3F0107-04, Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds
| ML070320122 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 01/29/2007 |
| From: | Young D Progress Energy Florida |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 3F0107-04 | |
| Download: ML070320122 (10) | |
Text
Progress Energy Crystal River Nuclear Plant Docket No. 50-302 Operating License No. DPR-72 January 29, 2007 3F0107-04 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds
References:
- 1.
NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors"
- 2.
PEF to NRC letter dated July 26, 2004, Crystal River Unit 3 - 60 Day Response to NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors"
- 3.
PEF to NRC letter dated February 7, 2006, Crystal River Unit 3 - Response to Item (2)(a) of NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors"
- 4.
PEF to NRC letter dated September 18, 2006, Crystal River Unit 3 - Supplemental Information and Revised Commitment Regarding 60 Day Response to NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors"
Dear Sir:
In October of 2006, while performing inspections of its pressurizer Alloy 82/182 butt welds in accordance with MRP-139, a PWR licensee discovered several circumferential indications in its pressurizer surge, safety and relief nozzles. Because of the potential importance of this issue, Florida Power Corporation, doing business as Progress Energy Florida Inc. (PEF) is submitting this letter to notify you of actions planned for inspecting and mitigating Alloy 600/82/182 butt welds on pressurizer spray, surge and relief lines at Crystal River Unit 3 (CR-3).
Inspection of pressurizer Alloy 600/82/182 butt welds per MRP-139 at CR-3 has not yet been completed, but we will complete our inspection and mitigation activities on these locations during Refuel Outage 15 (15R), which is scheduled for Fall 2007. Details concerning inspection and mitigation activities for pressurizer Alloy 600/82/182 butt welds at CR-3 are provided in Attachment 1.
Results of inspections during 14R (10-29-05 through 12-10-05) are shown in Attachment 2,.
These examinations were performed using visual aids and visual examination personnel certified in accordance with Progress Energy's written practice and ASME Section XI, as supplemented by the March 2002 Progress Energy Florida, Inc.
Crystal River Nuclear Plant 15760 W. Powerline Street Crystal River, FL 34428 7 1
/ I
U.S. Nuclear Regulatory Commission 3F0107-04 Page 3 of 4 If CR-3 should shut down due to excessive primary system unidentified leakage, and if the leakage cannot be confirmed to originate from a source other than the pressurizer, a bare metal visual examination of Alloy 600/82/182 butt weld locations on the pressurizer will be performed to determine whether the leakage originated at those locations.
The NRC will be informed prior to any revision of the information contained in this letter.
This letter contains regulatory commitments as shown in Attachment 3.
Our staff is available to meet with the NRC to discuss any of the information in this letter. If there are any questions, please contact Mr. Paul Infanger, Supervisor, Licensing and Regulatory Programs at (352) 563-4796.
Sincerely, Dale E. Young Vice President Crystal River Nuclear Plant DEY/seb Attachments:
- 1.
Inspection and Mitigation Summary for Alloy 600/82/182 Pressurizer Butt Welds
- 2.
Results of 14R Inspections of Alloy 600/82/182 Pressurizer Butt Welds
- 3.
NRC Project Manager NRC Regional Office NRC Resident Inspector
U.S. Nuclear Regulatory Commission Page 2 of 4 3F0107-04 Electric Power Research Institute (EPRI) report as applicable. The Bare Metal Visual examinations on the weld and adjacent base metal in the immediate visible vicinity found no evidence of boric acid, through-wall leakage, or component degradation on the pressurizer shell or dissimilar metal welds. As such, no follow up NDE was required and no corrective actions or repairs were necessary.
Future inspections of pressurizer butt welds at CR-3 will be performed in accordance with industry guidance (MRP-139). The results of future inspections or mitigations of pressurizer Alloy 600/82/182 butt weld locations will be reported to the NRC within 60 days of startup from the outage during which they are performed.
In addition to the inspection and mitigation actions described above and in the attached tables, CR-3 has enhanced its procedure for monitoring primary system leakage.
CR-3 implements a Reactor Coolant System leakage monitoring program as described in station procedure Surveillance Procedure SP-317, RC System Water Inventory Balance.
In addition, plant operators monitor parameters such as Reactor Building sump level and Reactor Building radiation monitors.
This leakage determination process involves stabilization of the plant to minimize inaccuracies and then using a software program to calculate a Reactor Coolant System mass balance using a linear regression algorithm. The typical duration of this surveillance period is 6 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> during steady state conditions and is performed at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
CR-3 utilizes a statistical approach to analyzing the Unidentified Leakage results obtained from the SP-317 leakage calculation. In addition to the absolute Unidentified Leakage limits defined in the station's Technical Specifications, the following action levels are prescribed where U is defined as a 90 day rolling average of Unidentified Leakage and a (currently.02 gpm) is defined as the standard deviation.
" ACTION LEVEL 1 - Five consecutive unidentified leakage results are > U plus 0
- VALIDATE quality of instrumentation by inspection or trending, (Makeup Tank, Reactor Coolant Drain Tank, etc.).
-LOOK for changes in Reactor Building sump rate of rise.
- CHECK RM-A6 (Reactor Building Radiation Monitor) count rate for trends.
- CHECK for changes for Auxiliary Building Sump rate of rise.
" ACTION LEVEL 2 - Three consecutive unidentified leakage results are > U plus 2a
- COMPLETE actions of Action Level 1.
- PERFORM another surveillance within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to verify leak rate.
- WALK DOWN Makeup and Purification System for potential leaks.
- RECORD results of above inspections in Superintendent of Shift Operations Log.
" ACTION LEVEL 3 - Any unidentified leakage results are > U plus 35
- COMPLETE actions of Action Level 1 and Action Level 2.
- As determined by Plant Management, PERFORM a Reactor Building entry.
Also, the Reactor Coolant System Engineer reviews pertinent Reactor Coolant System parameters and leakage results as a part of routine system monitoring activities.
Reactor Coolant System leakage is given a high priority by CR-3 management.
This sensitivity is reflected by taking actions beyond that of the procedural requirements on a routine bases. Reactor Coolant System Unidentified Leakage information is included in daily plant information meetings and is a point of discussion at senior plant management meetings.
The enhanced guidance provides adequate assurance that structural integrity is maintained and that any primary system pressure boundary leakage is discovered in a timely manner.
U.S. Nuclear Regulatory Commission 3F0107-04 Page 4 of 4 STATE OF FLORIDA COUNTY OF CITRUS Dale E. Young states that he is the Vice President, Crystal River Nuclear Plant for Florida Power Corporation, doing business as Progress Energy Florida, Inc.; that he is authorized on the part of said company to sign and file with the Nuclear Regulatory Commission the information attached hereto; and that all such statements made and matters set forth therein are true and correct to the best of his knowledge, information, and belief.
Dale E. Young k
Vice President Crystal River Nuclear Plant The foregoing document was acknowledged before me this O
day of 2007, by Dale E. Young.
Signature of Notary B I.
State of Florida
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AVrfflAAl.AAJ1f1lfO*4nn (Print, type, or stamp Commissioned Name of Notary Public)
Personally ý/
Produced Known
-OR-Identification
PROGRESS ENERGY FLORIDA, INC.
CRYSTAL RIVER - UNIT 3 DOCKET NUMBER 50 - 302 / LICENSE NUMBER DPR - 72 Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds Inspection and Mitigation Summary for Alloy 600/82/182 Pressurizer Butt Welds
U.S. Nuclear Regulatory Commission 3F0107-04 Page 1 of I Inspection and Mitigation Summary for Alloy 600/82/182 Pressurizer Butt Welds MRP-139 Volumetric Mitigation Nozzle Inspection Requirement Completed or to Met or to be Met be Completed Comments Function /
Susceptible Outage Start Date Outage Material Designation Description Designation (MM/YYYY)
Designation Nozzle-to Safe end 4 inch Spray Line weld, A600 safe end 15R 11/07 15R Structural Weld Overlay Nozzle Safe End and safe end to pipe weld Nozzle-to extension 4 inch Spray Line pin weld, A600 Internal to pressurizer vessel, Nozzle Extension extension pin and NA NA None Pin extension pin to pipe non-pressure retaining weld 2.5 inch Pressure Nozzle-to safe end Relief Nozzle weld only 15R 11/07 15R Structural Weld Overlay (RCV-8) 2.5 inch Pressure Nozzle-to safe end Relief Nozzle weld15R 11/07 15R Structural Weld Overlay (RCV-9) 2.5 inch Pressure Nozzle-to safe end Relief Nozzle weld15R 11/07 15R Structural Weld Overlay (RCV-11) 10 inch Surge Nozzle-to safe end 15R 11/07 15R Structural Weld Overlay Nozzle weld only
PROGRESS ENERGY FLORIDA, INC.
CRYSTAL RIVER - UNIT 3 DOCKET NUMBER 50 - 302 / LICENSE NUMBER DPR - 72 Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds Results of 14R Inspections of Alloy 600/82/182 Pressurizer Butt Welds
U.S. Nuclear Regulatory Commission 3F0107-04 Page 1 of 1 Results of 14R Inspections of Alloy 600/82/182 Pressurizer Butt Welds Function /
Susceptible Material PDI Qualified 14R Inspections 14R Results Designation Description Inspection Nozzle Safe End None VT-2, BMV, UT No evidence of leakage or degradation safe end to pipe weld 4 inch Spray Line Nozzle-to extension pin Nozzle Extension weld, A600 extension PNoz pin and extension pin to Pin pipe weld 2.5 inch Pressure 2.5 nchPresure Nozzle-to safe end weld Relief Nozzle ozle None VT-2, BMV No evidence of leakage or degradation (RCV-8) only 2.5 inch Pressure Nozzle-to safe end weld Relief Nozzle None VT-2, BMV No evidence of leakage or degradation (RCV-9) only 2.5 inch Pressure Nozzle-to safe end weld Relief Nozzle onlyNone VT-2, BMV No evidence of leakage or degradation (RCV-11) 10 inch Surge Nozzle-to safe end weld None VT-2, BMV No evidence of leakage or degradation Nozzle only
PROGRESS ENERGY FLORIDA, INC.
CRYSTAL RIVER - UNIT 3 DOCKET NUMBER 50 - 302 / LICENSE NUMBER DPR - 72 Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds Regulatory Commitments
U.S. Nuclear Regulatory Commission 3F0107-04 Page 1 of 1 List of Regulatory Commitments The following table identifies those actions committed to by Progress Energy Florida (PEF) in this document.
Any other actions discussed in the submittal represent intended or planned actions by PEF.
They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the Supervisor, Licensing and Regulatory Programs of any questions regarding this document or any associated regulatory commitments.
Commitment Due Date The results of future inspections or mitigations of 60 days after the end of 15R pressurizer Alloy 600/82/182 weld locations will be scheduled for Fall 2007 reported to the NRC within 60 days of startup from the outage during which they are performed.
If CR-3 should shut down due to excessive primary Ongoing until mitigation of system unidentified leakage, and if the leakage cannot be pressurizer Alloy 82/182 welds confirmed to originate from a source other than the pressurizer, a bare metal visual examination of Alloy 600/82/182 weld locations on the pressurizer will be performed to determine whether the leakage originated at those locations.
CR-3 will mitigate and inspect the pressurizer Alloy End of 15R scheduled for Fall 600/82/182 butt welds during Refuel Outage 15 (15R),
2007 scheduled for Fall 2007.