ML110050485

Attachment to E-mail, Kilby, to Miller, Information Related to Seabrook'S Proposed H License Amendment Request

ML110050485
Person / Time
Site:	Seabrook
Issue date:	01/05/2011
From:	Kilby G Nextera Energy
To:	Geoffrey Miller Office of Nuclear Reactor Regulation
Shared Package
ml110050509	List: ML110050327 ML110050485
References
Download: ML110050485 (2)

Text

Draft The information below is a draft of NextEras proposed plan for steam generator (SG) tube inspections in the event that primary water stress corrosion cracking (PWSCC) is detected during the limited SG tube inspections planned for refueling outage 14.

3.2 SG Inspections During Refueling Outage 14 (OR14) in the Spring 2011 At the conclusion of the fall 2009 refueling outage, NextEra had met all periodic SG inspection requirements for the current 90 effective full power months inspection period. During the 2009 inspection, however, a single ODSCC indication was detected at the top of tubesheet in one tube in SG-C. As a result of this condition, TS 6.7.6.k.d.3 reduces the maximum interval between inspections from two operating cycles to one operating cycle, and the TS requires inspection for the specific degradation mechanism that caused the crack indication (i.e., ODSCC). The scope of tube inspections planned for OR14 is limited to +/-3 inches from the top of tubesheet on the hot leg to detect ODSCC. However, if the inspection in OR14 detects the presence of PWSCC in the tubesheet region during the planned inspection, then an expansion to the full depth of the tube sheet would be required unless an alternate repair criterion is approved by the NRC.

In a phone call with the NRC on November 9, 2010, NextEra discussed its plans for limited SG inspections during OR14 and the potential need for a temporary amendment if PWSCC is detected. The NRC stated that a full depth inspection of a portion of tubes within the tubesheet would be required if PWSCC is detected in the tubesheet during the planned OR14 inspection. The NRC staff further stated that such a full depth inspection would be required to confirm that the condition of the tubes with the tubesheet is consistent with the condition of tubes at other plants that have been granted a similar temporary license amendment.

To provide additional support for approval of the requested amendment, NextEra proposes to expand the scope of SG inspections as outlined below if PWSCC is detected during SG inspections in OR14.

a. If PWSCC is detected in the expanded area of the tubing within the tubesheet on the hot leg side, then tube inspections will expand to 15.2 inches below the top of the tubesheet in 100% of the tubes in the affected SG and in 20% of the tubes in each unaffected SG.

b. In addition, if PWSCC is detected in the expanded area of the tubing within the tubesheet on the hot leg side, a 20% sample of tubes will be inspected full depth from top of tubesheet to the end of the tube on the hot leg side in the affected steam generator. Expansion to the unaffected SG is not required.

Draft

• If cracks are detected below the H* depth of 15.2 inches from the top of tubesheet in more than 5% of the tubes inspected or a circumferential crack of 360° is detected, then full depth inspections will expand to 100% sample on the hot leg side in the affected steam generator. Expansion to the unaffected SG is not required.

c. Plugging/repair of the crack indications located below 15.2 inches from the top of tubesheet is not required.