ML071350226

Request for Additional Information on the Proposed Amendment on Steam Generator Tube Surveillance Tube Repair

ML071350226
Person / Time
Site:	San Onofre
Issue date:	05/17/2007
From:	Kalyanam N NRC/NRR/ADRO/DORL/LPLIV
To:	Rosenblum R Southern California Edison Co
Kalyanam N, NRR/DORL/LP4, 415-1480
References
TAC MD2584, TAC MD2585
Download: ML071350226 (7)

Text

May 17, 2007 Mr. Richard M. Rosenblum Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128

SUBJECT:

SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 -

REQUEST FOR ADDITIONAL INFORMATION ON THE PROPOSED AMENDMENT ON STEAM GENERATOR TUBE SURVEILLANCE PROGRAM, TUBE REPAIR (TAC NOS. MD2584 AND MD2585)

Dear Mr. Rosenblum:

By letter dated July 14, 2006 (Agencywide Documents Access and Management System Accession No. ML061990071), Southern California Edison submitted an application to change the San Onofre Nuclear Generating Station, Units 2 and 3, technical specifications (TS) related to steam generator tube integrity TS. The proposed amendment incorporates a description of the parent tube inspection limitation adjacent to the nickel-band portion of the lower sleeve joint and provides the bases for the structural and leakage integrity of the joint being ensured with the existing inspection of the parent tube adjacent to the nickel-band region.

After reviewing your request, the Nuclear Regulatory Commission staff has determined that additional information as required below is needed to complete the review. We discussed this request for additional information (RAI) with your staff by telephone and they agreed to provide a response to the RAI before the end of June 2007.

If you have any questions, please contact me at (301) 415-1480.

Sincerely,

/RA/

N. Kalyanam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361 and 50-362

Enclosure:

Request for Additional Information cc: See next page

ML071350226 *No major change from Staff provided RAI OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/DCI/CSGB* NRR/LPL4/BC NAME NKalyanam JBurkhardt AHiser THiltz DATE 5/16/07 5/16/07 2/12/07 5/17/07 REQUEST FOR ADDITIONAL INFORMATION REGARDING SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 STEAM GENERATOR TUBE SURVEILLANCE TECHNICAL SPECIFICATION AMENDMENT DOCKET NOS. 50-361 AND 50-362

1. Several analyses were performed as part of the original qualification program of the sleeves as documented in Topical Report (TR) CEN-630-P, Revision 2, Repair of 3/4 Inch OD Steam Generator Tubes Using Leak Tight Sleeves, dated June 1997.

However, in your letter dated July 14, 2006, you addressed only the tensile and leakage testing of the sleeve joint. Please discuss why the additional analyses/testing are not applicable to this proposal or provide the technical justification demonstrating that the lower sleeve joint (without taking credit for the nickel-band portion of the joint) still meets the original acceptance criteria.

2. Your proposed revisions to your Technical Specifications (TSs) were based on the version of the TSs that were applicable in July 2006. However, these pages were subsequently changed for Amendments 206 and 198, issued on November 9, 2006, for San Onofre Nuclear Generating Station, Units 2 and 3 (SONGS 2 and 3). Please discuss your plans for updating your submittal.

In addition, since your proposal is an exception to the requirement that the tubes shall be inspected with the objective of detecting flaws of any type that may be present along the length of the tubes and that may satisfy the applicable tube repair criteria, you may want to consider adding a footnote to this requirement. Such a footnote should indicate that this requirement would not apply to the portion of the parent tube adjacent to the nickel-band portion (the lower half) of the lower joint for the repair process discussed in TS 5.5.2.11.f.1 that is formed by hard rolling; however, inspections with a +PointTM coil (or equivalent technique) should be performed in this area and tubes with flaws should be plugged in accordance with TS 5.5.2.11.c.3. If you elect to reference the basis for this proposed exception to the inspection requirements in your TS, please include the entire technical basis which would include any responses to the Nuclear Regulatory Commission staffs requests for additional information.

3. The end-cap load associated with three-times-the-normal operating pressure differential reported in the July 14, 2006, letter appear to be different than those in the original TR.

Please discuss the reason for the differences.

4. The axial load capabilities of the joints in the recent testing appear higher than the results in the original testing. Please discuss the reasons for this. If the reason is attributed to using first slip loads rather than no slip loads, please provide the no slip loads for the recent testing and discuss whether the conclusions are still valid when the no slip loads are used.

5. Please discuss whether the load displacement curves for all the specimens were similar to the load displacement curves provided in the July 14, 2006, letter. If not, please provide all the load displacement curves.

6. It appears that many of the sleeves in the test program yielded prior to reaching first slip load. Please confirm that no yielding occurred at an axial force less than that associated with the most limiting of 3P or 1.4 times accident loading conditions.

7. Please discuss the nature of the electric discharge machining notch in specimen Tensile 11. Please provide the load displacement curve for this specimen.

8. Please discuss how it was determined that the sleeve was not slipping within the tube given the load displacement curves. Was it assumed that the sudden drop in load corresponds to the first slip?

9. There appears to be a discrepancy between some of the loads reported on page 4-3 and those in Table 4-3. Please clarify.

10. The high-temperature leak tests were performed in collars made from 1018 carbon steel material. Given the thermal expansion coefficient of this material (compared to the actual tubesheet material), it is not clear that these results are conservative. As a result, discuss the need to modify your approach for addressing leakage through the sleeve joints.

11. The leakage testing program described in your July 14, 2006, letter consisted of primary-to-secondary pressure differentials of 1500 pounds per square inch (psi) and 2560 psi; however, leakage testing was not performed after load cycling tests to analyze how the cyclic loading could affect the leakage. Please provide the technical justification demonstrating that leakage through the sleeve is not affected by cyclic loading. Alternatively, provide leakage test data obtained from specimens that were subjected to cyclic loading prior to testing.

12. Please clarify the sentence on page 2-1 of SG-SGDA-05-48-P, Revision 1, which reads, In the hydraulically expanded condition the tube experiences additional wall thinning prior to completion of the wall thinning operation of the sleeve.

13. In Section 2.1, it was indicated that the torque used to roll the sleeve specimens bounds the torque used for actual installations. Please clarify that the torque for the test specimens was lower than the torque used for the actual field installations (i.e., it was a lower bound).

14. Please discuss how it was verified that the microlok-to-nickel band interface was adjacent to the tube separation.

15. Several of the test specimens had internal pressurization. Please discuss whether this internal pressurization contributed to the actual load on the sleeve. If so, please discuss whether this was accounted for in the load displacement curves.

16. Hydraulic expansion was used to simulate a tube explosively expanded into the tubesheet region. The hydraulic expansion pressure used was intended to simulate the radial contact pressure associated with an explosively expanded tube within a tubesheet. Please discuss whether the radial contact pressure simulated corresponded to the mean or lower bound of the test data for explosively expanded tubes.

17. For the sleeves installed at SONGS 2 and 3, please confirm that the torque used in installing the sleeves was greater than the torque used in fabricating the test specimens.

18. In preparing the circumferentially separated specimens for the Combustion Engineering simulation testing, please confirm that not only the tube collar was saw cut, but also that the tube was cut.

19. In sections 4.2 and 4.3 of Westinghouse TR SG-SGDA-05-48-NP, Revision 1, the end-cap loading associated with three-times-the-normal operating pressure was provided. Please discuss whether the end-cap loading for these different cases was determined in the same manner. In addition, please provide the differential pressures assumed in section 4.3 along with the assumed tube-wall thickness.

20. In section 6, it does not appear that the text in the third paragraph is consistent with the data presented in Table 6-1. For example, the specimens that did not leak do not appear to be correctly referenced. In addition, the bounding leak rate appears to be misquoted. Please clarify.

San Onofre Nuclear Generating Station Units 2 and 3 cc:

Mr. Daniel P. Breig Director, Radiologic Health Branch Southern California Edison Company State Department of Health Services San Onofre Nuclear Generating Station P.O. Box 997414, MS 7610 P. O. Box 128 Sacramento, CA 95899-7414 San Clemente, CA 92674-0128 Resident Inspector/San Onofre NPS Mr. Douglas K. Porter, Esquire c/o U.S. Nuclear Regulatory Commission Southern California Edison Company Post Office Box 4329 2244 Walnut Grove Avenue San Clemente, CA 92674 Rosemead, CA 91770 Mayor Mr. David Spath, Chief City of San Clemente Division of Drinking Water and 100 Avenida Presidio Environmental Management San Clemente, CA 92672 P. O. Box 942732 Sacramento, CA 94234-7320 Mr. James T. Reilly Southern California Edison Company Chairman, Board of Supervisors San Onofre Nuclear Generating Station County of San Diego P.O. Box 128 1600 Pacific Highway, Room 335 San Clemente, CA 92674-0128 San Diego, CA 92101 Mr. James D. Boyd, Commissioner Mark L. Parsons California Energy Commission Deputy City Attorney 1516 Ninth Street (MS 31)

City of Riverside Sacramento, CA 95814 3900 Main Street Riverside, CA 92522 Mr. Ray Waldo, Vice President Southern California Edison Company Mr. Gary L. Nolff San Onofre Nuclear Generating Station Assistant Director - Resources P.O. Box 128 City of Riverside San Clemente, CA 92764-0128 3900 Main Street Riverside, CA 92522 Mr. Brian Katz Southern California Edison Company Regional Administrator, Region IV San Onofre Nuclear Generating Station U.S. Nuclear Regulatory Commission P.O. Box 128 611 Ryan Plaza Drive, Suite 400 San Clemente, CA 92764-0128 Arlington, TX 76011-8064 Mr. Michael R. Olson San Diego Gas & Electric Company 8315 Century Park Ct. CP21G San Diego, CA 92123-1548 March 2006

San Onofre Nuclear Generating Station Units 2 and 3 cc:

Mr. Steve Hsu Department of Health Services Radiologic Health Branch MS 7610, P.O. Box 997414 Sacramento, CA 95899 Mr. A. Edward Scherer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128 March 2006