L-2009-168, Response to Request for Additional Information, Third Interval Relief Request 31

Response to Request for Additional Information, Third Interval Relief Request 31

ML092090126
Person / Time
Site:	Saint Lucie
Issue date:	07/20/2009
From:	Katzman E Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2009-168
Download: ML092090126 (23)

Text

Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 July 20, 2009 F=PL L-2009-168 10 CFR 50.4 10 CFR 50.55a U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Re: St. Lucie Unit 1 Docket No. 50-335 Response to Request for Additional Information Unit I Third Interval Relief Request 31 On February 6, 2009, FPL submitted relief request 31 for the St. Lucie Unit 1 Third ISI Interval.

The relief request dealt with the impracticality to meet the code required volume coverage of some welds in the reactor vessel as required by the ASME Code, 1989 Edition, no addenda, as clarified by Code Case N-460 due to configuration and/or the presence of permanent attachments. Relief is requested in accordance with 10CFR50.55a(g)(5)(iii). The NRC requested additional information via email that was subsequently posted in ADAMS as ML091590627.

The responses to the RAI questions are within Attachment 1. Attachment 2 contains the revised relief request.

Sincerely, Eric S. Katzman Licensing Manager St. Lucie Plant Attachments ESK/KWF an FPL Group company

-I St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 1 Page 1 of 2 2.1 Request for Relief 31, ASME Code,Section XI, Examination Category B-A, Items B 1.11, B1.12, B 1.21 and B1.22, Reactor Pressure Vessel Shell Welds and Bottom Head Welds The licensee's submittal states in section 6.0, Proposed Alternative and Basis for Use, first paragraph:

FPL [Florida Power and Light Company] performed inservice examinations of selected welds in accordance with the requirements of 10 CFR 50.55a, plant technical specifications, and the 1989 Edition, No Addenda, of the American Society of MechanicalEngineers (ASME) Boiler and Pressure Vessel Code, Section X1.

In the fourth paragraph of the same section, the licensee's submittal states:

FPL performed ultrasonic[(UT)] examinations of all reactor vessel welds in accordance with the requirements of 10 CFR 50.55a, plant technical specifications, and the 1995 Edition, No Addenda, of ASME [Code,] Section X1 to the maximum extent possible.

2.1.1 Please clarify which Edition and Addenda of the ASME Code,Section XI was used to examine the reactor pressure vessel (RPV) welds.

FPL Response: The typographical error has been corrected in the paragraph. FPL performed inservice examinations of selected welds in accordance with the requirements of 10CFR50.55a, plant technical specifications, and the 1989 Edition, No Addenda, of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI. The 1995 Edition with Addenda through 1996 was utilized for ASME Section XI, Appendix VIII.

7 St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 1 Page 2 of 2 The licensee requested relief from examining 100% of the ASME Code-required volumes for RPV welds: Shell-to-Lower Shell Circumferential Weld (9-203), RPV Circumferential Bottom Head-to-Lower Shell Weld (10-203), RPV Upper Shell Longitudinal Seam Weld at 15 Degrees (1-203B) and RPV Lower Head Peel Segment Welds (204-03-A through F). The licensee has provided technical descriptions and sketches; however, it is unclear from the licensee's submittal how these appurtenances specifically limit the subject examinations. For example, the roll-out sketches do not provide dimensions and there is no description of the ultrasonic scanning apparatus, or any other details of the listed obstruction (e.g., size, shape, proximity to the weld, etc.).

2.1.2 Please submit further specific information to support the basis for each limited examination in Request for Relief 31, and therefore, demonstrate impracticality. Include descriptions (written and/or sketches, as necessary) of the interferences to applied nondestructive examination (NDE) techniques. As applicable, describe NDE equipment, show accessibility limitations, and discuss whether alternative methods or advanced technologies could be employed to maximize ASME Code coverage.

FPL Response: Figure 1 has been added which provides an illustration of the contact UT head used for scanning from the vessel shell. Additional figures have been added to provide the dimensions and locations of obstructions and views of each of the affected welds showing the interference caused by the permanent attachments on the TWS robot and the affect the obstructions had on scanning. The Ultrasonic (UT) techniques for each weld were reviewed to determine if additional coverage could be achieved. For the welds included in this relief request, it is not possible to remove the permanently attached obstructions to increase ASME Code coverage without significant work, increased radiation exposure, and/or damage to the plant.

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 1 of 20 St. Lucie Unit I THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 Relief Request In Accordance with 10 CFR50.55a(g)(5)(iii)

--Inservice Inspection Impracticality--

1. ASME Code Component(s) Affected Class 1 pressure retaining welds in the reactor pressure vessel (RPV).

2. Applicable Code Edition and Addenda The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Rules for Inservice Inspection of Nuclear Power Plant Components,Section XI, 1989 Edition, No Addenda. The 1995 Edition with Addenda through 1996 was utilized for ASME Section XI, Appendix VIII.

3. Applicable Code Requirement Cxat Item No. Examnin~ation Requirements B1.10 Essentially 100% volumetric examination of all B-A B1.11 longitudinal and circumferential shell welds (does not B13.12 include shell to flange weld).

B1.20 Essentially 100% volumetric examination of accessible

___ B1.22 length of circumferential and meridional head welds.

As defined by 10CFR50.55a(g)(6)(ii)(A)(2) and ASME Code Case N-460, essentially 100% means more than 90% of the examination volume of each weld where reduction in coverage is due to interference by another component or part geometry.

4. Impracticality of Compliance Due to the configuration of the Reactor Vessel, it is impractical to meet the examination coverage requirements of the ASME Code,Section XI, 1989 Edition, No Addenda, as clarified by Code Case N-460. Relief is requested in accordance with 10 CFR 50.55a(g)(5)(iii). These areas were found during the 3rd 10-year inservice inspection interval.

When examined, the welds listed within this request did not receive the required code volume coverage due to their configuration and/or the presence of permanent attachments. These scanning limitations prohibit essentially 100% ultrasonic examination coverage of the required examination volume.

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 2 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION I Described below, coupled with figures, are details of the examination limitations by weld description. Figure 1 provides an illustration of the contact UT head used for scanning from the vessel shell. Figures 2 through 15 provide the dimensions and locations of obstructions and views of each of the affected welds showing the interference caused by the permanent attachments on the Trans World System (TWS) robot and the affect of the obstructions on scanning.

RPV Intermediate Shell-to-Lower Shell Circumferential Weld (9-203)

Examination Category B-A, Item B1.11 The examination of the Figure IWB-2500-2 A-B-C-D volume is limited due to the six surveillance capsule holders. Access to approximately 16.9% of the examination volume is restricted. The remaining examination volume was examined with techniques which have been qualified by demonstration in accordance with Supplements 4 & 6 of the 1995 Edition with Addenda through 1996 of the ASME Code Section XI, Appendix VIII, using the Performance Demonstration Initiative Protocol. This weld was examined from both sides of the weld, scanning both parallel and perpendicular. These ultrasonic examinations did not reveal any recordable or reportable flaws in accordance with the ASME Code Section XI, 1989 Edition, No Addenda.

Figure 2 is a view of the TWS robot in the vessel shell region showing scan limitations caused by the six surveillance capsule holders. The weld is covered by the six surveillance capsule holders. Figure 3 provides dimensional information for the six surveillance capsule holders and their affect on scanning.

Figure 4 is a roll out view showing the reactor vessel inside surface scan areas (cross hatched) and the locations of limited areas due to the presence of the six surveillance capsule holders.

RPV Circumferential Bottom Head-to-Lower Shell Weld (10-203)

Examination Category B-A, Item B1.21 The examination of the Figure IWB-2500-3 A-B-C-D volume is limited due to the proximity of the Core Barrel Stabilizers and Core Lugs. Access to approximately 29.4% of the examination volume is restricted. The remaining examination volume was examined with techniques which have been qualified by demonstration in accordance with Supplements 4 & 6 of the 1995 Edition with Addenda through 1996 of the ASME Code Section XI, Appendix VIII, using the Performance Demonstration Initiative Protocol. This weld was examined from both sides of the weld, scanning both parallel and perpendicular to the weld. The ultrasonic examination identified three IWB-3510 acceptable indications in accordance with the ASME Code Section XI, 1989 Edition, No Addenda, acceptance criteria.

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 3 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 Figure 5 is a view of the TWS robot in the vessel shell region showing scan limitations caused by the Core Barrel Stabilizers and Core Lugs. Figure 6 provides dimensional information for the core barrel stabilizers and core lugs and their locations in the reactor vessel. Figure 7 is a roll out view showing the reactor vessel inside surface scan areas (cross hatched) for the bottom head-to-lower shell weld and the locations of limited areas due to the presence of the core barrel stabilizers and core lugs.

RPV Upper Shell Longitudinal Seam Weld at 15 Degrees (1-203B)

Examination Category B-A, Item B1.12 The examination of the Figure IWB-2500-2 A-B-C-D volume is limited due to the outlet nozzle at zero degrees integral extension. Access to approximately 36.8%

of the examination volume is restricted. The remaining examination volume was examined with techniques which have been qualified by demonstration in accordance with Supplements 4 & 6 of the 1995 Edition with Addenda through 1996 of the ASME Code Section XI, Appendix VIII, using the Performance Demonstration Initiative Protocol. This weld was examined from both sides of the weld, scanning both parallel and perpendicular. These ultrasonic examinations did not reveal any recordable or reportable flaws in accordance with the ASME Code Section XI, 1989 Edition, No Addenda.

Figures 8 and 9 are views of the TWS robot in the vessel shell region showing the scan limitation caused by the outlet nozzle at zero degrees integral extension. Figure 10 provides dimensional information and the affect the outlet nozzle at zero integral extension had on scanning. Figure 11 is a roll out view showing the reactor vessel inside surface scan areas (cross hatched) for the upper shell longitudinal seam weld at 15 degrees.

RPV Lower Head Peel Segment Welds (204-03-A through F)

Examination Category B-A, Item B1.22 The examination of the Figure IWB-2500-3 E-F-G-H volume is limited due to the proximity of the flow baffle. Access to approximately 46.7% of welds 204-03-B, 204-03-D, 204-03-F and 56.6% of welds 204-03-A, 204-03-C, 204-03-E examination volume is restricted due to limited access behind the flow baffle.

The remaining examination volume was examined with techniques which have been qualified by demonstration in accordance with Supplements 4 & 6 of the 1995 Edition with Addenda through 1996 of the ASME Code Section XI, Appendix VIII, using the Performance Demonstration Initiative Protocol. The welds were examined from both sides of the weld, scanning both parallel and perpendicular to the weld. These ultrasonic examinations did not reveal any recordable or reportable flaws in accordance with the ASME Code Section XI, 1989 Edition, No Addenda.

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 4 of 20 St. Lucie Unit I THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 Figures 12 and 13 are views of the TWS robot in the vessel shell region showing scan limitations due to limited access behind the flow baffle and core lugs.

Figure 14 provides dimensional information for the core lugs and core baffle and their affect on scanning. Figure 15 is a roll out view showing the reactor vessel inside surface scan areas (cross hatched) for the peel segment welds and the locations of the core lugs.

5. Burden Caused by Compliance It is not possible to obtain ultrasonic interrogation of greater than 90% of the required examination volume due to interference caused by configuration and/or permanent attachments. Examinations were performed to the maximum extent possible. For the welds listed in this relief request, it is not possible to remove the permanently attached obstructions to increase ASME Code coverage without significant work, increased radiation exposure, and/or damage to the plant.

6. Proposed Alternative and Basis for Use Proposed Alternative

1) Periodic system pressure tests in accordance with ASME Section XI Category B-P, Table IWB-2500-1.

2) Conduct ultrasonic examinations to the maximum extent possible.

Basis FPL performed inservice examinations of selected welds in accordance with the requirements of 10CFR50.55a, plant technical specifications, and the 1989 Edition, No Addenda, of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section X1. The 1995 Edition with Addenda through 1996 was utilized for ASME Section X1, Appendix VIII. When a component has conditions which limit the examination volume, Florida Power and Light is required to submit the information to the enforcement and regulatory authorities having jurisdiction at the plant site. This Relief Request has been written to address areas where those types of conditions exist and the required amount of coverage was reduced below the minimum acceptable.

FPL performed mechanized ultrasonic examinations of the reactor vessel during the November 2008 refueling outage.

10 CFR 50.55a(g)(4) recognizes that throughout the service life of a nuclear power facility, components which are classified as ASME Code Class 1, Class 2, and Class 3 must meet the requirements set forth in the ASME Code to the extent practical within the limitations of design, geometry and materials of construction of the components.

K-St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 5 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 The mechanized techniques employed for examination from the RPV inside have been demonstrated in accordance with Supplements 4 & 6 of the 1995 Edition with Addenda through 1996 of the ASME Code Section XI, Appendix VIII, using the Performance Demonstration Initiative Protocol. The Ultrasonic (UT) techniques for each weld were reviewed to determine if additional coverage could be achieved. Access for examination of the affected welds from the outside of the reactor vessel is not possible. Access and permanently installed attachments inside the reactor vessel limit additional scanning of the welds included in this request for relief.

In addition to the required ultrasonic examination, the interior of the reactor vessel, including welded attachments, received a visual examination in accordance with Table IWB-2500-1, Examination Categories B-N-i, B-N-2 and B-N-3. The visual examinations revealed no indications.

The subject welds were also examined in the second interval during the 10-year reactor vessel examination. The second interval examinations did not reveal any reportable flaws.

The extent of examination volume achieved ultrasonically, the alternate scans performed, and the system pressure tests provide assurance of an acceptable level of quality and safety.

7. Duration of Proposed Alternative Third Inservice Inspection Interval February 11, 1998 to February 10, 2008

8. References 10CFR50.55a ASME Section XI, "Rules For Inservice Inspection of Nuclear Power Plant Components,"

1989 Edition, No Addenda ASME Section XI, Division 1, Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds, Section Xl, Division 1" ASME Section XI, Appendix VIII, "Rules For Inservice Inspection of Nuclear Power Plant Components," 1995 Edition with Addenda through 1996

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 6 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION I CONTACT E*OCK END CONTACT HEAD DIRECTIONAL ARROW 2x3 jT HEAD CON Fl("C.U1 RAT 10 N FOR SHELI. SSC.ANNING (AS VIEWED FROM BACK OF ROBOHANOD COUPLING)

Illustration of the typical UT head configuration used for vessel shell weld scanning. Overall head dimensions are approximately 12" x 8".

Figure 1

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 7 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 RPV Intermediate Shell-to-Lower Shell Circumferential Weld (9-203)

View of TWS robot in vessel shell region showing scan limitation caused by the surveillance capsule holders. The weld is covered by the surveillance capsule holders.

Figure 2

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 8 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION I 270' AND, DIMENSIONS SHON IN.INCHES.

'TOL£ SCAN ARE-A. ,OF" WELD','--.20 IS LIMITED DUE ITO6: SURVEILLNCE HOLDERS T'OTAL WE.LD. LEN(VH= 5416.R1 "INC-HES, SHO-$UIWEILLANCE" HOLDER OBSTRUCTED RPV Intermediate Shell-to-Lower Shell Circumferential Weld (9-203)

Figure 3

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 9 of 20 St. Lucie Unit I THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 1' 270 ' IT 9i 18i' 7-203 RPV Intermediate Shell-to-Lower Shell Circumferential Weld (9-203)

Figure 4

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 10 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 RPV Circumferential Bottom Head-to-Lower Shell Weld (10-203)

View of TWS robot in lower vessel shell region showing scan limitation caused by the Core Barrel Stabilizers and Core Lugs. The weld examination is obstructed by the Core Barrel Stabilizers and Core Lugs.

Figure 5

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 11 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1

-SURVEILLANCE HdLDERý,

CORE BARREL

,STABILIZER-90'

-WEL, 1O31-ý203I BAFFLE-TyP, 9x.

RPV Circumferential Bottom Head-to-Lower Shell Weld (10-203)

Figure 6

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 12 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 i59 270" q 90* 180.

V/I WO.... ...... 5 RPV Circumferential Bottom Head-to-Lower Shell Weld (10-203)

Figure 7

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 13 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 RPV Upper Shell Longitudinal Seam Weld at 15 Degrees (1-203B)

View of TWS robot in upper vessel nozzle belt region showing scan limitation caused by the outlet nozzle reinforcement. The weld intersects the outlet nozzle and limits head movement.

Figure 8

, I . x St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 14 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 RPV Upper Shell Longitudinal Seam Weld at 15 Degrees (1-203B)

View of TWS robot in upper vessel nozzle belt region showing scan limitation caused by the outlet nozzle reinforcement. The weld intersects the outlet nozzle and limits head movement.

Figure 9

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 15 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 Ii J.

RPV Upper Shell Longitudinal Seam Weld at 15 Degrees (1-203B)

Figure 10

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 16 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION I 180" 2 70" 0 90" i 80-7-203. -

• .-, - ,(l* /- ,\ /+/ */ \ ,/ 'I

/ IL 71 203A 1' 2038 1 -

8-203 ....

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2"' -0 A 2-2DH t 220 <203 32038

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255' 5 135.-

A!"20i 0-0 _________________________ _________________________

Figure 11

1 0 'A St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 17 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 RPV Lower Head Peel Segment Welds (204-03-A through F)

View of TWS robot in lower head above flow baffle showing scan limitation caused by the baffle and core lugs. This view shows both the circumferential weld and peel welds. The affected lower head peel welds are partially covered by the baffle.

Figure 12

I I A1 St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 18 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION I RPV Lower Head Peel Segment Welds (204-03-A through F)

View of TWS robot in lower head below flow baffle showing scan limitation caused by the baffle. The affected welds are partially covered by the baffle. The affected lower head peel welds are partially covered by the baffle.

Figure 13

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2 Page 19 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 FLOW RPV Lower Head Peel Segment Welds (204-03-A through F)

Figure 14

St. Lucie Unit 1 L-2009-168 Docket No. 50-335 Attachment 2

0 Page 20 of 20 St. Lucie Unit 1 THIRD INSPECTION INTERVAL RELIEF REQUEST NUMBER 31, REVISION 1 1 00 270" 0 90, 180" 0 0;,

M-203 0 01

.. .......i l m m -'r-2D4-02 20,-0-C . 204-03-A 204-03-F 204-03-E 20.-03-D.

210' 03B 20- 330' 30 9(0 150" RPV Lower Head Peel Segment Welds (204-03-A through F)

Figure 15