ML071210254

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Revision to Entergy Response to NRC Request for Additional Information Related to Repair of the Core Shroud Stabilizer Assemblies
ML071210254
Person / Time
Site: Pilgrim
Issue date: 04/24/2007
From: Bethay S
Entergy Nuclear Operations
To:
Document Control Desk, NRC/NRR/ADRO
References
2.07.041, TAC MD4918
Download: ML071210254 (4)


Text

rEnteg Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360 Stephen J. Bethay Director, Nuclear Assessment April 24, 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001

SUBJECT:

Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station Docket No. 50-293 License No. DPR-35 Revision to Entergy Response to NRC Request for Additional Information Related to Repair of the Core Shroud Stabilizer Assemblies (TAC NO.

MD4918)

REFERENCES:

1. Entergy Letter No. 2.07.039, Response to NRC Request for Additional Information Related to Repair of the Core Shroud Stabilizer Assemblies (TAC NO. MD4918), dated April 20, 2007 LETTER NUMBER: 2.07.041

Dear Sir or Madam:

The Attachment 1 provides Entergy's revised response to NRC Request for Additional Information, RAI-6. This submittal replaces page 6 of 12, in Attachment 1 of Reference 1.

There are no regulatory commitments made in this submittal.

If you have any questions or require additional information,: please contact Mr. Bryan Ford, Licensing Manager, at (508) 830-8403.

Sincerely, Stephen J etha  %"".

4o01

Entergy Nuclear Operations, Inc. Letter Number: 2.07.041 Pilgrim Nuclear Power Station Page 2 Attachment

1. Revised Response to NRC Request for Additional Information, RAI-6, Page 6 of 12, Related to Repair of Pilgrim Core Shroud Stabilizer Assemblies (TAC No. MD4918)

(1 page) cc: Mr. James S. Kim, Project Manager Plant Licensing Branch I-1 Division of Operator Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission One White Flint North 4D9A 11555 Rockville Pike Rockville, MD 20852 Regional Administrator, Region 1 U.S. Nuclear Regulator Commission 475 Allendale Road King of Prussia, PA 19406 Senior Resident Inspector Pilgrim Nuclear Power Station

ATTACHMENT 1 Revised Response to NRC Request for Additional Information, RAI-6, Page 6 of 12, Related to Repair of Pilgrim Core Shroud Stabilizer Assemblies (TAC No. MD4918)

(1 page)

RAI-6

In the staff's safety evaluation dated May 12, 1995, for installation of the four sets of stabilizer assemblies and core plate wedges, the staff indicated that the reinspection plan should include the (4) gusset plate welds and the core shroud H1 1 weld because the integrity of these welds is essential to maintaining tie rod preload. The Regulatory Commitments in Attachment 2 to the March 22, 2007, letter does not include inspection of the gusset plate welds and core shroud H1 1 weld. The staff requests that the licensee (a) either include the gusset plate and Hi 1 welds in the reinspection plan or explain why reinspection is not necessary.

Response

The following figures provide a cross section of the core shroud and the tie rod inspection points. As shown, the H1 1 weld is between the vessel and core support plate. The gusset plates are being inspected by EVT-1 methods during the current refueling outage. The inspection plan includes the locations necessary for assuring the structural integrity of the repair hardware. Future inspections will be performed consistent with the BWRVIP recommendations provided in BWRVIP-38 and BWRVIP-76-A.

EXAMINATION OF GUSSETS AND GUSSET WELDS Pilgrim has an installed (4) tie-rod system for the core shroud pre-emptive repair in the RPV.

The main load path from the lower section of the tie-rods to the RPV wall is through corresponding gusset plates and connecting welds at 450, 1350, 2250 and 3150. These gussets have been inspected as follows:

Gusset Location RFO11 (1997) RFO12 (1999) RFO16 (2007) (1) 450 x x 1350 x x 2250 x x 3150 x x Notes: (1) Examinations are in progress as part of equipment replacement.

Gusset integrity is essential to maintain tie rod preload. Therefore, inspection of the gussets and gusset welds are being performed as part of the tie rod equipment replacement during current outage. The H-1 1 weld integrity is not essential to maintain the tie rod preload.

Therefore, inspection of the H-1 1 weld is not necessary during the current outage.

Examination frequency complies with BWRVIP-38 guidelines. No relevant indications noted on these examinations.

In addition, Pilgrim has inspected 100% of the shroud support weld (top surface of H1 1) to the RPV wall in RFO15 with no relevant indications noted.

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