ML081400568

Correction to Request for Alternative W3-R&R-006 - Proposed Alternative to ASME Code Requirements for Weld Overlay

ML081400568
Person / Time
Site:	Waterford
Issue date:	05/20/2008
From:	Kalyanam N NRC/NRR/ADRO/DORL/LPLIV
To:	Entergy Operations
Kalyanam N, NRR/DORL/LPL4, 415-1480
References
TAC MD5388
Download: ML081400568 (7)

Text

May 20, 2008 Vice President, Operations Entergy Operations, Inc.

Waterford Steam Electric Station, Unit 3 17265 River Road Killona, LA 70057-3093

SUBJECT:

WATERFORD STEAM ELECTRIC STATION, UNIT 3 - CORRECTION TO REQUEST FOR ALTERNATIVE W3-R&R-006 - PROPOSED ALTERNATIVE TO ASME CODE REQUIREMENTS FOR WELD OVERLAY (TAC NO.

MD5388)

Dear Sir or Madam:

Entergy Operations, Inc. (the licensee) submitted by letter dated April 26, 2007, as revised by supplemental letter dated February 21, 2008, an alternative to the requirements of American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, IWA-4000 for mitigating primary water stress-corrosion cracking on nine specific dissimilar metal welds using preemptive full structural weld overlays at Waterford Steam Electric Station, Unit 3 (Waterford 3). The licensee proposed the alternative for the current second 10-year inservice inspection (ISI) interval which ends on May 30, 2008. Pursuant to paragraph 50.55a(a)(3)(i) of Title 10 of the Code of Federal Regulations (10 CFR), by letter dated April 21, 2008, the U.S. Nuclear Regulatory Commission (NRC) staff authorized the use of the proposed alternative for the second 10-year ISI interval at Waterford 3.

The NRC staff inadvertently issued pages 3, 9, and 11 of the Safety Evaluation with administrative errors. The corrected pages, with the changes denoted by the vertical bar on the right, are enclosed. Please note that Page 12 is being sent because of the overflow from Page 11.

The affected pages of the safety evaluation are enclosed.

Sincerely,

/RA/

N. Kalyanam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-382

Enclosure:

Safety Evaluation, pages 3,9,11, and 12 cc w/encl: See next page

ML081400568 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/BC NAME NKalyanam GLappert THiltz DATE 5/20/08 5/20/08 5/20/08 Waterford Steam Electric Station, Unit 3 (2/25/08) cc:

Senior Vice President Mr. Timothy Pflieger Entergy Nuclear Operations Environmental Scientist - Supervisor P.O. Box 31995 REP&R-CAP-SPOC Jackson, MS 39286-1995 Louisiana Department of Environmental Quality Vice President, Oversight P.O. Box 4312 Entergy Nuclear Operations Baton Rouge, LA 70821-4312 P.O. Box 31995 Jackson, MS 39286-1995 Parish President Council St. Charles Parish Senior Manager, Nuclear Safety P.O. Box 302

& Licensing Hahnville, LA 70057 Entergy Nuclear Operations P.O. Box 31995 Chairman Jackson, MS 39286-1995 Louisiana Public Services Commission P.O. Box 91154 Senior Vice President Baton Rouge, LA 70825-1697

& Chief Operating Officer Entergy Operations, Inc. Mr. Richard Penrod, Senior Environmental P.O. Box 31995 Scientist/State Liaison Officer Jackson, MS 39286-1995 Office of Environmental Services Northwestern State University Associate General Counsel Russell Hall, Room 201 Entergy Nuclear Operations Natchitoches, LA 71497 P.O. Box 31995 Jackson, MS 39286-1995 Resident Inspector Waterford NPS Manager, Licensing P.O. Box 822 Entergy Operations, Inc. Killona, LA 70057-0751 Waterford Steam Electric Station, Unit 3 17265 River Road Regional Administrator, Region IV Killona, LA 70057-3093 U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011

3.0 LICENSEE=S PROPOSED ALTERNATIVE

3.1 ASME Code Components Affected

The licensee proposes to install a preemptive full structural weld overlay on the DMWs listed in Table 1. The weld overlay will also be installed on six similar metal welds, also identified in Table 1.

TABLE 1 DISSIMILAR METAL WELD DETAILS Material Identification Nozzle Type Nozzle ISI Weld and Pipe Size carbon steel ISI weld Safe end (SE) (SST) Pipe/Fitting Pressurizer to Surge SA 508, Cl. 2 DMW 82/182 SA- 351, SST Weld SA-351, CF8M Line w/ SST Clad ID 16-017 CF8M (Cast ID 16-016 (1)

(Pipe) 12 in. NPS SST)

Pressurizer to Relief SA 508, Cl. 2 DMW 82/182 SA- 351, SST Weld SA-403, WP304 Valve (RC-317A) w/ SST Clad ID 26-006 CF8M (Cast ID 26-007 (Elbow) 6@ NPS SST)

Pressurizer to Relief SA 508, Cl. 2 DMW 82/182 SA- 351, SST Weld SA-403, WP304 Valve (RC-317B) w/ SST Clad ID 26-001 CF8M (Cast ID 26-002 (Elbow) 6@ NPS SST)

Pressurizer spare nozzle SA 508, Cl. 2 DMW 82/182 SA-351, CF8M SST Weld SA-403, (Capped) w/ SST Clad ID 26-010 (Cast SST) ID 26-011 WP304/316 4@ NPS (End Cap)

Pressurizer to spray line SA 508, Cl. 2 DMW 82/182 SA-182, SST Weld SA-376, TP304 4@ NPS w/ SST Clad ID 25-029 Type 316 ID 25-028 (1)

(Pipe)

Hot Leg 1 to SDC SA 105, Cl. 2 DMW 82/182 SA- 351, SST Weld SA-358, Type 304 (1) 14= NPS w/ SST Clad ID 15-008 CF8M ID 21-001 (Pipe)

(Cast SST)

Hot Leg 2 to SDC SA 105, Cl. 2 DMW 82/182 SA- 351, SST Weld SA-358, Type 304 (1) 14= NPS w/ SST Clad ID 06-006 CF8M ID 22-001 (Pipe)

(Cast SST)

Hot Leg 1 to Surge line SA 105, Cl. 2 DMW 82/182 SA- 351, SST Weld SA-351, CF8M (1) 12= NPS w/ SST Clad ID 15-009 CF8M ID 16-001 (Pipe)

(Cast SST)

Hot Leg to Drain SA 105, Cl. 2 DMW 82/182 SA-182, SST Weld SA-376, TP304 (1) 2@ NPS w/ SST Clad ID 15-006 Type 316 ID 32-001 (Pipe)

NPS = nominal pipe size; SDC = shutdown cooling; SST = stainless steel, Code Class 1 (1)

To facilitate preservice/ISI of these austenitic stainless steel welds, the preemptive structural weld overlay for each DMW will be extended across the stainless steel weld.

3.2 Code Requirements Subarticle IWA-4170(b) of the ASME Code,Section XI, requires that repairs and the installation of replacement items be performed in accordance with the Owner=s Design Specification and the original Construction Code of the component or system. Alternatively, Subarticle IWA-4170(b) of the ASME Code,Section XI, allows for use of later Editions and

4.3.2 Preservice Examination Section 3.0(b), APreservice Inspection,@ of Attachment 2, Reference 2, requires an UT of the installed weld overlay and the upper (outer) 25 percent of the original pipe-wall thickness.

The required examination volume is defined in Figure 2 of Attachment 2, Reference 2. The staff finds that the preservice examination requirements are acceptable because they are consistent with Code Case N-504-3; the ANO Request for Alternative ANO1-R&R-010; the Farley and Vogtle Relief Request ISI-GEN-ALT-06-03; and the ASME Code,Section XI, Appendix Q.

4.3.3 Inservice Examination Section 3.0(c) of Attachment 2 of Reference 2 requires inservice examination be conducted ultrasonically with the examination volume defined in Figure 2 of Attachment 2 of Reference 2. The requirements in Section 3.0(c) of Attachment 2 are consistent with the ANO Request for Alternative ANO1-R&R-010; the Farley and Vogtle Relief Request ISI-GEN-ALT-06-03; and the ASME Code,Section XI, Appendix Q with the following exception.

In Section V.A.3.c, Reference 2, the licensee discussed the inspection issues regarding cast stainless steel (CASS) which was used to fabricate the safe ends at the 7 nozzles specified in the DMW Details Table on Page 21 of 51 (of Reference 2). The licensee stated and the staff agrees that the UT has not been qualified in accordance with Appendix VIII, Supplement 11 of the ASME Code,Section XI, in the examination of CASS. The licensee stated further that a flaw with a depth of 75 percent of pipe thickness and circumference of 360 degrees will be assumed in the crack-growth calculation for the cast stainless steel safe ends. In light of the limited UT capability to examine CASS, the staff determined that the postulated 75 percent depth flaw in the crack-growth calculation was not sufficiently conservative to demonstrate the structural integrity of the CASS component.

The licensee stated that, to address this issue, it will perform UT examination during the first or second refueling outage following weld overlay application per Section 3.0(c)(1) in addition to performing UT examinations every 10 years, pending qualified PDI techniques for CASS.

The licensee further stated that until PDI procedures are qualified for CASS materials, it will perform Abest effort@ ISI of the CASS component per the ASME Code,Section XI, Appendix III. The use of Appendix III for examination of CASS is consistent with subarticle VIII-3110(c) of Appendix VIII to the ASME Code,Section XI. Once qualified, the licensee will implement these PDI procedures at the next scheduled ISI as required by Section 3.0(c) of , Reference 2.

The staff finds that the licensees strategy for additional examination of the CASS component is acceptable.

4.4 Proposed Ambient Temperature Temper Bead Welding The requirements for the proposed ambient temperature temper bead welding are discussed in Attachment 3 to Reference 2, and are based on Code Case N-638-1. The requirements in to W3-R&R-006 are consistent with Code Case N-638-1; the ANO Request for

accordance with the UT criteria of Appendix VIII, Supplement 11. Prior to the Supplement 11 program, EPRI was maintaining a performance demonstration program (the precursor to the PDI program) for weld overlay qualification under the Tri-party Agreement with the NRC, BWR Owner=s Group, and EPRI, as discussed in the NRC letter dated July 3, 1984. Later, the NRC staff recognized the EPRI PDI program for weld overlay qualifications as an acceptable alternative to the Tri-party Agreement in its letter dated January 15, 2002, to the PDI Chairman (ADAMS Accession No. ML020160532).

The PDI program is routinely assessed by the staff for consistency with the current ASME Code and proposed changes. The PDI program does not fully comport with the existing requirements of Supplement 11. The PDI representatives presented the differences between Supplement 11 and the PDI program at public meetings in which the NRC participated (Memorandum from Donald G. Naujock to Terence Chan, ASummary of Public Meeting Held January 31 - February 2, 2002, with PDI Representatives,@ March 22, 2002 (ADAMS Accession No. ML010940402), and Memorandum from Donald G. Naujock to Terence Chan, ASummary of Public Meeting Held June 12 through June 14, 2001, with PDI Representatives,@

November 29, 2001 (ADAMS Accession No. ML013330156)). Based on the discussions at these public meetings, the staff determined that the industry=s PDI program provides an acceptable level of quality and safety.

The licensee proposed to use the PDI program as indicated in Attachment 6 to Enclosure 3 of Reference 2, to satisfy the Appendix VIII, Supplement 11, qualification requirements. The PDI initiatives will be used for qualification of UT to detect and size flaws in the preemptive full structural weld overlays of this request. The NRC staff evaluated the differences between the PDI program and Supplement 11 as shown in Attachment 6 to W3-R&R-006. The NRC staff concludes that the justifications for the differences are acceptable and the PDI program provides an acceptable level of quality and safety. Therefore, the proposed Waterford 3 PDI program is acceptable for use in lieu of Supplement 11 of Appendix VIII to the ASME Code,Section XI.

4.6 Commitments As part of Request for Alternative W3-R&R-006, the licensee made the following commitments as shown in Enclosure 4 of Reference 2:

(1) The licensee will submit the following information to the NRC within 14 days from completing the final UTs of the completed weld overlays:

• Weld overlay examination results including a listing of indications detected,

• Disposition of all indications using the standards of ASME Code,Section XI, IWB-3514-2 and/or IWB-3514-3 criteria and, if possible, the type and nature of the indications, and

• A discussion of any repairs to the weld overlay material and/or base metal and the reason for the repairs.

(2) Prior to entry into Mode 4 start-up from RF15, the licensee will submit to the NRC a stress analysis summary demonstrating that the hot-leg piping and

pressurizer nozzles will perform their intended design functions after the weld overlay installation. The stress analysis report will include results showing that the requirements of NB-3200 and NB-3600 of the ASME Code,Section III, are satisfied. The stress analysis will also include results showing that the requirements of IWB-3000 of the ASME Code,Section XI, are satisfied. The results will show that the postulated crack including its growth in the nozzles will not adversely affect the integrity of the overlaid welds.

(3) Unless PDI procedures are qualified in time to support the preservice examinations required by Attachment 2, the licensee will perform a Abest effort@

preservice examination of the cast stainless steel region, following installation of the weld overlays during refueling outage RF15.

(4) Until PDI procedures are qualified to examine the upper 25 percent of the cast stainless steel, Entergy will perform Abest effort@ ISI of the region shown in Figure 2 of Attachment 2. Once qualified, the licensee will implement these PDI procedures at the next scheduled ISI as required by paragraph 3.0(c) of Attachment 2. Note: ISI of weld overlays for stainless steel welds is performed at the frequencies required by the Waterford 3 ISI Program as stipulated in Section V.A.3.

(5) ISI of the DMW weld overlays with cast stainless steel safe ends will be performed at a higher frequency than those without cast stainless steel safe ends. First, the initial UT inspection of the DMW weld overlays will be performed during the first or second refueling outage after installation. Then, instead of being inspected on a 25 percent sample basis, these weld overlays will be UT examined once every 10 years from the date of installation until such time when a technique is qualified to examine cast stainless steel in accordance with the PDI Program. Once the subject DMW overlays are UT examined by a qualified PDI technique (for cast stainless steel) and no planar flaws are detected, then the DMW overlays will be placed into a population in which 25 percent of that population is examined once every 10 years. Until such time, the UT inspections of the subject DMW overlays (with cast stainless steel safe ends) will not be credited to satisfy the 25 percent sample inspection requirement. Note: ISI of weld overlays for stainless steel welds is performed at the frequencies required by the Waterford 3 ISI Program as stipulated in Section V.A.3.j.

The NRC staff finds that the above commitments are acceptable because the weld overlay examination results and stress analysis will provide verification of the condition of the weld overlays after installation.

5.0 CONCLUSION

The NRC staff has reviewed the licensee=s submittal and determined that Request for Alternative W3-R&R-006 (Reference 2), will provide an acceptable level of quality and safety.

Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the use of Request for Alternative W3-R&R-006 for the installation of full structural weld overlays on the dissimilar metal welds of the Pressurizer Nozzle to Surge Line, Pressurizer Nozzle to Relief Valve (two