ML043030322
| ML043030322 | |
| Person / Time | |
|---|---|
| Site: | Waterford  (NPF-038) |
| Issue date: | 10/27/2004 |
| From: | Dodds R Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-04-001, W3F1-2004-0091 | |
| Download: ML043030322 (9) | |
Text
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-== En tergy Entergy Operations, Inc.
17265 River Road Killona, La 70066 TPIS.A4 7.1' A440 Ralph A. Dodds Acting Director, Nuclear Safety Assurance Waterford-3 W3Fl -2004-0091 October 27, 2004 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
REFERENCES:
Response to NRC Generic Letter 2004-01, Requirements for Steam Generator Tube Inspections Waterford Steam Electric Station, Unit 3 Docket No. 50-382 License No. NPF-38 1
NRC letter dated August 30, 2004, Generic Letter 2004-01, Requirements for Steam Generator Tube Inspections 2
Entergy letter dated November 18, 2003, Combined Category C-3 and 15-Day Special Report SR-03-002-00 on the 12h Refueling Outage Steam Generator Tube Inservice Inspection (W3Fl-2003-0089)
Dear Sir or Madam:
Per Reference 1, the NRC issued Generic Letter 2004-01 regarding steam generator tube inspections. The NRC requested that all Pressurized Water Reactors (PWRs) who have not ceased operation provide information within 60 days of the date of the generic letter regarding past and proposed practices on inspection of steam generator tubes using the most appropriate I OCFR50, Appendix B inspection methods. The response to the requested information for Waterford-3 is provided in Attachment 1 to this letter. provides commitments being made as a result of our response to this generic letter. If you have any questions or require additional information, please contact Ron Williams at 504-739-6255.
I declare under penalty of perjury that the foregoing is true and correct. Executed on October 27, 2004.
Si rely, RAD/SAB/RLW/cbh Attachments:
- 1. Response to Generic Letter 2004-01 for Waterford-3
- 2. List of Regulatory Commitments
W3Fl-2004-0091 Page 2 cc:
Dr. Bruce S. Mallett U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Senior Resident Inspector Waterford 3 P.O. Box 822 Killona, LA 70066-0751 U.S. Nuclear Regulatory Commission Attn: Mr. Nageswaran Kalyanam MS 0-7D1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway Attn: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn Attn: N.S. Reynolds 1400 L Street, NW Washington, DC 20005-3502 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 Town Center Suite 300S 29th S. Main Street West Hartford, CT 06107-2445
Attachment I W3FI -2004-0091 Response to Generic Letter 2004-01 for Waterford-3
- Attachment 1 to W3F1-2004-0091 Page 1 of 4 Response to Generic Letter 2004-01 for Waterford-3 NRC Generic Letter 2004-01 Requirements for Steam Generator Tube Inspections, dated August 30, 2004 was sent to all holders of operating licenses for pressurized-water reactors (PWRs), except those who have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.
The generic letter requested the following information within 60 days:
NRC Requested Information I Addressees should provide a description of the SG tube inspections performed at their plant during the last inspection. In addition, if they are not using SG tube inspection methods whose capabilities are consistent with the NRC's position, addressees should provide an assessment of how the tube inspections performed at their plant meet the inspection requirements of the TS in conjunction with Criteria IX and Xl of 10 CFR Part 50, Appendix B, and corrective action taken in accordance with Appendix B, Criterion XVI. This assessment should also address whether the tube inspection practices are capable of detecting flaws of any type that may potentially be present along the length of the tube required to be inspected and that may exceed the applicable tube repair criteria.
Waterford-3 Response:
Waterford-3 has two Combustion Engineering Model 3410 steam generators. The tubing material in each steam generator is high temperature mill annealed (HTMA) Alloy 600. The tubes are expanded through the full depth of the tube sheet using an explosive process. Tube rows I through 18 are U-bends and rows 19 through 147 are square bends.
A detailed description of the inspections, including the inspection results, is provided in Waterford-3's letter dated November 18, 2003 (Ref 2). The following table provides a summary of the type of probe used for the inspection and the inspection scope performed at Waterford-3 during the last inspection in the fall of 2003 (RF12).
Location-Probe Scope Extent Bobbin 100% FL Full Length Egg-crates & Batwings Plus Point All identified Support +/- 1 inch bobbin l-codes Free Span, Sludge Pile, Bobbin 100%
Full Length Non-Dented-Supports Dents/Dings < 2 and 5 Bobbin 20%
+/- 1 inch on either side volts of denUding
Attachment I to W3F11-2004-0091 Page 2 of 4 Location I
Probe Scope Extent Tube Sheet Crevice Plus Point 100 %
Full Depth of tubesheet Non-expanded Tubes Free Span, Sludge Pile, Plus Point All Bobbin NIA
- Supports, I-codes Expansion Transition Plus Point 100% TTS HL
+3 to -8 Low Row 100% Rows 1-2 Support to Support Plus Point U-Bend 20% Rows 3-10 The Waterford-3 SG tube inspection scope is not consistent with the NRC's position with respect to inspections performed within the tube sheet. Waterford-3 has utilized the Combustion Engineering Owners Group (CEOG) Task 1154 which was developed to evaluate pull-out distance and leakage. Based on this analysis, the inspection scope was limited due to the fact that the tube could not burst and leakage was within safety analysis limits. Additional leakage was accounted for in the safety assessment for the un-inspected portion of the tube sheet. The other areas of the SG inspections are consistent with the NRC's position.
Entergy concludes that there is a potential for degradation to exist below the depth of tube inspections within the tubesheet region performed during RF12. This conclusion is based on recent inspection results from steam generators of similar designs. The appropriate tube inspection depth is being revised based on a joint Industry testing program provided in WCAP-16208-P, Revision 0 (NDE Inspection Length for CE Steam Generator Tubesheet Region Explosive Expansions, October 2004) that demonstrates that flaws below a defined inspection distance within the tubesheet are not a safety concern.
Requested Information 2 If addressees conclude that full compliance with the TS in conjunction with Criteria IX, Xl and XVI of 10 CFR Part 50, Appendix B, requires corrective actions, they should discuss their proposed corrective actions (e.g., changing inspection practices consistent with the NRC's position or submitting a TS amendment request with the associated safety basis for limiting the inspections) to achieve full compliance. If addressees choose to change their TS, the staff has included in the Attachment suggested changes to the TS definitions for a tube inspection and for plugging limits to show what may be acceptable to the staff in cases where the tubes are expanded for the full depth of the tubesheet and where the extent of the inspection in the tubesheet region is limited.
Waterford-3 Response:
Entergy is not consistent with the NRC's position with regard to the inspection scope by not performing inspections to the full depth of the tubesheet using the Plus Point probe where degradation could be expected to be present. Waterford-3 will increase the depth of inspections to W3Fl-2004-0091 Page 3 of 4 in the next RF13 refueling outage (spring 2005) to the analyzed safety assessment depth consistent with WCAP-16208-P, Rev. 0. The condition for limiting the Plus Point depth of SG tube inspection during the last refueling outage inspection has been entered into Waterford-3's corrective action program.
Entergy will submit a technical specification change consistent with the EPRI Generic Licensing Change Package (GLCP) as provided by Technical Specification Task Force (TSTF)-449, Revision 2, Steam Generator Tube Integrity. Entergy will submit this change as part of the NRC Consolidated Line Item Improvement Process (CLIIP) or as a Waterford-3 specific amendment request by February 15, 2005 if the CLIIP has not been released by the NRC. The specific limitation for tubesheet inspection depth using the Plus Point probe will be included with the proposed technical specification change. As discussed in the generic letter, the current limitation for use of the Plus Point probe in the subject region of the tubesheet does not constitute a non-compliance with the Waterford-3 technical specifications. Therefore, NRC approval of the proposed TSs does not need to occur prior to the resumption of power from the spring 2005 refueling outage SG tube inservice inspection.
Requested Information 3 For plants where SG tube inspections have not been or are not being performed consistent with the NRC's position on the requirements in the TS in conjunction with Criteria IX, Xl, and XVI of 10 CFR Part 50, Appendix B, the licensee should submit a safety assessment (i.e., a justification for continued operation based on maintaining tube structural and leakage integrity) that addresses any differences between the licensee's inspection practices and those called for by the NRC's position. Safety assessments should be submitted for all areas of the tube required to be inspected by the TS, where flaws have the potential to exist and inspection techniques capable of detecting these flaws are not being used, and should include the basis for not employing such inspection techniques. The assessment sh6uld include an evaluation of (1) whether the inspection practices rely on an acceptance standard (e.g., cracks located at least a minimum distance of x below the top of the tube sheet, even if these cracks cause complete severance of the tube) which is different from the TS acceptance standards (i.e., the tube plugging limits or repair criteria), and (2) whether the safety assessment constitutes a change to the Om ethod of evaluation" (as defined in 10 CFR 50.59) for establishing the structural and leakage integrity of the joint. If the safety assessment constitutes a change to the method of evaluation under 10 CFR 50.59, the licensee should determine whether a license amendment is necessary pursuant to that regulation.
Waterford-3 Response:
The RF12 outage Plus Point probe inspections were limited to eight inches below the top of tubesheet. Entergy has concluded that there is a potential for degradation to exist below the depth of tube inspections within the tubesheet region. A safety assessment that addresses the Waterford-3's RF12 inspection of the subject region is provided below. The results demonstrate that SG operability is maintained because there is no tube burst concern and that assumed leakage does not exceed the accident analysis assumed value of 0.5 gpm per SG.
The safety assessment does not constitute a change to the umethod of evaluation" (as defined in 10 CFR 50.59) for establishing the structural and leakage integrity of the joint.
- .Attachment I to W3FI-2004-0091 Page 4 of 4 Safety Assessment Waterford-3 inspected from +3" to -8" from the top of tubesheet (TTS) within the tubesheet region during the most recent October 2003 RF12 inspection. This limitation was based on the initial data developed partly under CEOG Task 1154 which estimated approximately 4 to 5 inches would satisfy both the pull-out and leakage criteria under postulated accident conditions.
Since that time, additional testing was conducted which concluded the initial data was not conservative due to the type of water used to evaluate the leakage. Initially, de-oxygenated de-mineralized water was used in the abandoned Connecticut Yankee tubesheet. These initial results were compared to the most recent test and it was concluded the initial data would be excluded from the dataset.
Westinghouse in WCAP 16208-P, Rev. 0 performed an assessment for determining the inspection depth within the tubesheet (C*). Based on this assessment, Waterford-3 would need to inspect to a depth of approximately 10.4 inches into the expansion region of the tubesheet.
To address the un-inspected portion of the generator, leakage estimates were based on the distribution identified between 8 and 12 inches of the tubesheet. A leakage value was then established and was added to the operational assessment for the full cycle estimate. This additional leakage was added to all other mechanisms and verified to be below the site limit based on postulated accident conditions. It was determined that the total leakage was 0.2774 gpm under main steam line break conditions which is within the site limit of 0.5 gpm per SG.
The impact of cracks potentially in-service in TTS zone between the C* depth (assumed to be -
12 inches for this assessment) and the RF12 depth (-8 inches) of inspection is given as follows:
Parameter Value Source Allowed Accident Leakage for Waterford-3 0.5 gpm or 720 TS 3 / 4.4.4 Bases (Cycle 13) gpd Operational Assessment (OA) Based 0.1 gpm Waterford ER-W3-Leakage Determination 2004-0041-000 Accident Leakage below C*
0.1 gpm WCAP-16208-P, RO Estimate of Number of Cracks (In Zone) 32 Westinghouse projection to 12" of TS Leakage per Crack 0.00242 90th percentile value gpm/crack Total Leakage [OA Leakage+ Below C*
0.2774 qpm [<0.5 gpm/SG accident Leakage + In-Zone Leakage (No. of in-zone assumed leakage]
cracks X leakage/crack)].
W3FI-2004-0091 List of Regulatory Commitments
. x Attachment 2 to W3Fl-2004-0091 Page 1 of I List of Regulatory Commitments The following table identifies those actions committed to by Entergy in this document. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
TYPE (Check one)
COMMITMENT SCHEDULED ONE-CONT COMPLETION TIME COMP DATE (If ACTION Required)
Waterford-3 will increase the depth of inspections starting X
RF13 with the next RF13 refueling outage (spring 2005), but the inspection requirement will be limited to the analyzed safety assessment depth consistent with WCAP-16208-P, Rev. 0.
Entergy is proposing to submit a technical specification X
By February 15, change consistent with the EPRI Generic Licensing Change 2005 Package (GLCP) as provided by Technical Specification Task Force (TSTF)-449, Revision 2, Steam Generator Tube Integrity. Entergy will submit this change as part of the NRC Consolidated Line Item Improvement Process (CLIIP) or as a Waterford-3 specific amendment request if the CLIIP has not been released by the NRC. The specific limitation for tubesheet depth inspection with the Plus Point probe will be included with the proposed technical specification change.