ML17037D054
| ML17037D054 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/27/2017 |
| From: | Perkins E Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CAC MF8092, CAC MF8093, CAC MF8094 | |
| Download: ML17037D054 (32) | |
Text
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~Entergx January 27, 2017 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy.Nuclear Operations, Inc.
Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth. MA 02360
SUBJECT:
Response to Requests for Additional Information - Relief Request on Volumetric Exam Requirements, PNPS-ISl-001, 002 & 003 (CAC NO. MF8092, MF8093 and MF8094)
Pilgrim Nuclear Power Station Docket No. 50-293 Renewed License No. DPR-35
REFERENCE:
NRC to Entergy Transmittal, "PILGRIM: Request for Additional Information -
Relief Request on Volumetric Exam Requirements, PNPS-ISl-001, 002 and 003 (CAC NOS. MF8092, MF8093 and MF8094)" (1.16.063)
LETTER NUMBER: 2.17.007
Dear Sir or Madam:
Pursuant to the request by the U.S. Nuclear Regulatory Commission Staff for additional information contained in the Reference, *please find attached the Pilgrim Nuclear Power Station responses.
Request for Relief PNPS-ISl-003 is being withdrawn. American Society of Mechanical Engineers Code Case N-700 limits inspection to one welded attachment to the reactor pressure vessel. The inspection of the reactor vessel to skirt support weld meets this requirement. As such, relief for the limited inspection of Reactor Vessel Attachment Weld, RPV-SBW-270 is not required.
Please contact me at (508) 830-8323 if you have any questions.
There are no regulatory commitments included in this letter.
Sincerely,
~~~~-Pb Everett P. Perkins, Tr:
Manager, Regulatory Assurance EPP/mw
E:ntergy Nuclear Operation-s, Inc.
Pilgrim Nuclear Power Station Attachments:
Letter No. 2.17.007 Page 2 of 2
- 1. Response to Request for Additional Information - Relief Request on Volumetric Exam Requirements, PNPS-ISl-001 (5 Pages)
- 2. Response to Request for Additional Information - Relief Request on Volumetric Exam Requirements, PNPS-ISl-002 (3 Pages)
- 3. Pilgrim Unit 1 Reference Drawings (19 Pages) cc:
Mr. Daniel H. Dorman Regional Administrator, Region I U.S. Nuclear Regulatory Commission 2100 Renaissance Blvd,., Suite,100 King of Prussia, PA 19406-2713 Ms. Booma Venkataraman, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8C2A Washington, DC 20555 NRC Senior Resident Inspector Pilgrim Nuclear Power Station to Letter Number 2.17.007 Response to Request for Additional Information - Relief Request on Volumetric Exam Requirements, PNPS-ISl-001 (5 Pages) to Letter No. 2.17.007 Page 1of5 REQUEST FOR ADDITIONAL INFORMATION RELIEF REQUEST ON VOLUMETRIC EXAM REQUIREMENTS, PNPS.;ISI- 001 PILGRIM NUCLEAR POWER STATION ENTERGY NUCLEAR OPERATIONS, INC.
DOCKET NO. 50-293 (CAC NO. MF8092)
Request for Additional Information (RAil 1 The licensee references both ASME Section XI 1998 Edition w/ 2000 Addenda, Table IWB-2500-1 and ASME Section XI 2001 Edition w/ 2003 Addenda, Table IWB-2500-1 as the codes of record for the submittal. Please identify the Code. of Record that applies to this relief request and clarify which aspects of the relief request refer to the ASME Section XI 1998 Edition w/ 2000 Addenda, and which aspects of the relief request refer to the ASME Section XI 2001 Edition w/ 2003 Addenda.
Response to RAI 1 Based on the below, the answer to the above question is the Code of Record for this relief request is ASME Section XI 2001 edition with 2003 addenda.
From SEP-ISl-PNPS-001 revision 003 1.1
Introduction:
This ISi Program Plan is developed in accordance with the requirements delineated in the 1998 Edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI with the 2000 Addenda. Relief Request PRR-18 allows Pilgrim to use the 2001 Edition through 2003 Addenda of the American Society of Mechanical.
Engineer\\:) (ASME) Boiler and Pressure Vessel Code Section XI for lnservice Inspection, related activities associated with Repairs, Replacements, Pressure Testing and Nondestructive (NOE) and the 2001 edition of the ASME Code Section XI for Performance Demonstration of Ultrasonic Examinations.
1.1.3 PNPS Fourth Ten-Year Interval ASME Code of Record 1.1.3.2 This PNPS Fourth Ten-Year ISi Program Plan is based on the requirements of 10CFR50.55a(b)(2) and was developed in accordance with the requirements delineated in the 1998 Edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI with the 2000 Addenda, Subsections IWA, IWB, IWC, IWD, IWE, and IWF per Inspection Program B of IWA-2432, including applicable ASME Code Cases and Relief Requests. Accordingly, this lnservice Inspection Plan provides the details necessary for performing the inservice inspection of the Pilgrim Class 1, 2, 3, and MC pressure retaining components and supports. Relief has been requested from those portions of the code that would constitute a burden to PNPS without a compensating increase in quality and safety, and from code requirements that are considered impractical. The applicable relief requests are discussed in Section 1.9 of this program plan and applicable ASME code cases are discussed in section 1.8. Augmented in-service inspections previously committed to by Boston Edison and/or Entergy Nuclear Northeast are also included. These augmented inservice inspection requirements are further discussed in Section 1.5.
to Letter No. 2.17.007 Page 2 of 5 The reference drawings are unclear as to what sections of the weld are being covered by the examinations and how the obstructions impede movement of the scanners. This can be attributed to overlapping scanner images, and unrepresented or unlabeled obstructions. Therefore, the NRC staff requests that the licensee graphically clarify what sections of the welds are covered by the examinations and identify where the obstructions lie on the figures which preclude examination of certain sections of the weld. Lastly where there are more than two scanner images on the same figure, implying
, more than one scan, please confirm which two scanners are associated with one scan and resultantly what sections of the weld are covered by that scan.
Response to RAI 2 Revised vendor drawings are provided in Attachment 3. There are different obstructions for different welds that are typical of the vessel interior. The figures with two scanner images are just to illustrate the placement of the scanner packages. The scanners were used in Head Up and Head Down motion where access allowed.
Weld RPV-L-2-339 A, states that there was a drop in coverage from the last inspection due to the differences in the design of the inside surface scanner utilized. This change in design resulted in a drop in coverage from 81% to 18%. Please justify how this examination provides an equivalent or greater standard of quality and safety with this drop in coverage.
Response to RAI 3 The reduced inspection coverage achieved in 2015 for RPV vertical upper shell weld RPV-L 339A was primarily due to the invessel robotic inspection tool not being able to fit between the RPV inner wall and the adjacent guide rod at 0° azimuth. Other interferences were Feedwater sparger end attachments and internal Core Spray piping. The nominal available clearance between the RPV wall and guide rod is 3.34 inches. The scanner used in 2005 was only 2 inches thick which allowed the vendor to achieve 81 % coverage. The scanner used by a different vendor in 2015 was thicker at nominally 3.59 inches with the tool horizontally oriented and 3.30 inches vertically. Although the nominal clearance of 3.34 inches is 0.040 inches greater than the vertically-oriented tool thickness dimension, tool access under the guide rod was not possible since nominal clearance values were used which do not account for tolerance stack-up or local deformations of the guide rod.
The vendor that performed the 2015 inspection had an existing agreement for refueling and inspection services. The reduction in expected coverage for the 2015 exam was unknown to Entergy until April 2015 when the access study was received from the vendor within weeks of the outage. At that point, it was not practical to attempt to locate and mobilize an alternative vendor to perform the inspections.
Although the reduction in coverage from 81 % in 2005 to 18% in the 2015 examination is significant, Entergy believes the 2015 examination provides a sufficient level of quality and safety for the following reasons.
to Letter No. 2.17.007 Page 3 of 5 There is no known degradation mechanism for this type of cladded carbon steel weld other than reduced fracture toughness due to neutron irradiation-induced embrittlement. The fracture toughness of reactor vessel weld RPV-L-2-339A and associated base metal is not significantly reduced by neutron irradiation exposure since the subject weld is located outside the Pilgrim RPV beltline region and will have an accumulated fluence at end of plant life that is still less than the 1. OOE 17 n/cm2 threshold fluence value referenced in 1 OCFR50 Appendix H. The accumulated fluence of this weld is calculated to be 4.28E15 n/cm2 at 54 EFPY according to Entergy calculation M1278, "Calculation for RPV Fluence Evaluation at End of Cycle 15 and 54 EFPY". Pilgrim is currently at approximately 31.6 EFPY and will permanently cease commercial operation in May 2019.
Correspondingly, fleet operating experience shows that verified cracking in BWR reactor vessel welds, even in beltline region welds, is virtually unknown in the industry. This weld is not located in the beltline region. Also, similar welds at different azimuths but in the same shell segment RPV-L-2-3398 and RPV-L-2-339C achieved 69% and 73.2% coverage with no indications.
Therefore, cracking at this non-beltline region weld is highly unlikely and the reduced inspection coverage achieved in 2015 still represents a meaningful inspection sample and provides adequate assurance that this weld will continue to maintain sufficient structural integrity for the remaining life of the plant.
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Please clarify.
Response to RAI 4 The correct percentage has been verified per the report ISl-VE-15-003 to be 56.2% coverage.
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to Letter Number 2.17.007 Response to Request for Additional Information - Relief Request on Volumetric Exam Requirements, PNPS-151-002 (3 Pages) to Letter No. 2.17.007 Page 1of3 REQUEST FOR ADDITIONAL INFORMATION RELIEF REQUEST ON VOLUMETRIC EXAM REQUIREMENTS, PNPS-ISI- 002 PILGRIM NUCLEAR POWER STATION ENTERGY NUCLEAR OPERATIONS, INC.
DOCKET NO. 50-293 (CAC NO. MF8093)
Request for Additional Information (RAil 1 In Attachment 2 of the licensee submittal, this relief request references both ASME Section XI 1998 Edition w/ 2000 Addenda, Table IWB-2500-1 and ASME Section XI 2001 Edition w/ 2003 Addenda, Table IWB-2500-1. Please identify the Code of Record that applies to this relief request and clarify which aspects of the relief request refer to the ASME Section XI 1'99a Edition w/ 2000 Add.enda, an<;t which aspects of the relief request.
refer to the ASME Section XI 2001 Edition w/ 2003 Addenda.
Response to RAI 1 Based on the below, the answer to the above question is the Code of Record for this submittal is ASME Section XI 2001 edition with 2003 addenda.
From SEP-ISl-PNPS-001 Revision 003:
1.1
Introduction:
This ISi Program Plan is developed in accordance with the requirements delineated in the 1998 Edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI with the 2000 Addenda. Relief Request PRR-18 allows Pilgrim to use the 2001 Edition through 2003 Addenda of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Cqde Section Xi'for In-service Inspection, related activities associated with Repairs, Replacements, Pressure Testing and Nondestructive (NOE) and the 2001 edition of the ASME Code Section XI for Performance Demonstration of Ultrasonic Examinations.
1.1.3 PNPS Fourth Ten-Year Interval ASME Code of Record 1.1.3.2 This PNPS Fourth Ten-Year ISi Program Plan is based on the requirements of 1 OCFR50.55a(b )(2) and was developed in accordance with the requirements delineated in the 1998 Edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI with the 2000 Addenda, Subsections IWA, IWB, IWC, IWD, IWE, and IWF per Inspection Program B of IWA-2432, including applicable ASME Code Cases and Relief Requests. Accordingly, this lnservice Inspection Plan provides the details necessary for performing the inservice inspection of the Pilgrim Class 1, 2, 3, and MC pressure retaining components and supports. Relief has been requested from those portions of the Code that would constitute a burden to PNPS without a compensating increase in quality and safety, and from Code requirements that are considered impractical.
The applicable relief requests are discussed in Section 1.9 of this program plan and applicable ASME code cases are discussed in Section 1.8. Augmented in-service inspections previously committed to by Boston Edison and/or Entergy N1,1clear Northeast are also included. These augmented inservice inspection requirements are further discussed in Section 1.5.
to Letter No. 2,17.007 Page 2 of 3 a) In Attachment 2, Section Ill of the licensee submittal, this relief request states that ultrasonic examinations were performed utilizing Entergy approved procedures specific to ferritic vessels greater than 2 inches in thickness. Please confirm that these
/
examinations were performed in accordance with the ASME Code, and provide the ASME Code requirement applied for these ultrasonic examinations (e.g.,Section XI, Appendix VIII, or Section V, Article 4, or other.)
b) If Section XI, Appendix VIII is applicable to this relief request, identify any Appendix VIII Supplements that were applied.
c) In Attachment 2, Section Ill of the licensee submittal, this relief request states that full coverage could not be obtained during ultr~sonic examination of the "non-Appendix VIII Pressurizer Nozzle-to-Vessel,welds listed in Attachment 6 Table 2-1." However, the Item 83.90 welds described in Attachment 2 and in Attachment 6, Table 2-1 of the licensee submittal, are reactor vessel welds and not pressurizer welds. Please clarify or correct the statement regarding "non-Appendix VIII Pressurizer Nozzle-to-Vessel welds".
Response to RAI 2 a) ASME Section XI, Appendix VIII, Supplements 4, 5, and 6 b) ASME Section XI, Appendix VIII, Supplements 4, 5, and 6 c) Attachment 2, Section Ill, first paragraph of the relief request should be changed to read as follows:
Ill. BASIS FOR RELIEF During ultrasonic examination of the Reactor Vessel Nozzle-to-Vessel welds listed in Table 1, greater than 90% coverage of the required examination volume could not be obtained. Examinations were performed utilizing Entergy approv~d procedures specific to Reactor Pressure Vessel Welds (Section XI, Appendix VIII).
a) For this relief request please confirm that inner radius examinations were performed as required by Section XI, Figures IWB-2500-7(a) through (d) of the ASME Code.
b) For any inner radius examinations as described in (a) above, please provide the ASME Code requirement applied for these volumetric examinations (e.g.,Section XI, Appendix VIII, with Supplement 5, or other.)
Response to RAI 3 a) The examination volume was in accordance with Section XI Fig. IWB-2500-7(a).
(Examination Zones in Barrel Type Nozzles Joined by Full Penetration Corner Welds) b) ASME Code Section XI, Appendix VIII, with Supplement 5. Code Case N-552 applies.
- to Letter No. 2.17.007 Page 3 of 3 In Attachment 2, Section Ill of the licensee submittal, this relief request states that 0, 45, 60 and 70 degree beam angles used in the axial and circumferential direction were not able to achieve greater than 90% code required volume. But the calculation sheets and sketches provided by the licensee do not indicate any beam angles other than 60 degrees. Please clarify if angles other than 60 degrees were used for scanning, and if so, why those angles were not included in the calculation sheets and sketches included in the licensee submittal.
Response to RAI 4 According to the inspection vendor, there are various angles used depending on the method of scanning that was used for each exam:
GEH uses 60°RL search units for S4 (Supplement 4) and S6 (Supplement 6) manual exams. GEH uses various shear wave search units for the inner 15% T (Supplement 5 per 1 OCFR50.55a) of the nozzle to vessel circumferential exams. Coverage examples in our previous attachment are all examples of manual coverages.
The reference to 0°, 45°S, 60°RL and 70°RL search units were in error in the original submittal.
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The exams performed early in the inspection interval used IWB-2500-?(a) for the exam
. volume. The later exams used Code Case N-613-1 Figure 1 for the exam volume.
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