ML062960064

Calvert Cliffs Nuclear Power Plant, Unit No. 1 - Request for Additional Information Regarding Flaw Evaluation of Dissimilar Metal Welds (TAC No. MD2351)

ML062960064
Person / Time
Site:	Calvert Cliffs
Issue date:	10/27/2006
From:	Milano P D NRC/NRR/ADRO/DORL/LPLI-1
To:	Spina J A Calvert Cliffs
Milano P D, NRR/DORL/LPLA, 415-1457
References
TAC MD2351
Download: ML062960064 (5)

Text

October 27, 2006Mr. James A. Spina, Vice PresidentCalvert Cliffs Nuclear Power Plant, Inc.

Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 1 - REQUEST FORADDITIONAL INFORMATION REGARDING FLAW EVALUATION OF DISSIMILAR METAL WELDS (TAC NO. MD2351)

Dear Mr. Spina:

By letter dated May 31, 2006, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee) provided itsevaluation of flaw indications found in the nozzle-to-safe end welds of the hot leg surge line and drain line during the 2006 refueling outage at Calvert Cliffs Nuclear Power Plant, Unit No. 1.

The flaw evaluation was provided to the Nuclear Regulatory Commission (NRC) in accordance with the requirements contained in Article IWB-3640, "Evaluation Procedures and Acceptance Criteria for Austenitic Piping," of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code.The NRC staff has reviewed the information provided and has determined that additionalinformation is needed to complete its review. Enclosed is the NRC staff's request for additional information (RAI). This RAI was discussed with your staff on October 23, 2006, and it was agreed that your response would be provided within 60 days from the date of this letter.If you have any questions, please contact me at 301-415-1457.Sincerely,/RA/Patrick D. Milano, Senior Project ManagerPlant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-317

Enclosure:

RAI cc w/encl: See next page

ML062960064OFFICELPLI-1/PMLPLI-1/LACFEB/BCLPLI-1/BCNAMEPMilanoSLittleKGrussRLauferDATE10/26/0610/24/0610/26/06 10/27/06 Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc:

PresidentCalvert County Board of Commissioners 175 Main Street Prince Frederick, MD 20678Mr. Carey Fleming, EsquireSr. Counsel - Nuclear Generation Constellation Generation Group, LLC 750 East Pratt Street, 17 th floorBaltimore, MD 21202Mr. Jay S. GainesDirector, Licensing Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702Resident InspectorU.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685Mr. R. I. McLean, ManagerNuclear Programs Power Plant Research Program Maryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor)

Tawes State Office Building Annapolis, MD 21401Regional Administrator, Region IU.S. Nuclear Regulatory Commission

475 Allendale Road King of Prussia, PA 19406Ms. Kristen A. Burger, EsquireMaryland People's Counsel 6 St. Paul Centre Suite 2102 Baltimore, MD 21202-1631Ms. Patricia T. Birnie, EsquireCo-Director Maryland Safe Energy Coalition P.O. Box 33111 Baltimore, MD 21218Mr. Roy HickokNRC Technical Training Center 5700 Brainerd Road Chattanooga, TN 37411-4017 REQUEST FOR ADDITIONAL INFORMATIONFLAW EVALUATION OF HOT LEG SURGE LINE AND DRAIN LINE NOZZLE WELDSCALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NO. 1DOCKET NO. 50-317By letter dated May 31, 2006, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee), submittedits evaluation of flaw indications found in the nozzle-to-safe end welds of the hot leg surge line and drain line during the 2006 refueling outage at Calvert Cliffs Nuclear Power Plant, Unit No. 1. In order to complete its review, the Nuclear Regulatory Commission (NRC) staff requests the following additional information. The specific references in the questions relate to the information in the flaw evaluation in Attachment 1 of the May 31, 2006, submittal.1. In Table 1, the wall thicknesses of the surge line and drain line are identified as1.313 inches and 0.375 inches, respectively. In Table 2, the wall thicknesses of the surge line and drain line are identified as 1.6 inches and 0.54 inch, respectively.(a) Discuss whether the discrepancies of the wall thickness between Tables 1 and 2are due to cladding in the pipe.(b) Discuss which thicknesses were used in the flaw evaluation.2. The surge nozzle piping loads, as shown in Table 3, did not include loads from thetransients such as heatup, cooldown and reflood. Discuss why transient loads were not considered in the flaw evaluation of the surge line nozzle.3. In Figures 2 and 3, the NRC staff observed that if the ratio of flaw depth (a) versus wallthickness (t) of the indication in the surge line were 1.0 (i.e., 100% through wall), the flaw would still be acceptable. The same observation is true for the drain line in Figures 10 and 11. This observation contradicts the limit (i.e., 0.75) on the a/t ratio as specified in Table C-5310-1 of Appendix C to Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Coder (ASME Code). Discuss whether the upper limit of 0.75 for the a/t ratio should be included in Figures 2, 3, 10, and 11. 4. On page 2, it is stated that Article C-5321 and Tables C-5310-1 through C-5310-4 ofAppendix C to the ASME Code,Section XI, were used for the flaw evaluation. However, prior to the use of the flaw evaluation methodology in the Article C-5000 procedures, certain screening criteria in Article C-4000 should be satisfied. Provide information to show that the screening criteria of Article C-4000 have been satisfied such that the flaw evaluation methodology of Article C-5000 can be appropriately applied to the surge and drain line nozzles. 5. Provide sketches or diagrams to show the locations of the indications in the surge anddrain line nozzles. The sketches should include the nozzle, safe end, weld, and pipe.

The sketches should show whether the indications are surface-connected or embedded.Enclosure 6. Identify the ASME Code material specifications of the nozzle, safe end, weld, and pipe. 7. Submit copies of References 1, 2a, 2b, and 2c.