ML043420167
| ML043420167 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/24/2004 |
| From: | Mauldin D Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 102-05182-CDM/SAB/RJR, EA-03-009 | |
| Download: ML043420167 (7) | |
Text
LAFS David Mauldin Vice President Nuclear Engineering and Support Palo Verde Nuclear Generating Station EA-03-009 Mail Station 7605 TEL (623) 393-5553 P.O. Box 52034 FAX (623) 393-6077 Phoenix, AZ 85072-2034 102-05182-CDM/SAB/RJR November 24, 2004 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
References:
- 1. APS letter 102-05075-CDM/SAB/RJR, "Relief Request No. 25-Request for Relaxation of First Revised NRC Order EA-03-009,Section IV.C.(5)(b) Requirements for CEDM Nozzles", dated March 19, 2004.
- 2. APS letter 102-05086-CDM/SAB/RJR, "Response to Request for Additional Information - Request for Relaxation of First revised NRC Order EA-03-009,Section IV.C(5)(b) Requirements for CEDM Nozzles", dated April 16, 2004.
- 3. APS letter 102-05094-CDM/SAB/RJR, "Response to Second Request for Additional Information - Request for Relaxation of First revised NRC Order EA-03-009,Section IV.C(5)(b) Requirements for CEDM Nozzles
- Relief Request No. 25", dated April 22, 2004.
- 4. APS letter 102-05123-CDM/TNW/RJR, "First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles", dated July 01, 2004.
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 2 Docket No. STN 50-529 Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles In Reference 1, Arizona Public Service Company (APS) requested relaxation from the requirements of First Revised Order EA-03-009,Section IV.C(5)(b)(i) to perform ultrasonic testing of each control element drive mechanism (CEDM) nozzle penetration. In References 2 and 3, APS provided responses to NRC questions regarding the relaxation request for the CEDM nozzles. In Reference 4, APS provided the updated minimum inspection coverage for PVNGS Units I and 3 required by the supporting Westinghouse analysis.
P, l
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- South Texas Project
- Wolf Creek
US Nuclear Regulatory Commission ATT: Document Control Desk' Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles Page 2 A review of the previous inspection data available for the Unit 2 CEDM penetration nozzles has been performed. Based upon this review, the penetrations in Unit 2, with the exception of penetration number 56, appear to have sufficient inspection coverage below the weld in order to perform the inspection distance identified in References 1 and 2. Nozzle 56 is the only nozzle requiring a revised analysis. The new analysis is described below.
Penetration No. 56 Finite element stress analyses were performed for a CEDM with a penetration nozzle angle of 35.7° using the Palo Verde Unit 2 as-built J-weld configuration obtained from penetration number 56. The as-built J-weld depth on the downhill side determined from the UT examination data for this penetration is 1.76 inches.
The resulting hoop stress distribution is compared with that obtained based on the as-designed J-weld configuration and shown in Figures 1 and 2. The end of the inspection zone on the downhill side for penetration number 56 is 0.36 inch below the weld after taking into account instrumentation measurement uncertainty. As shown in the downhill side figure, with the lower hoop stress magnitudes and the smaller tensile stress zone for the as-built J-weld configuration, none of the postulated through-wall flaws in the regions not inspected for penetration number 56 would propagate. The initial through-wall flaw size is postulated based on the same methodology as used in the relaxation request submittal (Reference 1). In addition, the uphill side hoop stress distributions, utilizing nominal fillet weld dimensions, are not significantly affected by the longer fillet weld leg on the downhill side and therefore there is no significant impact on the uphill side crack growth results. Figure 3 shows the finite element stress contour plots for a penetration nozzle angle of 35.70 using the Palo Verde Unit 2 as-built J-weld configuration. As a result, the minimum inspection coverage required below the weld on the downhill side for penetration number 56 is 0.36 inch.
Westinghouse Electric Corporation, on behalf of APS, has completed a review of the minimum inspection coverage for the Unit 2 CEDM nozzles, and Table 1, provided in References 1 and 2, has been revised accordingly. The revised minimum required inspection coverage below the weld for the Unit 2 CEDM penetrations is shown below in Table 1. The title of the Unit 2 table has also been revised to make the table unit-specific. Revision bars indicate the areas of change.
US Nuclear Regulatory Commission ATT: Document Control Desk Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles Page 3 Table 1 Palo Verde Unit 2 CEDM Nozzle Minimum Required Inspection Coverage Required by Westinghouse Letters LTR-PAFM-04-23 and LTR-PAFM-04-54, Revision 1 Stress Level for Lower Crack Extremity = 0 ksi 0e 0
=
Z Z
Z5cc rLH 0
1 0.45 1.7 7.5 2-21 0.45 1.7 28.0 22-45 0.45 1.8 35.7 46-85(2), 90-97 0.40 1.7 35.7 5036No Propagatfio-n 756 0.36 Predicted 51.5 86-89 0.35 1.9 NOTE 1: Nozzles receiving the minimum inspection coverage, but less than 1-inch inspection coverage, will be reported in accordance with First Revised Order EA-03-009,Section IV.E.
Note 2:
Nozzle 56 is treated separately.
I
US Nuclear Regulatory Commission ATT: Document Control Desk Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles Page 4 Figure 1 Hoop Stress vs Distance from Bottom of Weld, 35.7 Degrees (Downhill) 100,000 80,000 -
60,000-40,000 20,000-....
0.
0 0 -
. -I:t_
-20,000
-40,000 -
l 0.00 0.50 1.00 1.50 2.00 2.50 Distance from Bottom of Weld (in) a_
Design - Inside Design - Outside
-.-- - As-Built (1.76") - Inside
---a --- As-Built (1.76") - Outside CDl
US Nuclear Regulatory Commission ATT: Document Control Desk Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles Page 5 Figure 2 Hoop Stress vs Distance from Bottom of Weld, 35.7 Degrees (Uphill) 60,000 -
50,000 r a
30,000 e
20,000 10,000 00 0
-10,000
-20,000
-30,000 0.00 1.00 2.00 3.00 4.00 5.00 6.00 Distance from Bottom of Weld (in)
+
Design - Inside
+
Design - Outside
- As-Built (1.76") - Inside
--- w--- As-Built (1.76") - Outside CO Z
US Nuclear Regulatory Commission ATT: Document Control Desk Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles Page 6 Figure 3 Stress Contour Plots for Penetration Nozzle Angle (35.70) with As-Built Weld Depth of 1.76" ANSYS 8.0 MAY 9 2004 21:12:21 PLOT NO.
8 NODAL SOLUTION TIME=4004 Sy (AVG)
RSYS=11 PowerGraphics EFACET=1 AVRES=A11 iDX =. 444818 SMX_99274 4
-38958
-10000 10000 20000 30000 40000 50000 100000 ANS0S 8.0 MAY 9 2004 21:12:22 PLOT NO.
9 NODAL SOLUTION TINE=4004 Sz (AVG)
RSYS=1 1 Power-raphics EFACET=1 AVRES=A11 DMX
.444818 SMN =-54114 SNX =64668 E
-54114
-10000
_0 10000 20000 30000 Cal 40000 50000 100000 Operating plus Residual Hoop (SY) and Axial (SZ) Stress 35.7° CRDM (1.76-inch weld depth)
GO3
US Nuclear Regulatory Commission ATT: Document Control Desk Relief Request No. 25 for PVNGS Unit 2: Relaxation From First Revised NRC Order EA-03-009 - Additional Analysis Information for Control Element Drive Mechanism (CEDM) Nozzles Page 7 APS respectfully requests that your review and approval of the relaxation request submitted to you in Reference 1, as supplemented by References 2, 3, 4, and this letter, be completed for Unit 2 by March 31, 2005.
No commitments are being made to the NRC in this letter. Should you have any questions, please contact Thomas N. Weber at (623) 393-5764.
Sincerely, CDM/SAB/RJR cc:
J. E. Dyer B. S. Mallett M. B. Fields N. L. Salgado