ML082750518
| ML082750518 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 09/29/2008 |
| From: | Bajestani M Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML082750518 (16) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Spring City, TN 37381-2000 September 29, 2008 10 CFR 50.54f U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop: OWFN P1-35 Washington, D.C. 20555-0001 In the Matter of
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Docket No. 50-391 Tennessee Valley Authority
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WATTS BAR NUCLEAR PLANT (WBN) - UNIT 2 - SUPPLEMENTAL 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"
Reference:
TVA letter dated September 7, 2007, "Watts Bar Nuclear Plant (WBN) - Unit 2 -
Initial Responses to Bulletins and Generic Letters" The purpose of this letter is to provide the additional information regarding the WBN Unit 2 pressurizer and penetrations requested by 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." TVA's original response to the Bulletin was submitted on September 7, 2007 (Reference above). In TVA's original response, TVA provided an open action required for licensing to submit additional information after a review of the original equipment manufacturer (Westinghouse Electric Company) records was completed.
The WBN Unit 2 pressurizer is a Westinghouse Series 84 pressurizer. It is of the same design as the WBN Unit 1 pressurizer that has been in service from May 1996 to the present. The WBN Unit 2 pressurizer has never been in service. provides NRC requests and TVA's responses. In order to facilitate NRC review, the additional Westinghouse information has been incorporated into the Attachment submitted in TVA's September 7, 2007 letter. Enclosure 2 provides the listing of open actions required for licensing made in Enclosure 1.
AlJD Printed on recycled paper
U.S. Nuclear Regulatory Commission Page 2 September 29, 2008 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 29th day of September, 2008.
If you have any questions, please contact me at (423) 365-2351.
Sincerely, Masoud,B' estani Watts a Unit 2 Vice President Enclosures cc (Enclosures):
Lakshminarasimh Raghavan U.S. Nuclear Regulatory Commission MS 08H4A One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 Patrick D. Milano, Senior Project Manager U.S. Nuclear Regulatory Commission MS 08H4 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 Loren R. Plisco, Deputy Regional Administrator for Construction U. S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 U. S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 NRC Resident Inspector Unit 2 Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 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 NRC Requested Information (1) All subject PWR licensees are requested to provide the following information within 60 days of the date of this bulletin.
(a) A description of the pressurizer penetrations and steam space piping connections at your plant. At a minimum, this description should include materials of construction (e.g., stainless steel piping and/or weld metal, Alloy 600 piping/sleeves, Alloy 82/182 weld metal or buttering, etc.), joint design (e.g.,
partial penetration welds, full penetration welds, bolted connections, etc.), and, in the case of welded joints, whether or not the weld was stress-relieved prior to being put into service. Additional information relevant with respect to determining the susceptibility of your plant's pressurizer penetrations and steam space piping connections to PWSCC should also be included.
TVA Response: The Watts Bar Nuclear Plant (WBN) Unit 2 pressurizer is similar in construction to WBN Unit 1. WBN Unit 2's pressurizer was manufactured by Westinghouse Electric Company (Westinghouse) and is identified as a Westinghouse Series 84 pressurizer. The size of the Westinghouse pressurizer varies with the plant thermal rating. The WBN Unit 2 pressurizer has an inside diameter of 84 inches (i.e., Series 84 pressurizers) with a nominal volume of 1,800 cubic feet. The pressurizer is a cylindrical vessel that is installed with its longitudinal axis in a vertical position.
The attached Table and Figures 1-6 contain details of the pressurizer penetrations and steam space piping connections as well as the additional information requested above.
Prior to placing the pressurizer in service, TVA will apply the Material Stress Improvement Process (MSIP) to the Pressurizer Power Operated Relief Valve connections, the safety relief valve connections, and the spray line nozzle and surge line nozzle connections.
(b) A description of the inspection program for Alloy 82/182/600 pressurizer penetrations and steam space piping connections that has been implemented at your plant. The description should include when the inspections were performed; the areas, penetrations and steam space piping connections inspected; the extent (percentage) of coverage achieved for each location which was inspected; EI-I
the inspection methods used; the process used to resolve any inspection findings; the quality of the documentation of the inspections (e.g., written report, video record, photographs); and, the basis for concluding that your plant satisfies applicable regulatory requirements related to the integrity of pressurizer penetrations and steam space piping connections. If leaking pressurizer penetrations or steam space piping connections were found, indicate what followup NDE was performed to characterize flaws in the leaking penetrations.
TVA Response: The WBN Unit 2 pressurizer has not been placed in service.
Prior to placing the pressurizer in service, TVA will apply MSIP to the Pressurizer Power Operated Relief Valve connections, the safety relief valve connections, and the spray line nozzle and surge line nozzle connections. The MSIP includes nondestructive examination (NDE) prior to and after completion.
(c) A description of the Alloy 82/182/600 pressurizer penetration and steam space piping connection inspection program that will be implemented at your plant during the next and subsequent refueling outages. The description should include the areas, penetrations and steam space piping connections to be inspected; the extent (percentage) of coverage to be achieved for each location; inspection methods to be used; qualification standards for the inspection methods and personnel; the process used to resolve any inspection indications; the inspection documentation to be generated; and the basis for concluding that your plant will satisfy applicable regulatory requirements related to the structural and leakage integrity of pressurizer penetrations and steam space piping connections. If leaking pressurizer penetrations or steam space piping connections are found, indicate what followup NDE will be performed to characterize flaws in the leaking penetrations. Provide your plans for expansion of the scope of NDE to be performed if circumferential flaws are found in any portion of the leaking pressurizer penetrations or steam space piping connections.
TVA Response: In accordance with NRC Staff recommendations contained in the bulletin, TVA will perform a bare metal visual (BMV) inspection of the upper pressurizer Alloy 600 locations at the first refueling outage. This inspection will be performed utilizing the "in-house" procedure titled "Visual Inspection of Alloy 600/82/182 Pressure Boundary Components." In accordance with plant procedures, personnel performing the inspection will be certified NDE inspectors qualified in the ASME Section Xl, VT-2 method. The extent of examination will be 100 percent of each weld circumference. The examination will be documented on written reports which may include photographs or video.
WBN Unit 2 will be under TVA's Corrosion Control Program. This program requires the performance of BMV examinations of Alloy 600/82/182 locations on the upper pressurizer penetrations each refueling outage until further guidance is provided by the Materials Reliability Project.
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(d) In light of the information discussed in this bulletin and your understanding of the relevance of recent industry operating experience to your facility, explain why the inspection program identified in your response to item (1)(c) above is adequate for the purpose of maintaining the integrity of your facility's RCPB and for meeting all applicable regulatory requirements which pertain to your facility.
TVA Response: TVA conducts each inspection with a questioning attitude in accordance with existing industry guidance that includes evaluating and determining the source of any boric acid deposit identified on the upper pressurizer penetrations and the steam space piping. These requirements are incorporated in the visual inspection guidance contained in TVA's Corrosion Control Program and inspection procedures. Implementation of these requirements precludes a through-wall crack remaining undetected for years.
(2) Within 60 days of plant restart following the next inspection of the Alloy 82/182/600 pressurizer penetrations and steam space piping connections, the subject PWR licensees should either:
(a) submit to the NRC a statement indicating that the inspections described in the licensee's response to item (1)(c) of this bulletin were completed and a description of the as-found condition of the pressurizer shell, any findings of relevant indications of through-wall leakage, followup NDE performed to characterize flaws in leaking penetrations or steam space piping connections, a summary of all relevant indications found by NDE, a summary of the disposition of any findings of boric acid, and any corrective actions taken and/or repairs made as a result of the indications found, or (b) if the licensee was unable to complete the inspections described in response to item (1)(c) of this bulletin, submit to the NRC a summary of the inspections performed, the extent of the inspections, the methods used, a description of the as-found condition of the pressurizer shell, any findings of relevant indications of through-wall leakage, followup NDE performed to characterize flaws in leaking penetrations or steam space piping connections, a summary of all relevant indications found by NDE, a summary of the disposition of any findings of boric acid, and any corrective actions taken and/or repairs made as a result of the indications found. In addition, supplement the answer which you provided to item (1)(d) above to explain why the inspections that you completed were adequate for the purpose of maintaining the integrity of your facility's RCPB and for meeting all applicable regulatory requirements which pertain to your facility.
TVA Response: TVA plans to submit the required response within 60 days after completion of the first refueling outage.
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Reference:
- 1. TVA letter dated February 11, 2005, "Sequoyah Nuclear Plant (SQN)
Units 1 and 2 and Watts Bar Nuclear Plant (WBN) Unit 1 - Supplemental 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,' dated May 28, 2004" El-4
Stress Penetration Materials Joint Design Relieved?
Nozzle: Low Alloy Steel Forging SA-508 Class 2a N/A Yes (prior to with Inconel 182 buttering liner insertion)
Weld Nozzle to Safe-end: Inconel 82/182 Full penetration butt No weld all around Safe-end: SS ASME SA-182, Grade 316L Forging N/A N/A Thermal Sleeve: ASME SA-213 Grade TP-304 SS Seamless Tubing N/A N/A 450, 0.12" bevel 4" Spray Nozzle Thermal Sleeve to Safe-End Weld: Inconel 82 groove partial No (qty. 1) penetration weld 450 around Liner: ASME SA-213 Grade TP-304 SS Seamless N/A N/A Tubing 300, 0.12" bevel Liner to Safe End Weld: Inconel 82 groove partial No penetration weld all around Liner to Cladding Weld: SS 309/308 0.12" x 0.31" fillet No weld all around Nozzle: Low Alloy Steel Forging SA-508 Class 2a Cladding: SS 309/308 Yes (cladding Buttering: Inconel 182 N/A
& buttering)
Buttering Tie-in: Inconel 182 Bowl Tie-in: SS 309/308 Weld Nozzle to Safe-end: Inconel 82/182 Full penetration butt No 14" Surge Nozzle weld all around (qty. 1)
Safe-end: SA-182, Grade 316L Forging N/A N/A Thermal Sleeve: SS, SA-240, Type 304, Plate N/A N/A 0.19" x 450 V-groove Thermal Sleeve to Safe-End Weld: Inconel 82 partial penetration No weld 450 around I
Stress Penetration Materials Joint Design "Relieved?
Nozzle: Low Alloy Steel Forging SA-508 Class 2a N/A Yes Buttering: Inconel 182 Weld Nozzle to Safe-end: Inconel 82/182 Full penetration butt No weld all around 6" Safety Nozzle Safe-end: SS ASME SA-182, Grade 316L Forging N/A N/A (qty. 3)
Liner: ASME SA-213 Grade TP-304 SS Seamless 6" Relief Nozzle Tubing N/A N/A (qty. 1) 300, 0.12" bevel Liner to Safe End Weld: Inconel 82 groove partial No penetration weld all around 0.12" x 0.31" fillet Liner to Cladding Weld: SS 309/308 No weld all around 2
Stress Penetration Materials Joint Design relv Relieved?
Heater: SS: SA-213, Grade TP 316 tubing N/A N/A Heater Adaptor: SS SA-182, Grade F316 Forging N/A N/A 0.19" fillet weld all Adapter to Heater Element Weld: SS 309/308 around No Heater around Penetrations 0.19" fillet weld all (qty. 78)
Heater Well to Adapter Weld: SS 309/308 around No 0.19" R partial Heater Well to Lower Head Cladding Weld: SS penetration J-groove No 309/308 weld and 0.19" fillet weld all around Tubing: SS ASME SA-213, Grade TP 316 Tubing N/A N/A Coupling: SS ASME SA-182, Grade F316 Forging N/A N/A Level &
0.19" R partial Temperature Tubing to Shell Cladding Weld: SS 309/308 penetration J-groove No Instrumentation weld and 0.12" fillet Taps weld all around Partial penetration J-Tubing to Coupling Weld: SS 309/308 groove weld and 0.25" No fillet weld all around Forging: Low Alloy Steel Forging SA-508 Class 2aN/A N/A 2a Manway (qt 1)
Insert: SS, ASME SA-240, Type 304, Plate N/A N/A Cover: SA-533 Gr. A Class 1 Plate N/A N/A 3
Liner: SA-213 Grade TP-304 SS Seamless Tubing
.19 APPROX CLADDING 43.00 SPHERICAL RADIUIS-Nozzle: SA-508 Class 2a Buttering: Inconel 182
/
Nozzle to Safe-End SWeld: Inconel 82.'182 Safe-End: SA-182.
Grade 316L Liner to Safe-Emid Weld: Inconel 82 Cladding:
SS 309,308 Thermal Sleeve to Safe-End Weld:
Inconel 82 Note: This weld is for 45 degrees aim circumference of thernmal sleeve.
NOM Liner to Cladding I
Weld: SS 309j308 Theimal Sleeve: SA-213. Grade TP-304 SS Seamless Tubing Figure 1 Watts Bar Unit 2 Pressurizer Spray Nozzle Sketch 4
1.19 MIN CLADDING 3.40 Weld Nozzle to Safe-End: Incoliel 82182 Singe Nozzle:
SA-508 Class 2a Thermal Sleeve:
SA-240, Type 304 SURGE NOZZLE Thermal Sleeve to Safe-End Weld:
Inconel 82 This weld is for 45 degrees on cihcumfreitce of thermal sleeve Butteiing: Inconel 182 Cladding to Buttering Tie-in: Inconel 182 Figure 2 Watts Bar Unit 2 Pressurizer Surge Nozzle Sketch 5
NOM
-2.57 APPROX
.19 APPROX CLADDING I Inconel 182 Butfering Nozzle to Safe-End Weld:
Inconel 82'182 8.00 NOM DIAMETER CLADDING*"
Liner to Liner: SA-213. Grade TP Safe-End: SA-182, Cladding
.304 SS Sealess Tubing Liner to Safe-End Giade 316L Weld:
Weld: Inconel 82 SS 309;308 SAFETY & RELIEF NOZZLES Figure 3 Watts Bar Unit 2 Pressurizer Safety & Relief Nozzle Sketch 6
Heater Element to Adapter Weld:
"SS 309.308 Heater Well to Adapter Weld:
SS 309.308 Heater Elemenl Figure 4 Watts Bar Unit 2 Pressurizer Heater Penetration Sketch 7
Coupling: SS SA-182, Grade F316 Tubing: SS SA-213, 6.44 TbigWeld:
Ossl309i08 IGade TP 316 Ttlbiq.(g
.50 NOM Tubing to Shell Cladding Weld: SS 309/308 Figure 5 Watts Bar Unit 2 Pressurizer Level & Temperature Instrumentation Tap Sketch 8
240., Type 304,
.750 Plate NOM Figure 6 Watts Bar Unit 2 Pressurizer Manway Sketch 9
Summary of Open Actions Required for Licensing Bulletin 04 Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized Water-Reactors
- 1.
Prior to placing the pressurizer in service, TVA will apply the Material Stress Improvement Process (MSIP) to the Pressurizer Power Operated Relief Valve connections, the safety relief valve connections, the spray line nozzle and surge line nozzle connections.
- 2.
TVA will perform a bare metal visual (BMV) inspection of the upper pressurizer Alloy 600 locations at the first refueling outage.
- 3.
TVA plans to submit the required response within 60 days after completion of the first refueling outage.
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