L-PI-05-074, Response to Request for Additional Information Regarding the Unit 1 Inservice Lnspection Summary Report, Interval 3, Period 3, Refueling Outage Dates: 9-10-2004 to 11-23-2004 Fuel Cycle 22
| ML052340676 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  (DPR-042, DPR-060) |
| Issue date: | 08/22/2005 |
| From: | Thomas J. Palmisano Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-PI-05-074 | |
| Download: ML052340676 (7) | |
Text
Committed to Nuclear Excellence /
U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 License Nos. DPR-42 and DPR-60 Response to Request for Additional Information Regarding the "Unit 1 lnservice lnspection Summary Report, Interval 3, Period 3, Refueling Outage Dates: 9-10-2004 to 1 1-23-2004 Fuel Cycle 22: 12-7-2002 to 1 1-23-2004"
Reference:
Letter from Nuclear Management Company, LLC (NMC) to Nuclear Regulatory Commission (NRC), "Unit 1 lnservice lnspection Summary Report, Interval 3, Period 3, Refueling Outage Dates: 9-10-2004 to 11-23-2004 Fuel Cycle 22: 12-7-2002 to 1 1-23-2004" dated February 22, 2005.
Prairie Island submitted an lnservice lnspection Summary Report following the Fall 2004 Unit 1 refueling outage on February 22, 2005 (Reference). By electronic mail, dated June 27, 2005, the NRC requested additional information regarding the steam generators installed during the outage. The enclosure to this letter contains the response to that request.
Summarv of Commitments This letter contains no new commitments and no revisions to existing commitments.
' - ? d / U Thomas J. Palmisano Site Vice President, Prairie Island Nuclear Generating Plant Nuclear Management Company, LLC Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Prairie Island, USNRC Resident Inspector, Prairie Island, USNRC 171 7 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121
ENCLOSURE Response to Request for Additional Information Regarding the "Unit 1 Inservice Inspection Summary Report, Interval 3, Period 3, Refueling Outage Dates: 9-1 0-2004 to 1 1-23-2004 Fuel Cycle 22: 12-7-2002 to 1 1-23-2004" Response to Request for Additional Information, 4 pages plus Figure 1 Figure 2 Page 1 of 4
Enclosure Response to Request for Additional Information The NRC questions are in bold type face. Letters "a" through "g" have been added to improve the readability of the responses. The NMC responses are in italics type face.
- 1. General information concerning the design of your replacement steam generators was provided in the submittal. In order for the staff to better understand the design of your replacement steam generators, please provide the following information: (a) anti-vibration bar design (e.g., rectangular cross-section, penetrate to row 1, thickness, etc.), (b) number of tubes plugged (if any) in each steam generator prior to installation, (c) tubesheet thickness (with and without clad), (d) tubesheet map, and (e) a sketch of the steam generator depicting your tube support plate naming convention. Please (f) clarify whether any tubes (or portions of tubes) were stress relieved after bending. In addition, (g) please clarify if the first tube support plate is a flow distribution baffle (and, if so, any unique design features).
(a)
The bent portion of the tube bundle is supported by 5 sets (4 V-shaped and one straight) of anti-vibration bars (A VBs), all U-bends (Row I included) being supported.
ANTI-VIBRATION BAFF
__I RMOST T P The A VB assembly is composed of:
Four sets of V-shaped A VBs with the ends of A VBs of each set being linked together by clamps that maintain spacing of A VBs and restrict U-bend out-of-plane motion. The clamped sets of A VB ends are fastened to hoops that maintain in-plane configuration and prevent lift off of A VB system under transient and accident conditions. The V-shaped A VBs penetrate to Rows 27 and 15, One set of straight A VBs with their upper ends linked together (U-bend out-of-plane) and fitting into slots machined in the uppermost tube support plate (TSP) providing a sliding connection for their lower ends. The straight A VBs provide support for all U-bends in the center of the U-bend.
The rectangular cross-section of the A VBs is approximately 0.5"X 0.3".
Page 2 of 4
Enclosure Response to Request for Additional Information (b)
There were 0 (zero) tubes plugged prior to and during the installation of the replacement steam generators.
(c)
The tubesheet minimum thickness without the clad is 21.46 inches. The clad has a minimum of 0.375 inch thickness.
(d)
See Figure I for the tubesheet map. The 6 no-tube areas are the locations of the tube support plate tie-rods (12 total).
(e)
See Figure 2 for the sketch of the steam generator showing the tube support plates. The eight stainless steel tube support plates are designated by number and letter (for cold or hot leg side) from the tubesheet upward.
Eddy Current Testing Landmark Designation 08H/08C 0 7H/O 7C 06H/06C 05H/05C 04 H/04C 03 H/03C 02 H/02C OIH/OlC Top of Tubesheet (TSHfTSC)
Tube End (TEH/TEC)
The tube hole configuration is a broached quatrefoil.
(5)
After bending, the entire tube for all tubes in rows 1 through 9 were stress relieved for a minimum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at greater than 1320 OF.
(g)
The first tube support plate is NOT a flow distribution baffle. Except for the no-tube lane in the top tube support plate, the tube support plates are identical in configuration. The top tube support plate (TSP8) does not have flow slots in the no-tube lane. Instead, the no-tube lane of TSP8 has small openings for capturing the straight anti-vibration bars plus flow holes.
Page 3 of 4
Enclosure Response to Request for Additional Information On pages 7 and 9 of your submittal, you stated that 6 tubes in steam generator 11 and 5 tubes in steam generator 12 were found to be in "non-conformance" with your criteria. Please clarify if these tubes were plugged.
There were no tubes plugged prior to and during the installation of the replacement steam generators. Indications in the tubes were in non-conformance with the contracted acceptance criteria related to dings/bulges/expansion transition anomalies and percent through wall (the measured value of 15% for one tube exceeded the contract limit of 7%). These criteria were all conservative with respect to technical specification and industry standards for tube repairs.
Page 4 of 4
Figure 1: Tubesheet Map PlNGP U1 M ode1 5611 9 Replacement Steam Generator Cold Leg Tubesheet Map (COL 1 on M anway Side)
Column
Figure 2: Framatome ANP Model 56/19 Replacement Steam Generator