ML052700047

Draft RAI Re. SG Kinetic Expansion Inspection and Repair Criteria

ML052700047
Person / Time
Site:	Three Mile Island
Issue date:	09/23/2005
From:	Tam P NRC/NRR/DLPM/LPD1
To:	Distel D, David Helker AmerGen Energy Co
Tam P, NRR/DLPM, 415-1451
References
TAC MC7001
Download: ML052700047 (4)

Text

From: Peter Tam To: David Distel; David Helker Date: 9/23/05 10:50AM

Subject:

Draft RAI re. SG Kinetic Expansion Inspection and Repair Criteria (TAC MC7001)

Dave:

Following please find followup questions raised by Emmett Murphy, our reviewer, in response to previous RAI responses from you. Please set up a conference call with me for quick disposition of these questions:

(1) The licensee has not provided sufficient information for the staff to conclude that no eddy current measurement error allowance need be added to the measured circumferential length of ID IGA or PWSCC flaws which may be of sufficient length (e.g., 0.64 inches) to be structurally significant. Please provide an appropriate circumferential length allowance with accompanying justification. Alternatively, commit to plugging or repair of tubes with circumferential components exceeding 90 degrees.

(2) Additional information should be provided to demonstrate that FLB is less limiting than MSLB from the standpoint of accident leakage. The licensee has provided sufficient information to conclude that MLSB is more limiting than FLB in terms of leakage from circumferential flaws. However, the licensee has not provided information as to why FLB is not limiting in terms of leakage from axial flaws, and why total leakage from axial and circumferential flaws might not be higher than for MSLB. The licensee has not compared the differential pressures loads associated with each accident. If FLB has substantially higher differential pressures, it will have a higher driving force for producing leakage through axial flaws than does an MSLB. Furthermore, the higher pressures associated with FLB would tend to produce a larger tubesheet bow effect than would exist for MSLB.

(3) What is the "critical value" when performing the extreme value tests on the ID IGA indications? The reporting requirements in Section 8.9 of ECR #2-01121, Rev. 2, should be modified to state "If growth is detected or if the extreme value test is not met: NRC shall be notified ..."

(4) Why are statistical tests for growth not performed for depth? Although structural acceptance criteria are not affected by depth, the leakage calculation is affected. An alternative to performing statistical tests on depth would be to add a reporting requirement to notify the NRC by telephone during the outage if MSLB leakage based on the as-found condition of the tubing reaches 33 gallons (2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) or 100 gallons (30 day). This would be a big enough increase in leakage compared to 1R15 to suggest a possible growth in flaw depth.

(5) AmerGen has submitted its inspection acceptance criteria and updated leakage assessment methodology (ECR #02-01121, Revision 2) for the staff's review and approval.

However, Attachment 3 of AmerGen's May 3, 2005 letter, "Regulatory Commitments," commits to certain actions. In part, these commitments include an UFSAR update which references the inspection acceptance criteria in ECR #2-01121, Rev. 2. Attachment 3 further states that any other actions discussed in the submittal representing intended or planned actions by AmerGen are described to the NRC for information and are not regulatory commitments. The staff requests that Attachment 3 be clarified (or a commitment added) to state that any changes to the inspection acceptance criteria, inspection scope and methods, growth assessment methodology, accident leakage assessment methodology, and reporting requirements as defined in ECR #2-01121, Rev 2, will be subject to NRC staff review and approval.

(6) In its August 11, 2005, response to NRC Question 2, AmerGen stated that it would provide the results of a best-estimate leakage assessment for the limiting LBLOCA in the 90-day report required by TS 4.19.5.b. This should be included in the list of commitments to NRC (Attachment 3 of May 3, 2005 package) and reporting requirements in Section 8.9 of ECR

1. 2-01121, Rev 2.

This e-mail aims solely to prepare you and others for the requested conference call. It does not at this time formally request for information, and it does not formally convey an NRC staff position.

Peter S. Tam, Senior Project Manager Project Directorate I-1 Division of Licensing Project Management Office of Nuclear Reactor Regulation e-mail: pst@nrc.gov Tel.: 301-415-1451 CC: Emmett Murphy; Kenneth Karwoski; Louise Lund Mail Envelope Properties (4334164A.94B : 12 : 334)

Subject:

Draft RAI re. SG Kinetic Expansion Inspection and Repair Criteria (TAC MC7001)

Creation Date: 9/23/05 10:50AM From: Peter Tam Created By: PST@nrc.gov Recipients Action Date & Time OWGWPO02.HQGWDO01 Delivered 09/23/05 10:51 AM KJK1 CC (Kenneth Karwoski) Opened 09/23/05 10:53 AM TWGWPO01.HQGWDO01 Delivered 09/23/05 10:51 AM LXL CC (Louise Lund) Opened 09/23/05 11:00 AM David Transferred 09/23/05 10:51 AM distel (David Distel) owf2_po.OWFN_DO Delivered 09/23/05 10:50 AM ELM CC (Emmett Murphy) Opened 09/23/05 10:51 AM exeloncorp.com Transferred 09/23/05 10:51 AM david.helker (David Helker)

Post Office Delivered Route OWGWPO02.HQGWDO01 09/23/05 10:51 AM TWGWPO01.HQGWDO01 09/23/05 10:51 AM David INTernet:exeloncorp.

com owf2_po.OWFN_DO 09/23/05 10:50 AM exeloncorp.com Files Size Date & Time MESSAGE 5455 09/23/05 10:50AM Options Auto Delete: No Expiration Date: None Notify Recipients: Yes

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