W3F1-2009-0062, Response to NRC Request for Additional Information for Alternative W3-ISI-016, Inspection of Reactor Pressure Vessel Head Control Element Drive Mechanism Nozzles During Third Ten-Year Inservice Inspection Interval
| ML093080128 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 11/02/2009 |
| From: | Murillo R Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3-ISI-016, W3F1-2009-0062 | |
| Download: ML093080128 (10) | |
Text
v-EnterWy Entergy Operations, Inc.
17265 River Road Killona, LA 70057-3093 Tel 504-739-6715 Fax 504-739-6698 rmurill@entergy.com Robert J. Murillo Licensing Manager Waterford 3 W3F1-2009-0062 November 2, 2009 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Response to NRC Request for Additional Information for Alternative W3-ISI-016, Inspection of Reactor Pressure Vessel Head Control Element Drive Mechanism Nozzles during Third Ten-Year Inservice Inspection Interval Waterford Steam Electric Station, Unit 3 Docket No. 50-382 License No. NPF-38
REFERENCES:
- 1.
Entergy Letter to the NRC dated October 19, 2009, Request for Alternative W3-ISI-016, Inspection of Reactor Pressure Vessel Head Control Element Drive Mechanism Nozzles during Third Ten-Year.
Inservice Inspection Interval (W3F1-2009-0058)
Dear Sir or Madam:
As discussed in Reference 1, Entergy Operations, Inc (Entergy) requested relief from the inspection requirements of American Society of Mechanical Engineers (ASME) Code Case N-729-1, as conditioned by 10CFR50.55a(g)(6)(ii)(D), for Waterford 3 Steam Electric Station, Unit 3 (Waterford 3) for the fall 2009 (RF1 6) refueling outage. Specifically, the bottom of the Waterford 3 control element drive mechanism (CEDM) nozzles contains threads that could not be effectively examined in accordance with the First Revised NRC Order EA-03-009. The conditions that required Entergy to submit a relaxation request to the Order remain with Code Case N-729-1 as conditioned by 10CFR50.55a.
On October 28, 2009, the NRC requested additional information related to the proposed Alternative W3-ISI-016. Please find attached Entergy's response to this request for additional information.
The response to this request includes no new commitments.
C-04-7A
W3F1-2009-0062 Page 2 If you have any questions or require additional information, please contact me at 504-739-6715.
Sincerely, R"M/RJP
Attachment:
Response to NRC Request for Additional Information for Alternative W3-ISI-016, Inspection of RPV Head Control Element Drive Mechanism Nozzles during Third Ten-Year Inservice Inspection Interval
W3F1-2009-0062 Page 3 cc:
Mr. Elmo E. Collins, Jr.
Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Waterford Steam Electric Station Unit 3 P.O. Box 822 Killona, LA 70066-0751 U. S. Nuclear Regulatory Commission Attn: Mr. N. Kalyanam Mail Stop O-07D1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway ATTN: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn ATTN: N.S. Reynolds 1700 K Street, NW Washington, DC 20006-3817 Morgan, Lewis & Bockius LLP ATTN: T.C. Poindexter 1111 Pennsylvania Avenue, NW Washington, DC 20004 Louisiana Department of Environmental Quality Office of Environmental Compliance Surveillance Division P. O. Box 4312 Baton Rouge, LA 70821-4312 American Nuclear Insurers Attn: Library 95 Glastonbury Blvd.
Suite 300 Glastonbury, CT 06033-4443
Attachment to W3FI-2009-0062 Response to NRC Request for Additional Information for Alternative W3-ISI-016, Inspection of RPV Head Control Element Drive Mechanism Nozzles During Third Ten-Year Inservice Inspection Interval
Attachment to W3F1-2009-0062 Page 1 of 6 Entergy Operations, Inc.
Waterford Steam Electric Station, Unit 3 Response to NRC Request for Additional Information For Alternative W3-1SI-016, Inspection of RPV Head Control Element Drive Mechanism Nozzles During Third Ten-Year Inservice Inspection Interval By letter dated October 19, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML092940243), Entergy Operations, Incý (the licensee), submitted its third 10-year inservice inspection interval Request for Alternative, W3-1SI-01 6, from the inspection requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Code Case N-729-1, for Waterford 3 Steam Electric Station, Unit 3 (Waterford 3). We have reviewed the application and determined that additional information contained in the enclosure is needed to complete the review.
Entergy is providing the following responses to these requests below.
- 1. Please specify the manufacturer, heat and heat treatment of the control element drive mechanism (CEDM) penetration tubes. Has this specific material shown an industry history of primary water stress corrosion cracking?
Response
The CEDM nozzles at Waterford 3 were supplied by Standard Steel and are fabricated from heat numbers A08846, A09042, and A09321 each having a SB-166 material specification. As discussed in the response to Question 1 of Reference 3, the Waterford 3 CEDM nozzles are not of the known material heats that have exhibited cracking.
- 2. Please describe any changes in the values of the "free span lengths" in the Table "Waterford 3 CEDM Nozzle As-Built Free Span Lengths" in Enclosure 2 of Reference 1 that have resulted from previous inspections.
Response
Waterford 3 freespan lengths were measured during the spring 2005 (RF1 3) refueling outage examinations from ultrasonic testing (UT) data which may vary due to UT data interpretation. The freespan lengths from the RF13 data is compared to the data contained in Reference 1 and is shown in Table 1 below. The RF13 measured freespan lengths from ultrasonic data vary from 0.00" to 0.16" from that provided in Reference 1.
As discussed in response to questions 3 and 4 below, the as-measured UT freespan lengths are bounded by analysis.
Attachment to W3F1-2009-0062 Page 2 of 6
- 3. Please describe any changes due to further analysis that have been made in the predicted crack growth per cycle found in Table 13 in Reference 2.
Response
The analysis provided in Table 13 in Reference 2 has not been revised. However, in an effort to identify what as-found conditions would require reanalysis, Entergy performed an evaluation of the variables that could negatively affect the analysis provided in Reference 2.
This evaluation was provided to the NRC in a subsequent response to additional information on October 24, 2003 (Question 2 of Reference 3). From this evaluation, the one variable that has the potential to negatively affect the current analysis is the distance between the top of the blind zone and the bottom of the weld when this distance is shortened by a reduction in the nozzle length. To assess this affect, an iterative analysis using varying lengths between the blind zone and the bottom of the weld was performed to identify the threshold length that would require an augmented inspection. Based on the results of the evaluation, the trigger for requiring augmented inspections was based on the Minimum Propagation Lengths provided in the following table reproduced from Reference 3.
The NRC documented the acceptability of these conclusions as discussed, in Reference 4.
Nozzle Group Assumed Available Minimum Propagation (Head Angle Degrees)
Propagation Length Length (inch)
(inch) 0 1.029 0.265 7.8 1.002 0.250 29.1 0.637 0.160 49.7 0.420 0.160
- 4. Please verify that comparing the "free span length" values found in Reference 1 with the values for predicted crack growth per cycle found in Table 13 of Reference 2 is appropriate to show that postulated cracks outside of the ultrasonic examination area will not propagate to the root of the J-groove weld during one refueling cycle.
Response
As discussed above, the minimum required inspection co{verage for'one cycle of operation varies from 0.160" to 0.265" based on the nozzle group (head angle degrees). This is the minimum distance required to ensure that a postulated flaw would not grow to the toe of the J-groove weld in one fuel cycle. The smallest RF1 3 measured CEDM nozzle freespan length is 0.44.inches. As provided in Table 1 below, the RF13 freespan lengths exceed the bounding single cycle crack propagation length of 0.265" in all cases.
Attachment to W3F1-2009-0062 Page 3 of 6
- 5. Please verify that the bounding estimate of the crack growth per cycle for each nozzle is that for the nozzle angle in Table 13 that is greater than or equal to the nozzle angle being considered.
Response
The selected locations (See response to Question 3) were 00, 7.80, 29.1°, and 49.70 with the 00 head angle at the vertical centerline of the RPV head, the 49.70 head angle location being the outermost nozzles. The results of the stress analysis at each location are bounding for nozzles higher on the head (e.g., analysis for 29.10 bounds the intermediate nozzles between 7.80 and 29.1°).
As discussed in the "Analysis Conclusions" section of Reference 2, additional analyses were performed to assess the potential for postulated cracks to grow from along the bottom of the 49.70 CEDM nozzle at the mid-plane location to the weld in one cycle of operation. The evaluations indicate that cracks in the blind zone of the CEDM nozzle will not grow into the welds of any of the 91 CEDM nozzles at Waterford 3 within one cycle of operation. Table 1 of Reference 2, indicates that the CEDM nozzles by head angle location are bounded by these evaluations. The as measured CEDM nozzle freespan lengths as provided in Table 1 below, for their respective head angle locations, do not alter this conclusion.
References
- 1. Entergy letter dated August 13, 2004, "Response to NRC Request for Additional Information Pertaining to Waterford 3 Relaxation Request #4 to NRC Order EA-03-009 for the Control Element Drive Mechanism Nozzles (TAC No. MC2643)" (CNRO-2004-0039)
[ADAMS Accession No. ML0432320558].
- 2. Entergy letter dated September 15, 2003, "Enclosure 2 to CNRO-2004-00038" [ADAMS Accession No. ML032790354].
- 3. Entergy letter dated October 24, 2003, Response to a Request for Additional Information Pertaining to Relaxation Request to NRC Order EA-03-009 for the Control Element Drive Mechanism Nozzles (CNRO-2003-0057) [ADAMS Accession No. ML033110181];
- 4. NRC Letter to Entergy dated March 22, 2005, Waterford Steam Electric Station, Unit 3 (Waterford 3) - Relaxation Request from U.S. Nuclear Regulatory Commission (NRC)
First Revised Order EA-03-009 for Control Element Drive Mechanism (CEDM) Nozzles (TAC No. MC2643) [ADAMS Accession No. ML050820683]
Attachment to W3F1-2009-0062 Page 4 of 6 Table I Comparison of Waterford 3 Freespan Lengths Waterford Unit 3 As Measured Freespan from Freespan - April 2005 of Reference I DELTA Penetration Lower Exam Extent Lower Exam Extent Number (Bottom - Start)
(Bottom - Start) 1 1.24 1.32
-0.08 2
1.20 1.36
-0.16 3
1.08 1.20
-0.12 4
1.20 1.24
-0.04 5
1.40 1.36 0.04 6
1.24 1.40
-0.16 7
1.24 1.28
-0.04 8
1.24 1.20 0.04 9
1.20 1.28
-0.08 10 1.24 1.24 0.00 11 1.04 1.12
-0.08 12 0.92 0.96
-0.04 13 1.32 1.32 0.00 14 1.28 1.36
-0.08 15 1.32 1.40
-0.08 16 1.24 1.16 0.08 17 1.00 1.08
-0.08 18 1.24 1.28
-0.04 19 1.24 1.32
-0.08 20 0.92 0.92 0.00 21 1.04 1.08
-0.04 22 1.12 1.20
-0.08 23 1.08 1.08 0.00 24 1.12 1.16
-0.04 25 1.12 1.16
-0.04 26 0.96 0.96 0.00 27 0.92 0.92 0.00 28 1.00 1.04
-0.04 29 1.00 1.08
-0.08 30 1.08 1.12
-0.04 31 1.20 1.28
-0.08 32 1.08 1.12
-0.04 33 1.32 1.32 0.00 34 1.04 1.08
-0.04 35 0.96 0.92 0.04 36 0.88 0.92
-0.04 37 1.12 1.12 0.00
Attachment to W3F1-2009-0062 Page 5 of 6 Table 1 Comparison of Waterford 3 Freespan Lengths Waterford Unit 3 As Measured Freespan from Freespan - April 2005 of Reference 1 DELTA Penetration Lower Exam Extent Lower Exam Extent Number (Bottom - Start)
(Bottom - Start) 38 0.92 0.96
-0.04 39 1.04 1.04 0.00 40 1.00 1.08
-0.08 41 1.20 1.20 0.00 42 1.16 1.20
-0.04 43 0.96 0.94 0.02 44 0.92 1.04
-0.12 45 0.96 0.92 0.04 46 1.08 1.16
-0.08 47 0.84 0.98
-0.14 48 0.80 0.92
-0.12 49 1.00 1.04
-0.04 50 1.04 1.08
-0.04 51 1.00 1.00 0.00 52 1.00 1.04
-0.04 53 1.12 1.20
-0.08 54 0.76 0.84
-0.08 55 0.76 0.80
-0.04 56 0.72 0.76
-0.04 57 1.00 1.04
-0.04 58 1.00 1.08
-0.08 59 1.04 1.08
-0.04 60 0.76 0.84
-0.08 61 1.00 0.96 0.04 62 1.04 1.08
-0.04 63 1.04 1.12
-0.08 64 0.80 0.68 0.12 65 0.84 0.88
-0.04 66 0.64 0.80
-0.16 67 0.72 0.80
-0.08 68 0.72 0.80
-0.08 69 0.72 0.80
-0.08 70 0.84 0.88
-0.04 71 0.84 0.88
-0.04 72 0.80 0.84
-0.04 73 1.12 1.16
-0.04 74 1.12 1.20
-0.08 75 0.88 0.96
-0.08
Attachment to W3F1-2009-0062 Page 6 of 6 Table I Comparison of Waterford 3 Freespan Lengths Waterford Unit 3 As Measured Freespan from Freespan - April 2005 of Reference 1 DELTA Penetration Lower Exam Extent Lower Exam Extent Number (Bottom - Start)
(Bottom - Start) 76 0.96 1.04
-0.08 77 0.80 0.76 0.04 78 0.64 0.60 0.04 79 0.44 0.44 0.00 80 0.76 0.80
-0.04 81 1.00 1.04
-0.04 82 0.76 0.84
-0.08 83 0.92 0.90 0.02 84 1.04 1.08
-0.04 85 0.92 1.00
-0.08 86 0.52 0.64
-0.12 87 0.48 0.40 0.08 88 0.64 0.68
-0.04 89 0.52 0.56
-0.04 90 0.88 1.04
-0.16 91 0.48 0.56
-0.08