ref: TE M3-EV-05-0002 Rev. 1 this sheet revised 07/17/2007 Part 1 Basic Data ( dashed boxes are inputs) | |||
Inputs: Inputs: ' | |||
Line No:'SWP-075N222 Sys Function:!FT-438 upstrm instr tubing I | |||
Pipe Dia Nom. Wall Thk, I 1.05 In 0.154 In I | |||
Piping tso: 1c1-swP-95 Sh 2 Pipe Mat'ljss 466 CDA 706 Joint:,I SW P95-FW-38 rilling Mat'l*SB 61or 62 Side of Joint: IDnstrm I | |||
I Ref. Bond *strength;*- * -7,500 psr---.. ., | |||
Jf. Orlentation:tn~ __________ | |||
* ____ | |||
* __: Bond Adjustmer-it 10% | |||
Measured Ave. Bond 42% (calculated, For bond measurements, see sheet 'UT Readings') | |||
42 % >= 60 % ? No, Detailed assessment required Part 2 Bond Data Summary '(data from sheet 'Bond Cales') | |||
Offsets based on adjusted bond: | |||
Dx.x , *0.117 in Dyy 0.038 In Doffset 0.123 In (23% of pipe radius) | |||
Alpha -12.5 degrees - rotation angle of principal axes Calculated effective bond data are in p,rinclpal axes system, and are based on adjusted bond. | |||
Actual AdJusted Bxx 46% 40% | |||
Byy 34% 27% | |||
Bbend 34% 27% 10 ~~-----3!KE-----t.:!~4 Bpress 42% 35% | |||
y | |||
~ | |||
Note: Plot is figurative only, actual braze bond Is cylindrical, not 7 through-wall. | |||
X 3SWP-V222-FW38.xls Page 5 of 19 | |||
. Serial No. 21-292 | |||
** **---*------ ...... - .... bo-cket No: so:*423--**--****- | |||
Attachment 4, Page 7 of 24 M3-E.V-08-0006 Page 6 Sheet 2 of 4 Braze Bond Structural Assessment Joint SWP95-FW~38 Part 3 Calculated Bond Load Capability Lookup Tbl: l,insert per MIISpec D 1.05 in D.nom D.od *Linsert tnom 0.154 in 3/4 1.05 11/32 Pipe Z 0.085 in"3 1 1.315 7/16 Linsert 0.344 in (f/Om lookup table at right) 1.5 1.9 5/8 | |||
. Smax(100%) 26,169 psi (from formula at right) 2 2.375 21/32 2.5 2.875 25/32 Load Capability (Allowable Nominal Pipe Stress) 3 3.5 53/64 (Based on bond levels from Part 2) | |||
Actual Adjusted Sxx 12,134 10,391 psi stress based on shear allow. and percent bond Syy 8,984 7,015 psi 2 nD *Linsert Sallow 8,984 7,015 psi S mJb adj) "' b adj' *'tma> | |||
4*Zpipe Part 4 Pipe Stress Data (stress calc Inputs) (data from Part 1) | |||
Stress CaldI NP-SWP-95-V222 . | |||
7I Pipe Dia 1.05 in Rev/ CCNL Rev. 2,_ CCN O_~ _______ _J Norn. WallThk 0.154 ill Line No: SWP-075-V222 Pipe Mat'I SB 466 CDA 706 Sys Function: FT-43B upstrm instr tubing Fitting Mat'l SB 61or 62 Piping lso: CI-SWP-95 Sh 2. A.pressure 0.825 in"2 Joint: SWP95-FW-38 ~.pipe 0.085 Tn13- - -.- | |||
lnpuls: | |||
Design Pressure 1 | |||
100 psig j Max Op. Pressure , 100 pslg . , Calculated Nominal Stresses Sip ! 170 psi !sp_offset 119 psi Eq. 8 (P+DL) I 2448 psi I Sust'd 81 1695 psi Eq. 9 (NIU)* 5238 psi I N/U 9' 3466 psi Eq. 9F (Design Basiso! . __640~psi __ .!Faulted 9F' 4205 psi Max Pipe Nominal Stress 4205 psi Apply Safety Factor of 1.5 6308 psi Part 5 Structural Integrity Determination Joint SWP95-FW-38 Joint Load Capability 7,015 psi (from Part 3) 1,s*oeslgn Basis Load 6,308 psi (from Part 4) | |||
~ | |||
Check: 6,308 < 7,015 ===> Braze is adequate for design basis loads Monitor until repair/repla~ement 3SWP-V222"FW38.xls Page 6 of 19 | |||
... : .... ,....Serial ~Q,21.-2J!L...... .. | |||
Docket No. 50-423 Attachment 4, Page 8 of 24 M3-EV-08-0008 Page 7 Sheet 3 of 4 Braze Bond Measurements Joint SWP95-FW-38 R Rmin Bond Adjustment 10% 1 0.75 Reading Angle Meas. Bond Adj Bond PlotValue Adj Plot Max Min 1 o[ 40%! 33% 0.050 0.833 1 0.75 1 | |||
2 30 4o% 33% 0.850 0.833 1 0.75 1 | |||
3 eo! 40%, 33% 0.850 0.833 1 0.75 4 90i 30%j 22% | |||
33% | |||
0.825 0,850 0.806 0.833 1 | |||
1 0.75 0.75 5 120*I 40%: | |||
6 1501 20%1 11% 0.800 0.778 1 0.75 7 1ao: 30%: 22% 0.825 0.806 1 0.75 8 2101 30%1 22% 0.825 0.806 1 0.75 9 240: 60%: 56% 0.900 0.889 1 0.75 10 | |||
* 2701 80%1 78% 0.950 0.944 1 0.75 11 300: 60%: 56% 0.900 0.889 1 0.75 12 3301I 30%1I 22% 0.825 0.806 1 0.75 13 360 1 0%' 0% 0.750 0.750 1 0.75 14 390! o3/4! 0% 0.750 0.750 1 0.75 15 420 1 0%' 0% 0.750 0.750 1 0.75 16 450! 0%! 0% 0.750 0.750 1 0.75 1 | |||
17 480 0%1 0% 0.750 0.750 1 0.75 18 510!I 0%: 0% 0.750 0.750 1 0.75 19 5401 0%j 0% 0.750 0.750 1 0.75 20 570 1** _ .. ..,_ ...... | |||
0%' :J 0% 0.750 0.750 1 0.75 Nreadings 12 Ave 42% 35% G9:G21 dTheta 30 Min 20% 11% | |||
degrees Max 80% 78% | |||
3SWP-V222-FW38.xls Page 7 of 19 | |||
. . )* Serial No. 21-292 | |||
.. "i'.'>ocket No~*so:*423*- .. | |||
Attachment 4, Page 9 of 24 t.\3,EV-03-0006 Pago(? | |||
Sh..14 oJ4 Braze Bond Calculations Joint *sWP95-FW-38 Boflset NreaOings EQulvalenl band ba,ed on measured bond readings, w!1houl adjustment 1DV, 12 D AIIGI* Meas. Bond db'cw db'co~..,1 db'.$1n'QOJ &ln{lholu) db*,tn db'41n'2 1,05 0 401', 1,000 o. oo o. 00 0.000 0.000 0.000 0.000 30 4DV, O.e.G 0.3-16 0,300 0,173 0,500 0.200 0.100 AOlfsellnpl( 60 D1/4 o.500 0.200 0,100 0.173 0.8&6 0.3"8 0,300 0 d,g<!'!I 90 30% 0.000 0.000 0,000 0.000 1.000 0.31XI 0.300 O.OOOr>d 120 401/4 -0.500 -0,200 0,100 -0,173 0,8&6 0.:HS 0.300 150 201/4 -usa -0,173 0,150 -0.0$7 0.500 0.100 0.050 1BO 3Dl', -1.000 -0.300 0.:300 0.000 0,000 0.000 0,000 210 3011 -0,000 -0.260 0,225 0.130 -0,500 -0,150 0.075 240 oov. .0.500 -0.300 0.150 0,260 -0.SSS -O.S20 0.460 270 BOl', 0.000 0.000 0.000 0,000 .1.000 -0.800 0.800 300 601/4 0.500 0.300 0,150 -USO .O,BOl .0.$20 0,450 330 301/4 o.ses 0.260 0.225 -0.130 -0,500 -0,150 0.075 360 OY. 1,000 0,000 0.000 0,000 0,000 0.000 0.000 390 O1/4 0,866 0.000 0.000 0.000 0,500 0.000 0.QOO 20 O1/4 0,500 0,000 0.000 0,000 o.ess 0,000 0,000 4i0 OY, 0,000 0.000 0.000 0.000 1,000 0,000 0.000 400 01/4 .0,500 0.000 0,000 0.000 0,8&6 0.000 0.000 610 01/4 -0,00G 0.000 0.000 0.000 o.soo 0.000 0,000 540 OY, -1,000 0.000 0.000 0.000 0.000 0.000 0.000 5'10 OV, -0,666 0.000 0.000 0.00D <l.500 0.000 0.000 0.000 0.023 2,100 O.D87 0.000 .0.071 2.900 Bprus ry opw IX 411/4 0.0S5 0.175 -0,169 Rorfso\ Vol/sel SW a,v x.i<<..1 0.093 0.029 0.174 0.011 ,O,Q!9 BByy as% eave 40',(, BB,oc: 46'/i, Dyy.J) 0,17Z OUJ) 0.2n | |||
;14'/o 6'/i, B)'l*b,,.,o axy=o 1an 2arp11a iln 2illpho 180 ohecl< alpha | |||
-0,0SS 0.011 0.930 -0.360 .\l.3$6 .0,188ra:I fAtst;'. FAtsE ,*IUdeg IJ-tt*rr-=t Equivalent bond based on ad/usted bond readings | |||
"'*4 * , .. ,11(1.:1 MglO Ad).BoM db'o,o Clb'COS42 db*$fn*oos sln(lheb) cro*srr1 d~",lrl'l 0 33% 1,000 0~J3 0.333 0.000 0.000 0.000 0.000 30 333/4 0,866 0.28~ 0,260 0,144 O.IIOO 0,16! 0.0&:l 60 33% o.soo 0.167 0.083 0,144 0,668 0.289 0.250 90 XI1/4 0.000 0,000 0.000 0.000 ,.ooo 0.222 0.222 1iG 3311 -0,500 .\l,187 0.083 -0,144 0.8f8 0,28!1 o.iso 150 1111, -0.866 -0,<WG 0.083 ,0,()49 0,600 0,000 0.0~& | |||
180 ZIY, | |||
....~*1/4r,., ..,,~..,(*1 210 22f, | |||
*1.000 | |||
-0.1!66 | |||
-0,222 | |||
<l.192 0,222 0,167 0.000 0.056 0.000 | |||
-0.500 0.000 | |||
-0,111 0.000 0,056 ty,*P'rr-'rl1'"** | |||
240 56% ,0,500 -0.276 0.139 0.241 .o.ooe -0,491 M17 270 701', 0,000 0,000 0.000 0,000 *1,000 ,0,776 0,778 300 6Qll o.500 0,278 0,139 ,0,241 ,Q,WI o-0.481 D.417 l._.,*D"u.. '1.:*'lltr1 330 221', o.eea 0.192 0,167 -0.096 ,O,IOQ .0,11\ o,oss 360 OIi 1,000 0.000 0.000 0.000 0,000 0.000 0.000 D | |||
* tr, -r *t ,lo 390 0% o.eoo 0.000 0.000 0.000 0,500 0.000 0.000 420 0% MOO 0.000 0.000 0.000 0,6GO 0.000 0.000 4i!O 0% 0.000 0.000 0.000 0.000 I.GOO 0.000 0.000 BO 0% ,0,:SO0 0.000 0.000 0.00D o.esa 0.000 0.000 510 0% .o.esa 0.000 0.000 0.000 0.500 0,000 0.000 540 0% *1,000 0.000 0.000 0.000 0.000 0.000 0,000 570 0% ,0,1)6<1 0.000 0.000 0,000 ,0,600 0.000 0.000 0.000 0,025 1.667 0.096 0.000 -0,078 2,558 dlDtl<<O ry Bpyy 8PXi dl<ltk=Q IX BP'-" | |||
0.072 0.139 0,009 0,352 -0,22J 0.213 flonsel Voffsot By,, a,v Syy*B>X Xolf,el Bu | |||
'I,.,.,- "rt: .. ,",y;l:...,,fl*alt "'t"'{,-a) 0,123 BByy 0.03& 0,137 27% eave 0.014 0.333 33% BBl<X | |||
-0,117 0.196 39% | |||
Byy,.D 0,13" 8"'.Jl 0,19!1 | |||
.._..* ~ * ¥ * , ( t o ) - D,t"-'(h) .27% 0% | |||
Byy,!IJo<,O Bxr-o ,,. 2a1i,iii oot2,lpt,,, $In 2alp!la tan died< alpha o,_.,*s,t,.,<,..>-¥*mO l -0.0S& 0.014 FAlSE FAI.SE | |||
-0,467 0,908 ,Q,423 ,0,467 M&a1Uf&d Bonds Ad osledB s Bond VIII.Jot cafculatt4 a\ A,.ol'l'lt\"' | |||
* 8004 W'tln~let.1l1lad 1tA,.6'fuit 11'lg{a Yol!sel 8'f'I )(o/1.. 1 Bill Yo1fte1 B'f'I XOlf,.I 81:ll 0,029 35% -0.089 46% O.0Ja 27% -0.117 ~9 3SWP.\12tt,FW38Jds Pnge 8 of 19 | |||
~-* *--- -**.>' ..............~ *****~*****...... . | |||
, . ***-**, ** | |||
* SeFial No; -2~ ... 292- * * ** ,* ** ...... ***--- | |||
Docket No. 50-423 Attachment 4, Page 1Oof 24 Teclmical Evaluation No. M3-EV-08-0006, Rev. 00, page 9 ofl9 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 5.0 SAFETY SIGNIFCANCE Tµis technical evaluation is prepared in support of an operability determination and is not a change to the design or operation of the plant as described in the.licensing basis. Therefore a 50.59 screen is not required. Because the evaluation shows the piping meets approved evaluation criteria there is no impact on safety of plant operations. | |||
==6.0 CONCLUSION== | |||
S The degraded socket welded fitting described in CR Reference 3.1 has been evaluated according to the NRC approved methodology documented in Reference 3.4 and determined to be structurally acceptable for continued service until such time a Code Repair can be performed. | |||
According to NRC agreement documented in Reference 3.4 and 3.5, the limitations for use require r~pair of FW-38 at the earliest of the following: | |||
* next schedule outage of sufficient duration to complete repairs, or a scheduled shutdown greater than 30 days | |||
* next refueling outage | |||
* time at which the flaw/leak size is predicted to exceed the flaw/leak size accepted by evaluation | |||
\ | |||
In addition, compliance with the accepted methodology requires periodic reassessments ofFW-38 and augmented examination of five other similar joints, as detailed in Reference 3 .8, Sections 2.6 and 2.4 respectively. | |||
7.0 ATTACHMENTS Item Description No. Pages 1 Braze Bond UT Readings 5 2 Structural Assessment ofFW-37 (info) 4 3 Independent Review Comments 1 Total pages of attachments 10 9 | |||
Page 9 of 19 | |||
.......,,..._____ . _,. ...... **---~*--*** . Serial.No. 21-292 _. | |||
Docket No. 50-423 Attachment 4, Page 11 of 24 | |||
) | |||
' A'.fTAGHMENr*1 .. | |||
.. *r. | |||
Ut,.:TRAS.ONU:; CALfstt.A"ftO~* . . .DATA.SHEET .. | |||
Page _l._of-f:1-_ | |||
Plant: .I') ill sfotrn .. Unit: .3 AW@ Number. t:1.3 .. o<J- O.'J..S2C | |||
* Purpo~e: Eng. t.11£0 * /J/11. ' . | |||
Cal Block Number. f't ~ 7 7 </ 'i .. ' . *ca1*Block Temp | |||
-~ l".,;-lJ l* - d..llJ C, , **SH lJ . , Tuermome.ter SIN.& Dua Date '3/4 . | |||
Search1:1n1t lnstrwnenl*&.Setlitgs' ,IJ If Jtf.Jt' Manutaewrer ,/l'/HJ | |||
* Mfg,/*Modet' #::S SM1.tor'.flll)e I!. ............ SWl'al Number OOt'. 11 a 100, Frequency. .1: Aitn:z. .. | |||
~ | |||
Raooa | |||
* I'/ . | |||
.-...:t...,_11 Cl'I AJS | |||
. | |||
* Size & Srnioe Mii!erlal 60 Modi;ITorc | |||
* C l\lelay .~ # ~ll) ~ | |||
Search UnllAngle* ,eo 'Purser /ltM.'I 60 | |||
* *Milas11red*Aiigle * . IJa .. ReJect* .., <'J,. | |||
3erlal Number- | |||
* Froou1mcw J | |||
* fl J.':OC'IG~ 40 | |||
.i ' ,Qabla TVl!e, t.en'Mll {JOB.I I,:;: , Damping, .. | |||
* No. of Cbruloot<l!'tl : | |||
.. ~Value *. | |||
1:,00 0/.lM. | |||
~ | |||
.0 )19 | |||
* 20 | |||
.. P,vlse Rep Rafe ,uo1. 2 4 6 8 10. | |||
'. Ga!nSe\tfng "'IA | |||
~ents'CChefllll *. Cl:\llbraUons. ; Timo 'CRTSefup , Inches | |||
\., $keldl I "Vi'I ...... lnUl\'ll Callbrallon . )11'\f'I*. Metal*.Path N/A suoptemenl.\l I y Fl(llll eallbral!on f,1/1, Oe!')lh 1.0 ~~ | |||
f'irlil CallbraUon a.oco Ooup(snl DAI& | |||
8f8nll * <nr,ildSa.+~ | |||
t'latcfl. Number OG'J'lf'I A SAP Batch Mgmt. | |||
No. OO<<l07Sl.3i Component ID Component Type Commenw, I ** | |||
i . | |||
J;°M f{, Ct,11? Q/llf f:{t) ~i Rm. -,a .n1i/lt'-. ,'fnlll-l't. ISP u ..*on.M t<iJ: .lJ<:wPx If l'.l'.l | |||
.*Examlner(Pririt~Slgn) Pl,P/.ni,./ niui.... 1--,,. '-* *I* | |||
1.r~ | |||
Lever .;g_ Dal~ :ti1,//0'Z examiner (Print{!,, Sign} /J/ A Level ~Lll Oate 'l,Jf.4 | |||
*Reviewer (Slgnatur111) Level ..oare ' | |||
MP-UT*45 Lever of Us.e . Rev. 0.00-01 | |||
'. Page*10 of 11 I | |||
i .; | |||
Reference-J.. | |||
* ge-lO-of 19.. | |||
* _.':,,. ..*..... _... Serial./llo,-2-1-,292 * .., --* | |||
Docket No. 50-423 Attachment 4, Page 12 of 24 | |||
/ft It FW-37 | |||
,. . P@int No-. *1st Signal (no bond) 2nd Slgnal (bond) | |||
I 1 GO L/0 2 (;O ~o 3 d..0 ~o | |||
.4 40 bO 5 so . | |||
O i . | |||
.I 6 | |||
7 | |||
~o zo 4-0 60 8* | |||
9, GO ~o ,t 40 60 10 a.o .' -~o 11, | |||
*1.2 | |||
~o so bO *lfO 13 /J ~ ........ | |||
i | |||
'i I | |||
* 14 | |||
*1:5* ------- | |||
A | |||
.,,'II 1*6 I | |||
I .. | |||
. Total Average i. | |||
I | |||
* i_P.age--l~l--of-JJ)................................. .', ' .....:.... . | |||
.., ..... _ .... ,.... -* ... . ..... -*"*-*-- .. . ......-..-*-*--*-* .... :...... *.. ,... . . ... .. .. ..........SerlaLNo .. 21-292 . . .. | |||
Docket No. 50-423 Attachment 4, Page 13 of 24 M3-- /i.V.. O'l* tJ'Pt!J6 k O 12t-, 12.. . | |||
'I I , | |||
FtJ- 3Z .* . | |||
.Point N-o-. .-1st'Signal (no bond) 2na Si.gnaJ. (bond) 1 6.0 ... , | |||
'10 : | |||
2 60 'I<!) | |||
3 | |||
.4.. | |||
60 .~o 70 30. | |||
5 GO 40 "6 | |||
so ~o 7 70 30 | |||
-8.* 70 30 *. | |||
9* 4-0 60 10' *. cl.., .. '60 ' | |||
11* ... | |||
lfO 60 ., | |||
I I . | |||
1:2 7o* JO II 1*3 ,J ~ . *. | |||
I I | |||
1,4 ~ | |||
l l* | |||
*1:5 ~ | |||
i 1*6 -~ A Total Avera.ge Sw H f" | |||
**1*-u, .. ,.,,, ..,,, .. | |||
,P~ge-i2 of 19 .. | |||
...*,*., .. ' , .... ,..........................:. .... . . .. .. ,,_.. ~!'lr@L~q. 21:292 ... | |||
Docket No. 50*423 Attachment 4, Page 14 of 24 I * | |||
''l | |||
..2na Signal. (band_) | |||
I | |||
*Polnt Nn-. *tsf'.Signal (no bond.) | |||
*1 GO . l/0 I *f 2 ~o. ~o 3 GO 1/:0 4 C;O 'tO | |||
*5 .JJP .Np 40 | |||
**a Nf NP ~o . | |||
I | |||
\" :" . 7 'ID ,o : | |||
/. | |||
fl 'tO *GO 9* I ~ * /, | |||
' to- N /. | |||
11- *' | |||
./.*. : | |||
1:2 /* | |||
'1*3 / ' .... " | |||
1:4. / | |||
' *f5 / I" 1*6 I/ | |||
: I I | |||
* l | |||
! Tota.t Average I | |||
i ;. . . | |||
I * | |||
*Page l 3 Qt-** 1\}"" ........ * ......... .. ... ........... ____.___..,.......... | |||
*.*. '" , t ' *****-*** .. , ............. -~.. * | |||
.. i. *** ' | |||
. ____ . ... ..... ___ . _§@ri?l.N9.,. ?1-2~2. ... , .. __ ...... .. | |||
Docket No. 50-423 Attachment 4, Page 15 of 24 Attachment*1:t:xam Data Sheaf Millstone Power Station ULTRASONIC_EX'AMINATION | |||
.STRAIGHT BE~ MEASUREMENTS' Instrument & Settfngs Compont~f'Data Manufaoturer . | |||
* Component T"""' II ModeiNo. J.. Component Dis. I Atteclunent.s. | |||
Raogo Velocity, Block Tlilckol!SS Instr11111.ent*Readlng Min. Max. | |||
Zero Value ~tlal Cal Tolc:ninco Intcnmdiato Intermediate l | |||
* Final Manufacturer TypcNo, , ** Coatings Factor Data | |||
. ScrlalNo. Brand* Surface Painted YO | |||
* FrC((Uenoy . Batch*No. ACT*mlls .. ,-JI Sizo | |||
* ACTX3mlls= . /.t} | |||
"Avcrago Coat.Ing Thickness Sketcli/Conuneats Ar/!li | |||
* AttJiqli,Ph,ito(ll) <1fRll~~t* C~ndltfons S~cly | |||
.StiJ I | |||
.I. | |||
i *, BXllmlner(print&sign) M/r:l@e,7 Beehler/Jtl<<./4,t," | |||
j LtwelA Date_3/11/Q:L '. | |||
~eviewer(sign) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____,Level _ _ _ _ Date _ _ _ _ _. | |||
1 ANJ!ANU If-Required (Sign) Date ___Nl.._A...,.__ | |||
LevelofUse MP-UT-5 | |||
*Reference Rev. 000-05 Pa e23 of2S | |||
:Page 14 of 19 ' . | |||
l,._.wG-*,..-- -* ''"-*"'-**-*----*---------*--~-*-*-**-*.,-..,.****- ---*-**-*-.,.\-..,_....., ... **---*,._,,,.._._ .. ,_,. ****- | |||
* 0 , I * | |||
,. ' . . .~ - . ,., .......:-. Serial No. 21-292 | |||
~.'----**--*- UockefNo. 50~423*--*- .. --* ---- | |||
Attachment 4, Page 16 of 24 M3-EV"08-0006 Rev. 00 Page 15 Sheet 1 of 4 Braze Bond Structural Assessment , Joint SWP95-FW37 Ref: TE M3-EV-05-0002 Rev. 1 this sheet revised 07/17/2007 Part 1 Basic Data ( dashed boxes are inputs) ln.£!!ls: __________ *--" __ Inputs: | |||
Line No:jSWP-075-V222 I Pipe Dia j 1.05 in j Sys Functlon:1FT-438 upstrm instr tubing , Norn. Wal/Thk, 0.154 in Piping lso:jCI-SWP-95 Sh 2 I Pipe Mat'J1SB 466 CDA 706 Joint: :SWP95-FW37 Fitting Mat'l!SB_~1or_~~-- __ * ...! | |||
Side ofJolnt:1Upstrm I Ref. Bond Strength: 7,500 psi Jt. Orientation: :!~r" ____ . __________ _; Bond Adjustment 10% | |||
Measured Ave. Bond 59% (calculated. For bond measurements, see sheet 'UT Readings') | |||
59 % >= 60 % ? No, Detailed assessment required Part 2 Bond Data Summary (data from sheet 'Bond Cales') | |||
Off.sets based on adjusted bond: | |||
Dxx -o.oos in* | |||
Dyy -0.026 in Doffset 0.027 in (5% of pipe radius) | |||
Alpha 9.7 degrees - rotation angle of principal axes Calculated effective bond data are in principal axes system, and are based on adjusted bond. | |||
Actual Adjusted Bxx 66% 62% | |||
Byy 52% 47% | |||
Bbend 52% 47% 4 Bpress 59% 55% | |||
Note: Plot is figurative only, actual braze bond Is cylindrical, not through-wall. | |||
3SWP-V222-FW37.xls P!!ge 15 of 19 | |||
.... -** .--~-*--*****--*~*--*-----** | |||
-~ - . . *-' *-* - - ......Docl<eTNii"'o0'.:-423-***-... | |||
Serial No. 21-292 . J ........... _ | |||
Attachment 4, Page 17 of 24 M3-EV-08-0006 Rev. 00 Page 16 Sheet 2 of 4 Braze Bond Structural Assessment Joint SWP95-FW37 Part 3 Calculated Bond Load Capability Lookup Toi: L,lnsert per MUSpec D 1.05 in D.nom D.od Linsert tnom 0.154 In 3/4 1.05 11/32 PipeZ o.085 in"3 1 1.315 7116 Llnsert 0.344 iri (from lookup table at right) 1.5 1.9 518 Smax{100%) 26, 169 psi (from formula at right) 2 2.375 21132 2.5 2.875 25/32 Load Capability (Allowable Nominal Pipe Stress) 3 3.5 53/64 | |||
{Based on bond levels from Part 2) | |||
Actual Adjusted Sxx 17,213 16,218 psi stress based on shear allow. and percent bond sv; 13,695 12,295 psi 2 JtD *Linsert Sallow 13,695 12,295 psi S mJb adj)= b adj' *'tma, 4*Zpipe Part 4 Pipe Stress Data (stress calc Inputs) (data from Part 1) | |||
Stress Cale:- NP:swP. .9s~V222 . . - .... - k .. iI Pipe Dia 1.05 in I | |||
Rev/ CCN1 Rev. 2, CCN 0 ________ _J Norn. Wall Thk 0.154 in Line No: SWP-075-V222 Pipe Mat'I SB 466 CDA 706 Sys Function: FT-438 upstrm instr tubing Fitting Mal'I SB 61 or 62 Piping iso: CI-SWP-95 Sh 2 A.pressure 0.825 in"2 Joint: SWP95-FW37 Z.pipe 0.085 Tn'i.3 - * *- | |||
fnnuts: | |||
StressNodelnta;r___ .----*-----**7 p ,A Aft. Stress Node*n ' I | |||
* max press a ' SP offset;; D0 rroor*----''--- | |||
S/F Usedl 2.1 I - 2 p!pe | |||
.... - - .. - - - - - - - - - - - * - .... - ....J Primary SIF 1.575 S-Slp %end S=--+s p_o rns~... +s1PB*-- | |||
Inputs: psif press Design Pressure 100 psig 1 1 Max Op. Pressure , . 100 psig , Calculated Nominal Stresses | |||
* Sip ! 170 psi Jsp_offset 27 psi Eq. 8 (P+DL)t 2448 psi I Sust'd 8' 1619 psi Eq. 9 (NIU)* 5238 psi | |||
* N/U 9' 3391 psi Eq. 9F (Design BastsoL ___ ~Q2_p!JL ___ F_a_u_lte_d_9_F_'_ _4_1_3_0 psi Max Pipe Nominal Stress. 4130 psi Apply Safety Factor of 1.5 6195 psi Part 5 Structural Integrity Determination Joint SWP95-FW37 Joint Load Capability . 12,295 psi (from Part 3) 1,S*Deslgn Basis Load 6,195 psi (from Part 4) | |||
Check: 6,195 < 12,295 ==:;:> Braze is adequate for design basis loads | |||
* Monitor until repair/replacement 3SWP-V222~FW37.xls Pqge 16 of 19 | |||
** *,, ' " o,o **** | |||
r~*****, r,,, .. ~,~ .. ~-**-*-*~-**.. ~ ,..,.. ,~-,~.-* 0 **, | |||
.serial No. 2.1-292 ______ .. * --------- | |||
Docket No. 50-423 Attachment 4, Page 18 of 24 M3-EV-08-0006 Rev. 00 Page 17 Sheet 3 of 4 Braze Bond Measurements Joint SWP95-FW37 R Rmin Bond Adjustment 10% 1 0.75 Reading Angle Meas. Bond Adj Bond PlotValue Adj Plot Max Min 1 o: 40%: 33% 0.850 0.833 1 0.75 2 30' 40%j 33% 0.850 0.833 1 0.75 I | |||
3 60*I 80%: 78% 0.950 0.944 1 0.75 4 90J 60%1 56% 0.900 0.889 1 0.-75 5 120: 50%: 44% 0.875 0.861 1 0.75 6 1501 80%1 783/4 0.950 0.944 1 0.75 7 1ao: 60%: 56% 0.900 0.889 1 *0.75 8 2101 40%1 33% 0.850 0.833 1 0.75 9 240: 60%: 56% 0.900 0.889 1 0.75 10 2101t 80%1I 78% 0.950 0.944 1 0.75 11 300 1 80% 1 78% 0.950 0.944 1 0.75 12 3301I 40%! 33% 0.850 0.833 1 0.75 13 360 1 0%' 0% 0.750 0.750 1 0.75 14 390! 0%! 0% 0.750 0,750 1 0.75 1 | |||
15 420 0%1 0% 0.750 0.750 1 0.75 16 450!I 0%*I 0% 0.750 0.750 1 0,75 17 4801 0%1 0% 0.750 0.750 1 0.75 18 510: 0%: 0% 0.750 0.750 1 0.75 19 5401 0%1 0% 0.750 0.750 1 0.75 20 510:_____ 9o/ctl 0% 0.750 0.750 1 0.75 N~eadlngs 12 Ave 593/4 55% G9:G21 dTheta 30 Min 40% 33% | |||
degrees Max 80% 78% | |||
Page 17 of 19 | |||
.. * . .. t ..... ~-* - ,,.. .. ., I "' ., ...' Serial No. i1-292 . | |||
..ocic1<ema:**so*-42:r*** -** | |||
Attachment 4, Page 19 of 24 f.13-EV.-OB-0006 Rev, 00 Po9e18 Shcel4 oC4 Bra:.:e Bond Calculations Joint SWP95-FW37 Bolr,e\ Nreadiogs Equfvalon\ bond based on measured bond readings, WilhoUI adjuslmenl 10% 12 D ~le Mea,. Bond <<>Sllhola) db"co$ db'cos*z db'sln'<<>$ sln(1heta) db'*ln db'sltr'2 1,05 0 401\ 1,000 MOO 0.400 0,000 0.000 OJ>OO 0.000 30 40% 0.868 o.:146 O.:JOO 0,173 0,600 0200 0.100 N>fl$cilllJ)ul 60 60¥, o.soo o. 00 0.200 0,:146 0,8liG o.m 0.600 o degrees 90 60% 0.000 0.000 0.000 0.000 1.000 0~00 0.600 O.OOOrad 120 60% .0.500 -0,250 0,125 ,0,217 0.6"8 0.433 0.375 160 80% -0.866 .0.6!n 0,600 .0.:146 MOO 0.400 0.200 160 601\ *1,000 .0.600 0.600 0.000 0.000 0.000 0.000 210 40% *0.866 -0.348 0,:)00 0.173 -0.600 .0.200 0.100 240 WY, *-0.500 *0,300 0.150 0-260 -0.866 *0.520 0,460 210 60% 0.000 0.000 0.000 0.000 -1.000 .o.eoo o.eoo 300 MOO o. oo MOO -G.:146 .0,66G -0.G93 0.600 | |||
:)30 40o/, o.a,s 0.345 o.:ioo .(),173 *0,600 .0.200 G.100 | |||
:)60 0% 1,000 0.000 0.000 0.000 0,000 0.000 o.DQO 390 0% 0.886 0.000 0.000 0.000 0.500 0.000 0.000 420 0% 0.500 nooo 0000 0.000 0.866 0.000 0.000 450 0% 0.000 0.000 0.000 0.000 1,000 0.000 0.000 480 0% *O.SOO 0.000 0.000 O.Ooo 0,866 0.000 0.000 510 OIi -0.866 0.000 0.000 0.000 MOO 0,000 0,000 540 0% .1.000 0.000 0.000 0.000 0.000 0.000 0.000 670 0% -0.666 0.000 0.000 0.000 *D,500 0.000 0.000 0.000 *0.025 3.175 .0.130 0.000 .0.007 3.925 Bpruo c:h,:Ok,,Q ry epyy Bpxy c/recJ<<O BpJIX 59¥, *0.042 0.265 --0.011 o.sn .0.012"' 0.327 Rorrm 0,023 Yollsel | |||
.o.on Byy 0.264 a.., | |||
.0,011 BY)l+BM 0.591 Xolrael | |||
-0.006 BM 0.:127 BByy $3\1. Save 59% BBxx 66% | |||
BYYJI 0.262 8lU<..P 0.329 521/4 66o/, | |||
Uil'U>r-0 Bxy=O lan:Z.lpha e<>>2olpha *In 2alpha tao ched< elpha | |||
.0.063 -0.011 0.351 o.9<< 0.331 0.351 0.169 111d FAI.SE FALSE 9,7 d<9 Eqvivalent bond based on adjusted bond readings l:,~ | |||
~. | |||
* II di l~ .. otr.w:t Angle MJ.8ond e<>>(llle!a) db'"'° db"COS112 db*sin*cos *in[lhela) db ..ln db'11n'2 1 0 333/4 1.000 0,333 O.:J:l3 Q.QIJO 0.000 0.000 0.000 r.,.*~*:£*, ...(ej 30 33% 0.868 o.m 0.250 0.1<< 0.500 0,167 0.083 60 78% 0.500 O.Je9 0.194 0,337 0.868 o.614 0.563 90 563/4 0,000 0,000 0.000 0.000 1.000 0.656 0.556 | |||
"*** i*I:*roh(*f 120 150 44¥1 78% | |||
.0.500 | |||
.O,BB8 | |||
-0.222 | |||
.0.674 0,111 0.583 | |||
-0.192 | |||
-0,337 0.866 o.soo 0,385 0.389 0,333 0.194 180 611% *1.000 -0.556 0.556 0.000 0.000 0.000 0.000 u,1* ;t*I:.,*""(*l-,.,(o, 2\0 3311 ,O.S68 .,0.289 0.250 0,144 .0.600 -0.167 0.083 240 ser, .o.m -0,278 0.135 0,241 -0,886 -0,481 MIT | |||
&y,::::a fr1r **r./*b1v 210 78% 0.000 0,000 0.000 o,oao *1.000 ,D.778 o.ne 300 7811 0.500 0.389 0,194 -0,337 *0.86& .Q.674 0.563 Ba*lr,.-.-,J*t.1 ., 330 33% 0.868 0,289 0.250 ,0.144 *0.500 .0.167 0.083 360 ov. 1.000 0.000 0.000 0.000 0,000 0.000 0000 D C Ir. | |||
* 390 0% 0,Sli6 0.000 0.000 0.000 0.600 0.000 0.000 420 Of, 0.500 0.000 0.000 0.000 0,866 0.000- 0.000 1o.{toJ*r7 450 0% 0.000 0.000 0.000 0.000 1.000 0.000 0.000 | |||
,,.(,ol- l11y,-*,l 4IIO 0% .0,500 0.000 nooo 0.000 0,886 0.000 0.000 510 DY, .0.866 0.000 0,000 0.000 0.500 0,000 0.000 J(&yy- e,J'' O,y 540 0% *1.000 0.000 0.000 0.000 0.()00 0.000 0.000 570 0Y, .0.666 0.000 0.000 0.000 -0,500 0.000 0.000 r*(l-a)* ,.,(1,,(>o))-/l*l\.g o.aoo .0.027 2,861 .0,144 0.000 *0.000 3.694 Jt11y,-e.~** **,,' Bpreu dleck:Q ry 8p)Y Bp,y -lr-0 nc BpJIX 5511 .0.050 0.238 -0.012 0.54G -0.016 0.308 | |||
.,. 3/411il(,1q(i--a.)) | |||
Rattscl Voffset Syy Bxy XoR,e\ Bxx | |||
",_yy= | |||
~ ,, | |||
*7*co,{l-o), "D.t*bl>o) 0,027 .o.~s 0.237 -0.012 Byy+B"" | |||
0.545 .0.008 0.308 1 BByy 47o/, Bave 543/4 BBxx 623/4 ByyJI 0.235 B)O<JI 0.310 | |||
.._.... "n;"*-¥-,--,t,..) ...1...(2..) 473/4 62% I 811'8""° BxyeO l;ln2atpha C0120lpha '1n !!alpha Ian cha<:k alpha | |||
*, .*r* *,r>>C**I - 9v; '-**h**l 0 .0.071 FA1.Se | |||
.0.012 FAI.SE 0.352 0,943 0.3:lZ 0,352 0.169 rad 9,7 deg Mta.suted BGnds B<rNIYol\>o,-..,ll<ID1A_otl,.ler,gle Bordv,\Joscalc<l;ledalA...olf,o\otqo Yaflse1 8yy Xolfsel Yolr,et Byy Xoff**t a,.. | |||
*0.022 53% *O. 6 -0.026 47% *0,008 62% | |||
3SWP*V222-FW37,xl& | |||
fage 18 of !9 | |||
..***. .!.***** * *Serial*No-: 21 s-292 ** .... ** ....,-..... _.* | |||
Docket No. 50-423 Attachment 4, Page 20 of 24 | |||
, Technical Evaluation No. M3'-EV-08-0006, Rev. 00, page 19 of 19 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075.Y222 Independent Reviewer Comment and Resolution Sheet(s) | |||
(ER/EV) No. M2-EV-08-0006 Rev. 0 Page 1 of 1 Independent Reviewer: Thomas Steahr ~ ( / tk.::: Date J/r;/o'c? | |||
Comment No. ER/EV Section Comment All Minor edits 19 Page 19 of 19 | |||
Serial No. 21-292 | |||
.........- ..... --.... - ..... _.,, ............................ **-***--------...- ...... _ ... Docket No ...50-~42_3_ _ | |||
Attachment 4, Page 21 of 24 ATTACHMENT 1 ULTRASONIC CALIBRATION DATA SHEET ' | |||
Page \ of,_\__ | |||
Plant: MI LLS:fo ~f:' Unll: "3 AWO Number: ,M,3 ~ O'a ...- ct.(\ ~ :l | |||
==Purpose:== | |||
(t-JC;i:I i,..,)tt'.R.! I\.)~ .Ir-J~OR./V\8TION Cat Block Temp ~JA Cal Block Number M"i"E'-0:2.0 lS' | |||
~s~,c.\-.)..\.o:::>\ SI-\.~\ Thermometer S/N & Oue Dale bl /.A DWGNo. | |||
Search Unit Instrument & S&ttings Manufacturer ltr:1...d Mfg./MOdel \(.I". | |||
Style or Type ~ . ,..,, . ,. .... Serial Number ~l"V'I n,15 too Frequency [,::..,.,,Nll.l:r,. Ranne \.o'' ,tu- II 6 Sizel!o Shape * .::).5" Material Veloolty .\&:>tvO 80 MOdeTorC C Delay ~o.3"15 Search Unil Angle Cl> Pulser N_ 1111.., 80 Measured Angle ,_,(A Reieet O"I. | |||
Serial Nun'lber oo*a~,.N Freauency .;.,_<;:\ 40 Cable Typ&, .Length lo~-l~L!/( *1 1-u& Damping ,.,.cc,,,..,,... | |||
No. of Connectors 0 zero Value l<.t. I 4'4> 20 Pulse Rep Rate l\lrLL 2 4 6 8 10 GalnSeWng ~IA Allachments (Check) Callbrntions Time CRT~tvp Inches Sketch Sheet 1 i-.)1..6 tn!Ual Callbrallon ,~~4 MetalPalh 1-l/A Suppl,ements I Final Csllbrnllon ~*JA Depth .O'' | |||
Final CallbraUon Ht.:;~ | |||
Coupiant Data Brand ...... _ ... --C""" | |||
Bateh Number c,t~1,...-.A SAP Batch Mgmt. | |||
No. ,'>_"','?, | |||
component ID component Type comments t:'W-~<;1, 1"""".,i:"1' -.;:...., NT ltl:'11 \.(J~_,\Jt) :::' v .A J\,'I II Examiner (Print & Sign ll.(.)\:\1-Ji:'"'\l .... A =-Yll ' I , . ~ ~ f L.evel :11: Date ,::,/',;),'1. lr,-t Examlner (Pr:lqt & Sign) u V Level bl[t's. Date ,-J(A Reviewer (Signature) ~ ~ Level -:0: Date 5/-!:l~_<>'i. | |||
MP*UT--45 Level of Use Rev. 000~01 Page 10 of 11 Reference | |||
Serial No. 21-292 . | |||
_ _____,___ ,. ... ,..................--... - ...-~*---, .... _,. ______ .........,_....... -* .......... - . . -*........------* .. ---*---*-* ...QoGket*Noc*50*423--*--**-- .. *" .. .. | |||
Attachment 4, Page 22 of 24 f\JJ .. 3>'o Awo M?>-O'o-O'-{\'o:i.. | |||
Point No. 1st Signal (no bond) 2nd Signaf (bond) 1 Li,() 4D 2 ~o 40 3 ,D I :-2,o 4 (c,5 35 5 loo 40 6 ,o 2>0 7 70 3o 8 y,'5 1,$ | |||
9 I.QO Yo 10 l.oO !.fO 11 -,o &:> | |||
12 70 30 | |||
- Average Lf5 °/.. 3$ "'/. | |||
Serial No. 21-292 | |||
. ****-*--*- ......... Docket No:*so0'423*** | |||
Attachment 4, Page 23 of 24 ATTACHMENT 1 ULTRASONIC CALIBRATION DATA SHEET Page or_-a_ | |||
Plant: M p .. 1_,5!:'QNf:* | |||
* Unlt: '3 ' | |||
AWO Number. f!1 ~ - Q '.o ... ~41<33 Purpose; E: ~ C'-;i:I N~t' Q.1 !-..le;. ;(1-J~O~c)Tf OI\J Cal Block Temp i-.1/ A Cal Block Number °18-,loo OWGNo, d>:52.\ :i..- ~, 00 \ SH, ::tl Thermomer~r SIN & Due Date ~LA Search Unll Instrument & Setfings Manuracturer .,.,,,_,. Mrg./Model \(l!,/VSJ,) $':U.. .I.I nll !)'T' n, SIYleorTwe ~.luV\.AIIA Serial Number r,rit'_ ls)C::l. 100 Frequencv ""C, "'11-l?. Range l.t"lnll Slze&Shape .:z.~' Material Velocity \ "I :1 (! 80 Mode Tore c:. Delay -.'.2..~":l Search Unit Angle co Pulser 'l">vAl. 60 Meas*ured Angle NIA ReJoCI o-/. | |||
Serial Number r,,-,'nX.\.)\J Frequency 1.-'21 40 Cable Type, Length or.~1,'l/l~ Damping I ,.,,..,., °"M No. of Connectors (") Zero Value l{,OM 9, 20 I Pulse Rep Rate \.\-\G,1-1 2 4 a 8 10 GalnSeWllg \JIA Attachments (Cheek) Callbratlons lime CRTSelup Inches Sketch Sheet I iJ/A lnltlal Call~rallon OC\!><t Mel;ilPath iJ A Supplemenls I . Final Calibratron NIA Deplh l. (\ ... | |||
Final Ca!ibrallon \000 Counlant Data erand '"UNt>S..l\~l':' | |||
Balch Number a c,,, :i_c, A | |||
-SAP Batch Mgmt. | |||
No. n HU | |||
._-"l_":I,,;: | |||
Component ID ComponentType Comments | |||
'Fw- '!. 'i\ ~e.A, ~lb ~nll\.lT 'l=~Ll-"'<--"- uO ~ .... AAA Examiner (Print & Stgn)~~ g,Q!ieli-lilJi<.MA~ t fl.l ~'"of - Level :rr Date "eL'.J.t;lo"J. | |||
o/~t"ifa~ | |||
D Examiner (Print & Sign) Date | |||
~~ | |||
Level t,,l(~ | |||
Reviewer (Signature) LeveJ..:11: Date MP~UT*"45 Level of Use Rev. 000-01 Reference Page 10 o! 11 | |||
Serial No. 21-292 | |||
******~ **** >R - *"' *-~*-.**-*-***** ~,.. | |||
* I MO* .. 0 | |||
. ... . ... **-*~---*~---*-*-*' ........ ' ,.. . ** .. ' [)ockefNo. 50-423 _____ ... . . .... | |||
Attachment 41 Paae 2j g{ 24 *a Point No. 1st Signal (no bond) 2nd Signal {bond) 1 Ct,0 4 <? | |||
2 L,Q 40 3 -, 0 3o 4 (Q*S 3$' | |||
5 <oS ~s 6 l..; s :; s 7 "le, ~o 8 leO 4<> | |||
9 70 :>0 10 ~s :,$ | |||
11 lc5 35' 12 70 30 Total *1 <a 5" ({IS' Average ~5"/.. 3 S .. ? | |||
. *f | |||
\ | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 5 MECHANICAL TESTS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 5, Page 1 of 3 | |||
==1.0 BACKGROUND== | |||
The correlation developed by the testing conservatively determines a required bond level for a given intensity of joint loading. The results of these tests support the use of the comparison shown in Figure 2 of Attachment 2, for the structural integrity analysis. It is noted that the evaluation of testing results was with respect to a braze shear capability of 5.0 ksi, which in the final methodology has been increased to 7.5 ksi, provided that piping loads have an FS of 1.5 applied. For consistency with testing as performed, the 5.0 ksi shear capability discussed is retained in this attachment. | |||
2.0 TEST SAMPLE DESIGNS The effort to empirically confirm required bond levels for varying intensities of joint loadings consisted of three separate series of mechanical tests: | |||
a) specially fabricated joints with a controlled average bond level, b) specially fabricated joints that had disbondment on a contiguous arc-segment of the joint, and c) field sample piping joints, salvaged from piping removed from the plant. | |||
All joints were tested in three-point bending with the brazed fitting in the middle of the configuration. | |||
2.1 Specially Fabricated Joints with a Controlled Average Bond Level By a combination of machining and use of insert-groove type fittings, a series of test joints were fabricated with equivalent bond levels of 12, 30, 40 and 60 percent. The machining removed only about 30 mils of pipe thickness so that piping strength was not significantly affected. The samples were fabricated for two-inch and for three-inch joints. Three examples of each size and bond level were fabricated, for a total of 24 samples. (Of the 24 samples in this category, one of the 40 percent bond samples was subsequently found to have less than the fully intended bond and is excluded from the results.) | |||
2.2 Specially Fabricated Joints that had Disbondment on a Contiguous Arc-Segment of the Joint: | |||
These test items were intended to explore the effect of having a significantly non-uniform distribution of bond area around the circumference of the joint. Six samples were fabricated with disbondment segment angles of 36, 48, 72, 90, 108 and 126 degrees. The average bond levels for these samples, assuming perfect bond except in the disbonded segments, ranged from 90 percent down to 65 percent, respectively. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 5, Page 2 of 3 2.3 Field Sample Piping Joints: | |||
These joints were salvaged from piping that was removed from the plant after about 20 years of service and screened by Ultrasonic Testing (UT). Piping joints with the lowest of measured bond were selected for testing. | |||
The nine items selected for testing included the following: | |||
Description Quantity Two-inch couplings 3 Three-inch couplings 2 Three-inch tee (run sides) 1 Three-inch flanges 3 The couplings and the tee included two brazed joints subjected to test loads. | |||
The test flanges were mated to full strength flanges not under test. | |||
3.0 MECHANICAL TEST RESULTS The results from testing on each of the series of tests are described in the balance of this section. The referenced figures are included in Attachment 2. A test report has been incorporated into the Millstone Power Station plant records. | |||
3.1 Specially Fabricated Joints with a Controlled Average Bond Level: | |||
For the intentionally disbanded joints, all joints with 30 percent or better true bond, achieved full piping collapse strength with no failure of the bond. Refer to Attachment 2, Figure 3. As testing of each joint continued above the piping collapse load, one of the 40 percent true bond joints had indications of bond failure. The 12 percent true bond joints all experienced bond failure before reaching piping collapse load but withstood a minimum of 37 percent of the piping collapse load( refer to Figure 4). All test items achieved their test collapse load at a load well above that which would be predicted for a 5 ksi braze shear strength. | |||
3.2 Specially Fabricated Joints that had Disbandment on a Contiguous Arc-Segment of the Joint From 36 through 72 degrees of segment disbandment, the test items all achieved full piping collapse load. The test items from 90 through 126 degrees disbandment exhibited progressively lower collapse load, as shown in Attachment 2, Figure 5. At 126 degrees disbandment, the test item achieved about 60 percent of the piping collapse load. The load deflection curves for these joints did not exhibit any indications of bond failure, however at the extremes of deflection (well above the level that would be acceptable for application of this methodology) the higher angle joints were significantly distorted. For such large levels of deflection, it was apparent that the close | |||
Serial No. 21-292 Docket No. 50-423 Attachment 5, Page 3 of 3 mechanical fit-up of the pipe in socket configuration contributed to joint bending strength. All test items achieved their test collapse load at a load well above that which would be predicted for a 5 ksi braze shear strength. | |||
3.3 Field Sample Piping Joints The field sample test items exhibited considerable variation in collapse load for roughly similar UT bond readings. The variations were expected for the field samples. Figures 6 and 7 show the displacement load curve for the tested field samples. Bond failure limited the collapse load in the two-inch Joints 37 and 39, and the three-inch Joints 3 and 9. The load curve for Joint 9 has a slight discontinuity at 11.9 ksi that is conservatively considered to indicate initial bond failure, even though the load continues above this point. The collapse load for other samples was limited by the piping collapse load, which is equivalent to about 21 ksi. Even with the low UT bond readings, the field samples developed at least 50 percent of the piping collapse load. The higher than expected collapse load for some of the three-inch joints is believed to be partly due to the thickness of filler metal present as a fillet at the face of some of the joints. All test items achieved their test collapse load at a load well above that which would be predicted for a 5 ksi braze shear strength and the adjusted percent bond used in this methodology. | |||
The adequacy of the 5 ksi shear stress assumed in the methodology in Equation 3 of Figure 2, Attachment 2, for estimating joint strength is confirmed by the testing margins shown in the following table. | |||
Table 1: Test Load vs. Bond Shear Capacity Test Shear Test/ | |||
Average Adjusted Test Joint Collapse Capacity Shear UT% UT% | |||
Load, ksi Load, ksi Margin 36 65 61 22.8 15.8 1.44* | |||
37 27 19 11.6 4.9 2.41 39 55 50 19.6 13.0 1.52 2 45 39 27.3 9.0 3.02* | |||
3 47 41 22.6 9.6 2.38* | |||
4A 15 5 27.3 1.3 23.59* | |||
9 38 31 11.9 7.2 1.69 9J 48 42 28.6 9.8 2.95* | |||
31A 21 12 32.0 2.8 11.61* | |||
* Piping collapse load reached before bond failure or deflection run out. | |||
The data in Table 1 is plotted in Figure 9 of Attachment 2. Of the joints that were limited by bond failure prior to reaching piping collapse load, the minimum margin factor was 1.52. This minimum margin appears in Joint 39, with a 50 percent adjusted average bond. Review of detailed bond readings around the circumference of Joint 39 gives an equivalent adjusted bond of 43 percent for the bending axis used during the test, corresponding to a margin factor of 1. 74 for this test case. | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 6 ULTRASONIC TEST PROCEDURE MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 1 of 18 Nuclear Fleet a " - | |||
_.1n111vni Nondestructive Examination Procedure | |||
==Title:== | |||
Ultrasonic Examination of Brazed Joints - Millstone Unit 3 Service Water Piping Procedure Number Revision Number | |||
* NPQR Number ER-MP-NDE-UT-745 0 ER-MP-NDE-UT-745-NPQR, N/A Approval signatures on file with approval documentation for this procedure revision. | |||
R. C. Davies 04/04/2016 Independent Level Ill Review K. J. Hacker 04/04/2016 Corporate Level Ill Approval Level of Use: Reference | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 2 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 2 of 18 Record of Revision Re Page Paragraph Summary of Revision 0 All All New issue as a Millstone Site Specific NOE Procedure. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 3 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 3 of 18 Table of Contents 1.0 Purpose ...........................................................................................................................4 2.0 Scope ...............................................................................................................................4 3.0 Reference Documents .....................................................................................................4 4.0 Definitions ........................................................................................................................5 5.0 Personnel Qualifications .........................................................................,......................... 5 6.0 Equipment and Material Requirements ............................................................................ 5 7.0 Calibration ........................................................................................................................6 8.0 Examination .....................................................................................................................8 9.0 Recording of Results ........................................................................................................9 10.0 Data Recording .............................................................................................................. 10 - Typical Brazed Joint Calibration Report .......................................................... 12 - Typical Brazed Joint Examination Record ....................................................... 13 Figure 1 - Brazed Joint Examination lllustration ....................................................................... 14 Figure 2 - Illustration of Braze Joint with Insert Groove ........................................................... 15 Figure 3 - Illustration of Braze Joint with no Insert Groove (Face Fed) .................................... 15 Appendix I - Qualification Requirements for Brazed Joint Examination ................................... 16 1.0 Purpose ......................................................................................................................... 16 2.0 Prerequisites .................................................................................................................. 16 3.0 Examinations ................................................................................................................. 16 4.0 Qualification Records ...................................................................................................... 18 | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 4 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 4 of 18 1.0 Purpose 1.1 The purpose of this procedure is to define a process for the application of ultrasonic examination techniques for the examination of brazed pipe joints to establish the extent of braze bond. This procedure describes the equipment, material, and documentation requirements for ultrasonic (UT) examinations. | |||
2.0 Scope 2.1 This procedure is applicable to the manual contact ultrasonic examination of Millstone Unit 3, ASME Code Class 3, service water piping with brazed joints to establish the extent of braze bond. This procedure is applicable to brazed joints in nominal pipe size (NPS) of 3 inches and smaller. | |||
2.2 This procedure describes equipment and procedures that shall be used in the ultrasonic examination of brazed pipe joints. This procedure is written based on the techniques and methodology detailed in relief request IR-3-04, no additional qualification is required. | |||
3.0 Reference Documents 3.1 American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI, 2004 Edition with no Addenda. | |||
3.2 ER-AA-NDE-120, "Dominion Written Practice for Certification of Nondestructive Examination Personnel." | |||
3.3 ER-AA-NDE-121, "Dominion Written Practice for Certification of Nondestructive Examination Personnel in Accordance with ASME Section XI, Appendix VII Requirements." | |||
3.4 ER-AA-NDE-130, "Storage and Control of Calibrated NOE Equipment, Calibration Standards, and Consumable NOE Materials." | |||
3.5 ER-AA-NDE-140, "Processing of Dominion NOE Data." | |||
3.6 Fabrication and Inspection of Brazed Piping Systems, NAVSEA 0900-LP-001-7000, Dated January 1, 1973. | |||
3.7 Millstone Unit 3, Relief Request IR-3-04 "Alternative Brazed Joint Assessment Methodology", ML091310666 and ML092390141. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 5 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 5 of 18 4.0 Definitions 4.1 Face of Fitting - The annulus surrounding the socket end. | |||
4.2 Insert Groove - The groove in the fitting socket prepared to contain the brazing alloy ring. | |||
4.3 Land, Fitting - That portion of the fitting on the side of the insert groove nearest the middle of the fitting. | |||
4.4 Land, Center - That portion of the fitting between the grooves in a multiple insert fitting. | |||
4.5 Land, Pipe - That portion of fitting on the side of the insert groove toward the end of the fitting. | |||
5.0 Personnel Qualifications 5.1 The examiner shall be certified to a minimum of Level II in the ultrasonic method in accordance with ER-AA-NDE-120 or ER-AA-NDE-121. The examiner shall be responsible for and shall accept the results of the examination. | |||
5.1.1 In addition, the examiner shall maintain a current endorsement for the ultrasonic examination of brazed piping joints in accordance with Appendix I of this procedure. | |||
5.2 An assistant qualified to at least Trainee or Level I in the ultrasonic method may assist the examiner. The Trainee or Level I shall work under the direct supervision of the examiner and shall not evaluate or accept the examination results. | |||
6.0 Equipment and Material Requirements 6.1 All equipment and materials used to implement this procedure shall comply with the requirements of ER-AA-NDE-130, "Storage and Control of Calibrated NOE Equipment, Calibration Standards, and Consumable NOE Materials". | |||
6.2 Ultrasonic Instrument 6.2.1 A pulse-echo type of ultrasonic flaw detection instrument shall be used. | |||
The instrument shall be equipped with a stepped gain control calibrated in units of 1.0 dB or less. | |||
6.2.2 The instrument shall be used at the rated frequency of the search unit. | |||
6.2.3 The reject control shall be in the "off' position for all examinations. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 6 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 6 of 18 6.3 Search Units 6.3.1 The search units shall be dual element, straight beam (longitudinal wave) with nominal frequencies of 5.0 MHz. The maximum nominal element dimension shall not exceed 0.250". | |||
6.4 Cabling 6.4.1 Search unit cables shall be a maximum of 25' in length and may consist of RG-58, RG-174, or combination of RG-58 and RG-174 type cables with no more than 1 intermediate connector. | |||
6.4.2 The same cables and intermediate connections used for the calibration shall be used for the examination. | |||
6.5 Couplant 6.5.1 A suitable ultrasonic couplant shall be applied to the examination surface. The same couplant used for calibration shall be used for performing the examination. | |||
6.6 Calibration Blocks 6.6.1 The material from which the blocks are fabricated shall be acoustically similar but need not be identical to the fitting being examined. | |||
6.6.2 The calibration block used may be flat or of the same curvature as the component being examined with a surface finish representative of the scanning surface finish on the component to be examined. | |||
7.0 Calibration 7.1 The screen height and amplitude control linearity of the ultrasonic instrument shall be verified before and after examining all components to be examined during an outage or periods of use not to exceed three months. The linearity checks shall be performed in accordance with ER-AA-NDE-130. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 7 of 18 DOMINION ER-M P-N DE-UT-7 45 Revision 0 Page: 7 of 18 7.2 Time Base (Range) Calibration 7.2.1 A suitable linear screen range shall be established using a calibration block. | |||
7.2.2 The nominal bond thickness (pipe back wall) should appear at no greater than 85% of full screen width, although data taken beyond that point, up to 100% of full screen width is valid. | |||
7.3 Calibration Verification (Cal Check) 7.3.1 System calibration shall be checked on the calibration block. | |||
7.3.2 The time base calibration shall be recorded for at least one point within the calibrated range of the system established during the initial calibration and: | |||
7.3.3 7.3.3.1 At the finish of each examination or series of similar examinations; 7.3.3.2 At intervals not to exceed 4 hr during the examination; 7.3.3.3 When examination personnel are changed; 7.3.3.4 After any . interruption in system continuity (e.g., power interruptions, search unit change-outs, activation of new examination setups, etc.); | |||
7.3.3.5 After any instance of suspected system irregularity. | |||
7.3.4 Any change in probes or UT instruments from that used during the initial calibration shall be cause for a new calibration. When replacing cables of the same size, type, length and number of intermediate connectors as used during the original calibration, it is acceptable to perform a calibration check only. | |||
7.3.5 The system calibration shall be documented on the Brazed Joint Calibration Record, Attachment 1. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 8 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 8 of 18 8.0 Examination 8.1 Surface Condition Requirements 8.1.1 The outer surface of the fitting socket shall be prepared sufficiently to obtain satisfactory sound transmission, shall not be rounded in the longitudinal direction, and should be relatively parallel to the pipe surface. | |||
8.2 Examination Requirements 8.2.1 The surface of the brazed joint to be examined shall be laid out around the circumference in increments of 1/4 inch. Markings shall be numbered clockwise as viewed facing the fitting from the pipe. These increments shall be measured on the outside diameter of the fitting. | |||
8.2.2 Brazed joints shall be examined using a straight-beam (longitudinal wave) method as illustrated in Figure 1. Signals typically occur from the following sources; the insert groove (if present), the fitting inside diameter, areas of disband (if present), the pipe inside diameter and possible multiple reflections. | |||
8.2.3 To examine a joint, the search unit is placed over the area of the brazed joint intended to be bonded and moved around the circumference in 1/4 inch increments (see paragraph 8.2.1) and in a number of axial increments determined by the number of lands, land or engagement area width and the search unit size. The percent of bond is determined for each circumferential increment. | |||
8.2.4 A static examination technique shall be used. For the static examination technique, placement of the search unit shall be in accordance with paragraph 8.2.3 for each circumferential and axial increment. The instrument gain shall be adjusted so that the bond signal (pipe back wall) amplitude plus the no bond signal amplitude equals 100% for each increment. | |||
8.2.5 For fittings containing insert grooves, as illustrated in Figure 2, place the search unit on each increment so that the search unit active area is over one land only. Note the first back reflection of the insert groove, inside diameter of the fitting (no bond) and the inside diameter of the pipe (bond) signal on the screen. If necessary, check the back reflections with an un-brazed fitting of the same size to ensure positive signal identification. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 9 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 9 of 18 8.2.6 For fittings which contain no insert grooves, as illustrated in Figure 3, place the search unit on each increment so that the active area covers 1/2 of the land width of the fitting in the engagement area. Note the inside diameter of the fitting (no bond) and the inside diameter of the pipe (bond) signal on the screen. If necessary, check the back reflections with an un-brazed fitting of the same size to ensure positive signal identification. | |||
8.2.7 Limitations or other conditions that prevent a complete examination of the required volume shall be documented on the examination data sheet. | |||
9.0 Recording of Results 9.1 The "bond" and "no bond" signal amplitude values for all increments examined shall be recorded on the "Brazed Joint Examination Report", Attachment 2. | |||
9.2 The increments for which no ultrasonic reading can be obtained shall be marked as follows: | |||
"X"- increments which are inaccessible due to fitting configuration. | |||
"NA"- Increments which are inaccessible due to piping configuration . | |||
"NP"- Increments in which there is a lack of ultrasonic penetration. | |||
9.3 The Increments of the above types shall be assigned percent bond values as follows: | |||
"NA" = 0% bond "NP" and "X" - Increments up to a total length not exceeding 20 percent of the circumference of the land shall be assigned a percentage bond value equal to that of the lowest readable increment adjacent to the "X" or "NP" increments or 60 percent whichever is the least. "X" or "NP" increments in excess of 20 percent of the circumference shall be assigned a bond value of 0 percent. The examiner may, at his discretion, shift the incremental scale so that the minimum number of increments that contain "X", "NP", of "NA" values.* | |||
*NOTE - Within the 20 percent limitation, two or more adjoining "X" and/or "NP" increments are considered a group of increments if the average of the remaining increments is 60 percent or more. The outermost two of any group, within the 20 percent maximum limitation, shall be rated on the basis of the adjacent readable increment. The inner increments of the group shall be assigned a zero value for calculation purposes. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 10 of 18 DOMINION ER-M P-N DE-UT-7 45 Revision 0 Page: 10 of 18 9.4 The bond percentage for the joint shall be determined by a simple average of all the bond readings taken at each increment. | |||
10.0 Data Recording 10.1 Calibration and examination data shall be recorded on data sheets and as a minimum shall include the following: | |||
10.1.1 Calibration sheet identification. | |||
10.1.2 Names and certification levels of examination personnel. | |||
10.1.3 Examination procedure number and revision. | |||
10.1.4 Calibration block identification. | |||
10.1.5 Ultrasonic instrument serial number, manufacturer, and model identification. | |||
10.1.6 Ultrasonic instrument essential instrument settings. | |||
10.1.7 Search unit beam angle, mode of wave propagation in the material, nominal frequency, size, shape, and number of elements. | |||
10.1.8 Search unit manufacturer, model, and manufacturer's serial number. | |||
10.1.9 Search unit cable type, length, and number of intermediate connectors. | |||
10.1.10 Times and dates of initial calibration and subsequent calibration checks. | |||
10.1.11 Signal response amplitudes and sweep positions obtained from the calibration reflectors. | |||
10.1.12 Couplant type and batch number. | |||
10.1.13 Data sheet identification and date and time period of examination. | |||
10.1.14 Identification and location of the braze joint examined. | |||
10.1.15 A sketch of the component examined. | |||
10.1.16 Examination results including any limitations. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 11 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 11 of 18 10.2 All data records shall be reviewed and processed in accordance with ER-AA-NDE-140, "Processing of Dominion NOE Data". | |||
10.3 All results shall be turned over to Engineering for final evaluation of joint integrity. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 12 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 12 of 18 Brazed Joint Calibration Report l um,:* 1<<.4 Mlg : | |||
--------= S@,ial l'kl.: &rial f-lo.: -------=Sea.:r,r,h t:znit P,il;'g.: | |||
!:iedl.l<eh t~t!tlil Si:"': | |||
=------= F'r<<t*--.e,* S~ial t>kl*.: | |||
G::ivplan~; f3alcJ-r, No.: S,;_,.;;,n:.h L:l:iif. N:;rn. -~'1*iiJle: ~ f,'11;-.;u, *.Ang!.;,: _ _ __ | |||
Calrtrav.in ffioel,; ~;i.al No.. s~u"h L~il ,:.,,1:~e l!.e,ng!:!\.: eal:<:s, 1rj1po: _ _ __ | |||
R>!,r11n,-n~;;; Sx;ir,1,,;l;i,!Qr iS.1/4;,;;;k T*rpg; fl1$trumoot Sllottings lnilials fiaclft Rijjr,~ | |||
De-iay Vulo.!,1)':' Mii1. CaL Fr~-)' | |||
Rep. Ra!e OJ.mj:Mng Di~a:re'J id,oc,/i!'!E';til R'=;i!:<-1 UT Measurements Phys,lcal Dlmensklns Signa1ur@ Date OlJ-<9! | |||
Attachment 1 - Typical Brazed Joint Calibration Report | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 13 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 13 of 18 Bnu:ed Joint Examination Report C"if.\v.r.13/4:J~ | |||
::)~~"'-tin tf) | |||
[~t.;£~"(}1;;"\~10: - - - - - - - - - - - - - - - - - - - - - - s,1J.ffil L~t,: -----,-~----- --~ _ | |||
Lt""",ltzh:R,::TI: 5-l.ki Tl1T';(I'. | |||
;7 | |||
Inc!'ernent ffo Bond B-ond 5'<etch 1 | |||
2 J | |||
4 5 | |||
6 7 | |||
8 9 | |||
10 11 | |||
: 12. I 13 14 15 16 17 18 19 20 21 22 23 24 25 Comments 26 27 28 29 30 31 32 33 34 Total Averaae r.e,-1'-iS---,*-:~--L.,,..-'..-t-l--------.~~-£1~-tp,.,,,-,,,--;J~_-*j~====::::::;(:=lfr,,=*~:;:f;::l(',=,=~=.;,===========t;::,~=t.=;:_*=:?='1======(1;::if::::,§: | |||
)E_.1..7c.,..t~n-f4-,--L..,.---,,&,:--------s-l.V-tl:.':1.--,,,-------Ma~ S::ID-P~il~' | |||
li~1J1-,.,,-.,---l~"~ -----~ | |||
Attachment 2 - Typical Brazed Joint Examination Record | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 14 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 14 of 18 Transducer | |||
~ Insert Groove Brazing Ultrasonic Waves Alloy Pipe | |||
~~~~----~ ------Fitting Disband Area in outer land Figure 1 - Brazed Joint Examination Illustration | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 15 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 15 of 18 Insert Groove Brazing lloy Pipe | |||
- - - - - Fitting Disband Area in outer land Figure 2 - Illustration of Braze Joint with Insert Groove Brazing lloy Pipe | |||
- - - - - Fitting Disband Area Figure 3 - Illustration of Braze Joint with no Insert Groove (Face Fed) | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 16 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 16 of 18 Appendix I - Qualification Requirements for Brazed Joint Examination 1.0 Purpose 1.1 The purpose of this Appendix is to provide the additional requirements for the qualification of UT examiners for the ultrasonic examination of brazed piping joints. | |||
2.0 Prerequisites 2.1 Personnel who perform ultrasonic examinations of brazed joints shall also be trained, qualified, and certified as a Level II or Level Ill in the ultrasonic method in accordance with Dominion procedures ER-AA-NDE-120 or ER-AA-NDE-121. | |||
2.2 This Appendix defines the additional requirements for the UT Level II or Ill examiner to successfully obtain a qualification endorsement for brazed joint UT examination. | |||
3.0 Examinations 3.1 Required examinations for the brazed joint UT endorsement include written and practical examinations. These examinations shall be administered and graded in accordance with the ER-AA-NDE-121. The additional brazed joint UT endorsement qualification testing requirements are defined by 3.2 and 3.3 of this Appendix. | |||
3.2 The written examination shall consist of at least 17 questions covering the ultrasonic testing procedure for brazed pipe joint examination. | |||
3.2.1 The examination shall contain at least 10 questions on the operation of the ultrasonic equipment; 3.2.2 At least 5 additional questions on the ultrasonic procedure concerning the inspection of joints which fall into abnormal categories of a physical or administrative nature; 3.2.3 At least 2 additional questions concerning the recording of readings which the examiner makes. | |||
3.2.4 The minimum-passing grade for the written examination is 80%. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 17 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 17 of 18 3.3 The practical examination shall demonstrate the examiners ability to determine ultrasonically the bond of brazed joints. In addition the practical examination shall demonstrate the ability to recognize such technical deficiencies as insufficient beam penetration, poor transducer contact and interfering contact surface roughness from patterns displayed on the ultrasonic instrument screen. | |||
3.3.1 The candidate shall demonstrate ability to determine ultrasonically the bond in at least six brazed joins consisting of three different pipe sizes, with two brazed joints for each size. | |||
3.3.2 The joints shall exhibit from 40 to 80 percent bond with varying degrees of bonding in each. | |||
3.3.3 The percent bond readings obtained by the examiner shall be compared with the true bond. The true bond is considered to be the average percent bond readings obtained by at least three qualified examiners, using the same joints. In the absence of three qualified examiners, the true bond shall be established from reading obtained by the Level Ill testing examiner. | |||
3.3.4 Acceptance of the practical demonstration is based upon the arithmetic average of the six deviations from the true bond shall not vary by more than 8% from the true bond of any of the test joint specimens and no single joint deviation shall exceed 15%. | |||
3.4 Maintaining Proficiency 3.4.1 In order to maintain examiner proficiency for the brazed joint UT endorsement: | |||
3.4.1.1 The examiner shall either have performed a brazed joint UT examination, within the last six months, or; 3.4.1.2 Performed an examination of at least three brazed joint demonstration specimens, in accordance with the requirements of 3.3 above, within the last six months. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 18 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 18 of 18 3.5 Requalification 3.5.1 A qualified brazed joint UT examiner shall be requalified in accordance with the requirements of 3.2 and 3.3 above, prior to performing examinations: | |||
3.5.1.1 If the individual has not maintained proficiency for the brazed joint UT endorsement; 3.5.1.2 If the individual's performance is determined to be deficient; 3.5.1.3 At the end of three years from the endorsement qualification date. | |||
4.0 Qualification Records 4.1 Dominion shall document the ultrasonic examination personnel endorsement for brazed piping joint UT examination on the individuals' certification record. | |||
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 7 ADDITIONAL BASIS FOR BRAZE SHEAR STRESS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 1 of 4 This attachment provides the following two items: | |||
* Additional minimum brazed joint shear stress experimental values | |||
* Further justification for the proposed use of brazed joint shear strength and safety factor | |||
: 1. Minimum Brazed Joint Shear Stress Experimental Values The test data in Table 1 supports the proposed methodology in Request IR-4-09 for ev,aluating the structural integrity of brazed joints. Table 1 was derived from existing ASME Brazing Procedure Qualification Records of qualification tests performed in accordance with the ASME Boiler and Pressure Vessel Code, Section IX. Each test includes a set of either reduced or full section tensile tests. In order to pass these tests, the brazed joint must be at least as strong as the specified minimum tensile strength of the weaker of the two base metals joined. Figure 1 shows a simple schematic of a tensile test specimen. The tensile test specimen loads the braze bond in shear. The shear stress data in Table 1 was calculated by dividing the ultimate load by the theoretical shear area of each braze joint instead of the cross-sectional area of the pipe. Where failure occurred in the base metal (as was the case in all but two of the reported tests) the ultimate shear strength of the brazed joint was not measured but must be greater than the reported values. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 2 of 4 TABLE 1: MINIMUM BRAZE JOINT SHEAR STRESS Lap Shear Shear Type and Pipe O.o.<1l Specimen Length Area Load Stress Location of (in) (in 2) (lbs) (psi) failure (in) | |||
BPQR 112: three-inch P-110 Pipe to P-107 Fitting with Pre-placed BAg-1a Insert Ring Reduced Section tensile test data V-T1 0.750<1l 0.570 0.428 5,600 13,100 Ductile-Fitting V-T2 0.752 <1l 0.570 0.429 4,800 11,200 Ductile - Fitting 1 | |||
H-T1 0.753 <> 0.570 0.429 4,300 10,000 Ductile - Fitting H-T2 0.753 <1> 0.570 0.429 4,800 11,200 Ductile - Fitting BPQR 113: 3/4-inch P-107 Pipe to P-110 Fitting with Pre-placed Bag-7 Insert Ring Full Section tensile test data V-1 1.050 0.305 1.006 14,100 14,000 Ductile-Pipe V-2 1.050 0.305 1.006 14,800 14,700 Ductile - Pipe H-1 1.050 0.305 1.006 14,900 14,800 Ductile - Pipe H-2 1.050 0.305 1.006 15,100 15,000 Ductile - Pipe BPQR 113: 3/4-inch P-107 Pipe to P-101 Fitting Face Fed Bag-7 filler metal Full Section tensile test data V-1 1.040 0.250 0.817 12,900 15,800 Ductile - Braze V-2 1.040 0.250 0.817 14,700 18,000 Ductile-Pipe H-1 1.040 0.250 0.817 14,500 17,700 Ductile-Pipe H-2 1.040 0.250 0.817 12,900 15,800 Ductile - Braze NOTE: (1). A pipe O.D. is used unless the value given is annotated with this note. This note denotes the value shown is a dimension of width. | |||
In all but two of the reported tensile tests, the specimens failed in the base material and therefore do not provide an ultimate shear strength for the brazed joint. With a failure in the base material, the reported values demonstrate that the brazed joint was capable of carrying at least the reported shear stress without failure. Therefore, ultimate shear stress for brazed joints in specimens that failed in base material was higher than the reported values. | |||
In the two joints where failure occurred in the braze, the ultimate shear strength of the braze was 15,800 psi. Values of the other 10 specimens range from 10,000 to 18,000 psi. These values do not take into account any loss of shear area due to voids, inclusions or other flaws, which typically exceed 10 percent and may include up to 25 percent of the braze area and are still acceptable to ASME IX criteria. | |||
Considering the data from failures in either pipe of fitting base materials and the ideal assumptions of shear area that are used to derive shear stress of Table 1, the data reasonably supports a conclusion that the ultimate shear strength of these brazed joints is much greater than where failure occurred in pipe of fitting base materials. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 3 of 4 The indicated ultimate shear strength from the actual brazed joint failures is shown to be greater than 15,000 psi. As a conservative measure, a '2 times' margin has been used. This will result in a usable allowable shear stress value of 7,500 psi as input to the evaluation of the structural integrity of the braze joints using the methodology described in DENC request IR-4-09. | |||
: 2. Brazed Joint Shear Strength and Safety Factor Use in Evaluation DENC will revise the brazed joint evaluation procedure previously described in Request IR-4-09 in the following manner: | |||
(a) The braze joint shear strength assumed for evaluation purposes will be changed to 7,500 psi, as justified above. Thus, in Attachment 2, Figure 2 of the original submittal, the parameter -cmax in Equation 3 is 7,500 psi. | |||
(b) The piping analysis loads and equivalent stresses used to evaluate the braze joint will be multiplied by a safety factor of 1.5, which is conservative to factors required by ASME Ill Code Case N-513-4. Thus, in Attachment 2, Figure 2 of the Equation (1) reads: | |||
1.5 Seq < Smax(badj) | |||
(c) Corresponding changes will be made to the "Braze Bond Structural Assessment", shown by example in the original submittal, to implement (a) and (b) above. | |||
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 4 of 4 FIGURE 1: TENSILE TEST SPECIMEN SCHEMATIC Either the full pipe or reduced 3/4-inch wide tensile test specimens from the larger 3-inch pipes are being used for tensile testing. | |||
Shear area applies to this region of joint. | |||
NOTE: This schematic shows how the tensile test specimens that are described in Table 1 load the braze bond in shear.}} | |||
Revision as of 11:09, 18 January 2022
| ML21321A278 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 11/17/2021 |
| From: | Mark D. Sartain Dominion Energy Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 21-292 | |
| Download: ML21321A278 (82) | |
Text
{{#Wiki_filter:Dominion Energy Nuclear Connecticut, Inc. 5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion Dominion Energy.com November 17, 2021 Energy U.S. Nuclear Regulatory Commission Serial No. 21-292 Attention: Document Control Desk NRA/SS RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. MILLSTONE POWER STATION UNIT 3 ALTERNATIVE REQUEST IR-4-09 FOR USE OF AN ALTERNATIVE BRAZED JOINT ASSESSMENT METHODOLOGY TO DEMONSTRATE STRUCTURAL INTEGRITY OF CLASS 3 MODERATE-ENERGY PIPING Pursuant to 10 CFR 50.55a(z)(2), Dominion Energy Nuclear Connecticut, Inc. (DENC) requests Nuclear Regulatory Commission (NRC) approval to use an alternative to the requirements of IWD 3132.3(b) of the American Society of Mechanical Engineers (ASME) Code, Section XI, 2013 Edition. The proposed alternative evaluation method would allow for temporary acceptance of brazed joint leakage in moderate energy, copper-nickel and nickel-copper, Class 3, service water piping with cast bronze fittings. Temporary acceptance is based on determining the degree of remaining bonding through ultrasonic (UT) examination of the affected brazed joint (similar to the approach given in ASME Code Case N-874), in combination with performing a structural integrity assessment (utilizing the guidance of ASME Code Case N-513-4). Final repair of a leaking brazed joint would be performed during the next refueling outage following leakage identification. Until a repair is completed, periodic monitoring of a leaking joint would be performed to verify that the assumptions of the structural evaluation remain valid. With this approach, leaking brazed joints can be replaced in a systematic and planned manner, without unnecessary unavailability of safety related systems or components or unnecessary plant shutdowns. provides Relief Request IR-4-09. Attachments 2 and 3 provide applicable figures, and applicable brazed joint configurations and materials, respectively. provides a summary of previous applications of the approved brazed joint assessment methodology and a technical evaluation example. Attachment 5 describes the mechanical testing performed for MPS3. Attachment 6 provides a UT procedure for reference only (which is subject to change). Attachment 7 provides additional technical basis information related to braze shear stress.
Serial No. 21-292 Docket No. 50-423 Page 2 of 3 If you have any questions regarding this submittal, please contact Shayan Sinha at (804) 273-4687. Sincerely, Mark D. Sartain Vice President Nuclear Engineering & Fleet Support Attachments:
- 1. Alternative Request IR-4-09, Use of an Alternative Brazed Joint Assessment Methodology to Demonstrate Structural Integrity of Class 3 Moderate-Energy Piping
- 2. Applicable Figures
- 3. Applicable Brazed Joint Configuration and Materials
- 4. Summary of Previous Methodology Applications and Technical Evaluation Example
- 5. Mechanical Tests
- 6. Ultrasonic Test Procedure
- 7. Additional Basis for Braze Shear Stress Commitments made in this letter: None
Serial No. 21-292 Docket No. 50-423 Page 3 of 3 cc: U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 R. V. Guzman Senior Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 C2 Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 1 ALTERNATIVE REQUEST IR-4-09 1 USE OF AN ALTERNATIVE BRAZED JOINT ASSESSMENT METHODOLOGY TO DEMONSTRATE STRUCTURAL INTEGRITY OF CLASS 3 MODERATE-ENERGY PIPING MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. (DENC)
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 1 of 12 Alternative Request IR-4-09 In Accordance with 10 CFR 50.55a(z)(2) Hardship Without a Compensating Increase in Quality and Safety
- 1. ASME Code Component(s) Affected ASME Code Class: Code Class 3
References:
ASME Section XI, IWD-3132.3(b) Examination Category: N/A Item Number: N/A
Description:
Alternative Brazed Joint Assessment Methodology Components: Service Water System Brazed Piping Joints, Three Inches Nominal Size and Smaller Figure 1 in Attachment 2 shows a typical brazed joint. Attachment 3 provides additional details concerning applicable brazed joint materials, configuration, and brazing.
2. Applicable Code Edition and Addenda
ASME Section XI, 2013 Edition (No Addenda)
3. Applicable Code Requirement
IWD-3132.3 Acceptance bv Evaluation A component containing relevant conditions is acceptable for continued service if an evaluation demonstrates the component's acceptability in accordance with (a) or (b) below. (b) Temporary acceptance of flaws in moderate energy piping may be performed in accordance with Nonmandatory Appendix U, Supplement U-S1, and temporary acceptance of degradation in moderate energy vessels and tanks may be performed in accordance with Nonmandatory Appendix U, Supplement U-S2. The ASME Section XI Nonmandatory Appendix U requirements do not provide guidance specific to evaluation and temporary acceptance of brazed joint leakage. As such, leakage from an unisolable brazed joint could require removal of the unit from service to support isolation and draining of the associated service water train.
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 2 of 12 DENG is proposing to use an alternative evaluation method that would allow for temporary acceptance of brazed joint leakage in moderate energy, copper-nickel and nickel-copper, service water piping with cast bronze fittings. The proposed alternative evaluation method is similar to the guidance of ASME Code Case N-874, which is expected to be designated an acceptable code case for use in the upcoming Revision 20 of Regulatory Guide 1.147 (ADAMS Accession No. ML20120A631). One difference between this proposed alternative and Code Case N-874 is that additional provisions for acceptance when <60% bond is detectable are also included in the proposed alternative. Any brazed joint leakage that is detected and temporarily accepted using the proposed alternative evaluation criteria would be subject to ongoing monitoring and would be repaired in accordance with ASME Section XI Article IWA-4000 no later than the next refueling outage. The proposed alternative evaluation is also consistent with aspects of ASME Code Case N-513-4, which is listed by the NRG as an acceptable code case for use in the currently approved Revision 19 of Regulatory Guide 1.147.
4. Reason for Request
During the course of plant operation, minor leakage of brazed joints is sometimes observed through a defect in the braze bond between the pipe and fitting. Leakage is considered to be minor when it is at a rate of drops per minute, or if only moisture or salt deposits are visible. Section XI and Section Ill of the ASME Code do not have guidance applicable to evaluation of minor leakage through brazed joints caused by defects in braze bonding between piping and fittings. Section XI, IWD-3000, has no requirements pertaining to brazed joints. Therefore, Section XI does not have rules specific to examination and acceptance of relevant conditions observed in brazed joints. Lacking such guidance, the leaking joint must be repaired in accordance with IWD-3132.2. A safe alternative to the requirement to immediately repair a brazed joint with minor leakage can include a deferred, but planned, repair/replacement activity that permits continued plant operation based on an evaluation of continued acceptable integrity and functionality of the brazed joint. With this approach, leaking brazed joints can be replaced in a systematic and planned manner, without requiring unnecessary unavailability of safety related systems or components or the potential for unnecessary plant shutdowns. In some cases, performing an ASME Code repair on a degraded brazed joint might render certain safety-related systems or components inoperable, thereby potentially requiring a plant shutdown to comply with Technical Specification requirements. A plant shutdown would unnecessarily cycle plant components, which is not desirable in maintaining the structural integrity of the safety-related components. Additionally, the need to shut down the plant for implementing an ASME Code repair of a brazed
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 3 of 12 joint with minor leakage would result in hardship without a compensating increase in the level of quality and safety when the structural integrity of the degraded joint and associated system functionality can be ensured by appropriate evaluation.
- 5. Proposed Alternative and Basis for Use In lieu of the immediate repair requirement of IWD 3132.2, DENG proposes to perform a supplemental ultrasonic (UT) examination and comparison with alternative acceptance criteria. The UT examination will establish the extent of braze bond within the joint. The UT results will be compared with pre-established brazed joint bond levels required for structural integrity of the specific piping under consideration that accounts for the design basis loadings applicable to the condition. This method will establish the basis for determining joint integrity to the extent required for system operability.
The proposed methodology provides for continued monitoring until the nonconforming condition (e.g., minor leakage) is resolved through repair/replacement activities. Periodic monitoring of the joint and its leakage verifies that the assumptions used for the assessment remain valid. The overall methodology has been validated by performance of physical testing on an array of simulated bond configurations, and several brazed joints salvaged from MPS3 piping. 5.1 SCOPE The alternative is limited to brazed, Class 3, service water piping (typically constructed of copper-nickel or nickel-copper piping and cast bronze fittings) or on-skid equipment piping that has a design pressure of 150 psig or less and a design temperature of 150 degrees Fahrenheit or less. The piping nominal size is limited to three inches maximum. Basis: The limitation of pipe sizes to three inches or less ensures that the alternative is applied to piping for which it was intended and is comparable to the range of pipe sizes (two and three inches) included in the physical testing described in Attachment 5. The limitation to service water systems ensures that the operating pressure and temperature are well within the moderate energy range. The fluid contents of the piping are comparable to those examined for potential corrosion effects. 5.2 EXAMINATION As permitted by IWD-3200, "Supplemental Examinations," the brazed joint will be examined by UT using a straight beam technique that monitors the relative strengths of signals returned from the internal diameter (ID) of the pipe and the
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 4 of 12 fitting. This technique was derived from, and is consistent with, a technique standardized by the U.S. Navy for use on brazed shipboard piping. 1 The UT procedure in Attachment 6 is provided for reference only and is subject to change. The UT procedure will require that technicians be certified in accordance with ANSI/ ASNT CP-189, 1995 Edition. Only Level II or Ill certified technicians may perform or review the brazed joint UT results, and they must be familiar with brazed joint geometry and signal response characteristics. As a prerequisite, the examination surface must be suitably prepared to obtain satisfactory sound transmission. The joint circumference is marked at a number of locations such that they are spaced no greater than one inch apart. A straight beam longitudinal wave signal is required for the actual examination. At each marked location, the percent bond is recorded based on the relative strengths of signals received from the pipe ID and fitting ID. The procedure provides instructions to distinguish between fittings of the "face fed" and "insert" type, the latter of which have an internal groove in which a ring of braze filler material is inserted before brazing. The MPS3 UT procedure will provide suitable data sheets for documenting the braze bond readings and calibration data. The data sheets are reviewed by a certified Level II or Ill reviewer. The data sheets are then forwarded to Engineering for assessment. Basis for Nondestructive Examination Technique: The alternative UT examination is based on requirements for UT examination contained in the U.S. Navy standard for fabrication and inspection of brazed piping. It uses basic straight beam UT technology, and was utilized to confirm the quality of critical piping systems in the submarine fleet of the U.S. Navy. A brazed joint is considered acceptable without further evaluation by the standard if the average measured bond reading is 60 percent or more. Consistent with the referenced standard, the MPS3 procedure will require this work to be performed by certified UT technicians, using calibrated equipment and approved couplants. It will require examination at multiple locations around the circumference of the fitting. It will require review of the data by a Level II or Ill technician. The UT procedure has been reviewed and approved by a Level Ill technician in accordance with DENC's quality requirements. Previous trial demonstrations show that individual bond readings at a location on the fitting may vary, but the average reading is consistent among qualified examiners. 1 NAVSEA 0900-LP-001-7000, "Fabrication and Inspection of Brazed Piping Systems", dated January 1, 1973.
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 5 of 12 5.3 ASSESSMENT An assessment of the joint using this methodology includes the following considerations:
- System performance and indirect effects assessments,
- Adjustment of bond readings to account for uncertainties,
- A review of the design basis stress analysis of the piping to determine required joint strength, and
- Comparison of the adjusted bond readings with the prequalified bond levels that have been shown empirically by physical testing to assure structural integrity.
5.3.1 SYSTEM EFFECTS As a prerequisite to structural assessment, knowledgeable engineering personnel assess the effect of the leak on the system and other nearby equipment. Typically, a brazed joint with a defect in the braze material bonding will leak only drops per minute. The actual leak rate will be estimated and compared to service water system margins for loss or diversion of flow. In addition, a walkdown will be performed to identify any nearby equipment that may be affected by dripping or impingement spray from the leak. If required, a drip collection device or spray shield will be installed and maintained for the duration that the leak continues. Basis: ASME Code, Section XI Code Cases, such as N-513-4, permit continued operation of moderate energy systems with minor leakage when justified by evaluation of system performance. Similarly, the proposed alternative permits continued operation provided that the leakage rate will not . adversely affect required flows, and the leakage or spray will not adversely affect safety-related equipment. Typical flow from a brazed joint experiencing minor leakage is in terms of drops per minute. Even in a theoretical worst case of a joint having a total lack of braze material, the close tolerance between the pipe and fitting prevents significant flow. The total diametric clearance of a braze joint is about 0.005 inches. For a three-inch pipe, the maximum possible flow area would be nominally 0.027 square inches (e.g., 3.14 x 3.5 x 0.0025) through which the upper bound flow rate at 100 psig would be about 6 gpm, a very small flow rate in comparison to service water pump capacity. More realistic estimates and actual leak rates would be much lower. Therefore, the maximum potential braze joint leakage is very small. In addition, the proposed alternative requires a specific evaluation to assure that leakage does not unacceptably reduce system margins. Therefore, the system will meet all
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 6 of 12 functional requirements and maintain an equivalent level of quality and safety. 5.3.2 ACCEPTANCE THRESHOLD AND ADJUSTMENT OF BOND READINGS If the average measured bond reading is 60 percent or more, then no further assessment is required since the bond strength exceeds piping strength. If the average is less than 60 percent, then the bond readings as documented in the UT procedure are adjusted downwards on a sliding scale. The adjustments would be made such that all readings at 10 percent and below are assumed to be zero, and readings above 10 percent are adjusted using the following formula: bactj = 100 x (reading -10)/(100 -10) units of percent For example, a 50 percent UT reading would be adjusted to 44 percent bond level for assessment purposes. For simplicity, the adjustment may be applied to the average of the UT readings, or alternatively to each of the UT readings prior to averaging. The average of the adjusted readings is then used for assessment purposes. For bond readings that are significantly non-uniform around the circumference of the braze, an effective (lower) bond is computed based on the equivalent moment of the adjusted bond areas. If the average adjusted bond reading is above 55 percent, then the joint strength is considered equal to or better than the piping, and steps 5.3.3 and 5.3.4 below are not performed. Basis for acceptance threshold and adjustments of readings: Acceptance of average UT bond readings of 60 percent or more is the same as the acceptance criteria in the U.S. Navy standard that has been used for critical shipboard piping systems. The U. S. Navy criteria are applicable to systems rated 300 psig and greater. The 60 percent threshold criterion is therefore conservative for systems with design conditions of 150 psig or less. For further confirmation of the 60 percent threshold, testing has shown that if true bond in the joint exceeds 30 percent, then the piping collapse load occurs before any bond failure. The testing performed for MPS3 is described in Attachment 5. There is no braze bond failure mode because the piping deforms plastically to relieve the imposed load, and this occurs at loads greater than the maximum load permitted by the licensing basis analysis of the piping. The downward adjustment of bond readings beyond what is required by the U.S. Navy
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 7 of 12 standard is an introduced conservatism used to help correlate the data from actual piping samples, and accounts for uncertainties in bond readings. 5.3.3 CONSTRUCTION CODE QUALIFICATION STRESS ANALYSIS REVIEW The Construction Code qualification stress analysis of record is reviewed to determine design basis loadings at the subject brazed joint. Pressure, deadweight, and safe shutdown earthquake (SSE) loadings are included. The loads are either used directly or expressed in terms of equivalent pipe stress, so that stress analysis outputs may be used directly. The stress intensification factor (SIF) that may have been applied in Construction Code stress analysis is not required to be included in the summation of nominal stresses used for assessment. Basis for Stress Analysis Review: The review of stress analysis required by this proposal is a data gathering activity required to determine the primary loads imposed on the brazed joint. The primary loads consist of maximum operating pressure, deadweight, SSE seismic, and any transient dynamic loads that have been defined for the piping. Since the stress analysis is the calculation of record for qualifying the piping in accordance with licensing basis requirements, it is an acceptable source of input for assessing the structural integrity of brazed joints. The use of Construction Code stress values implicitly treats piping torsion loads as equivalent to bending moments. This is conservative because in the bonded joint, the torsional shear is half that calculated on an equivalent pipe stress basis. 5.3.4 COMPARISON OF ADJUSTED BOND TO REQUIRED BOND Equation 3 in Figure 2 of Attachment 2 was developed to give the allowable loading for an equivalent bond level. The equation is used for a comparison that is needed only when the average bond is less than 60 percent. When an equivalent adjusted bond of a brazed joint is determined, as described in Section 5.3.2, an allowable loading (Smax(badj)) can be obtained from the equation. This is the safe loading level that the joint can withstand. If the joint load demand that has been determined in Section 5.3.3, multiplied by a factor of safety (FS) of 1.5, is less than the allowable (1.5 Seq < Smax(badj)), then the brazed joint is concluded to have adequate structural integrity for continued service. The comparison is quantified as shown in Figure 2.
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 8 of 12 An example of a structural assessment performed for an actual leaking brazed joint is included in Attachment 4. One joint in the example is SWP95-FW-38, which was observed to have a 42 percent average measured bond. The measured bond values were adjusted as described above, and this effective bond level results in a joint load capability of 7.015 ksi nominal pipe stress. The 7.015 ksi load capability is adequate for the design basis loads of this example, since the joint load demand, including an FS of 1.5, is 6.308 ksi. Therefore, the example structural assessment concludes the joint can be left in service provided it is monitored until its permanent repair/replacement activity is completed. If a joint does not have adequate bond by this assessment, the comparison for determining the adequacy of structural integrity of the joint is not applicable. Prompt repair/replacement of the joint, or temporary non-Code repairs subject to NRC review and approval may be options for the resolution of nonconforming conditions, consistent with considerations in Inspection Manual Chapter (IMC) 0326, "Operability Determinations," dated 10/01/2019. Basis for Comparison of an Adjusted to Required Bonding: Brazed joints with reduced bond levels can retain a significant strength that is adequate for the structural integrity of the joint. DENG sponsored tests at an independent testing facility to demonstrate the correlation between reduced bond levels and joint strength. The tests and their results are described in Attachment 5. The correlation developed by the testing conservatively determined a required bond level for a given intensity of joint loading. The results of these tests support the use of the comparison shown in Figure 2 of for the structural integrity analysis. The estimated joint strength obtained using Equation 3 in Figure 2 is confirmed conservative by test results. Each of the tested joints achieved a collapse load above the load which would be predicted for a 7.5 ksi braze shear strength. This also confirms the acceptability of the 7.5 ksi maximum braze shear stress assumption that is used as an input to the Equation 3, shown in Figure 2. Additional basis for acceptability of this value is contained in Attachment 7. The evaluation of the test results considers the adjustment of bond readings imposed by this methodology, a joint load capacity that is based on a 7.5 ksi shear stress, and an imposed FS of 1.5 on loads and pressure. With all these considerations, the tests demonstrate that a margin of greater than 1.5 exists between test results and estimated
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 9 of 12 allowable joint load capacity from the actual piping removed from plant service. This margin provides an FS equivalent to what is provided by the ASME Code, Sections Ill and XI as discussed below. The ASME Code, Section Ill, Appendix F has been referenced by the NRG for evaluation of degraded conditions. 1 Appendix F, paragraph F-1331.1 (a) permits primary stress at levels up to 0.?Su (code specified ultimate tensile strength) and in paragraph (c), it permits primary membrane plus bending stress at levels up to (1.5)(0.?Su) = 1.05Su. The maximum FS resulting from these comparisons is 1.4 relative to ultimate strength. For shear across a section, paragraph F-1331.1 (d) limits shear to 0.42Su for an FS of 1.37 relative to (1 / 3)Su. The 7.5 ksi shear limit used at the braze bond is well below this Appendix F limit of 0.42Su for the pipe and fitting materials. The ASME Code, Section XI permits acceptance of planar flaws for which Appendix C requires an FS of 1.4 for circumferential flaws (paragraph C-2621) and requires an FS of 1.3 for axial flaws for faulted loads (paragraph C-2622). These FSs from Appendix C are also incorporated by reference in Code Case N-513-4. Considering the ASME Code references described above, an FS of 1.5 for design basis loadings in ductile materials provides an equivalent and acceptable level of safety as compared to the plant design basis and permitted methodologies for evaluation of flaws. 5.4 MONITORING The proposed alternative assessment methodology requires periodic monitoring to assure that the assumptions of the assessment remain valid. This monitoring will be in addition to the normal daily plant operator rounds, during which personnel observe for signs of leakage. The monitoring will be by visual observation of the appearance of the joint and its leak rate, plus re-examination of the joint by UT to reconfirm the percent bonding. The frequency of the monitoring will be approximately once every three months. The monitoring will continue as described until the joint is repaired or replaced. If there are changes in the nonconforming condition of an evaluated brazed joint with minor leakage that may impact its assessment for adequate structural integrity or its functionality, a Condition Report will be generated in accordance with the Millstone Power Station Corrective Action Program. The UT readings on the joint will also be repeated and reassessed. 1 NRC Inspection Manual, Inspection Manual Chapter 0326, "Operability Determinations," October 1, 2019.
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 10 of 12 Monitoring Basis: The degree and frequency of periodic monitoring is conservative because the braze defect that permits this form of leakage stems from original construction or
- fabrication and is not the result of a progressive degradation mechanism.
Conditions that are applicable to the use of this methodology arise from defects in braze material inside a socket joint and will have a very low leak rate. At MPS3, there have been no conditions where the piping has disengaged from brazed fitting sockets. Consequently, no conditions have been observed that would have impacted the ability to maintain adequate system flow. This positive operating experience is due to the inherent structural integrity of brazed joints in service water systems. To further address the potential for degradation, a search and review of external operating experience was performed. Braze failures in closed loop and electrical cooling systems such as generator stator cooling have been attributed to corrosion. However, there was no operating experience indicating progressive failure for open loop seawater systems. To confirm the conclusion that no progressive failure mechanism applies, DENG disassembled and examined two specimens that had already been removed from Millstone Power Station seawater service, and that were reported to have low bonding. The surface examination of the separated fitting and pipe surfaces did not reveal evidence of braze metal corrosion product. Since these examined joints are typical of plant construction and had seen nearly 20 years of service with no degradation of the bond, it is concluded that periodic visual monitoring of leak rate for this condition is acceptable, and monitoring may be scheduled on a quarterly basis. The periodic visual monitoring of leak rate will ensure that degradation to system functional margins does not occur. 5.5 REPAIR/ REPLACEMENT If the assessment concludes that a brazed joint with leakage retains adequate structural integrity and functionality, an operability determination can be used to document an 'operable but not fully qualified' status. A timely repair/replacement activity can be planned in accordance with 10 CFR Part 50, Appendix B. Consistent with the Millstone Power Station Corrective Action Program, the permanent Code repair/replacement for this type of nonconforming condition will be considered timely if completed during the next cold shutdown of sufficient duration, or the next refueling outage, whichever comes first. If a joint does not have adequate bond by this assessment, the methodology for determining the adequacy of structural integrity of the joint is not applicable. Prompt repair/replacement of the joint, or temporary non-Code repairs subject to
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 11 of 12 NRC review and approval may be options for the resolution of nonconforming conditions, consistent with considerations in IMC 0326. Basis: The bases for continued operation prior to repair of the joint are that system functionality is maintained as justified in Section 5.3.1 above, structural integrity of the joint is maintained as justified in Section 5.3.4, and there is no progressive braze bond failure mechanism that would alter these conclusions over time. Compensatory actions for the condition are administratively controlled under the Millstone Power Station Corrective Action Program. These include, but are not limited to, the periodic monitoring of leakage for the condition or housekeeping measures to contain minor leakage from affected piping. The application of this methodology will be consistent with considerations of IMC 0326 for the resolution of nonconforming conditions. The permanent repair/replacement of the brazed joint assessed using this methodology will be in accordance with ASME Code, Section XI, IWA-4000. 5.6 AUGMENTED EXAMINATION: If minor leakage is observed at a brazed joint, five similar brazed joints will be selected for augmented leakage examination. The additional joints will be selected based on consideration of adjacency, train, fitting type, or other factors that may be evident from the specific condition. Selected joints for augmented examination will be consistent with ASME Code Case N-513-4. If leakage is observed in similar joints, the resolution of each nonconforming condition will be evaluated in accordance with the Millstone Power Station Corrective Action Program, and the extent of condition will be documented and addressed. Basis: The examination of the additional joints is consistent with current practice for the resolution of nonconforming conditions, (e.g., application of ASME Code Case N-513-4). Augmented examinations provide information regarding the extent of condition being evaluated and are consistent with current Millstone Power Station procedures for responding to leakage in service water piping.
5.7 CONCLUSION
It is proposed that in lieu of the immediate repair requirement of IWA-3132.2, DENC will perform a supplemental UT examination and comparison with alternative acceptance criteria. As justified above, DENC concludes that the proposed brazed joint assessment methodology, as an alternative to immediate ASME Code repair or replacement, provides reasonable assurance of structural integrity of degraded brazed joints. Therefore, pursuant to 10 CFR 50.55a(z)(2), the proposed alternative concludes that performance of an immediate ASME
Serial No. 21-292 Docket No. 50-423 Attachment 1, Page 12 of 12 Code repair or replacement of MPS3 degraded brazed joints that are considered to be acceptable using the proposed methodology would result in hardship without a compensating increase in the level of quality and safety.
- 6. Duration of Proposed Alternative This proposal requests approval for the use of an alternative brazed joint assessment methodology for the duration of MPS3's fourth 10-year lnservice Inspection (ISi) interval, which began on February 23, 2019, and ends on February 22, 2029.
- 7. Precedents A similar request for alternative was granted for the second ISi interval (Relief Request IR-2-38) per letter dated February 28, 2007 (ADAMS Accession No. ML070580514), and for the third ISi interval (Relief Request IR-3-04) per letter dated November 30, 2009 (ADAMS Accession No. ML093221042).
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 2 APPLICABLE FIGURES MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 1 of 9 TABLE OF CONTENTS Figure 1: Typical Brazed Joint Configuration 2 Figure 2: Equations for Brazed Joint Assessment 3 Comparison of Brazed Joint Load vs. Capacity Figure 3: Two Inch Couplings: Fabricated Samples at (a) 30% (above) and (b) 60% bond 4 Figure 4: Two Inch Joints: Two Fabricated Samples with 12% Bond 5 Figure 5: Arc Segment Disbandment, (a) 90 (above) and 6 (b) 126 Degrees Arc Figure 6: Two Inch Braze Field Sample Test Curve 7 Figure 7: Three Inch Braze Field Sample Test Curve 8 Figure 8: Test Results for Specially Fabricated Joints 9 Figure 9: Test Results for Joints Removed From Service 10
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 2 of 9 Weepage location 7A bondlny Braze ftller motel Pipe pipe and fitting -+- ....... -+- ....... t t t t t t t t t t t t Internal Fluid Pressure jA Figure 1: Typical Brazed Joint Configuration
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 3 of 9 ( 1) (2) S Ip = longitudinal pressure stress Unintensified pipe stresses from Code S di = deadload stress qualification analysis Ssse = SSE seismic stress S dyn = dynamic stress (if defined) 2 n D *Lins *tmax (3) Smax(badj) = - * - - - - -
- b a d j 4 zpipe D = pipe outside diameter Lins = depth of fitting socket excluding any insert groove Zpipe = piping section modulus
'tmax = 7500 psi (maximum braze shear stress) b adj = adjusted effective bond Figure 2: Equations for Brazed Joint Assessment Comparison of Brazed Joint Load vs. Capacity
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 4 of 9 5000 l!i**l!liiill!!* Raw 450<.l
-Corre,c.ted 4000 3500
- B .la)O e
i 2500
..5 .:moo 1500
- 1000 I J
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0 O ~5 0.5 0.75 l25 15 1.75 " 015pla~mcnt (111} Figure 3: Two Inch Couplings: Fabricated Samples at (a) 30% (above) and (b) 60% bond
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 5 of 9 5000 4500
-Corrected 4000
]500
..... 3000
.:::i e
-a0 250{)
....I 200{1 1500 1000 500 u
0 O 25 0.5 0.75 1.25 I5 1.75 .., DLc;pJacement (in; 5ll00 4500 4000
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.2lll'IIJ 1500 I fl{10 500 0
0 <J 15 0.5 O 75 I 25 I5 I 7.5 "' Dtiplarctnert (in) Figure 4: Two Inch Joints: Two Fabricated Samples with 12% Bond
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 6 of 9 5000
....... , Ra\\t 4500
-Co~ted 4000 3500
-6
~
3000
'1j 2500 3 :woo 1500 I 0()0 .
~
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u 015 05 O75 1.15 J.5 l.75 "' Ol,i).11Jac~menl (in) Figure 5: Arc Segment Disbondment, (a) 90 (above) and (b) 126 Degrees Arc
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 7 of 9 40 No bond failure 2" Coupling
-Stress,136 Joint 36, 65% bond l!1l QI
.:I ti) 30
\ 2" Coupling
-Stre.'is,137
-Stress,139 (Unadjusted bc,nd rea_d_ing_s)
Joint 39, 55% bond
- 8. 20
~ Partial bond failure *a ~
10 2" Coupling Joint 37, 27% bond 0 0.25 0.5 0.75 l.25 1.5 I.75 2 2" FieldSamples Disiincement (in) Figure 6: Two Inch Braze Field Sample Test Curve 40 C 30 g ,-? 2 ~~==...-:=----4A --~~--
...~ 3 - ~ - 3 IA ti) t 20
~
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----~
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-J2,45% *5 -J3,47%
rJ -J4A, 15% IO
---J9,38%
-J9J,48% Unadjusted bond readings
-J31A,21%
0 0.1 0.2 0.3 0.4 0.5 3" Field Samples DJs placement (in) Figure 7: Three Inch Braze Field Sample Test Curve
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 8 of 9 ~ 45 U) 0 40 ~ I -~~ C: 35 30 No bond failure, pipe collapse governs F 2" test 25 3" test
=
ln e 20 I-' - - - -1 .A .- -- ,- _,. -- ~ . .
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~~
l iB" 0 .... I I I I 0% 20% 40% 60% 80% 100o/o Percent True Bond Figure 8: Test Results for Specially Fabricated Joints
Serial No. 21-292 Docket No. 50-423 Attachment 2, Page 9 of 9
. No bond failure, pipe_ ll. 2 11 Field Samples collapse governs 0
,,,. o 3" Field Samples cP
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Adjusted Percent Bond Figure 9 .. Test Results for Joints Removed From Service
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 3 APPLICABLE BRAZED JOINT CONFIGURATION AND MATERIALS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No. 21-292 Docket No. 50-423 Attachment 3, Page 1 of 2 1.0 MATERIALS Typical materials of construction for brazed piping are copper-nickel (SB-466) or nickel alloy (SB-165) annealed piping, and cast bronze fittings and valves (SB-61 or SB-62) dimensioned to MIL-F-1183. The brazing alloy is SFA 5.8 BAg-1, BAS-1a, or BAg-7. ASME, Section Ill Code minimum properties of the piping and fitting materials are: Yield, Ultimate, Material Item Sh, ksi ksi ksi SB466 Pipe 8.7 13 38 CDA706 SB-165 Pipe 17.5 28 70 SB-61 fitting 8.5 16 34 SB-62 fitting 7.5 14 30 2.0 CONFIGURATION As shown in Figure 1 of Attachment 2, a typical brazed joint fitting has a deep socket for inserting the pipe. Although it appears similar to a socket welded joint, the fabrication and structural behavior are quite different. Whereas the socket weld achieves its joint strength by a fillet weld, resulting in fusion of similar material between the pipe and the outer face of the fitting, the braze achieves its strength by surface bonding of the outside of the pipe to the inside of the fitting socket using a dissimilar metal braze filler of silver alloy. The resulting braze filler metal is very thin (approximately 1 to 5 mils). The load transfer between pipe and fitting is thus primarily by shear through the braze filler. It is noted that there is no inherent stress concentration factor like that normally applicable to socket welds because there is no significant pipe wall bending induced by the shear load transfer over a length that is several wall thicknesses long. The following has been excerpted from a standard piping handbook. 1 The length of lap in a joint, the shear strength of the brazing alloy, and the average percentage of the brazing surface area that normally bonds are the principal factors determining the strength of brazed joints. The shear strength may be calculated by multiplying the width by the length of lap by the percentages of bond area and by taking into consideration the shear strength of the alloy used. For the standard braze joint fittings used at MPS3, the joint overlap is about four to one. The smallest overlap occurs in a three-inch joint, with an overlap length of 3.6 times pipe wall thickness. 1 Crocker and King, Piping Handbook, 5th Edition, McGraw-Hill Book Company, page 7-212
Serial No. 21-292 Docket No. 50-423 Attachment 3, Page 2 of 2 3.0 BRAZED JOINT FUNCTIONAL CHARACTERISTICS Since the piping loads causing longitudinal stress in the pipe are all transferred by shear stress through the brazed bond, the shear stress in the brazed bond is directly related to longitudinal pipe stress divided by a factor equal to the overlap ratio. Thus, for a fully bonded brazed joint, the shear stress is about one fourth of the piping longitudinal stress. If the bond is only 50 percent of maximum, then the bond shear stress will be about half the piping longitudinal stress. Given that piping and brazing filler metals have similar strength, a brazed joint has more than enough residual strength to tolerate moderate bond imperfections. Consequently, the joint is not the weak link in the piping assembly. Consistent with this inherent over-design of brazed joints, the Construction Codes, such as Section Ill of the ASME Code and ANSI B31.1, require only visual inspection of the resulting bond. ND-5360, Visual Acceptance Standards for Brazed Joints, states "Brazing metal shall give evidence of having flowed uniformly through a joint by the appearance of an uninterrupted, narrow, visible line of brazing alloy at the joint." Surface exams such as by liquid penetrant are not required. Volumetric exams are not specified or even defined for brazed joints. If the lack of bond is severe, then the brazed joint becomes the weak link in the piping assembly. It fails by shear failure of the brazed bond. Brazing with a lower level of bond may however be acceptable if the piping design basis loads are low enough. A brazing material defect with minor leakage is not the result of a flaw in the pipe or fitting pressure boundary. The pressure-retaining boundary retains its structural integrity. Although the shear load transfer between the pipe and fitting is clearly a pressure boundary function, the brazing material functions more as a sealant between the connected components and less like a pressure boundary. With regard to structural integrity, imperfections in the sealant function of the braze material are permissible, provided its load transfer function retains adequate margin. Thus, because there is no direct degradation of the pressure boundary, the available flaw evaluation methodologies such as in ASME Code Case N-513-4 or Generic Letter 90-05, are not directly applicable. In addition, the characterization of braze imperfections is very different from the planar flaws or loss of wall thickness that are addressed in ASME Code, Section Ill, IWA-3000.
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 4
SUMMARY
OF PREVIOUS METHODOLOGY APPLICATIONS AND TECHINCAL EVALUATION EXAMPLE MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No. 21-292 Docket No. 50-423 Attachment 4, Page 1 of 24 Summary of Previous Methodology Applications During the second MPS3 inservice inspection (ISi) interval, the brazed joint methodology, as approved, was employed in three instances (under IR-2-38). In two of the instances, the leaking joints were repaired within 90 days of discovery and in the third instance, the repair was performed at the next refueling outage. For the third instance, this attachment provides a summary of the original assessment, subsequent UT monitoring, and final repair. During the third MPS3 ISi interval, there were no instances which required use of the brazed joint methodology as approved by the NRC under alternative request IR-3-04. Example of Methodology Application This example relates to a brazed joint that was discovered to be leaking on March 4, 2008. The following activities were then performed. Date Activity Document Remarks 3/11/2008 UT Examination AWO M30802596 Attached to Technical Evaluation 3/13/2008 Engineering Technical Evaluation Included with this Assessment M2-EV-=08-0006 attachment. 5/29/2008 UT Re-examination AWO M30804182 Inspection sheet included with this attachment. 8/26/2008 UT Re-examination AWO M30804183 Inspection sheet included with this attachment. 10/8/2008 Begin MPS3 refueling NA outage 11/2/2008 Brazed Joint Repair AWOM30802598, per .Brazed joints replaced DM3-00-0192-08 with butt welds and socket welds The table shows the 90-day reinspection frequency requirement of the methodology was satisfied. Note: The first examination and technical evaluation addressed nearby brazed joints that were not leaking and therefore met construction code requirements. These additional examinations were done for information only. Subsequent examinations addressed the leaking joint only.
Serial No. 21-292 * . ... -**. __
- ... -*-- -BockefNo. s6~423* .....
Attachment 4, Page 2 of 24 QA Non-QA
~
DB or LB document change required? yes D no ~ TECHNICAL EVALUATION for Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 Millstone Unit 3 M3-EV-08-0006 Rev.00 3/13/2008 . u' 1'11\IZ ~lr1\o~
/" pages 11 3/IJ/or Preparer - Glenn Gardner Date 3/{3/oe Independent Reviewer - Thomas Steahr Date Engineering Approver - Martin Van Haltern Date
- Page I of 19
-p-****u-H-~ .,,
' *I _,.
Technical Evaluation No. M3-EV-08-0006, Rev. 00, page 2 of 19 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 Section ~ Table of Contents 2 1.o*puRPOSE 3
2.0 BACKGROUND
3
3.0 REFERENCES
3 4.0 DISCUSSION 4 5.0 SAFETY-SIGNIFICANCE 9
6.0 CONCLUSION
S 9 7.0 LIST OF ATTACHMENTS 9 Pages in body 9 Pages in attachments 10 Total pages 19 2 P~ge 2 of 19
.....,.__ . -~-.-----Serial No .. 21-2~2 Docket No. 50-423 Attachment 4, Page 4 of 24 Technical Evaluation No. M3-EV-08-0006, Rev. 00, page 3 of19 Evaluation ofUnit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 1.0 PURPOSE The purpose of thi.s evaluation is to deterrnine the structural integrity of a leaking brazed joint in service water instrumentation piping to flow indicator FT-43B, upstream of root valve 3SWP*V222. This3/4" piping branches off line 3SWP-030-09S-3. The brazed joint was identified as having evidence of leakage in CR-08-02368. A subsequent UT exam characterized the extent ofbrazedjoint bond (Reference 3.3). This document provides a structural evaluation to support continued operation pending repair and summarizes requirements to monitor its condition. *
2.0 BACKGROUND
- A method for evaluating the structural integrity of degraded brazed joint was developed in Reference 3.4 and accepted by the NRC in Reference 3.S. The Reference 3.4 Technical Evaluation provides a spreadsheet based evaluation tool to assess the structural acceptability of degraded (including leaking) brazed joints. This Technical Evaluation, in conjunction with the
- UT procedure (Reference 3.6), provides the basis and specific instructions for examination, structural evalµation and reinspection requirements for degraded brazed joints in Millstone Unit 3 service water piping. Procedure MP-24-ENG-FAP947 (Reference 3.8) summarizes all requirements for responding to service water leaks.
The spreadsheet documented in the Reference 3.4 Technical Evaluation implements the approved methodology for evaluating brazed joint integrity. Its data inputs include calculated piping stress levels and the ur bond readings for the joint. The sheet is self documenting and provides a conclusion on whether the joint is acceptable for design basis loading. Specific directions for use of the spreadsheet are contained in Reference 3.4 and are not repeated here.
3.0 REFERENCES
3.1 CR-08-02092, Unplanned TRM for Minor Seepage From A SWP Strainer Backwash Line 3~SWP-003-021-3 Brazed Joint, dated 3/04/2008. 3.2 . Drawing No. 25212-21001 sheet 21, Rev. 9 ./ 3.3 Ultrasonic Examination Straight Beam Measurements, AWO Number M3-08-02596, dated 03/11/2008 (Attachment 1). 3.4 Technical Evaluation M3-EV-05-0002 "Examination and Structural Assessment of Brazed Joints" Revision O1 dated 7/l 7/07. 3.5 "Safety Evaluation by the Office of Nuclear Reactor Regulation, relief Request IR-2-38", US NRC, Transmitted by the letter dated February 28, 2007, Dominion licensing file 07~ 0153. 3 Page 3 of 19
_, ....,------ . **-- _,, ___ *--***-****-* ......,.......-,. _____ Serial Np. 21-292 . Docket No. 50-423 **-* * - - Attachment 4, Page 5 of 24 Technical Evaluation No. M3-EV-08-0006, Rev. 00, page 4 of 19 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 3.6 Procedure MP-UT-45 Rev 00-01 "Ultrasonic Examination Procedure for Examination of Brazed Joints- Millstone Unit 3 Service Water Piping". 3.7 Calculation No. NP-SWP-95-V222, Rev. 2 Change 0, "Root Valve Piping: Support Requirement Verification". / 3.8 Procedure MP-24-ENG-FAP947, Rev. 001-01, "Non-Code Repairs in Safety Class 3 Piping", dated 9/24/2007 4.0 DISCUSSION The UT was obtained on three brazed joints, FW-37, FW-38 and FW-8. Only FW-38 was leaking arid that degraded condition is the one specifically evaluated here, FW-3 7 was not leaking and had greater braze bond than FW-38. FW-8 was at a flange that had interfering studs so only a partial set of readings was obtained on it; however it had readings comparable to FW-
- 38. As discussed in Reference 3.4 the ASME Code does not have a requirement for minimum braze bond. Thus there is no degraded or non~conforming condition for either FW-37 and FW-8 and they are not considered to be a structural integrity concern requiring detailed evaluation.
For information only the braze bond readings and evaluation summary for FW-37 are attached. The formal evaluation of the leaking braze joint FW"38 is documented on the following spreadsheet pages. The braze bond UT readings are transcribed directly into the 'UT Readings' sheet. To account for 12 data points, the data input range for the average bond was modified to only consider the 12 data points, and zero percent bond readings were input for the other eight data point inputs that were not needed. A similar change was made on the 'Bond Cales' sheet for the "BPress" on lines 29 and 65. Finally, on the summary sheet, the plot range was changed in order to show only the relevant 12 data points. Note that the methodology does specify a minimum number of UT data points and 12 points on the approximately 1.5" OD of th~ elbow
- fitting give a data point spacing of about 0.4 inches which is comparable with the UT probe size.
4 Page4 of 19 *
. Serial No. 21-292 t, * * * . .
DockeCNo. so'.423 -***-*- ..... *****- Attachment 4, Page 6 of 24 M3-EV-08-0006 Page 5 Sheet 1 of 4 Braze Bond Structural Assessment Joint SWP95-FW-38 Ref: TE M3-EV-05-0002 Rev. 1 this sheet revised 07/17/2007 Part 1 Basic Data ( dashed boxes are inputs) Inputs: Inputs: ' Line No:'SWP-075N222 Sys Function:!FT-438 upstrm instr tubing I Pipe Dia Nom. Wall Thk, I 1.05 In 0.154 In I Piping tso: 1c1-swP-95 Sh 2 Pipe Mat'ljss 466 CDA 706 Joint:,I SW P95-FW-38 rilling Mat'l*SB 61or 62 Side of Joint: IDnstrm I I Ref. Bond *strength;*- * -7,500 psr---.. ., Jf. Orlentation:tn~ __________
- ____
- __: Bond Adjustmer-it 10%
Measured Ave. Bond 42% (calculated, For bond measurements, see sheet 'UT Readings') 42 % >= 60 % ? No, Detailed assessment required Part 2 Bond Data Summary '(data from sheet 'Bond Cales') Offsets based on adjusted bond: Dx.x , *0.117 in Dyy 0.038 In Doffset 0.123 In (23% of pipe radius) Alpha -12.5 degrees - rotation angle of principal axes Calculated effective bond data are in p,rinclpal axes system, and are based on adjusted bond. Actual AdJusted Bxx 46% 40% Byy 34% 27% Bbend 34% 27% 10 ~~-----3!KE-----t.:!~4 Bpress 42% 35% y
~
Note: Plot is figurative only, actual braze bond Is cylindrical, not 7 through-wall. X 3SWP-V222-FW38.xls Page 5 of 19
. Serial No. 21-292
** **---*------ ...... - .... bo-cket No: so:*423--**--****-
Attachment 4, Page 7 of 24 M3-E.V-08-0006 Page 6 Sheet 2 of 4 Braze Bond Structural Assessment Joint SWP95-FW~38 Part 3 Calculated Bond Load Capability Lookup Tbl: l,insert per MIISpec D 1.05 in D.nom D.od *Linsert tnom 0.154 in 3/4 1.05 11/32 Pipe Z 0.085 in"3 1 1.315 7/16 Linsert 0.344 in (f/Om lookup table at right) 1.5 1.9 5/8
. Smax(100%) 26,169 psi (from formula at right) 2 2.375 21/32 2.5 2.875 25/32 Load Capability (Allowable Nominal Pipe Stress) 3 3.5 53/64 (Based on bond levels from Part 2)
Actual Adjusted Sxx 12,134 10,391 psi stress based on shear allow. and percent bond Syy 8,984 7,015 psi 2 nD *Linsert Sallow 8,984 7,015 psi S mJb adj) "' b adj' *'tma> 4*Zpipe Part 4 Pipe Stress Data (stress calc Inputs) (data from Part 1) Stress CaldI NP-SWP-95-V222 . 7I Pipe Dia 1.05 in Rev/ CCNL Rev. 2,_ CCN O_~ _______ _J Norn. WallThk 0.154 ill Line No: SWP-075-V222 Pipe Mat'I SB 466 CDA 706 Sys Function: FT-43B upstrm instr tubing Fitting Mat'l SB 61or 62 Piping lso: CI-SWP-95 Sh 2. A.pressure 0.825 in"2 Joint: SWP95-FW-38 ~.pipe 0.085 Tn13- - -.- lnpuls: Design Pressure 1 100 psig j Max Op. Pressure , 100 pslg . , Calculated Nominal Stresses Sip ! 170 psi !sp_offset 119 psi Eq. 8 (P+DL) I 2448 psi I Sust'd 81 1695 psi Eq. 9 (NIU)* 5238 psi I N/U 9' 3466 psi Eq. 9F (Design Basiso! . __640~psi __ .!Faulted 9F' 4205 psi Max Pipe Nominal Stress 4205 psi Apply Safety Factor of 1.5 6308 psi Part 5 Structural Integrity Determination Joint SWP95-FW-38 Joint Load Capability 7,015 psi (from Part 3) 1,s*oeslgn Basis Load 6,308 psi (from Part 4)
~
Check: 6,308 < 7,015 ===> Braze is adequate for design basis loads Monitor until repair/repla~ement 3SWP-V222"FW38.xls Page 6 of 19
... : .... ,....Serial ~Q,21.-2J!L...... ..
Docket No. 50-423 Attachment 4, Page 8 of 24 M3-EV-08-0008 Page 7 Sheet 3 of 4 Braze Bond Measurements Joint SWP95-FW-38 R Rmin Bond Adjustment 10% 1 0.75 Reading Angle Meas. Bond Adj Bond PlotValue Adj Plot Max Min 1 o[ 40%! 33% 0.050 0.833 1 0.75 1 2 30 4o% 33% 0.850 0.833 1 0.75 1 3 eo! 40%, 33% 0.850 0.833 1 0.75 4 90i 30%j 22% 33% 0.825 0,850 0.806 0.833 1 1 0.75 0.75 5 120*I 40%: 6 1501 20%1 11% 0.800 0.778 1 0.75 7 1ao: 30%: 22% 0.825 0.806 1 0.75 8 2101 30%1 22% 0.825 0.806 1 0.75 9 240: 60%: 56% 0.900 0.889 1 0.75 10
- 2701 80%1 78% 0.950 0.944 1 0.75 11 300: 60%: 56% 0.900 0.889 1 0.75 12 3301I 30%1I 22% 0.825 0.806 1 0.75 13 360 1 0%' 0% 0.750 0.750 1 0.75 14 390! o3/4! 0% 0.750 0.750 1 0.75 15 420 1 0%' 0% 0.750 0.750 1 0.75 16 450! 0%! 0% 0.750 0.750 1 0.75 1
17 480 0%1 0% 0.750 0.750 1 0.75 18 510!I 0%: 0% 0.750 0.750 1 0.75 19 5401 0%j 0% 0.750 0.750 1 0.75 20 570 1** _ .. ..,_ ...... 0%' :J 0% 0.750 0.750 1 0.75 Nreadings 12 Ave 42% 35% G9:G21 dTheta 30 Min 20% 11% degrees Max 80% 78% 3SWP-V222-FW38.xls Page 7 of 19
. . )* Serial No. 21-292
.. "i'.'>ocket No~*so:*423*- ..
Attachment 4, Page 9 of 24 t.\3,EV-03-0006 Pago(? Sh..14 oJ4 Braze Bond Calculations Joint *sWP95-FW-38 Boflset NreaOings EQulvalenl band ba,ed on measured bond readings, w!1houl adjustment 1DV, 12 D AIIGI* Meas. Bond db'cw db'co~..,1 db'.$1n'QOJ &ln{lholu) db*,tn db'41n'2 1,05 0 401', 1,000 o. oo o. 00 0.000 0.000 0.000 0.000 30 4DV, O.e.G 0.3-16 0,300 0,173 0,500 0.200 0.100 AOlfsellnpl( 60 D1/4 o.500 0.200 0,100 0.173 0.8&6 0.3"8 0,300 0 d,g<!'!I 90 30% 0.000 0.000 0,000 0.000 1.000 0.31XI 0.300 O.OOOr>d 120 401/4 -0.500 -0,200 0,100 -0,173 0,8&6 0.:HS 0.300 150 201/4 -usa -0,173 0,150 -0.0$7 0.500 0.100 0.050 1BO 3Dl', -1.000 -0.300 0.:300 0.000 0,000 0.000 0,000 210 3011 -0,000 -0.260 0,225 0.130 -0,500 -0,150 0.075 240 oov. .0.500 -0.300 0.150 0,260 -0.SSS -O.S20 0.460 270 BOl', 0.000 0.000 0.000 0,000 .1.000 -0.800 0.800 300 601/4 0.500 0.300 0,150 -USO .O,BOl .0.$20 0,450 330 301/4 o.ses 0.260 0.225 -0.130 -0,500 -0,150 0.075 360 OY. 1,000 0,000 0.000 0,000 0,000 0.000 0.000 390 O1/4 0,866 0.000 0.000 0.000 0,500 0.000 0.QOO 20 O1/4 0,500 0,000 0.000 0,000 o.ess 0,000 0,000 4i0 OY, 0,000 0.000 0.000 0.000 1,000 0,000 0.000 400 01/4 .0,500 0.000 0,000 0.000 0,8&6 0.000 0.000 610 01/4 -0,00G 0.000 0.000 0.000 o.soo 0.000 0,000 540 OY, -1,000 0.000 0.000 0.000 0.000 0.000 0.000 5'10 OV, -0,666 0.000 0.000 0.00D <l.500 0.000 0.000 0.000 0.023 2,100 O.D87 0.000 .0.071 2.900 Bprus ry opw IX 411/4 0.0S5 0.175 -0,169 Rorfso\ Vol/sel SW a,v x.i<<..1 0.093 0.029 0.174 0.011 ,O,Q!9 BByy as% eave 40',(, BB,oc: 46'/i, Dyy.J) 0,17Z OUJ) 0.2n
;14'/o 6'/i, B)'l*b,,.,o axy=o 1an 2arp11a iln 2illpho 180 ohecl< alpha
-0,0SS 0.011 0.930 -0.360 .\l.3$6 .0,188ra:I fAtst;'. FAtsE ,*IUdeg IJ-tt*rr-=t Equivalent bond based on ad/usted bond readings
"'*4 * , .. ,11(1.:1 MglO Ad).BoM db'o,o Clb'COS42 db*$fn*oos sln(lheb) cro*srr1 d~",lrl'l 0 33% 1,000 0~J3 0.333 0.000 0.000 0.000 0.000 30 333/4 0,866 0.28~ 0,260 0,144 O.IIOO 0,16! 0.0&:l 60 33% o.soo 0.167 0.083 0,144 0,668 0.289 0.250 90 XI1/4 0.000 0,000 0.000 0.000 ,.ooo 0.222 0.222 1iG 3311 -0,500 .\l,187 0.083 -0,144 0.8f8 0,28!1 o.iso 150 1111, -0.866 -0,<WG 0.083 ,0,()49 0,600 0,000 0.0~&
180 ZIY,
....~*1/4r,., ..,,~..,(*1 210 22f,
*1.000
-0.1!66
-0,222
<l.192 0,222 0,167 0.000 0.056 0.000
-0.500 0.000
-0,111 0.000 0,056 ty,*P'rr-'rl1'"**
240 56% ,0,500 -0.276 0.139 0.241 .o.ooe -0,491 M17 270 701', 0,000 0,000 0.000 0,000 *1,000 ,0,776 0,778 300 6Qll o.500 0,278 0,139 ,0,241 ,Q,WI o-0.481 D.417 l._.,*D"u.. '1.:*'lltr1 330 221', o.eea 0.192 0,167 -0.096 ,O,IOQ .0,11\ o,oss 360 OIi 1,000 0.000 0.000 0.000 0,000 0.000 0.000 D
- tr, -r *t ,lo 390 0% o.eoo 0.000 0.000 0.000 0,500 0.000 0.000 420 0% MOO 0.000 0.000 0.000 0,6GO 0.000 0.000 4i!O 0% 0.000 0.000 0.000 0.000 I.GOO 0.000 0.000 BO 0% ,0,:SO0 0.000 0.000 0.00D o.esa 0.000 0.000 510 0% .o.esa 0.000 0.000 0.000 0.500 0,000 0.000 540 0% *1,000 0.000 0.000 0.000 0.000 0.000 0,000 570 0% ,0,1)6<1 0.000 0.000 0,000 ,0,600 0.000 0.000 0.000 0,025 1.667 0.096 0.000 -0,078 2,558 dlDtl<<O ry Bpyy 8PXi dl<ltk=Q IX BP'-"
0.072 0.139 0,009 0,352 -0,22J 0.213 flonsel Voffsot By,, a,v Syy*B>X Xolf,el Bu
'I,.,.,- "rt: .. ,",y;l:...,,fl*alt "'t"'{,-a) 0,123 BByy 0.03& 0,137 27% eave 0.014 0.333 33% BBl<X
-0,117 0.196 39%
Byy,.D 0,13" 8"'.Jl 0,19!1
.._..* ~ * ¥ * , ( t o ) - D,t"-'(h) .27% 0%
Byy,!IJo<,O Bxr-o ,,. 2a1i,iii oot2,lpt,,, $In 2alp!la tan died< alpha o,_.,*s,t,.,<,..>-¥*mO l -0.0S& 0.014 FAlSE FAI.SE
-0,467 0,908 ,Q,423 ,0,467 M&a1Uf&d Bonds Ad osledB s Bond VIII.Jot cafculatt4 a\ A,.ol'l'lt\"'
- 8004 W'tln~let.1l1lad 1tA,.6'fuit 11'lg{a Yol!sel 8'f'I )(o/1.. 1 Bill Yo1fte1 B'f'I XOlf,.I 81:ll 0,029 35% -0.089 46% O.0Ja 27% -0.117 ~9 3SWP.\12tt,FW38Jds Pnge 8 of 19
~-* *--- -**.>' ..............~ *****~*****...... .
, . ***-**, **
- SeFial No; -2~ ... 292- * * ** ,* ** ...... ***---
Docket No. 50-423 Attachment 4, Page 1Oof 24 Teclmical Evaluation No. M3-EV-08-0006, Rev. 00, page 9 ofl9 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075-V222 5.0 SAFETY SIGNIFCANCE Tµis technical evaluation is prepared in support of an operability determination and is not a change to the design or operation of the plant as described in the.licensing basis. Therefore a 50.59 screen is not required. Because the evaluation shows the piping meets approved evaluation criteria there is no impact on safety of plant operations.
6.0 CONCLUSION
S The degraded socket welded fitting described in CR Reference 3.1 has been evaluated according to the NRC approved methodology documented in Reference 3.4 and determined to be structurally acceptable for continued service until such time a Code Repair can be performed. According to NRC agreement documented in Reference 3.4 and 3.5, the limitations for use require r~pair of FW-38 at the earliest of the following:
- next schedule outage of sufficient duration to complete repairs, or a scheduled shutdown greater than 30 days
- next refueling outage
- time at which the flaw/leak size is predicted to exceed the flaw/leak size accepted by evaluation
\
In addition, compliance with the accepted methodology requires periodic reassessments ofFW-38 and augmented examination of five other similar joints, as detailed in Reference 3 .8, Sections 2.6 and 2.4 respectively. 7.0 ATTACHMENTS Item Description No. Pages 1 Braze Bond UT Readings 5 2 Structural Assessment ofFW-37 (info) 4 3 Independent Review Comments 1 Total pages of attachments 10 9 Page 9 of 19
.......,,..._____ . _,. ...... **---~*--*** . Serial.No. 21-292 _.
Docket No. 50-423 Attachment 4, Page 11 of 24
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' A'.fTAGHMENr*1 ..
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Ut,.:TRAS.ONU:; CALfstt.A"ftO~* . . .DATA.SHEET .. Page _l._of-f:1-_ Plant: .I') ill sfotrn .. Unit: .3 AW@ Number. t:1.3 .. o<J- O.'J..S2C
- Purpo~e: Eng. t.11£0 * /J/11. ' .
Cal Block Number. f't ~ 7 7 </ 'i .. ' . *ca1*Block Temp
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Search1:1n1t lnstrwnenl*&.Setlitgs' ,IJ If Jtf.Jt' Manutaewrer ,/l'/HJ
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- fl J.':OC'IG~ 40
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- No. of Cbruloot<l!'tl :
.. ~Value *.
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\., $keldl I "Vi'I ...... lnUl\'ll Callbrallon . )11'\f'I*. Metal*.Path N/A suoptemenl.\l I y Fl(llll eallbral!on f,1/1, Oe!')lh 1.0 ~~
f'irlil CallbraUon a.oco Ooup(snl DAI& 8f8nll * <nr,ildSa.+~ t'latcfl. Number OG'J'lf'I A SAP Batch Mgmt. No. OO<<l07Sl.3i Component ID Component Type Commenw, I ** i . J;°M f{, Ct,11? Q/llf f:{t) ~i Rm. -,a .n1i/lt'-. ,'fnlll-l't. ISP u ..*on.M t<iJ: .lJ<:wPx If l'.l'.l
.*Examlner(Pririt~Slgn) Pl,P/.ni,./ niui.... 1--,,. '-* *I*
1.r~ Lever .;g_ Dal~ :ti1,//0'Z examiner (Print{!,, Sign} /J/ A Level ~Lll Oate 'l,Jf.4
*Reviewer (Slgnatur111) Level ..oare '
MP-UT*45 Lever of Us.e . Rev. 0.00-01
'. Page*10 of 11 I
i .; Reference-J..
- ge-lO-of 19..
- _.':,,. ..*..... _... Serial./llo,-2-1-,292 * .., --*
Docket No. 50-423 Attachment 4, Page 12 of 24
/ft It FW-37 ,. . P@int No-. *1st Signal (no bond) 2nd Slgnal (bond)
I 1 GO L/0 2 (;O ~o 3 d..0 ~o
.4 40 bO 5 so .
O i .
.I 6
7
~o zo 4-0 60 8*
9, GO ~o ,t 40 60 10 a.o .' -~o 11,
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. Total Average i.
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.., ..... _ .... ,.... -* ... . ..... -*"*-*-- .. . ......-..-*-*--*-* .... :...... *.. ,... . . ... .. .. ..........SerlaLNo .. 21-292 . . ..
Docket No. 50-423 Attachment 4, Page 13 of 24 M3-- /i.V.. O'l* tJ'Pt!J6 k O 12t-, 12.. .
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.Point N-o-. .-1st'Signal (no bond) 2na Si.gnaJ. (bond) 1 6.0 ... ,
'10 :
2 60 'I<!) 3
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60 .~o 70 30. 5 GO 40 "6 so ~o 7 70 30
-8.* 70 30 *.
9* 4-0 60 10' *. cl.., .. '60 ' 11* ... lfO 60 ., I I . 1:2 7o* JO II 1*3 ,J ~ . *. I I 1,4 ~ l l*
*1:5 ~
i 1*6 -~ A Total Avera.ge Sw H f"
**1*-u, .. ,.,,, ..,,, .. ,P~ge-i2 of 19 ..
...*,*., .. ' , .... ,..........................:. .... . . .. .. ,,_.. ~!'lr@L~q. 21:292 ...
Docket No. 50*423 Attachment 4, Page 14 of 24 I *
l
..2na Signal. (band_)
I
*Polnt Nn-. *tsf'.Signal (no bond.)
*1 GO . l/0 I *f 2 ~o. ~o 3 GO 1/:0 4 C;O 'tO
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Docket No. 50-423 Attachment 4, Page 15 of 24 Attachment*1:t:xam Data Sheaf Millstone Power Station ULTRASONIC_EX'AMINATION
.STRAIGHT BE~ MEASUREMENTS' Instrument & Settfngs Compont~f'Data Manufaoturer .
- Component T"""' II ModeiNo. J.. Component Dis. I Atteclunent.s.
Raogo Velocity, Block Tlilckol!SS Instr11111.ent*Readlng Min. Max. Zero Value ~tlal Cal Tolc:ninco Intcnmdiato Intermediate l
- Final Manufacturer TypcNo, , ** Coatings Factor Data
. ScrlalNo. Brand* Surface Painted YO
- FrC((Uenoy . Batch*No. ACT*mlls .. ,-JI Sizo
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"Avcrago Coat.Ing Thickness Sketcli/Conuneats Ar/!li
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~eviewer(sign) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____,Level _ _ _ _ Date _ _ _ _ _.
1 ANJ!ANU If-Required (Sign) Date ___Nl.._A...,.__ LevelofUse MP-UT-5
*Reference Rev. 000-05 Pa e23 of2S
- Page 14 of 19 ' .
l,._.wG-*,..-- -* "-*"'-**-*----*---------*--~-*-*-**-*.,-..,.****- ---*-**-*-.,.\-..,_....., ... **---*,._,,,.._._ .. ,_,. ****-
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,. ' . . .~ - . ,., .......:-. Serial No. 21-292
~.'----**--*- UockefNo. 50~423*--*- .. --* ----
Attachment 4, Page 16 of 24 M3-EV"08-0006 Rev. 00 Page 15 Sheet 1 of 4 Braze Bond Structural Assessment , Joint SWP95-FW37 Ref: TE M3-EV-05-0002 Rev. 1 this sheet revised 07/17/2007 Part 1 Basic Data ( dashed boxes are inputs) ln.£!!ls: __________ *--" __ Inputs: Line No:jSWP-075-V222 I Pipe Dia j 1.05 in j Sys Functlon:1FT-438 upstrm instr tubing , Norn. Wal/Thk, 0.154 in Piping lso:jCI-SWP-95 Sh 2 I Pipe Mat'J1SB 466 CDA 706 Joint: :SWP95-FW37 Fitting Mat'l!SB_~1or_~~-- __ * ...! Side ofJolnt:1Upstrm I Ref. Bond Strength: 7,500 psi Jt. Orientation: :!~r" ____ . __________ _; Bond Adjustment 10% Measured Ave. Bond 59% (calculated. For bond measurements, see sheet 'UT Readings') 59 % >= 60 % ? No, Detailed assessment required Part 2 Bond Data Summary (data from sheet 'Bond Cales') Off.sets based on adjusted bond: Dxx -o.oos in* Dyy -0.026 in Doffset 0.027 in (5% of pipe radius) Alpha 9.7 degrees - rotation angle of principal axes Calculated effective bond data are in principal axes system, and are based on adjusted bond. Actual Adjusted Bxx 66% 62% Byy 52% 47% Bbend 52% 47% 4 Bpress 59% 55% Note: Plot is figurative only, actual braze bond Is cylindrical, not through-wall. 3SWP-V222-FW37.xls P!!ge 15 of 19
.... -** .--~-*--*****--*~*--*-----**
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Serial No. 21-292 . J ........... _ Attachment 4, Page 17 of 24 M3-EV-08-0006 Rev. 00 Page 16 Sheet 2 of 4 Braze Bond Structural Assessment Joint SWP95-FW37 Part 3 Calculated Bond Load Capability Lookup Toi: L,lnsert per MUSpec D 1.05 in D.nom D.od Linsert tnom 0.154 In 3/4 1.05 11/32 PipeZ o.085 in"3 1 1.315 7116 Llnsert 0.344 iri (from lookup table at right) 1.5 1.9 518 Smax{100%) 26, 169 psi (from formula at right) 2 2.375 21132 2.5 2.875 25/32 Load Capability (Allowable Nominal Pipe Stress) 3 3.5 53/64 {Based on bond levels from Part 2) Actual Adjusted Sxx 17,213 16,218 psi stress based on shear allow. and percent bond sv; 13,695 12,295 psi 2 JtD *Linsert Sallow 13,695 12,295 psi S mJb adj)= b adj' *'tma, 4*Zpipe Part 4 Pipe Stress Data (stress calc Inputs) (data from Part 1) Stress Cale:- NP:swP. .9s~V222 . . - .... - k .. iI Pipe Dia 1.05 in I Rev/ CCN1 Rev. 2, CCN 0 ________ _J Norn. Wall Thk 0.154 in Line No: SWP-075-V222 Pipe Mat'I SB 466 CDA 706 Sys Function: FT-438 upstrm instr tubing Fitting Mal'I SB 61 or 62 Piping iso: CI-SWP-95 Sh 2 A.pressure 0.825 in"2 Joint: SWP95-FW37 Z.pipe 0.085 Tn'i.3 - * *- fnnuts: StressNodelnta;r___ .----*-----**7 p ,A Aft. Stress Node*n ' I
- max press a ' SP offset;; D0 rroor*-------
S/F Usedl 2.1 I - 2 p!pe
.... - - .. - - - - - - - - - - - * - .... - ....J Primary SIF 1.575 S-Slp %end S=--+s p_o rns~... +s1PB*--
Inputs: psif press Design Pressure 100 psig 1 1 Max Op. Pressure , . 100 psig , Calculated Nominal Stresses
- Sip ! 170 psi Jsp_offset 27 psi Eq. 8 (P+DL)t 2448 psi I Sust'd 8' 1619 psi Eq. 9 (NIU)* 5238 psi
- N/U 9' 3391 psi Eq. 9F (Design BastsoL ___ ~Q2_p!JL ___ F_a_u_lte_d_9_F_'_ _4_1_3_0 psi Max Pipe Nominal Stress. 4130 psi Apply Safety Factor of 1.5 6195 psi Part 5 Structural Integrity Determination Joint SWP95-FW37 Joint Load Capability . 12,295 psi (from Part 3) 1,S*Deslgn Basis Load 6,195 psi (from Part 4)
Check: 6,195 < 12,295 ==:;:> Braze is adequate for design basis loads
- Monitor until repair/replacement 3SWP-V222~FW37.xls Pqge 16 of 19
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.serial No. 2.1-292 ______ .. * ---------
Docket No. 50-423 Attachment 4, Page 18 of 24 M3-EV-08-0006 Rev. 00 Page 17 Sheet 3 of 4 Braze Bond Measurements Joint SWP95-FW37 R Rmin Bond Adjustment 10% 1 0.75 Reading Angle Meas. Bond Adj Bond PlotValue Adj Plot Max Min 1 o: 40%: 33% 0.850 0.833 1 0.75 2 30' 40%j 33% 0.850 0.833 1 0.75 I 3 60*I 80%: 78% 0.950 0.944 1 0.75 4 90J 60%1 56% 0.900 0.889 1 0.-75 5 120: 50%: 44% 0.875 0.861 1 0.75 6 1501 80%1 783/4 0.950 0.944 1 0.75 7 1ao: 60%: 56% 0.900 0.889 1 *0.75 8 2101 40%1 33% 0.850 0.833 1 0.75 9 240: 60%: 56% 0.900 0.889 1 0.75 10 2101t 80%1I 78% 0.950 0.944 1 0.75 11 300 1 80% 1 78% 0.950 0.944 1 0.75 12 3301I 40%! 33% 0.850 0.833 1 0.75 13 360 1 0%' 0% 0.750 0.750 1 0.75 14 390! 0%! 0% 0.750 0,750 1 0.75 1 15 420 0%1 0% 0.750 0.750 1 0.75 16 450!I 0%*I 0% 0.750 0.750 1 0,75 17 4801 0%1 0% 0.750 0.750 1 0.75 18 510: 0%: 0% 0.750 0.750 1 0.75 19 5401 0%1 0% 0.750 0.750 1 0.75 20 510:_____ 9o/ctl 0% 0.750 0.750 1 0.75 N~eadlngs 12 Ave 593/4 55% G9:G21 dTheta 30 Min 40% 33% degrees Max 80% 78% Page 17 of 19
.. * . .. t ..... ~-* - ,,.. .. ., I "' ., ...' Serial No. i1-292 .
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Attachment 4, Page 19 of 24 f.13-EV.-OB-0006 Rev, 00 Po9e18 Shcel4 oC4 Bra:.:e Bond Calculations Joint SWP95-FW37 Bolr,e\ Nreadiogs Equfvalon\ bond based on measured bond readings, WilhoUI adjuslmenl 10% 12 D ~le Mea,. Bond <<>Sllhola) db"co$ db'cos*z db'sln'<<>$ sln(1heta) db'*ln db'sltr'2 1,05 0 401\ 1,000 MOO 0.400 0,000 0.000 OJ>OO 0.000 30 40% 0.868 o.:146 O.:JOO 0,173 0,600 0200 0.100 N>fl$cilllJ)ul 60 60¥, o.soo o. 00 0.200 0,:146 0,8liG o.m 0.600 o degrees 90 60% 0.000 0.000 0.000 0.000 1.000 0~00 0.600 O.OOOrad 120 60% .0.500 -0,250 0,125 ,0,217 0.6"8 0.433 0.375 160 80% -0.866 .0.6!n 0,600 .0.:146 MOO 0.400 0.200 160 601\ *1,000 .0.600 0.600 0.000 0.000 0.000 0.000 210 40% *0.866 -0.348 0,:)00 0.173 -0.600 .0.200 0.100 240 WY, *-0.500 *0,300 0.150 0-260 -0.866 *0.520 0,460 210 60% 0.000 0.000 0.000 0.000 -1.000 .o.eoo o.eoo 300 MOO o. oo MOO -G.:146 .0,66G -0.G93 0.600
- )30 40o/, o.a,s 0.345 o.:ioo .(),173 *0,600 .0.200 G.100
- )60 0% 1,000 0.000 0.000 0.000 0,000 0.000 o.DQO 390 0% 0.886 0.000 0.000 0.000 0.500 0.000 0.000 420 0% 0.500 nooo 0000 0.000 0.866 0.000 0.000 450 0% 0.000 0.000 0.000 0.000 1,000 0.000 0.000 480 0% *O.SOO 0.000 0.000 O.Ooo 0,866 0.000 0.000 510 OIi -0.866 0.000 0.000 0.000 MOO 0,000 0,000 540 0% .1.000 0.000 0.000 0.000 0.000 0.000 0.000 670 0% -0.666 0.000 0.000 0.000 *D,500 0.000 0.000 0.000 *0.025 3.175 .0.130 0.000 .0.007 3.925 Bpruo c:h,:Ok,,Q ry epyy Bpxy c/recJ<<O BpJIX 59¥, *0.042 0.265 --0.011 o.sn .0.012"' 0.327 Rorrm 0,023 Yollsel
.o.on Byy 0.264 a..,
.0,011 BY)l+BM 0.591 Xolrael
-0.006 BM 0.:127 BByy $3\1. Save 59% BBxx 66%
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.0.063 -0.011 0.351 o.9<< 0.331 0.351 0.169 111d FAI.SE FALSE 9,7 d<9 Eqvivalent bond based on adjusted bond readings l:,~
~.
- II di l~ .. otr.w:t Angle MJ.8ond e<>>(llle!a) db'"'° db"COS112 db*sin*cos *in[lhela) db ..ln db'11n'2 1 0 333/4 1.000 0,333 O.:J:l3 Q.QIJO 0.000 0.000 0.000 r.,.*~*:£*, ...(ej 30 33% 0.868 o.m 0.250 0.1<< 0.500 0,167 0.083 60 78% 0.500 O.Je9 0.194 0,337 0.868 o.614 0.563 90 563/4 0,000 0,000 0.000 0.000 1.000 0.656 0.556
"*** i*I:*roh(*f 120 150 44¥1 78%
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&y,::::a fr1r **r./*b1v 210 78% 0.000 0,000 0.000 o,oao *1.000 ,D.778 o.ne 300 7811 0.500 0.389 0,194 -0,337 *0.86& .Q.674 0.563 Ba*lr,.-.-,J*t.1 ., 330 33% 0.868 0,289 0.250 ,0.144 *0.500 .0.167 0.083 360 ov. 1.000 0.000 0.000 0.000 0,000 0.000 0000 D C Ir.
- 390 0% 0,Sli6 0.000 0.000 0.000 0.600 0.000 0.000 420 Of, 0.500 0.000 0.000 0.000 0,866 0.000- 0.000 1o.{toJ*r7 450 0% 0.000 0.000 0.000 0.000 1.000 0.000 0.000
,,.(,ol- l11y,-*,l 4IIO 0% .0,500 0.000 nooo 0.000 0,886 0.000 0.000 510 DY, .0.866 0.000 0,000 0.000 0.500 0,000 0.000 J(&yy- e,J O,y 540 0% *1.000 0.000 0.000 0.000 0.()00 0.000 0.000 570 0Y, .0.666 0.000 0.000 0.000 -0,500 0.000 0.000 r*(l-a)* ,.,(1,,(>o))-/l*l\.g o.aoo .0.027 2,861 .0,144 0.000 *0.000 3.694 Jt11y,-e.~** **,,' Bpreu dleck:Q ry 8p)Y Bp,y -lr-0 nc BpJIX 5511 .0.050 0.238 -0.012 0.54G -0.016 0.308
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..***. .!.***** * *Serial*No-: 21 s-292 ** .... ** ....,-..... _.* Docket No. 50-423 Attachment 4, Page 20 of 24
, Technical Evaluation No. M3'-EV-08-0006, Rev. 00, page 19 of 19 Evaluation of Unit 3 Service Water Brazed Joint Flaw, Line 3SWP-075.Y222 Independent Reviewer Comment and Resolution Sheet(s)
(ER/EV) No. M2-EV-08-0006 Rev. 0 Page 1 of 1 Independent Reviewer: Thomas Steahr ~ ( / tk.::: Date J/r;/o'c? Comment No. ER/EV Section Comment All Minor edits 19 Page 19 of 19
Serial No. 21-292
.........- ..... --.... - ..... _.,, ............................ **-***--------...- ...... _ ... Docket No ...50-~42_3_ _
Attachment 4, Page 21 of 24 ATTACHMENT 1 ULTRASONIC CALIBRATION DATA SHEET ' Page \ of,_\__ Plant: MI LLS:fo ~f:' Unll: "3 AWO Number: ,M,3 ~ O'a ...- ct.(\ ~ :l
Purpose:
(t-JC;i:I i,..,)tt'.R.! I\.)~ .Ir-J~OR./V\8TION Cat Block Temp ~JA Cal Block Number M"i"E'-0:2.0 lS'
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Search Unit Instrument & S&ttings Manufacturer ltr:1...d Mfg./MOdel \(.I". Style or Type ~ . ,..,, . ,. .... Serial Number ~l"V'I n,15 too Frequency [,::..,.,,Nll.l:r,. Ranne \.o ,tu- II 6 Sizel!o Shape * .::).5" Material Veloolty .\&:>tvO 80 MOdeTorC C Delay ~o.3"15 Search Unil Angle Cl> Pulser N_ 1111.., 80 Measured Angle ,_,(A Reieet O"I. Serial Nun'lber oo*a~,.N Freauency .;.,_<;:\ 40 Cable Typ&, .Length lo~-l~L!/( *1 1-u& Damping ,.,.cc,,,..,,... No. of Connectors 0 zero Value l<.t. I 4'4> 20 Pulse Rep Rate l\lrLL 2 4 6 8 10 GalnSeWng ~IA Allachments (Check) Callbrntions Time CRT~tvp Inches Sketch Sheet 1 i-.)1..6 tn!Ual Callbrallon ,~~4 MetalPalh 1-l/A Suppl,ements I Final Csllbrnllon ~*JA Depth .O Final CallbraUon Ht.:;~ Coupiant Data Brand ...... _ ... --C""" Bateh Number c,t~1,...-.A SAP Batch Mgmt. No. ,'>_"','?, component ID component Type comments t:'W-~<;1, 1"""".,i:"1' -.;:...., NT ltl:'11 \.(J~_,\Jt) :::' v .A J\,'I II Examiner (Print & Sign ll.(.)\:\1-Ji:'"'\l .... A =-Yll ' I , . ~ ~ f L.evel :11: Date ,::,/',;),'1. lr,-t Examlner (Pr:lqt & Sign) u V Level bl[t's. Date ,-J(A Reviewer (Signature) ~ ~ Level -:0: Date 5/-!:l~_<>'i. MP*UT--45 Level of Use Rev. 000~01 Page 10 of 11 Reference
Serial No. 21-292 . _ _____,___ ,. ... ,..................--... - ...-~*---, .... _,. ______ .........,_....... -* .......... - . . -*........------* .. ---*---*-* ...QoGket*Noc*50*423--*--**-- .. *" .. .. Attachment 4, Page 22 of 24 f\JJ .. 3>'o Awo M?>-O'o-O'-{\'o:i.. Point No. 1st Signal (no bond) 2nd Signaf (bond) 1 Li,() 4D 2 ~o 40 3 ,D I :-2,o 4 (c,5 35 5 loo 40 6 ,o 2>0 7 70 3o 8 y,'5 1,$ 9 I.QO Yo 10 l.oO !.fO 11 -,o &:> 12 70 30 - Average Lf5 °/.. 3$ "'/.
Serial No. 21-292
. ****-*--*- ......... Docket No:*so0'423***
Attachment 4, Page 23 of 24 ATTACHMENT 1 ULTRASONIC CALIBRATION DATA SHEET Page or_-a_ Plant: M p .. 1_,5!:'QNf:*
- Unlt: '3 '
AWO Number. f!1 ~ - Q '.o ... ~41<33 Purpose; E: ~ C'-;i:I N~t' Q.1 !-..le;. ;(1-J~O~c)Tf OI\J Cal Block Temp i-.1/ A Cal Block Number °18-,loo OWGNo, d>:52.\ :i..- ~, 00 \ SH, ::tl Thermomer~r SIN & Due Date ~LA Search Unll Instrument & Setfings Manuracturer .,.,,,_,. Mrg./Model \(l!,/VSJ,) $':U.. .I.I nll !)'T' n, SIYleorTwe ~.luV\.AIIA Serial Number r,rit'_ ls)C::l. 100 Frequencv ""C, "'11-l?. Range l.t"lnll Slze&Shape .:z.~' Material Velocity \ "I :1 (! 80 Mode Tore c:. Delay -.'.2..~":l Search Unit Angle co Pulser 'l">vAl. 60 Meas*ured Angle NIA ReJoCI o-/. Serial Number r,,-,'nX.\.)\J Frequency 1.-'21 40 Cable Type, Length or.~1,'l/l~ Damping I ,.,,..,., °"M No. of Connectors (") Zero Value l{,OM 9, 20 I Pulse Rep Rate \.\-\G,1-1 2 4 a 8 10 GalnSeWllg \JIA Attachments (Cheek) Callbratlons lime CRTSelup Inches Sketch Sheet I iJ/A lnltlal Call~rallon OC\!><t Mel;ilPath iJ A Supplemenls I . Final Calibratron NIA Deplh l. (\ ... Final Ca!ibrallon \000 Counlant Data erand '"UNt>S..l\~l':' Balch Number a c,,, :i_c, A -SAP Batch Mgmt. No. n HU
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Component ID ComponentType Comments
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o/~t"ifa~ D Examiner (Print & Sign) Date
~~
Level t,,l(~ Reviewer (Signature) LeveJ..:11: Date MP~UT*"45 Level of Use Rev. 000-01 Reference Page 10 o! 11
Serial No. 21-292
******~ **** >R - *"' *-~*-.**-*-***** ~,..
- I MO* .. 0
. ... . ... **-*~---*~---*-*-*' ........ ' ,.. . ** .. ' [)ockefNo. 50-423 _____ ... . . ....
Attachment 41 Paae 2j g{ 24 *a Point No. 1st Signal (no bond) 2nd Signal {bond) 1 Ct,0 4 <? 2 L,Q 40 3 -, 0 3o 4 (Q*S 3$' 5 <oS ~s 6 l..; s :; s 7 "le, ~o 8 leO 4<> 9 70 :>0 10 ~s :,$ 11 lc5 35' 12 70 30 Total *1 <a 5" ({IS' Average ~5"/.. 3 S .. ?
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Serial No. 21-292 Docket No. 50-423 ATTACHMENT 5 MECHANICAL TESTS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No. 21-292 Docket No. 50-423 Attachment 5, Page 1 of 3
1.0 BACKGROUND
The correlation developed by the testing conservatively determines a required bond level for a given intensity of joint loading. The results of these tests support the use of the comparison shown in Figure 2 of Attachment 2, for the structural integrity analysis. It is noted that the evaluation of testing results was with respect to a braze shear capability of 5.0 ksi, which in the final methodology has been increased to 7.5 ksi, provided that piping loads have an FS of 1.5 applied. For consistency with testing as performed, the 5.0 ksi shear capability discussed is retained in this attachment. 2.0 TEST SAMPLE DESIGNS The effort to empirically confirm required bond levels for varying intensities of joint loadings consisted of three separate series of mechanical tests: a) specially fabricated joints with a controlled average bond level, b) specially fabricated joints that had disbondment on a contiguous arc-segment of the joint, and c) field sample piping joints, salvaged from piping removed from the plant. All joints were tested in three-point bending with the brazed fitting in the middle of the configuration. 2.1 Specially Fabricated Joints with a Controlled Average Bond Level By a combination of machining and use of insert-groove type fittings, a series of test joints were fabricated with equivalent bond levels of 12, 30, 40 and 60 percent. The machining removed only about 30 mils of pipe thickness so that piping strength was not significantly affected. The samples were fabricated for two-inch and for three-inch joints. Three examples of each size and bond level were fabricated, for a total of 24 samples. (Of the 24 samples in this category, one of the 40 percent bond samples was subsequently found to have less than the fully intended bond and is excluded from the results.) 2.2 Specially Fabricated Joints that had Disbondment on a Contiguous Arc-Segment of the Joint: These test items were intended to explore the effect of having a significantly non-uniform distribution of bond area around the circumference of the joint. Six samples were fabricated with disbondment segment angles of 36, 48, 72, 90, 108 and 126 degrees. The average bond levels for these samples, assuming perfect bond except in the disbonded segments, ranged from 90 percent down to 65 percent, respectively.
Serial No. 21-292 Docket No. 50-423 Attachment 5, Page 2 of 3 2.3 Field Sample Piping Joints: These joints were salvaged from piping that was removed from the plant after about 20 years of service and screened by Ultrasonic Testing (UT). Piping joints with the lowest of measured bond were selected for testing. The nine items selected for testing included the following: Description Quantity Two-inch couplings 3 Three-inch couplings 2 Three-inch tee (run sides) 1 Three-inch flanges 3 The couplings and the tee included two brazed joints subjected to test loads. The test flanges were mated to full strength flanges not under test. 3.0 MECHANICAL TEST RESULTS The results from testing on each of the series of tests are described in the balance of this section. The referenced figures are included in Attachment 2. A test report has been incorporated into the Millstone Power Station plant records. 3.1 Specially Fabricated Joints with a Controlled Average Bond Level: For the intentionally disbanded joints, all joints with 30 percent or better true bond, achieved full piping collapse strength with no failure of the bond. Refer to Attachment 2, Figure 3. As testing of each joint continued above the piping collapse load, one of the 40 percent true bond joints had indications of bond failure. The 12 percent true bond joints all experienced bond failure before reaching piping collapse load but withstood a minimum of 37 percent of the piping collapse load( refer to Figure 4). All test items achieved their test collapse load at a load well above that which would be predicted for a 5 ksi braze shear strength. 3.2 Specially Fabricated Joints that had Disbandment on a Contiguous Arc-Segment of the Joint From 36 through 72 degrees of segment disbandment, the test items all achieved full piping collapse load. The test items from 90 through 126 degrees disbandment exhibited progressively lower collapse load, as shown in Attachment 2, Figure 5. At 126 degrees disbandment, the test item achieved about 60 percent of the piping collapse load. The load deflection curves for these joints did not exhibit any indications of bond failure, however at the extremes of deflection (well above the level that would be acceptable for application of this methodology) the higher angle joints were significantly distorted. For such large levels of deflection, it was apparent that the close
Serial No. 21-292 Docket No. 50-423 Attachment 5, Page 3 of 3 mechanical fit-up of the pipe in socket configuration contributed to joint bending strength. All test items achieved their test collapse load at a load well above that which would be predicted for a 5 ksi braze shear strength. 3.3 Field Sample Piping Joints The field sample test items exhibited considerable variation in collapse load for roughly similar UT bond readings. The variations were expected for the field samples. Figures 6 and 7 show the displacement load curve for the tested field samples. Bond failure limited the collapse load in the two-inch Joints 37 and 39, and the three-inch Joints 3 and 9. The load curve for Joint 9 has a slight discontinuity at 11.9 ksi that is conservatively considered to indicate initial bond failure, even though the load continues above this point. The collapse load for other samples was limited by the piping collapse load, which is equivalent to about 21 ksi. Even with the low UT bond readings, the field samples developed at least 50 percent of the piping collapse load. The higher than expected collapse load for some of the three-inch joints is believed to be partly due to the thickness of filler metal present as a fillet at the face of some of the joints. All test items achieved their test collapse load at a load well above that which would be predicted for a 5 ksi braze shear strength and the adjusted percent bond used in this methodology. The adequacy of the 5 ksi shear stress assumed in the methodology in Equation 3 of Figure 2, Attachment 2, for estimating joint strength is confirmed by the testing margins shown in the following table. Table 1: Test Load vs. Bond Shear Capacity Test Shear Test/ Average Adjusted Test Joint Collapse Capacity Shear UT% UT% Load, ksi Load, ksi Margin 36 65 61 22.8 15.8 1.44* 37 27 19 11.6 4.9 2.41 39 55 50 19.6 13.0 1.52 2 45 39 27.3 9.0 3.02* 3 47 41 22.6 9.6 2.38* 4A 15 5 27.3 1.3 23.59* 9 38 31 11.9 7.2 1.69 9J 48 42 28.6 9.8 2.95* 31A 21 12 32.0 2.8 11.61*
- Piping collapse load reached before bond failure or deflection run out.
The data in Table 1 is plotted in Figure 9 of Attachment 2. Of the joints that were limited by bond failure prior to reaching piping collapse load, the minimum margin factor was 1.52. This minimum margin appears in Joint 39, with a 50 percent adjusted average bond. Review of detailed bond readings around the circumference of Joint 39 gives an equivalent adjusted bond of 43 percent for the bending axis used during the test, corresponding to a margin factor of 1. 74 for this test case.
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 6 ULTRASONIC TEST PROCEDURE MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 1 of 18 Nuclear Fleet a " - _.1n111vni Nondestructive Examination Procedure
Title:
Ultrasonic Examination of Brazed Joints - Millstone Unit 3 Service Water Piping Procedure Number Revision Number
- NPQR Number ER-MP-NDE-UT-745 0 ER-MP-NDE-UT-745-NPQR, N/A Approval signatures on file with approval documentation for this procedure revision.
R. C. Davies 04/04/2016 Independent Level Ill Review K. J. Hacker 04/04/2016 Corporate Level Ill Approval Level of Use: Reference
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 2 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 2 of 18 Record of Revision Re Page Paragraph Summary of Revision 0 All All New issue as a Millstone Site Specific NOE Procedure.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 3 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 3 of 18 Table of Contents 1.0 Purpose ...........................................................................................................................4 2.0 Scope ...............................................................................................................................4 3.0 Reference Documents .....................................................................................................4 4.0 Definitions ........................................................................................................................5 5.0 Personnel Qualifications .........................................................................,......................... 5 6.0 Equipment and Material Requirements ............................................................................ 5 7.0 Calibration ........................................................................................................................6 8.0 Examination .....................................................................................................................8 9.0 Recording of Results ........................................................................................................9 10.0 Data Recording .............................................................................................................. 10 - Typical Brazed Joint Calibration Report .......................................................... 12 - Typical Brazed Joint Examination Record ....................................................... 13 Figure 1 - Brazed Joint Examination lllustration ....................................................................... 14 Figure 2 - Illustration of Braze Joint with Insert Groove ........................................................... 15 Figure 3 - Illustration of Braze Joint with no Insert Groove (Face Fed) .................................... 15 Appendix I - Qualification Requirements for Brazed Joint Examination ................................... 16 1.0 Purpose ......................................................................................................................... 16 2.0 Prerequisites .................................................................................................................. 16 3.0 Examinations ................................................................................................................. 16 4.0 Qualification Records ...................................................................................................... 18
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 4 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 4 of 18 1.0 Purpose 1.1 The purpose of this procedure is to define a process for the application of ultrasonic examination techniques for the examination of brazed pipe joints to establish the extent of braze bond. This procedure describes the equipment, material, and documentation requirements for ultrasonic (UT) examinations. 2.0 Scope 2.1 This procedure is applicable to the manual contact ultrasonic examination of Millstone Unit 3, ASME Code Class 3, service water piping with brazed joints to establish the extent of braze bond. This procedure is applicable to brazed joints in nominal pipe size (NPS) of 3 inches and smaller. 2.2 This procedure describes equipment and procedures that shall be used in the ultrasonic examination of brazed pipe joints. This procedure is written based on the techniques and methodology detailed in relief request IR-3-04, no additional qualification is required. 3.0 Reference Documents 3.1 American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI, 2004 Edition with no Addenda. 3.2 ER-AA-NDE-120, "Dominion Written Practice for Certification of Nondestructive Examination Personnel." 3.3 ER-AA-NDE-121, "Dominion Written Practice for Certification of Nondestructive Examination Personnel in Accordance with ASME Section XI, Appendix VII Requirements." 3.4 ER-AA-NDE-130, "Storage and Control of Calibrated NOE Equipment, Calibration Standards, and Consumable NOE Materials." 3.5 ER-AA-NDE-140, "Processing of Dominion NOE Data." 3.6 Fabrication and Inspection of Brazed Piping Systems, NAVSEA 0900-LP-001-7000, Dated January 1, 1973. 3.7 Millstone Unit 3, Relief Request IR-3-04 "Alternative Brazed Joint Assessment Methodology", ML091310666 and ML092390141.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 5 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 5 of 18 4.0 Definitions 4.1 Face of Fitting - The annulus surrounding the socket end. 4.2 Insert Groove - The groove in the fitting socket prepared to contain the brazing alloy ring. 4.3 Land, Fitting - That portion of the fitting on the side of the insert groove nearest the middle of the fitting. 4.4 Land, Center - That portion of the fitting between the grooves in a multiple insert fitting. 4.5 Land, Pipe - That portion of fitting on the side of the insert groove toward the end of the fitting. 5.0 Personnel Qualifications 5.1 The examiner shall be certified to a minimum of Level II in the ultrasonic method in accordance with ER-AA-NDE-120 or ER-AA-NDE-121. The examiner shall be responsible for and shall accept the results of the examination. 5.1.1 In addition, the examiner shall maintain a current endorsement for the ultrasonic examination of brazed piping joints in accordance with Appendix I of this procedure. 5.2 An assistant qualified to at least Trainee or Level I in the ultrasonic method may assist the examiner. The Trainee or Level I shall work under the direct supervision of the examiner and shall not evaluate or accept the examination results. 6.0 Equipment and Material Requirements 6.1 All equipment and materials used to implement this procedure shall comply with the requirements of ER-AA-NDE-130, "Storage and Control of Calibrated NOE Equipment, Calibration Standards, and Consumable NOE Materials". 6.2 Ultrasonic Instrument 6.2.1 A pulse-echo type of ultrasonic flaw detection instrument shall be used. The instrument shall be equipped with a stepped gain control calibrated in units of 1.0 dB or less. 6.2.2 The instrument shall be used at the rated frequency of the search unit. 6.2.3 The reject control shall be in the "off' position for all examinations.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 6 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 6 of 18 6.3 Search Units 6.3.1 The search units shall be dual element, straight beam (longitudinal wave) with nominal frequencies of 5.0 MHz. The maximum nominal element dimension shall not exceed 0.250". 6.4 Cabling 6.4.1 Search unit cables shall be a maximum of 25' in length and may consist of RG-58, RG-174, or combination of RG-58 and RG-174 type cables with no more than 1 intermediate connector. 6.4.2 The same cables and intermediate connections used for the calibration shall be used for the examination. 6.5 Couplant 6.5.1 A suitable ultrasonic couplant shall be applied to the examination surface. The same couplant used for calibration shall be used for performing the examination. 6.6 Calibration Blocks 6.6.1 The material from which the blocks are fabricated shall be acoustically similar but need not be identical to the fitting being examined. 6.6.2 The calibration block used may be flat or of the same curvature as the component being examined with a surface finish representative of the scanning surface finish on the component to be examined. 7.0 Calibration 7.1 The screen height and amplitude control linearity of the ultrasonic instrument shall be verified before and after examining all components to be examined during an outage or periods of use not to exceed three months. The linearity checks shall be performed in accordance with ER-AA-NDE-130.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 7 of 18 DOMINION ER-M P-N DE-UT-7 45 Revision 0 Page: 7 of 18 7.2 Time Base (Range) Calibration 7.2.1 A suitable linear screen range shall be established using a calibration block. 7.2.2 The nominal bond thickness (pipe back wall) should appear at no greater than 85% of full screen width, although data taken beyond that point, up to 100% of full screen width is valid. 7.3 Calibration Verification (Cal Check) 7.3.1 System calibration shall be checked on the calibration block. 7.3.2 The time base calibration shall be recorded for at least one point within the calibrated range of the system established during the initial calibration and: 7.3.3 7.3.3.1 At the finish of each examination or series of similar examinations; 7.3.3.2 At intervals not to exceed 4 hr during the examination; 7.3.3.3 When examination personnel are changed; 7.3.3.4 After any . interruption in system continuity (e.g., power interruptions, search unit change-outs, activation of new examination setups, etc.); 7.3.3.5 After any instance of suspected system irregularity. 7.3.4 Any change in probes or UT instruments from that used during the initial calibration shall be cause for a new calibration. When replacing cables of the same size, type, length and number of intermediate connectors as used during the original calibration, it is acceptable to perform a calibration check only. 7.3.5 The system calibration shall be documented on the Brazed Joint Calibration Record, Attachment 1.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 8 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 8 of 18 8.0 Examination 8.1 Surface Condition Requirements 8.1.1 The outer surface of the fitting socket shall be prepared sufficiently to obtain satisfactory sound transmission, shall not be rounded in the longitudinal direction, and should be relatively parallel to the pipe surface. 8.2 Examination Requirements 8.2.1 The surface of the brazed joint to be examined shall be laid out around the circumference in increments of 1/4 inch. Markings shall be numbered clockwise as viewed facing the fitting from the pipe. These increments shall be measured on the outside diameter of the fitting. 8.2.2 Brazed joints shall be examined using a straight-beam (longitudinal wave) method as illustrated in Figure 1. Signals typically occur from the following sources; the insert groove (if present), the fitting inside diameter, areas of disband (if present), the pipe inside diameter and possible multiple reflections. 8.2.3 To examine a joint, the search unit is placed over the area of the brazed joint intended to be bonded and moved around the circumference in 1/4 inch increments (see paragraph 8.2.1) and in a number of axial increments determined by the number of lands, land or engagement area width and the search unit size. The percent of bond is determined for each circumferential increment. 8.2.4 A static examination technique shall be used. For the static examination technique, placement of the search unit shall be in accordance with paragraph 8.2.3 for each circumferential and axial increment. The instrument gain shall be adjusted so that the bond signal (pipe back wall) amplitude plus the no bond signal amplitude equals 100% for each increment. 8.2.5 For fittings containing insert grooves, as illustrated in Figure 2, place the search unit on each increment so that the search unit active area is over one land only. Note the first back reflection of the insert groove, inside diameter of the fitting (no bond) and the inside diameter of the pipe (bond) signal on the screen. If necessary, check the back reflections with an un-brazed fitting of the same size to ensure positive signal identification.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 9 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 9 of 18 8.2.6 For fittings which contain no insert grooves, as illustrated in Figure 3, place the search unit on each increment so that the active area covers 1/2 of the land width of the fitting in the engagement area. Note the inside diameter of the fitting (no bond) and the inside diameter of the pipe (bond) signal on the screen. If necessary, check the back reflections with an un-brazed fitting of the same size to ensure positive signal identification. 8.2.7 Limitations or other conditions that prevent a complete examination of the required volume shall be documented on the examination data sheet. 9.0 Recording of Results 9.1 The "bond" and "no bond" signal amplitude values for all increments examined shall be recorded on the "Brazed Joint Examination Report", Attachment 2. 9.2 The increments for which no ultrasonic reading can be obtained shall be marked as follows:
"X"- increments which are inaccessible due to fitting configuration.
"NA"- Increments which are inaccessible due to piping configuration .
"NP"- Increments in which there is a lack of ultrasonic penetration.
9.3 The Increments of the above types shall be assigned percent bond values as follows:
"NA" = 0% bond "NP" and "X" - Increments up to a total length not exceeding 20 percent of the circumference of the land shall be assigned a percentage bond value equal to that of the lowest readable increment adjacent to the "X" or "NP" increments or 60 percent whichever is the least. "X" or "NP" increments in excess of 20 percent of the circumference shall be assigned a bond value of 0 percent. The examiner may, at his discretion, shift the incremental scale so that the minimum number of increments that contain "X", "NP", of "NA" values.*
*NOTE - Within the 20 percent limitation, two or more adjoining "X" and/or "NP" increments are considered a group of increments if the average of the remaining increments is 60 percent or more. The outermost two of any group, within the 20 percent maximum limitation, shall be rated on the basis of the adjacent readable increment. The inner increments of the group shall be assigned a zero value for calculation purposes.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 10 of 18 DOMINION ER-M P-N DE-UT-7 45 Revision 0 Page: 10 of 18 9.4 The bond percentage for the joint shall be determined by a simple average of all the bond readings taken at each increment. 10.0 Data Recording 10.1 Calibration and examination data shall be recorded on data sheets and as a minimum shall include the following: 10.1.1 Calibration sheet identification. 10.1.2 Names and certification levels of examination personnel. 10.1.3 Examination procedure number and revision. 10.1.4 Calibration block identification. 10.1.5 Ultrasonic instrument serial number, manufacturer, and model identification. 10.1.6 Ultrasonic instrument essential instrument settings. 10.1.7 Search unit beam angle, mode of wave propagation in the material, nominal frequency, size, shape, and number of elements. 10.1.8 Search unit manufacturer, model, and manufacturer's serial number. 10.1.9 Search unit cable type, length, and number of intermediate connectors. 10.1.10 Times and dates of initial calibration and subsequent calibration checks. 10.1.11 Signal response amplitudes and sweep positions obtained from the calibration reflectors. 10.1.12 Couplant type and batch number. 10.1.13 Data sheet identification and date and time period of examination. 10.1.14 Identification and location of the braze joint examined. 10.1.15 A sketch of the component examined. 10.1.16 Examination results including any limitations.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 11 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 11 of 18 10.2 All data records shall be reviewed and processed in accordance with ER-AA-NDE-140, "Processing of Dominion NOE Data". 10.3 All results shall be turned over to Engineering for final evaluation of joint integrity.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 12 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 12 of 18 Brazed Joint Calibration Report l um,:* 1<<.4 Mlg :
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Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 13 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 13 of 18 Bnu:ed Joint Examination Report C"if.\v.r.13/4:J~
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Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 14 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 14 of 18 Transducer
~ Insert Groove Brazing Ultrasonic Waves Alloy Pipe
~~~~----~ ------Fitting Disband Area in outer land Figure 1 - Brazed Joint Examination Illustration
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 15 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 15 of 18 Insert Groove Brazing lloy Pipe
- - - - - Fitting Disband Area in outer land Figure 2 - Illustration of Braze Joint with Insert Groove Brazing lloy Pipe
- - - - - Fitting Disband Area Figure 3 - Illustration of Braze Joint with no Insert Groove (Face Fed)
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 16 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 16 of 18 Appendix I - Qualification Requirements for Brazed Joint Examination 1.0 Purpose 1.1 The purpose of this Appendix is to provide the additional requirements for the qualification of UT examiners for the ultrasonic examination of brazed piping joints. 2.0 Prerequisites 2.1 Personnel who perform ultrasonic examinations of brazed joints shall also be trained, qualified, and certified as a Level II or Level Ill in the ultrasonic method in accordance with Dominion procedures ER-AA-NDE-120 or ER-AA-NDE-121. 2.2 This Appendix defines the additional requirements for the UT Level II or Ill examiner to successfully obtain a qualification endorsement for brazed joint UT examination. 3.0 Examinations 3.1 Required examinations for the brazed joint UT endorsement include written and practical examinations. These examinations shall be administered and graded in accordance with the ER-AA-NDE-121. The additional brazed joint UT endorsement qualification testing requirements are defined by 3.2 and 3.3 of this Appendix. 3.2 The written examination shall consist of at least 17 questions covering the ultrasonic testing procedure for brazed pipe joint examination. 3.2.1 The examination shall contain at least 10 questions on the operation of the ultrasonic equipment; 3.2.2 At least 5 additional questions on the ultrasonic procedure concerning the inspection of joints which fall into abnormal categories of a physical or administrative nature; 3.2.3 At least 2 additional questions concerning the recording of readings which the examiner makes. 3.2.4 The minimum-passing grade for the written examination is 80%.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 17 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 17 of 18 3.3 The practical examination shall demonstrate the examiners ability to determine ultrasonically the bond of brazed joints. In addition the practical examination shall demonstrate the ability to recognize such technical deficiencies as insufficient beam penetration, poor transducer contact and interfering contact surface roughness from patterns displayed on the ultrasonic instrument screen. 3.3.1 The candidate shall demonstrate ability to determine ultrasonically the bond in at least six brazed joins consisting of three different pipe sizes, with two brazed joints for each size. 3.3.2 The joints shall exhibit from 40 to 80 percent bond with varying degrees of bonding in each. 3.3.3 The percent bond readings obtained by the examiner shall be compared with the true bond. The true bond is considered to be the average percent bond readings obtained by at least three qualified examiners, using the same joints. In the absence of three qualified examiners, the true bond shall be established from reading obtained by the Level Ill testing examiner. 3.3.4 Acceptance of the practical demonstration is based upon the arithmetic average of the six deviations from the true bond shall not vary by more than 8% from the true bond of any of the test joint specimens and no single joint deviation shall exceed 15%. 3.4 Maintaining Proficiency 3.4.1 In order to maintain examiner proficiency for the brazed joint UT endorsement: 3.4.1.1 The examiner shall either have performed a brazed joint UT examination, within the last six months, or; 3.4.1.2 Performed an examination of at least three brazed joint demonstration specimens, in accordance with the requirements of 3.3 above, within the last six months.
Serial No. 21-292 Docket No. 50-423 Attachment 6, Page 18 of 18 DOMINION ER-MP-NDE-UT-745 Revision 0 Page: 18 of 18 3.5 Requalification 3.5.1 A qualified brazed joint UT examiner shall be requalified in accordance with the requirements of 3.2 and 3.3 above, prior to performing examinations: 3.5.1.1 If the individual has not maintained proficiency for the brazed joint UT endorsement; 3.5.1.2 If the individual's performance is determined to be deficient; 3.5.1.3 At the end of three years from the endorsement qualification date. 4.0 Qualification Records 4.1 Dominion shall document the ultrasonic examination personnel endorsement for brazed piping joint UT examination on the individuals' certification record.
Serial No. 21-292 Docket No. 50-423 ATTACHMENT 7 ADDITIONAL BASIS FOR BRAZE SHEAR STRESS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 1 of 4 This attachment provides the following two items:
- Additional minimum brazed joint shear stress experimental values
- Further justification for the proposed use of brazed joint shear strength and safety factor
- 1. Minimum Brazed Joint Shear Stress Experimental Values The test data in Table 1 supports the proposed methodology in Request IR-4-09 for ev,aluating the structural integrity of brazed joints. Table 1 was derived from existing ASME Brazing Procedure Qualification Records of qualification tests performed in accordance with the ASME Boiler and Pressure Vessel Code, Section IX. Each test includes a set of either reduced or full section tensile tests. In order to pass these tests, the brazed joint must be at least as strong as the specified minimum tensile strength of the weaker of the two base metals joined. Figure 1 shows a simple schematic of a tensile test specimen. The tensile test specimen loads the braze bond in shear. The shear stress data in Table 1 was calculated by dividing the ultimate load by the theoretical shear area of each braze joint instead of the cross-sectional area of the pipe. Where failure occurred in the base metal (as was the case in all but two of the reported tests) the ultimate shear strength of the brazed joint was not measured but must be greater than the reported values.
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 2 of 4 TABLE 1: MINIMUM BRAZE JOINT SHEAR STRESS Lap Shear Shear Type and Pipe O.o.<1l Specimen Length Area Load Stress Location of (in) (in 2) (lbs) (psi) failure (in) BPQR 112: three-inch P-110 Pipe to P-107 Fitting with Pre-placed BAg-1a Insert Ring Reduced Section tensile test data V-T1 0.750<1l 0.570 0.428 5,600 13,100 Ductile-Fitting V-T2 0.752 <1l 0.570 0.429 4,800 11,200 Ductile - Fitting 1 H-T1 0.753 <> 0.570 0.429 4,300 10,000 Ductile - Fitting H-T2 0.753 <1> 0.570 0.429 4,800 11,200 Ductile - Fitting BPQR 113: 3/4-inch P-107 Pipe to P-110 Fitting with Pre-placed Bag-7 Insert Ring Full Section tensile test data V-1 1.050 0.305 1.006 14,100 14,000 Ductile-Pipe V-2 1.050 0.305 1.006 14,800 14,700 Ductile - Pipe H-1 1.050 0.305 1.006 14,900 14,800 Ductile - Pipe H-2 1.050 0.305 1.006 15,100 15,000 Ductile - Pipe BPQR 113: 3/4-inch P-107 Pipe to P-101 Fitting Face Fed Bag-7 filler metal Full Section tensile test data V-1 1.040 0.250 0.817 12,900 15,800 Ductile - Braze V-2 1.040 0.250 0.817 14,700 18,000 Ductile-Pipe H-1 1.040 0.250 0.817 14,500 17,700 Ductile-Pipe H-2 1.040 0.250 0.817 12,900 15,800 Ductile - Braze NOTE: (1). A pipe O.D. is used unless the value given is annotated with this note. This note denotes the value shown is a dimension of width. In all but two of the reported tensile tests, the specimens failed in the base material and therefore do not provide an ultimate shear strength for the brazed joint. With a failure in the base material, the reported values demonstrate that the brazed joint was capable of carrying at least the reported shear stress without failure. Therefore, ultimate shear stress for brazed joints in specimens that failed in base material was higher than the reported values. In the two joints where failure occurred in the braze, the ultimate shear strength of the braze was 15,800 psi. Values of the other 10 specimens range from 10,000 to 18,000 psi. These values do not take into account any loss of shear area due to voids, inclusions or other flaws, which typically exceed 10 percent and may include up to 25 percent of the braze area and are still acceptable to ASME IX criteria. Considering the data from failures in either pipe of fitting base materials and the ideal assumptions of shear area that are used to derive shear stress of Table 1, the data reasonably supports a conclusion that the ultimate shear strength of these brazed joints is much greater than where failure occurred in pipe of fitting base materials.
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 3 of 4 The indicated ultimate shear strength from the actual brazed joint failures is shown to be greater than 15,000 psi. As a conservative measure, a '2 times' margin has been used. This will result in a usable allowable shear stress value of 7,500 psi as input to the evaluation of the structural integrity of the braze joints using the methodology described in DENC request IR-4-09.
- 2. Brazed Joint Shear Strength and Safety Factor Use in Evaluation DENC will revise the brazed joint evaluation procedure previously described in Request IR-4-09 in the following manner:
(a) The braze joint shear strength assumed for evaluation purposes will be changed to 7,500 psi, as justified above. Thus, in Attachment 2, Figure 2 of the original submittal, the parameter -cmax in Equation 3 is 7,500 psi. (b) The piping analysis loads and equivalent stresses used to evaluate the braze joint will be multiplied by a safety factor of 1.5, which is conservative to factors required by ASME Ill Code Case N-513-4. Thus, in Attachment 2, Figure 2 of the Equation (1) reads: 1.5 Seq < Smax(badj) (c) Corresponding changes will be made to the "Braze Bond Structural Assessment", shown by example in the original submittal, to implement (a) and (b) above.
Serial No. 21-292 Docket No. 50-423 Attachment 7, Page 4 of 4 FIGURE 1: TENSILE TEST SPECIMEN SCHEMATIC Either the full pipe or reduced 3/4-inch wide tensile test specimens from the larger 3-inch pipes are being used for tensile testing. Shear area applies to this region of joint. NOTE: This schematic shows how the tensile test specimens that are described in Table 1 load the braze bond in shear.}}