ML070800361
| ML070800361 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar, Sequoyah  |
| Issue date: | 06/11/2007 |
| From: | Boyce T H NRC/NRR/ADRO/DORL/LPLII-2 |
| To: | Campbell W R Tennessee Valley Authority |
| Moroney B T, NRR/DORL, 415-3974 | |
| References | |
| G-RR-1, TAC MD2381, TAC MD2382, TAC MD2383 | |
| Download: ML070800361 (20) | |
Text
June 11, 2007Mr. William R. Campbell, Jr.Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2, AND WATTS BAR NUCLEARPLANT, UNIT 1 - REQUEST FOR RELIEF G-RR-1 REGARDING PREEMPTIVE WELD OVERLAYS ON PRESSURIZER NOZZLES (TAC NOS. MD2381, MD2382 AND MD2383)
Dear Mr. Campbell:
By letter dated June 16, 2006, as supplemented by letters dated October 20, November 21,November 30, 2006, and April 26, 2007, Tennessee Valley Authority (TVA) submitted Request for Relief G-RR-1 for the use of alternatives to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) requirements at the Sequoyah Nuclear Plant (SQN), Units 1 and 2, and the Watts Bar Nuclear Plant (WBN), Unit 1. TVA also proposed alternatives to ASME Code Cases N-638-1 and N-504-1 to allow performing full structural preemptive weld overlays (PWOLs) on dissimilar metal butt welds on the pressurizer surge, spray, relief and safety nozzles. In the October 20, 2006, supplement, the request for WBN Unit 1 was withdrawn. The U. S. Nuclear Regulatory Commission (NRC) staff discontinued its review for WBN Unit 1 under TAC No. MD2383 at that time and there is no consideration of WBN Unit 1 in the enclosed safety evaluation.Based on its review of your submittals, the NRC staff has concluded that the proposedalternatives to Code Cases N-638-1 and N-504-1 will provide an acceptable level of quality and safety. Therefore, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section50.55a(a)(3)(i), the staff authorizes the proposed alternatives for the installation of PWOLs over the welds identified in the relief request during the Cycle 15 (fall 2007) refueling outage at SQN Unit 1 and the Cycle 14 (fall 2006) refueling outage at SQN Unit 2. Verbal authorization for the Cycle 14 refueling outage at Unit 2 was given on November 16, 2006, during a conference call between the NRC staff and the SQN staff. The NRC staff also concluded that the proposed alternatives to ASM E Code Appendix VIII,Supplement 11, will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternatives are authorized for the remainder of the third 10-year ISI intervals at SQN, Units 1 and 2, which began on June 1, 2006, and will end on May 31, 2015.The bases for the NRC staff's conclusions are contained in the enclosed safety evaluation.
W. R. Campbell, Jr.-2-If you have any questions, please contact the SQN Project Manager, Brendan Moroney, at(301) 415-3974.Sincerely, /RA/Thomas H. Boyce, ChiefPlant Licensing Branch II-2 Division of Operating Reactor Office of Nuclear Reactor RegulationDocket Nos. 50-327, 50-328 and 50-390
Enclosure:
Safety Evaluation cc w/enclosure: See next page
ML070800361NRR-028OFFICELPL2-2/PMLPL2-2/LA CPNB/BCOGCLPL2-2/BCNAMEBMoroneyRSolaTChanby memo//emailDRothTBoyceDATE6/ 7/ 076/ 7/0702/22/07//5/16/07 5 /30 /07 6 / 11 /07 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIONINSERVICE INSPECTION PROGRAM RELIEF REQUEST NO. G-RR-1 TENNESSEE VALLEY AUTHORITYSEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2DOCKET NOS. 50-327 AND 50-32
81.0INTRODUCTION
By letter dated June 19, 2006, as supplemented by letters dated October 20, November 21,November 30, 2006, and April 26, 2007, Tennessee Valley Authority (TVA, the licensee) submitted Request for Relief G-RR-1 for the Sequoyah Nuclear Plant (SQN), Units 1 and 2.
Specifically, G-RR-1 proposed alternatives to the repair requirements of American Society of Mechanical Engineers (ASME) Code Case N-504-2, "Alternative Rules for Repair of Class 1, 2, and 3 Austenitic Stainless Steel Piping,Section XI, Division 1" (N-504-2), Code Case N-638-1,"Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW [Gas Tungsten Arc Welding]Temper Bead Technique,Section XI, Division 1" (N-638-1), and Appendix VIII, Supplement 11 to the 1995 Edition including 1996 Addenda of the ASME Code,Section XI. The alternatives would be used to perform full structural preemptive weld overlays (PWOLs) on pressurizer spray, safety, relief and surge nozzle safe end to nozzle dissimilar metal butt welds. The subject welds were fabricated using NiCrFe Alloy 82/182 weld material to butter the nozzle weld geometry ends and to weld the safe ends. This weld material has demonstrated a propensity for primary water stress corrosion cracking (PWSCC). The licensee intends to mitigate the effects of cracking on specific SQN welds by applying full structural PWOLs prior to the onset of PWSCC. The licensee proposes applying PWOLs over the welds identified in the Unit 1, Cycle 15 (fall 2007) and Unit 2, Cycle 14 (fall 2006) refueling outages.
The PWOLs installed during these refueling outages will remain in place for the life of the plant, including the period of extended operation.
2.0 REGULATORY EVALUATION
Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(4), ASME CodeClass 1, 2, and 3 components (including supports) will meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, "Rules for Inservice Inspection (ISI) of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ISI Code of record for SQN for the third 10-year ISI interval is the 2001 Edition ofthe Code with the 2003 Addenda.In accordance with 10 CFR 50.55a(g)(6)(ii)(C)(1), the implementation of Supplements 1through 8, 10, and 11 of Appendix VIII to Section XI, 1995 edition with the 1996 addenda of theASME Code, is required on a phased schedule ending on November 22, 2002. Supplement 11 was required to be implemented by November 22, 2001. Pursuant to 10 CFR 50.55a(g)(4)(iv), ISI items may meet the requirements set forth insubsequent editions and addenda of the ASME Code that are incorporated by reference in 10 CFR 50.55a(b), subject to the limitations and modifications listed therein, and subject to Commission approval. Portions of editions and addenda may be used provided that related requirements of the respective editions and addenda are met.Pursuant to 10 CFR 50.55a(a)(3), alternatives to requirements may be authorized by the U. S. Nuclear Regulatory Commission (NRC) if the licensee demonstrates that: (i) the proposed alternatives provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. The licensee submitted the subject relief request, pursuant to 10 CFR 50.55a(a)(3)(i), which proposed alternatives to the implementation of the ASME Code,Section XI, Appendix VIII, Supplement 11, N-638-1, and N-504-2, for thedeposition of PWOLs.
3.0 TECHNICAL EVALUATION
3.1Code Requirements for which Relief is RequestedUnder the rules of IWA-4220, repairs shall be performed in accordance with the originalConstruction Code. Later editions and addenda of the Construction Code or of ASME Section III, either in their entirety or portions thereof, and Code Cases may be used. Thelicensee proposes to use the following Code Cases with alternatives:ASME Code Cases N-638-1 and N-504-2, with conditions as specified in RegulatoryGuide (RG) 1.147, Revision 14, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1," andASME Code Section XI, 1995 Edition including Addenda through 1996, Appendix VIII,Supplement 11, which is required to be implemented per 10 CFR 50.55a(g)(6)(ii)(C).3.2Licensee's Proposed Alternatives to N-504-2The licensee proposes using N-504-2 for full structural PWOLs for the pressurizer spray,safety, relief and surge nozzle safe end to nozzle dissimilar metal butt welds (listed in Tables 1, 2 and 4 of the licensee's June 16, 2006, submittal) with the following alternatives:Use of a nickel-based alloy weld material, Alloy 52/52M rather than the lowcarbon (0.035 percent maximum) austenitic stainless steel. Relaxation from the requirement to perform delta ferrite measurements to meetthe 7.5 Ferrite Number (FN) requirement of N-504-2. The FN requirement cannot be met because the Alloy 52/52M weld material is 100 percent austenitic and contains no delta ferrite.3.2.1 Licensee's Basis for ReliefThe licensee stated that the weld overlay (WOL) has been designed consistent with therequirements of N-504-2 with the specific thickness and length computed according to the guidance provided in Code Case N-504-2. Code Case N-504-2 is accepted for use along with Nonmandatory Appendix Q in the current RG 1.147, Revision 14. For the WOL of the identified welds at TVA, the base material will be ferritic material (P3) with existing nickel alloy weld metal (F43) to which an austenitic stainless steel (P8) safe-end is welded. Industry operational experience has shown that PWSCC in Alloy 82/182 will blunt at the interface with stainless steel base metal, ferritic base metal, or Alloy 52/52M weld metal. TVA plans to apply a 360-degree structural WOL to control growth in any PWSCC crack and maintain weld integrity. The WOL will induce compressive stress in the weld, thus impeding growth of any reasonably shallow cracks. Furthermore, the overlay will be sized to meet structural requirements independent of the existing weld. In lieu of austenitic stainless steel filler material, the overlay weld metal will be a nickel alloy. The weld metal used may be ERNiCrFe-7A (alloy 52M, UNS N06054) or ERNiCrFe-7 (alloy 52 UNS N06052). This weld metal is assigned F43 by ASME per Code Case 2142-2. The requirements of ASME Secti on III, NB-2400 will be applied to all fillermaterial. The chromium content of Alloy 52M is 28 - 31.5 percent, identical to that of Alloy 52.
The main difference in Alloy 52 vs. Alloy 52M is a higher niobium content (0.5 - 1 percent). The difference in chemical composition between Alloy 52 and Alloy 52M improves the weldability of the material and pins the grain boundaries thus reducing the likelihood of separation between the grains and hot tearing during weld puddle solidification. These filler materials were selected for their improved resistance to PWSCC. Alloys 52 and 52M contain about 30 percent chromium, which imparts excellent corrosion resistance. The existing Alloy 82/182 weld and the Alloy 52/52M overlay are nickel-based and have ductile properties and toughness similar to austenitic stainless steel piping welds at pressurized water reactor operating temperature.
These filler materials are suitable for welding over the ferritic nozzle or pipe Alloy 82/182 weld and the austenitic stainless steel pipe or safe ends.Delta ferrite measurements will not be performed for WOL repairs made of Alloy 52/52M weld metal. Welds of alloy 52/52M are 100 percent austenitic and contain no delta ferrite due to the high nickel composition (approximately 60 percent nickel).3.2.2Staff Evaluation of Alternatives to N-504-2Under the rules of IWA-4220, repairs shall be performed in accordance with the Owner'sDesign Specification and the original Construction Code. Later editions and addenda of the Construction Code or of ASME Section III, either in their entirety or portions thereof, and CodeCases may be used. In addition to the above, defects shall be removed or reduced in size in accordance with IWA-4420. Alternatively, the component may be evaluated and accepted in accordance with the design rules of either the Construction Code, or Section III, when theConstruction Code was not Section III. N-504-2 is being used by the licensee to performPWOLs for pressurizer spray, safety, relief and surge nozzle safe end to nozzle dissimilar metal welds. N-504-2 was conditionally approved by the staff for use under RG 1.147, Revision 14.Therefore, the use of N-504-2 as an alternative to the mandatory ASME Code repair provisions is acceptable to the staff, provided that all conditions and provisions of the Code Case are complied with. The first proposed alternative to the N-504-2 provisions involves the use of a nickel-based alloyweld material, rather than the low carbon austenitic stainless steel. The licensee stated that Paragraph (b) of N-504-2 requires that the reinforcement weld material shall be low carbon (0.035 percent maximum) austenitic stainless steel. In lieu of the stainless steel weld material,Alloy 52/52M, a consumable welding wire highly resistant to PWSCC, was proposed for the overlay weld material. The NRC staff notes that the use of 52/52M material is consistent with weld filler material used to perform similar WOLs at operating boiling water reactor (BWR) facilities. The Electric Power Research Institute (EPRI) has performed studies in qualifying WOLs (full structural, design, and barrier overlays) for application in BWRs, and in these applications, the studies have not identified any issues associated with shrinkage stress or weld contraction stresses. The similarities of design between BWR nozzles and the full structural weld PWOLs in the licensee's relief request provide reasonable assurance that there is a correlation in the performance of weld shrinkage and weld contraction stresses in the subject weld. The staff concludes that the proposed use of Alloy 52/52M weld material for the full structural PWOLs provide an acceptable level of quality and safety and is, therefore, acceptable.The second proposed alternative to the N-504-2 provisions involved Paragraph (e) of N-504-2which requires as-deposited delta ferrite measurements of at least 7.5 Ferrite Number for the weld reinforcement. The licensee proposed that delta ferrite measurements will not be performed for this overlay because the deposited Alloy 52/52M material is 100 percent austenitic and contains no delta ferrite due to the high nickel composition (approximately60 percent nickel). N-504-2 allows the use of WOL repair by deposition of weld reinforcement on the outside surface of the pipe in lieu of mechanically reducing the defect to an acceptable flaw size. However, N-504-2 is designed for WOL repair of austenitic stainless steel piping. Therefore, the material requirements regarding the carbon content limitation (0.035 percent maximum) and the delta ferrite content of at least 7.5 FN, as delineated in N-504-2, paragraphs (b) and (e), apply only to austenitic stainless steel WOL materials to ensure its resistance tostress corrosion cracking. These requirements are not applicable to Alloy 52/52M, a nickel-based material that the licensee will use for the WOLs. The NRC staff notes that the licensee is performing full structural PWOLs on dissimilar metalwelds made of Alloy 182 material. For material compatibility in welding, the NRC staff considers that Alloy 52/52M is a better choice of filler material than austenitic stainless steel material for this weld joint configuration. Alloy 52/52M contains about 30 percent chromium, which would provide excellent resistance to PWSCC in the reactor coolant environment. This material is identified as F-No. 43 Grouping for Ni-Cr-Fe, classification UNS N06052 Filler Metal and has been previously approved by the NRC staff for similar applications. Material UNS N06052 is approved for use in ASME Code Section II, which the staff has accepted byreference in its endorsement of ASME Code Section XI. The NRC staff concludes that the licensee's proposed use of Alloy 52/52M for the WOLs as an alternative to the requirements of N-504-2, paragraphs (b) and (e) will provide an acceptable level of quality and safety and is, therefore, acceptable. 3.3Licensee's Proposed Alternatives to N-638-1The licensee proposes using N-638-1 for full structural PWOLs for the pressurizer spray,safety, relief and surge nozzle safe end to nozzle dissimilar metal butt welds (listed in Tables 1, 2 and 4 of the licensee's June 16, 2006, submittal) with the following alternatives:*The maximum area of an individual weld, based on the finished surface over theferritic material, shall be 300 sq. in., which is an alternative to Paragraph 1.0(a) in N-638-1.*Paragraph 4.0(c) in N-638-1 requires temperature monitoring by weldedthermocouples per IWA-4610(c). The licensee proposes using a contact pyrometer.*In lieu of the required ultrasonic examination of 4.0(b) in N-638-1, which states,"The final weld surface and a band around the area defined in para. 1.0(d) shall be examined using a surface and ultrasonic methods when the completed weld has been at ambient temperature for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The ultrasonic examination shall be in accordance with Appendix I," only the required liquid penetrant examination will be performed. The ultrasonic examination in the remaining area will be in accordance with N-504-2 and Appendix Q. Also, TVA is proposing a modification to the above requirement to allow the 48-hour hold time to begin following completion of the third temperbead layer, instead of after the completed weld has been at ambient temperature for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. *In lieu of the ultrasonic examination acceptance criteria of the Construction Codein the RG 1.147, Rev. 14 condition for the use of N-638-1, the acceptance criteria of ASME Section XI Nonmandatory Appendix Q, as stipulated in the conditions of RG-1.147, Rev. 14, for the use of N-504-2 will be applied for the entire structural weld overlay.3.3.1Licensee's Basis for ReliefThe licensee stated that the PWOLs may require welding on more than 100 sq. in. of surface. The PWOL will extend to the transition taper of the low alloy steel nozzle so that qualified ultrasonic testing (UT) of the required volume can be performed. The licensee also stated that there have been a number of temper bead WOL repairs applied to safe-end to nozzle welds in the nuclear industry. The licensee indicated that ASME Code Case N-432-1, which is approved for use in RG 1.147, allows temper bead welding on low alloy steel nozzles without limiting the temper bead weld surface area. The two additional conditions required by N-432-1 that are not required by N-638-1 are that temper bead welds have preheat applied and that the procedure qualification be performed on the same specification, type, grade and class of material. The elevated preheat would present a radiation exposure burden when performing the repair. For the application of the WOLs or repairs, for some of the dissimilar metal welds addressed inthis request, it is not possible to perform a meaningful UT examination of the required band of base material because of the existing nozzle configurations. This occurs with the SQN safety and relief valve nozzle and the spray line nozzle areas. This Code Case applies to any type of welding where a temper bead technique is to be employed and is not specifically written for aWOL repair. However, it is believed that for this type of repair any major base material cracking would take place in the heat affected zone (HAZ) directly below the WOL or in the underlying Alloy 82/182 weld deposit and not in the required band of material out beyond the overlay.
Therefore, it is assumed that if this cracking were to occur it would be identified by the ultrasonic examination of the WOL and not performing the required base material ultrasonic examination should be considered acceptable.Preheat and interpass temperatures for the weld pad will be measured using a contactpyrometer. Interpass temperature will be monitored for the first three layers at each repair location. On the first repair location, the interpass temperature measurements will be taken every three to five passes. After the first three layers, interpass temperature measurements will be taken every six to ten passes for the subsequent layers. The heat input for layers beyond the third layer will not have a metallurgical effect on the low alloy steel. This is acceptable due to the location of the repair and area radiation dose rate. The placement of welded thermocouples for monitoring weld interpass temperatures is determined to be not beneficial based on dose costs. Therefore, welded thermocouples are not planned for use to monitor interpass temperature during welding.The modification to the requirement to allow the 48-hour hold time to begin following completionof the third temperbead layer, instead of after the completed weld has been at ambient temperature for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, is based on the following discussion. In December 2006, EPRI issued Technical Report 1013558, "48-Hour Hold Requirements forAmbient Temperature Temperbead Welding" (ADAMS Accession No. ML070670060). A summary of the EPRI discussion is as follows: The microstructure in the P-3 material directly beneath the temperbead WOLconsists of a tempered martensite or tempered upper bainite that has excellent toughness, combined with a modest maximum hardness (of the order of Rockwell [Rc] 30 or lower). The microstructure at the toe of the temperbead WOL in the P-3 weld heat affected zone (HAZ) at the outside diameter (OD) surface where tempering is somewhat limited may have a very small HAZ with a maximum hardness of the order of Rc36, at a distance of approximately 40 mils from the toe of the WOL. At a depth of approximately 2 to 2.5 mm (80 to 100 mils) beneath the toe of the WOL, the hardness is reduced to less than 294 Knoop hardness (29 Rc), a hardness level well below that required to cause hydrogen cracking. Sources of hydrogen include moisture, poor shielding gas, and contamination. It isnoted that moisture in the shielding gas or high humidity is not a problem for GTAW temperbead welding. Contamination will affect the weld, and should be identified either during the welding process or during the subsequent NDE of the overlay. Good welding practice should eliminate this problem for the temperbead WOL.Tensile stresses should not be an issue for cold cracking as the thermal stressesdiminish with each weld overlay layer. Following the final layer, it is expected that the maximum surface temperature at the toe of the WOL in the P-3 HAZ would reach temperatures only on the order of 400 degrees Fahrenheit (oF) to 500 oF. Slow cooling to ambient temperatures from these temperatures wouldbe expected to produce relatively small stresses.The diffusion rate for hydrogen is greater in ferritic material than in austeniticmaterials, but the solubility of hydrogen in austenite is from five to seven times greater in the austenite than in the ferrite or martensite. Consequently, due to the temperatures expected during the welding of the temperbead layers, and during the welding of the non-temperbead WOL layers, the temperature should be sufficient for the hydrogen to diffuse out of the material, either escaping the structure or diffusing into the austenite, where it can be held in much greater quantities. Thus, even if hydrogen is produced, a large hydrogen inventory in the P-3 material is not expected.Based on the above discussion, EPRI Technical Report 1013558 concludes that there is notechnical basis for waiting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after cooling to ambient temperature before beginning the NDE of the completed weld.In addition to the EPRI report, the ASME Section XI Code Committee approved Revision 4 toASME Code Case N-638 in October 2006 to allow the 48-hour hold time to begin after completing the third weld layer when using austenitic filler metals. Paragraph 4(a)(2) of the code case states in part: "When austenitic materials are used, the weld shall be nondestructively examined after the three tempering layers (i.e., layers 1, 2, and 3) have been in place for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />." The ASME Section XI technical basis for this change is documented in an ASME white paper (ADAMS Accession No. ML070790679). The ASME white paper points out that introducing hydrogen to the ferritic HAZ is limited to the first weld layer since this is the only weld layer that makes contact with the ferritic base material. While the potential for introducing hydrogen to the ferritic HAZ is negligible during subsequent weld layers, these layers provide a heat source that accelerates the dissipation of hydrogen from the ferritic HAZ in non-water backed applications. Furthermore, the solubility of hydrogen in austenitic materials such as Alloy 52M is much higher than that of ferritic materials while the diffusivity of hydrogen in austenitic materials is lower than that of ferritic materials. As a result, hydrogen in the ferritic HAZ tends to diffuse into the austenitic weld metal which has a much higher solubility for hydrogen. This diffusion process is enhanced by heat supplied in subsequent weld layers. Like the EPRI report, the ASME white paper concludes that there is sufficient delay time to facilitate detecting potential hydrogen cracking when NDE is performed 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing the third weld layer. 3.3.2Staff Evaluation of Alternatives to N-638-1The licensee is applying a 360-degree, full structural PWOL to reduce the susceptibility of theoriginal weld to the initiation and growth of PWSCC and ultimately to maintain weld integrity.
The full structural PWOL will fulfill all structural requirements, independent of the existing weld.
Operational experience has also shown that PWSCC in Alloy 82/182 will blunt at the interface with stainless steel base metal, carbon steel base metal, or Alloy 52/52M weld metal, if cracking were to occur. To eliminate the need for preheat and post-weld heat treatment under the Construction Code,the industry developed a temper bead welding technique, which was published as N-638-1.
The NRC endorsed N-638-1 in RG 1.147, Revision 14. The temper bead technique carefully controls heat input and bead placement, which allows subsequent welding passes to stress-relieve and temper the heat affected zones of the base material and preceding weld passes. The welding is performed with low hydrogen electrodes under a blanket of inert gas.
The inert gas shields the molten metal from moisture and hydrogen. Therefore, the need for the preheat and post-weld heat treatment specified by the ASME Construction Code is not necessary to produce a sound weld using the temper bead process in N-638-1.The licensee intends to follow the methodology of N-638-1, except paragraph 1.0(a), whichrequires the maximum area of an individual weld, based on the finished surface, to be limited to 100 square inches (sq. in.), and the depth of the weld to exceed one-half of the ferritic base metal thickness. This condition is not being met because the design for the WOL covers an area up to approximately 300 sq. in. which exceeds the limitations of N-638-1. The licensee will perform an evaluation to determine the effect of exceeding the 100-sq. in. area limitation for temper bead welding onto a low alloy steel nozzle. This evaluation will be conducted under the guidance of N-504-2. Paragraphs (g)(2) and (g)(3) of N-504-2 require consideration of the residual stresses produced by the WOL with other applied loads on the system. The evaluation of other welds and components in the system is to consider potential increases in loading, including shrinkage effects, due to all WOLs in the reactor coolant system. These welds and components are to meet the applicable stress limits of the Construction Code. The staff considers this evaluation important in assuring that the reactor coolant system will not be adversely effected after PWOLs are deposited. The staff notes that several similar WOLs have been applied to Boiling Water Reactor (BWR)facilities (such as Nine Mile Point 2, Perry, and Duane Arnold) with similar geometry and overlay dimensions. The SQN WOL design is generally similar to the design applied in BWR feedwater, core spray, and recirculation nozzles. Published literature shows that compressive stress remains on the inside surface near the weld, which supports mitigation of some degradation mechanisms, such as PWSCC. In some cases, the extended overlay results in higher compressive stress than the 100-sq. in. case. Thus, increasing the overlay area is acceptable for this specific application, i.e., to support the mitigation of the PWSCC degradation mechanism and in this geometry (piping). Based on the preceding discussions and the fact that the licensee will perform the analyses required under N-504-2, the staff concludes that the modification to increase the PWOL to 300 sq. in. maximum, will provide an acceptable level of quality and safety and is, therefore, acceptable.The second alternative requested by the licensee is that full UT of the 1.5T band, which isrequired under Paragraph 4.0(b), will not be performed. Using Code Case N-638-1, the temperbead weld is for filling a cavity in the base metal. The licensee's application, however, is for structural WOL above the base metal, which results in a contour that is UT inspectible except for the edge taper where the overlay transitions to the nozzle surface and on the curvature of the nozzle. The proposed weld edge configuration has the same UT examination difficulties as are considered under ASME Section XI, Appendix Q. Appendix Q only requires asurface examination of the tapered area of the WOL. In addition to verifying the soundness of the weld, a purpose of the ultrasonic examination is to assure that delayed cracking, which may be caused by hydrogen introduced during the temperbead welding process or cracking in unannealed ferritic material, does not occur. In the unlikely event cracking does occur, it wouldbe initiated on the surface on which the welding is actually performed or in the heat affected zone immediately adjacent to the weld. The most appropriate technique to detect surface cracking is the surface examination technique. Therefore, use of a surface examination in the area of the WOL taper and band beyond the toe of the overlay on the ferritic material is acceptable in that it provides an acceptable level of safety and quality.The licensee's request would require that when ambient temperature temperbead welding isperformed on ferritic materials, the liquid penetrant and ultrasonic examinations will not be performed until at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completing of the third layer of the WOL. This requirement deviates from Code Case N-638-1 which requires that the liquid penetrant and ultrasonic examinations not be performed until at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the finished weld reaches the ambient temperature. This 48-hour hold time is specified to allow sufficient time for hydrogen cracking to occur (if it isto occur) in the HAZ of ferritic materials prior to performing NDE so that if hydrogen cracking does occur, NDE would be able to detect it. However, based on research and industry experience, EPRI has provided a technical basis for starting the 48-hour hold after completion of the third temperbead weld layer rather than waiting for the WOL to cool to ambient temperature, which is documented in Technical Report 1013558.In addition, the ASME Section XI Committee published a white paper to support the 48-hourhold time alternative. The ASME white paper concludes that there is sufficient delay time to facilitate the detection of potential hydrogen cracking when NDE is performed 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after completion of the third weld layer. The staff finds that 48-hour hold time after the third weld layer is acceptable because thelicensee has provided sufficient technical justification to show that hydrogen cracking in the WOL would not be likely to occur under the proposed alternative. The final alternative relates to conditions on code case use in RG 1.147, which establishes thefollowing condition on use of N-638-1: "UT examinations shall be demonstrated for the repaired volume using representative samples which contain construction type flaws. The acceptance criteria of NB-5330 of Section III edition and addenda approved in 10 CFR 50.55a apply to allflaws identified within the repaired volume." The use of Performance Demonstration Initiative (PDI) in lieu of ASME Code Section XI, Appendix VIII, Supplement 11 is acceptable, in that thePDI methodology uses construction type flaws in the standards used to qualify equipment, procedures, and personnel. (This is discussed in detail in section 3.3.4 of this evaluation).
Therefore, the condition established in RG 1.147 for the use of Code Case N-638-1 is met. In lieu of the acceptance criteria associated with this condition, the licensee proposes to use theacceptance criteria of ASME Section XI Nonmandatory Appendix Q, as stipulated in the conditions of RG-1.147, Rev. 14, for the use of N-504-2 for the entire structural weld overlay.
ASME Code Section III flaw acceptance standards are derived from the capability ofradiography to detect and size flaws originating from the fabrication process used during new facility construction. The ASM E Code Section III acceptance criteria do not allow for thepresence of any cracks or crack-like indications, regardless of their size, and are geared more towards volumetric flaws. The capability of radiography is a function of density differences, such as 2 percent or greater changes in density. The density changes normally associated withcracks, depending on orientation, are much less than the detection capability of radiography.
There is an inherent, unknown tolerance in the Section III acceptance criteria for radiographywhich encompasses tight cracks and densities below the detection capabilities of radiography.
Flaws detected using radiography are not precise enough for applying Section XI crack growth analyses, as flaw depth cannot be measured with radiography.Section III radiography is notapplicable for evaluating flaws for continued plant operations because of the difficulty associated with depth sizing flaws. The WOLs in this request are to mitigate PWSCC in dissimilar metal welds at SQN Units 1 and2, operating power plants. The application of Code Case N-504-2 is for applying austenitic (Alloy 52\52M) weld metal on austenitic base material. The application of Code Case N-638-1 is to apply austenitic weld metal on ferritic base material using a controlled heat input that relieves welding stresses and prevents crack sensitive microstructures in the ferritic material.
The purpose of N-638-1 is to establish an austenitic surface for the application of N-504-2 to complete the structural WOL. The N-638-1 applied weld metal is sandwiched between base metal and N-504-2 weld metal. Placing a flaw in N-638-1 weld metal using Section III radiography would be extremely difficult. Many flaws that are not detected or accurately sized with radiography have a high likelihood ofbeing detected and sized with UT, depending on orientation. These flaws are normally detected with UT during the Section XI preservice inspection. Also, the preservice UT is used to characterize flaws detected during the Section III radiography examination. The flaws ofconcern are the ones that cause failure immediately or grow to failure in the future. The Section Xl preservice acceptable flaw standards were developed to consider the materials in which the flaw indications are detected, the orientation and size of the indications, and ultimately the potential structural impact of the flaw on the component. The flaws detected during preservice inspections are subjected to periodic inservice inspections, as established inAppendix Q, Q-4300. This includes inspection frequencies for monitoring existing crack growth and identifying new cracks. Thus, the established preservice NDE acceptance criteria in Code Case N-504-2 for WOLsmade with Alloy 52/52M weld metal also applies to the portion of the WOL made during the application of N-638-1 as modified by this safety evaluation and the established preservice NDE acceptance criteria in Code Case N-504-2 and Appendix Q for WOLs made with Alloy 52/52M weld metal should also be applied to the portion of the WOL made during the application of N-638-1. Therefore, an acceptable level of safety and quality will be maintained.3.4ASME Code Section XI, 1995 Edition including Addenda through 1996, Appendix VIII, Supplement 11 Requirements for which Relief is RequestedPursuant to 10 CFR 50.55a(a)(3)(i), the licensee requested relief from the WOL requirements inthe following paragraphs to Section XI, Appendix VIII, Supplement 11 (only those itemsconsidered by the staff to be modifications to Appendix VIII Supplement 11 are listed in thissafety evaluation):Paragraph 1.1(b) limits the maximum thickness for which a procedure may be qualified. Also,the specimen set must include at least one specimen with overlay thickness within minus 0.10-inch to plus 0.25-inch of the maximum nominal overlay thickness for which the procedureis applicable.Paragraph 1.1(d)(1) requires that all base metal flaws be cracks in or near the butt weldheat-affected zone, open to the inside surface, and extending at least 75 percent through the base metal wall. Paragraph 1.1(e)(1) requires that at least 20 percent but not less than 40 percent of the flawsshall be oriented within +/-20 degrees of the axial direction. Paragraph 1.1(e)(1) also requires that the rules of IWA-3300 shall be used to determinewhether closely spaced flaws should be treated as single or multiple flaws. Specimens shall be divided into base and overlay grading units with each specimen containing one or both types of grading units.Paragraph 1.1(e)(2)(a)(1) requires that a base grading unit shall include at least 3 inches of thelength of the overlaid weld and the outer 25 percent of the overlaid weld and base metal on both sides.Paragraph 1.1(e)(2)(a)(3) requires that for unflawed base grading units, at least 1 inch ofunflawed overlaid weld and base metal shall exist on either side of the base grading unit.Paragraph 1.1(e)(2)(b)(1) requires that an overlay grading unit shall include the overlay materialand the base metal-to-overlay interface of at least 6 sq. in. The overlay grading unit shall be rectangular, with minimum dimensions of 2 in.Paragraph 3.1 requires examination procedures, equipment and personnel are qualified fordetection when the results of the performance demonstration satisfy the acceptance criteria of Table VII-S2-1 for both detection and false calls. The criteria shall be satisfied separately by the demonstration results for base grading units and for overlay grading units.Paragraph 3.2(b) requires that all extensions of base metal cracking into the overlay material byat least 0.1 in. are reported as being intrusions into the overlay material.3.4.1Licensee's Proposed Modification to ASME Code Section XI, 1995 Edition including Addenda through 1996, Appendix VIII, Supplement 11 In lieu of the requirements of ASME Code,Section XI, 1995 edition, 1996 Addenda,Appendix VIII, Supplement 11, the licensee proposed to use the PDI program as described inAttachment 5 of the licensee's submittal. The duration of the relief is for the remainder of the third 10-year inservice inspection interval.3.4.2Licensee's Basis for ReliefThe licensee stated that the ultrasonic examination of the completed PWOLs will beaccomplished in accordance with ASME Code,Section XI, 1995 Edition with the 1996 Addenda, Appendix VIII, Supplement 11 with the modifications described in Attachment 5of the submittal. These modifications were developed by the EPRI PDI program to implement the requirements of Appendix VIII. The licensee st ated that these EPRI Supplement 11modifications have previously been approved for use by the staff.3.4.3Staff Evaluation of Modification to ASME Code Section XI, 1995 Edition including Addenda through 1996, Appendix VIII, Supplement 11 The U.S. nuclear utilities created the PDI to implement performance demonstrationrequirements contained in Appendix VIII of Section XI of the Code. To this end, PDI hasdeveloped a program for qualifying equipment, procedures, equipment, and personnel in accordance with the ultrasonic testing criteria of Appendix VIII, Supplement 11. Prior tothe Supplement 11 program, EPRI was maintaining a performance demonstration program for WOL qualification under the Tri-party Agreement dated July 3, 1984. Instead of having two programs with similar objectives, the NRC staff recognized the PDI program for WOL qualifications as an acceptable alternative to the Tri-party Agreement in a letter dated January 15, 2002. The PDI program does not fully comport with the existing requirements of Supplement 11. The differences are discussed below.Paragraph 1.1(b) of Supplement 11 states limitations to the maximum thickness for which aprocedure may be qualified. The Code states that "The specimen set must include at least one specimen with overlay thickness within minus 0.10-inch to plus 0.25-inch of the maximum nominal overlay thickness for which the procedure is applicable." The Code requirement addresses the specimen thickness tolerance for a single specimen set, but is confusing when multiple specimen sets are used. The PDI proposed alternative states that "the specimen set shall include specimens with overlay not thicker than 0.10-inch more than the minimum thickness, nor thinner than 0.25-inch of the maximum nominal overlay thickness for which the examination procedure is applicable." The proposed alternative provides clarification on the application of the tolerance. The tolerance is unchanged for a single specimen set, however, it clarifies the tolerance for multiple specimen sets by providing tolerances for both the minimum and maximum thicknesses. The proposed wording eliminates confusion while maintaining the intent of the overlay thickness tolerance. Therefore, the staff finds this PDI Program revision acceptable.Paragraph 1.1(d)(1) requires that all base metal flaws be cracks. PDI determined that certainSupplement 11 requirements pertaining to location and size of cracks would be extremely difficult to achieve. For example, flaw implantation requires excavating a volume of base material to allow a pre-cracked coupon to be welded into this area. This process would add weld material to an area of the specimens that typically consists of only base material, and could potentially make ultrasonic examination more difficult and not representative of actual field conditions. In an effort to satisfy the requirements, PDI developed a process for fabricating flaws that exhibit crack-like reflective characteristics. Instead of all flaws being cracks as required by Paragraph 1.1(d)(1), the PDI WOL performance demonstrations contain at least 70 percent cracks with the remainder being fabricated flaws exhibiting crack-like reflective characteristics. The fabricated flaws are semi-elliptical with tip widths of less than 0.002 inches. The licensee provided further information describing a revision to the PDI Program alternative to clarify when real cracks, as opposed to fabricated flaws, will be used; "The use of alternative flaws shall be limited to the cases where implantation of cracks produces spurious reflectors that are uncharacteristic of actual flaws." The NRC reviewed the flaw fabrication process, compared the reflective characteristics between actual cracks andPDI-fabricated flaws, and found the fabricated flaws acceptable for this application.Paragraph 1.1(e)(1) requires that at least 20 percent but not less than 40 percent of the flawsshall be oriented within +/-20 degrees of the axial pipe direction. Flaws contained in the original base metal heat-affected zone satisfy this requirement. However, PDI excludes axial fabrication flaws in the WOL material. PDI has concluded that axial flaws in the overlay material are improbable because the overlay filler material is applied in the circumferential direction (parallel to the girth weld), therefore fabrication anomalies would also be expected to have major dimensions in the circumferential direction. The NRC finds this approach to implantation of fabrication flaws to be reasonable. Therefore, PDI's application of flaws oriented in the axial direction is acceptable. Paragraph 1.1(e)(1) also requires that the rules of IWA-3300 shall be used to determinewhether closely spaced flaws should be treated as single or multiple flaws. PDI treats each flaw as an individual flaw and not as part of a system of closely spaced flaws. PDI controls the flaws going into a test specimen set such that the flaws are free of interfering reflections from adjacent flaws. In some cases, this permits flaws to be spaced closer than what is allowed for classification as a multiple set of flaws by IWA-3300, thus potentially making the performance demonstration more challenging. Hence, PDI's application for closely spaced flaws is acceptable.Paragraph 1.1(e)(2)(a)(1) requires that a base grading unit shall include at least three inches ofthe length of the overlaid weld, and the base grading unit includes the outer 25 percent of the overlaid weld and base metal on both sides. The PDI program reduced the criteria to one inch of the length of the overlaid weld and eliminated from the grading unit the need to include both sides of the weld. The proposed change permits the PDI program to continue using test specimens from the existing WOL program that have flaws on both sides of the welds. These test specimens have been used successfully for testing the proficiency of personnel for over 16 years. The WOL qualification is designed to be a near-side (relative to the weld) examination, and it is improbable that a candidate would detect a flaw on the opposite side of the weld due to the sound attenuation and re-direction caused by the weld microstructure. However, the presence of flaws on both sides of the original weld (outside the PDI grading unit) may actually provide a more challenging examination, as candidates must determine the relevancy of these flaws, if detected. Therefore, PDI's use of the one-inch length of the overlaid weld base grading unit and elimination from the grading unit of the need to include both sides of the weld, as described in the revised PDI Program alternative, is acceptable.Paragraph 1.1(e)(2)(a)(3) requires that for unflawed base grading units, at least one inch ofunflawed overlaid weld and base metal shall exist on either side of the base grading unit. This is to minimize the number of false identifications of extraneous reflectors. The PDI program stipulates that unflawed overlaid weld and base metal exists on all sides of the grading unit and that flawed grading units must be free of interfering reflections from adjacent flaws which addresses the same concerns as the Code. Hence, PDI's application of the variable flaw-free area adjacent to the grading unit is acceptable.Paragraph 1.1(e)(2)(b)(1) requires that an overlay grading unit shall include the overlay materialand a base metal-to-overlay interface of at least six sq. in. The overlay grading unit shall be rectangular, with minimum dimensions of two inches. The PDI program reduces the basemetal-to-overlay interface to at least one inch (in lieu of a minimum of two inches) and eliminates the minimum rectangular dimension. This criterion is necessary to allow use of existing examination specimens that were fabricated in order to meet NRC Generic Letter 88-01. This criterion may be more challenging than the ASME Code Code because of the variability associated with the shape of the grading unit. Hence, PDI's application of the grading unit is acceptable. Paragraph 2.3 states that, for depth sizing tests, 80 percent of the flaws shall be sized at aspecific location on the surface of the specimen identified to the candidate. This requires detection and sizing tests to be separate. The PDI revised the WOL program to allow sizing to be conducted either in conjunction with, or separately from, the flaw detection test. If performed in conjunction with detection and the detected flaws do not meet the Supplement 11 range criteria, additional specimens will be presented to the candidate with the regions containing flaws identified. Each candidate will be required to determine the maximum depth of flaw in each region. For separate sizing tests, the regions of interest will also be identified and the maximum depth and length of each flaw in five of the regions will similarly be determined. In addition, PDI stated that grading units are not applicable to sizing tests, and that each sizing region will be large enough to contain the target flaw, but small enough that candidates will not attempt to size a different flaw. The above clarification provides a basis for implementing sizing tests in a systematic, consistent manner that meets the intent of Supplement 11. As such, this method is acceptable to the staff.Paragraphs 3.1 and 3.2 of Supplement 11 state that procedures, equipment and personnel (asa complete ultrasonic system) are qualified for detection or sizing of flaws, as applicable, when certain criteria are met. The PDI program allows procedure qualification to be performed separately from personnel and equipment qualification. Historical data indicate that, if ultrasonic detection or sizing procedures are thoroughly tested, personnel and equipment using those procedures have a higher probability of successfully passing a qualification test. In an effort to increase this passing rate, PDI has elected to perform procedure qualifications separately in order to assess and modify essential variables that may affect overall system capabilities. For a procedure to be qualified, the PDI program requires three times as many flaws to be detected (or sized) as shown in Supplement 11 for the entire ultrasonic system. The personnel and equipment are still required to meet Supplement 11. Therefore, the PDI program is acceptable because it exceeds ASME Code requirements for personnel, procedures, and equipment qualification.Paragraph 3.2(b) requires that all extensions of base metal cracking into the overlay material byat least 0.10-inch be reported as being intrusions into the overlay material. The PDI program omits this criterion because of the difficulty in actually fabricating a flaw with a 0.10-inch minimum extension into the overlay, while still knowing the true state of the flaw dimensions.
However, the PDI program requires that cracks be depth-sized to the tolerance of 0.125-inch as specified in Code. Since the Code tolerance is close to the 0.10-inch value of Paragraph 3.2(b), any crack extending beyond 0.10 inch into the overlay material would be identified as such from the characterized dimensions. The reporting of an extension in the overlay material is redundant for performance demonstration testing because of the flaw sizing tolerance.
Therefore, PDI's omission of highlighting a crack extending beyond 0.10 inch into the overlay material is acceptable.
4.0CONCLUSION
Based on the discussion above, the staff concludes that the proposed modifications to CodeCases N-638-1 and N-504-1 for full structural PWOLs of pressurizer spray, safety, relief and surge nozzle safe end to nozzle dissimilar metal welds at SQN will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the proposed alternatives for the installation of PWOLs over the welds identified in the relief request for the Cycle 15 (fall 2007) refueling outage at SQN Unit 1, and the Cycle 14 (fall 2006) refueling outage at SQN Unit 2.Secondly, based on the discussion above, the staff concludes that the alternatives to ASMECode Appendix VIII, Supplement 11, will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the proposed alternatives for the remainder of the third 10-year ISI interval, which began on June 1, 2006, and will end on May 31, 2015.All other ASME Code,Section XI requirements for which relief was not specifically requestedand approved remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.Principal Contributors: Edward Andruszkiewicz Timothy LupoldDate: June 11, 2007 Page 1 of 2William R. Campbell, Jr.SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:Mr. Ashok S. Bhatnagar Senior Vice President Nuclear Generation Development and Construction Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Preston D. Swafford Senior Vice President Nuclear Support Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Walter M. Justice II Interim Vice President Nuclear Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Mr. Michael D. Skaggs, Site Vice PresidentWatts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381Mr. Randy Douet, Site Vice PresidentSequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000General CounselTennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902Mr. John C. Fornicola, ManagerNuclear Assurance Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Mr. Robert H. Bryan, Jr., General ManagerLicensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Ms. Beth A. Wetzel, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801Mr. Glenn W. Morris, ManagerLicensing and Industry Affairs Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000Mr. David A. Kulisek, Plant ManagerSequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37384-2000Senior Resident InspectorSequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379County MayorHamilton County Courthouse Chattanooga, TN 37402-2801Mr. James D. Smith, Acting ManagerLicensing and Industry Affairs Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381 Page 2 of 2William R. Campbell, Jr.SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:Mr. Michael J. Lorek, Plant ManagerWatts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381Senior Resident InspectorWatts Bar Nuclear Plant U.S. Nuclear Regulatory Commission 1260 Nuclear Plant Road Spring City, TN 37381 County Executive 375 Church Street Suite 215 Dayton, TN 37321County Mayor P. O. Box 156 Decatur, TN 37322Mr. Lawrence E. Nanney, DirectorDivision of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532Ms. Ann P. Harris341 Swing Loop Road Rockwood, TN 37854