ML060950328

GALL AMP: XI.M9, BWR Vessels Internals (Audit Worksheet GALL Report AMP)

ML060950328
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	03/22/2006
From:	Morgan M NRC/NRR/ADRO/DLR/RLRC
To:	Office of Nuclear Reactor Regulation
morgan M NRR/NRC/DLR/RLRC, 415-2232
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Download: ML060950328 (7)

Text

AUDIT WORKSHEET GALL REPORT AMP PLANT: ______________________________

LRA AMP: __________________________ REVIEWER: ______________________

GALL AMP: XI.M9, BWR Vessel Internals DATE: __________________________

Program Auditable GALL Criteria Documentation of Audit Finding Element Program A. The program includes (a) inspection and flaw evaluation in Consistent with GALL AMP: Yes No Description conformance with the guidelines of applicable and staff- Document(s) used to confirm Criteria:

approved boiling water reactor vessel and internals project (BWRVIP) documents, and Comment:

B. (b) monitoring and control of reactor coolant water chemistry Consistent with GALL AMP: Yes No in accordance with the guidelines of BWRVIP-29 (Electric Document(s) used to confirm Criteria:

Power Research Institute [EPRI] TR-103515) to ensure the long-term integrity and safe operation of boiling water reactor (BWR) vessel internal components.

Comment:

1. Scope of A. The program is focused on managing the effects of cracking Consistent with GALL AMP: Yes No Program due to stress corrosion cracking (SCC), intergranular stress Document(s) used to confirm Criteria:

corrosion cracking (IGSCC), or irradiation assisted stress corrosion cracking (IASCC). The program contains preventive measures to mitigate SCC, IGSCC, or IASCC, inservice inspection (ISI) to monitor the effects of cracking on the Comment:

intended function of the components, and repair and/or replacement as needed to maintain the ability to perform the intended function of BWR vessel internals.

B. The BWRVIP documents provide generic guidelines intended Consistent with GALL AMP: Yes No to present the applicable inspection recommendations to assure Document(s) used to confirm Criteria:

safety function integrity of the subject safety-related reactor XI.M9 BWR Vessel Internals 1

Program Auditable GALL Criteria Documentation of Audit Finding Element pressure vessel internal components. The guidelines include information on component description and function; evaluate susceptible locations and safety consequences of failure; Comment:

provide recommendations for methods, extent, and frequency of inspection; discuss acceptable methods for evaluating the structural integrity significance of flaws detected during these examinations; and recommend repair and replacement procedures. The various applicable BWRVIP guidelines are as follows.

See the GALL Report, AMP XI.M9, BWR Vessel Internals, for more information.

2. Preventive A. Maintaining high water purity reduces susceptibility to Consistent with GALL AMP: Yes No Actions cracking due to SCC or IGSCC. Reactor coolant water Document(s) used to confirm Criteria:

chemistry is monitored and maintained in accordance with the guidelines in BWRVIP-29 (EPRI TR-103515). The program description and the evaluation and technical basis of monitoring and maintaining reactor water chemistry are presented in Comment:

Chapter XI.M2, Water Chemistry.

3. Parameters A. The program monitors the effects of cracking on the intended Consistent with GALL AMP: Yes No Monitored/ function of the component by detection and sizing of cracks by Document(s) used to confirm Criteria:

Inspected inspection in accordance with the guidelines of applicable and approved BWRVIP documents and the requirements of the American Society of Mechanical Engineers (ASME) Code,Section XI, Table IWB 2500-1 (2001 edition including the 2002 Comment:

and 2003 Addenda). An applicant may use the guidelines of BWRVIP-62 for inspection relief for vessel internal components with hydrogen water chemistry provided such relief is submitted under the provisions of 10 CFR 50.55a and approved by the staff.

XI.M9 BWR Vessel Internals 2

Program Auditable GALL Criteria Documentation of Audit Finding Element

4. Detection of A. The extent and schedule of the inspection and test Consistent with GALL AMP: Yes No Aging Effects techniques prescribed by the applicable and approved BWRVIP Document(s) used to confirm Criteria:

guidelines are designed to maintain structural integrity and ensure that aging effects will be discovered and repaired before the loss of intended function of BWR vessel internals. Inspection can reveal cracking. Vessel internal components are inspected Comment:

in accordance with the requirements of ASME Section XI, Subsection IWB, examination category B-N-2. The ASME Section XI inspection specifies visual VT-1 examination to detect discontinuities and imperfections, such as cracks, corrosion, wear, or erosion, on the surfaces of components.

This inspection also specifies visual VT-3 examination to determine the general mechanical and structural condition of the component supports by (a) verifying parameters, such as clearances, settings, and physical displacements, and (b) detecting discontinuities and imperfections, such as loss of integrity at bolted or welded connections, loose or missing parts, debris, corrosion, wear, or erosion.

B. The applicable and approved BWRVIP guidelines Consistent with GALL AMP: Yes No recommend more stringent inspections, such as enhanced Document(s) used to confirm Criteria:

visual VT-1 examinations or ultrasonic methods of volumetric inspection, for certain selected components and locations. The nondestructive examination (NDE) techniques appropriate for inspection of BWR vessel internals including the uncertainties Comment:

inherent in delivering and executing NDE techniques in a BWR, are included in BWRVIP-03.

5. Monitoring A. Inspections scheduled in accordance with the applicable and Consistent with GALL AMP: Yes No and Trending approved BWRVIP guidelines provide timely detection of Document(s) used to confirm Criteria:

cracks. The scope of examination and reinspection must be expanded beyond the baseline inspection if flaws are detected.

Comment:

6. Acceptance A. Any indication detected is evaluated in accordance with Consistent with GALL AMP: Yes No Criteria ASME Section XI or the applicable staff-approved BWRVIP Document(s) used to confirm Criteria:

XI.M9 BWR Vessel Internals 3

Program Auditable GALL Criteria Documentation of Audit Finding Element guidelines. Approved BWRVIP-14, BWRVIP-59, and BWRVIP-60 documents provide guidelines for evaluation of crack growth in stainless steels (SSs), nickel alloys, and low-alloy steels, respectively. Comment:

7. Corrective A. Repair and replacement procedures are equivalent to those Consistent with GALL AMP: Yes No Actions requirements in ASME Section XI. Repair and replacement is Document(s) used to confirm Criteria:

performed in conformance with the applicable and approved BWRVIP guidelines listed above. As discussed in the appendix to this report, the staff finds that licensee implementation of the guidelines in the staff-approved BWRVIP reports will provide an Comment:

acceptable level of quality for inspection and flaw evaluation of the safety-related components addressed in accordance with 10 CFR Part 50, Appendix B, corrective actions.

8. A. Site quality assurance (QA) procedures, review and approval Consistent with GALL AMP: Yes No Confirmation processes, and administrative controls are implemented in Document(s) used to confirm Criteria:

Process accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the appendix to this report, the staff finds that licensee implementation of the guidelines in the staff-approved BWRVIP reports will provide an acceptable level of quality for Comment:

inspection and flaw evaluation of the safety-related components addressed in accordance with the 10 CFR Part 50, Appendix B, confirmation process and administrative controls.

9. A. See Item 8, above. Consistent with GALL AMP: Yes No Administrative Document(s) used to confirm Criteria:

Controls Comment:

10. Operating A. Extensive cracking has been observed in core shrouds at Consistent with GALL AMP: Yes No Experience both horizontal (Nuclear Regulatory Commission [NRC] Generic Document(s) used to confirm Criteria:

Letter [GL] 94-03) and vertical (NRC Information Notice [IN]

97-17) welds. It has affected shrouds fabricated from Type 304 and Type 304L SS, which is generally considered to be more resistant to SCC. Weld regions are most susceptible to SCC, Comment:

XI.M9 BWR Vessel Internals 4

Program Auditable GALL Criteria Documentation of Audit Finding Element although it is not clear whether this is due to sensitization and/or impurities associated with the welds or the high residual stresses in the weld regions. This experience is reviewed in NRC GL 94-03 and NUREG-1544; some experiences with visual inspections are discussed in NRC IN 94-42.

B. Both circumferential (NRC IN 88-03) and radial cracking Consistent with GALL AMP: Yes No (NRC IN 92-57) has been observed in the shroud support Document(s) used to confirm Criteria:

access hole cover made from Alloy 600. Instances of cracking in core spray spargers have been reviewed in NRC Bulletin 80-13.

Comment:

C. Cracking of the core plate has not been reported, but the Consistent with GALL AMP: Yes No creviced regions beneath the plate are difficult to inspect. NRC Document(s) used to confirm Criteria:

IN 95-17 discusses cracking in top guides of United States and overseas BWRs. Related experience in other components is reviewed in NRC GL 94-03 and NUREG-1544. Cracking has also been observed in the top guide of a Swedish BWR. Comment:

D. Instances of cracking have occurred in the jet pump Consistent with GALL AMP: Yes No assembly (NRC Bulletin 80-07), hold-down beam (NRC Document(s) used to confirm Criteria:

IN 93-101), and jet pump riser pipe elbows (NRC IN 97-02).

Comment:

E. Cracking of dry tubes has been observed at 14 or more Consistent with GALL AMP: Yes No BWRs. The cracking is intergranular and has been observed in Document(s) used to confirm Criteria:

dry tubes without apparent sensitization, suggesting that IASCC may also play a role in the cracking.

Comment:

F. The program guidelines outlined in applicable and approved Consistent with GALL AMP: Yes No BWRVIP documents are based on an evaluation of available Document(s) used to confirm Criteria:

information, including BWR inspection data and information on the elements that cause SCC, IGSCC, or IASCC, to determine which components may be susceptible to cracking.

XI.M9 BWR Vessel Internals 5

Program Auditable GALL Criteria Documentation of Audit Finding Element Implementation of the program provides reasonable assurance Comment:

that cracking will be adequately managed so the intended functions of the vessel internal components will be maintained consistent with the current licensing basis (CLB) for the period of extended operation.

XI.M9 BWR Vessel Internals 6

EXCEPTIONS Item Program Elements LRA Exception Description Basis for Accepting Exception Documents Reviewed Number (Identifier, Para.# and/or Page #)

1.

2.

ENHANCEMENTS Item Program Elements LRA Enhancement Description Basis for Accepting Enhancement Documents Reviewed Number (Identifier, Para.# and/or Page #)

1.

2.

DOCUMENT REVIEWED DURING AUDIT Document Number Identifier (number) Title Revision and/or Date 1.

2.

3.

4.

XI.M9 BWR Vessel Internals 7