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ASME Section XI Meeting Notes (Task Group on Alloy 600) – May 2009
Company: Entergy Services Incorporated
Meeting Date: May 11, 2009
1. Call to Order
a. 125th Anniversary of ASME
4. Agenda approved
5. Minutes adopted
a. It was observed that the charter needs updated to reflect Section XI as a standards committee
6. Recurring Items
a. NRC report
i. Ted Sullivan reported. Next rule making to incorporate 2008.
NRC to have meetings (hopefully annually) with the materials
initiative folks. It includes
iii. NRC is in progress for a RIS on effects of weld overlay on leak before break. Dave Rudland of the NRC presented the item on PWSCC following the NRC report.
b. EPRI Report
EPRI Nuclear Power Council meeting in
On going work of interest includes extremely low
probability of rupture work and at
7. Agenda Action Items
a. Item 7.1, TG04-002 – Code Case Addressing Alloy 82/182 Butt Welds:
i. There are suggested changes to the published code case to address questions from the NRC.
ii. Section 3132.3 had questions on the definition of measurement accuracy and how it is determined. The proposed fix was to add a footnote 4 defining the measurement accuracy as tied to the baseline prior to flaw detection and tied to the last 3 inspections for items with identified flaws. It was questioned why we would use different wording than the wording in the base code. The decision was to use wording of "essentially unchanged" used in the current code.
iii. Concerns were raised on Section 3142.1(b)(2) dealing the potential for additional corrosion to further reduce the wall thickness. Mr. Gimble indicated the change was not needed due to the requirements of 3142.1(b)(1) to correct the condition thus removing the potential for corrosion. The decision was to allow the previous wording to stand.
iv. In section 9000 (e) the definition of cracked was modified to include exceptions for assuming cold leg nozzles are cracked that are in the procedure but that were not previously shown in the definition.
v. Table 1 Item (c) and (f) was changed to ensure that examination frequency does not exceed the design life of the weld overlay.
vi. Table 1 Item (g) and (j) removed the specification that the barrier is Alloy 52/152.
vii. Table 1 Item (h) changed to address un-cracked butt weld mitigated with cladding and remove wording on corrosion resistance.
viii. For Table 1 Items (g), (h), and (j) a surface exam is specified in addition to the volumetric methods vs an either/or approach.
ix. Note 6 and Note 12 previously called for a surface exam and referred to note 20. This action combines them.
x. Discussion on the NRC's concern with Note 11 to ensure the initial examinations were completed within 10 years of the completion of the mitigation for un-cracked welds took place. It was the clear intent to allow un-cracked welds to be examined in one shot vs being spread out over the interval. However, the examines still need to be completed within 10 years of the completion of the mitigation. The words were left as is with no change.
xi. Note 14 deleted reference to 100% through wall crack.
xii. Note 16 was modified to deal with the concern that cracks penetrating cladding would essentially result in unmitigated conditions.
xiii. Several figures changed for consistency with N-740.
xiv. Appendix I had minor changes.
8. David Rudland of the NRC's Office of Research presented results of an NRC PWSCC crack growth rate sensitivity analysis.
a. The analysis does not support the current supposed sample plan for hot leg inlays but it does for cold legs.
b. Significant discussion occurred on the basis for the conclusions.
9. TG RI-ISI joined TG Alloy 600 for initial discussions to ensure that overlap between actions within the groups did not result in issues with the code.
a. Discussion ensued on the specific requirements currently in Risk-Informed programs for PWSCC susceptible locations.
b. Agreed to have recurring interface.