ML042150438
| ML042150438 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry, Watts Bar, Sequoyah  |
| Issue date: | 10/06/2004 |
| From: | Marshall M NRC/NRR/DLPM/LPD2 |
| To: | Singer K Tennessee Valley Authority |
| Pascarelli,R J,NRC/NRR/DIPM,415-1245 | |
| References | |
| TAC MC1605, TAC MC1606, TAC MC1607, TAC MC1608, TAC MC1609, TAC MC1610 | |
| Download: ML042150438 (11) | |
Text
October 6, 2004 Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 1, 2, AND 3; SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2; AND WATTS BAR NUCLEAR PLANT UNIT 1 AMERICAN SOCIETY OF MECHANICAL ENGINEERS BOILER AND PRESSURE VESSEL CODE, CODE CASE N-513 RELIEF REQUEST (TAC NOS. MC1605, MC1606, MC1607, MC1608, MC1609 AND MC1610)
Dear Mr. Singer:
By a letter to the U.S. Nuclear Regulatory Commission (NRC) dated November 25, 2003 (ADAMS Accession No. ML033320222), the Tennessee Valley Authority (TVA) submitted a Relief Request (RR) pursuant to Title 10 of the Code of Federal Regulations (10 CFR),
Section 50.55a(a)(3)(i), for Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3; Sequoyah Nuclear Plant (SQN), Units 1 and 2; and Watts Bar Nuclear Plant (WBN), Unit 1. TVA requested relief from using the specific formula in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Case N-513 for the maximum allowable flaw width when planar flaw evaluation rules may be applied. As an alternative, TVA proposed the use of the formula for maximum allowable flaw width from Code Case N-513-1 with applicable errata while retaining the use of all the other provisions and requirements as shown in Code Case N-513.
Code Case N-513 is identified as approved for generic use in Regulatory Guide (RG)-1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 13.
Code Case N-513 is approved, with conditions, for generic use by licensees in 10 CFR 50.55a(b)(2). Code Case N-513-1, as approved and published in 2001 Edition and amended by errata in Supplement 5 to the ASME Code Cases for Nuclear Components, is currently not approved for generic use in 10 CFR 50.55a(b).
Based on our review of your submittal, we have concluded that the alternative proposed provides an acceptable level of quality and safety, and, therefore, is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the performance of piping evaluations to support the temporary continued operation of applicable ASME Class 3 piping systems in BFN Units 1, 2, and 3; SQN Units 1 and 2; and WBN Unit 1. All other ASME Code,Section XI, requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
K. W. Singer This relief is authorized for the remainder of the respective 10-year inservice inspection interval for BFN, Units 1, 2, and 3; SQN, Units 1 and 2; and WBN, Unit 1.
Sincerely,
/RA by BMozafari for/
Michael L. Marshall, Jr., Acting Chief, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-259, 50-260, 50-296, 50-327, 50-328 and 50-390
Enclosure:
Safety Evaluation cc w/enclosure: See next page
ML042150438 NRR-028 OFFICE PDII-2/PM PDII-2/LA PDII-2/PM PDII-2/PM NAME RPascarelli BClayton MComar KJabbour DATE 8/25/04 8/25/04 08/05/04 08/11/04 OFFICE PDII-2/PM EMCB/SC OGC PDII-2/SC(A)
NAME EBrown TChan* RWeisman MMarshall DATE 08/12/04 07/20/04 10 Sept 2004 10/06/04 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR RELIEF, GISI-3, ON THE EVALUATION CRITERIA FOR TEMPORARY ACCEPTANCE OF FLAWS IN CLASS 3 PIPING AT BROWNS FERRY, SEQUOYAH, AND WATTS BAR NUCLEAR POWER PLANTS DOCKET NOS. 50-259, 50-260, 50-296, 50-327, 50-328, and 50-390
1.0 INTRODUCTION
Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a(g), specifies that inservice inspection (ISI) of nuclear power plant components shall be performed in accordance with the requirements of the American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code (Code),Section XI. As stated in 10 CFR 50.55a(a)(3), alternatives to the requirements of Section 50.55a(g) may be used, when authorized by the U.S. Nuclear Regulatory Commission (NRC), if (i) the proposed alternatives would 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.
By a letter to the NRC dated November 25, 2003, Tennessee Valley Authority (TVA, the licensee) requested, pursuant to 10 CFR 50.55a(a)(3)(i), relief from using a specific formula in ASME Code Case N-513, Evaluation Criteria for Temporary Acceptance of Flaws in Class 3 Piping,Section XI, Division 1, to determine maximum flaw width for planar flaws. Instead, the licensee proposed to use the formula provided in Code Case N-513-1 while retaining the use of all other requirements of Code Case N-513. TVA will continue to comply with the current specific-use limitations included in 10 CFR 50.55a(b)(2)(xiii) and further described in Regulatory Guide (RG) 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 13. Specifically, TVA proposes to use the formula for computing the maximum width of a degraded flaw area (W m) as shown in Code Case N-513-1 instead of the formula specified in N-513 for computing the maximum width of a degraded flaw area. Code Case N-513 is identified as conditionally approved by the staff for generic use in RG-1.147 and is approved, with conditions, in 10 CFR 50.55a(b)(2). Code Case N-513-1 is not yet approved for generic use in 10 CFR 50.55a(b)(2). TVA will apply this alternative to the piping evaluations as necessary to support the temporary continued operation of applicable piping systems in Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3; Sequoyah Nuclear Plant (SQN), Units 1 and 2; and in Watts Bar Nuclear Plant (WBN), Unit 1.
BFN, Unit 1, is currently in the third period of its first 10-year inservice inspection (ISI) program interval and is in an extended shutdown. In accordance with the current Unit 1 ASME Section XI ISI program code-of-record (1974 Edition through the 1975 Addenda) paragraph IWA-2400, the Unit 1 first ISI program interval will be extended by a period equal to the length of the extended shutdown. By letter to the NRC dated March 1, 1988, TVA established that the current Unit 1 ISI program interval would be extended from its start on Enclosure
August 1, 1974, to a period of 1 year after restart of the unit. Unit 1 is currently scheduled for restart in May 2007.
BFN, Unit 2, is currently in the first period of its third 10-year ISI program interval which extends from May 25, 2001, through May 24, 2011. The BFN, Unit 2, ISI program code-of-record is the ASME Section XI, 1995 Code, with addenda through the 1996 Addenda.
BFN, Unit 3, is currently in the third period of its second 10-year ISI program interval which extends from November 19, 1996, through November 18, 2005. The BFN, Unit 3, ISI program code-of-record is the ASME Section XI, 1989 Code, with no addenda.
SQN, Units 1 and 2, are currently in the third period of their second program interval which extends from December 15, 1995, through May 31, 2006. The SQN ISI program code-of-record for both units is the 1989 Code.
WBN, Unit 1, is currently in the second period of its first 10-year interval which extends from May 27, 1996, through December 31, 2006. The WBN ISI program code-of-record is the 1989 Code.
2.0 REGULATORY EVALUATION
2.1 Licensees Evaluation In accordance with CFR 50.55a(a)(3)(i), TVA is requesting relief from using certain requirements of Code Case N-513, Evaluation Criteria for Temporary Acceptance of Flaws in Class 3 Piping,Section XI, Division 1, when performing the associated flaw evaluations.
These evaluations are used to determine whether degraded Class 3 piping meets the criteria for temporary acceptance and whether, based on that determination, a licensee may continue to use such piping until such time that a code acceptable repair or replacement can be performed on the piping. Specifically, TVA proposes to use the formula for W m as shown in the ASME published Code Case N-513-1 instead of the formula specified in N-513 (Revision 0) for computing the maximum width of a degraded flaw area, where planar flaw evaluation rules may be applied. TVA will apply this relief to the piping evaluations as necessary to support the temporary continued operation of applicable piping systems in BFN, Units 1, 2, and 3; SQN, Units 1 and 2; and WBN, Unit 1. According to TVA, the basis for using the equation from N-513-1 over the N-513 version of the formula is that the earlier version is unduly restrictive. The justification for this alternative is described in the discussion below.
Code Case N-513 is approved, with conditions, for generic use by licensees in 10 CFR 50.55a(b)(2)(xiii). Also, Code Case N-513 is identified as conditionally approved for generic use in RG 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 13 [dated June 13, 2003]. Code Case N-513-1, as approved and published in the 2001 Edition of the ASME Code and amended by errata in Supplement 5 to the ASME Code Cases for Nuclear Components, is currently not approved for generic use in 10 CFR 50.55a(b).
TVA will continue to apply the other remaining requirements of N-513 and the current specific use limitations in accordance with RG-1.147 and 10 CFR 50.55a(b)(2)(xiii).
2.1.1 System/Component(s) for Which Relief is Requested
TVA requests use of the proposed alternative for low to moderate energy Class 3 (or equivalent) pressure retaining piping subject to examination, evaluation, and repair or replacement using processes and procedures qualified to meet the ASME Section XI requirements. Low to moderate energy piping systems are defined by the ASME Code as systems whose maximum operating temperature does not exceed 200 °F and maximum operating pressure does not exceed 275 psig [pounds per square inch gauge].
2.1.2 Code Requirements In accordance with ASME Section XI, Article IWD-3000, Acceptance Standards (for Class 3 components), the rules of Article IWB-3000, Acceptance Standards (for Class 1 components),
may be used. As stated in IWB-3000, the acceptance criteria for volumetric and surface examinations are defined in IWB-3500. For examination indications or flaws that exceed the acceptance criteria of IWB-3500, the flaws may be further analytically evaluated for acceptance in accordance with the requirements and procedures of Article IWB-3600 and the associated ASME Section XI appendices. In accordance with 10 CFR 50.55a(b)(2)(xiii), Flaws in Class 3 Piping, licensees may use the provisions of ASME Code Case N-513, Evaluation Criteria for Temporary Acceptance of Flaws in Class 3 Piping, Revision 0, provided the specific limitations delineated in 10 CFR 50.55a(b)(2)(xiii)(A) and (B) are followed.
In accordance with the rules of Code Case N-513 paragraph 3.0(d)(1), when the flaw width, W m (in the area of the wall thinning that exceeds (tmin) is less than or equal to 0.5(Rotmin)1/2; where Ro is the outside radius of the pipe, the flaw can be classified as a planar flaw and evaluated under paragraphs 3.0(a) through 3.0(c) of the Code Case. In this N-513 equation, the variable, tmin, is equal to the minimum required wall thickness needed to maintain the integrity of the pipe for the given system pressure and is computed by the following formula:
pDo t min =
2( S + 0.4 p )
In this equation, p is defined as the maximum operating pressure at the flaw location, S is the allowable material stress at the operating temperature, and Do is the outside diameter of the pipe.
2.1.3 Relief Requested Pursuant to 10 CFR 50.55a(a)(3)(i), relief is requested to use the formula for W m as shown in paragraph 3.0(d)(1) of Code Case N-513-1 (i.e., when the width, W m of the flaw in the area of the wall thinning that exceeds tmin, is less than or equal to 0.5 (Rot)1/2, then the flaw can be classified as a planar flaw and evaluated under paragraphs 3.0(a) through 3.0(c) of Code Case N-513). In these cases, the value of t in this formula for W m equals the pipe thickness used in the flaw evaluation model. This value of t is usually a measured value determined by nondestructive examination thickness evaluation of the surrounding pipe wall area around the flaw, corrosion pit, or through-wall leak.
2.1.4 Basis for Relief
The formulas in question are the ones given in Article 3.0(d)(1) of both N-513 and N-513-1 for the quantity, W m, that defines the maximum width of a degraded area where planar flaw evaluation rules may be applied.
Specifically, the formula for W m given in Article 3.0(d)(1) of N-513 was revised in N-513-1 to replace the variable tmin with the variable t as follows:
Wm 0.5 Rot min {N-513}
Wm 0.5 Rot {N-513-1, with errata}
In N-513, tmin is defined as the required thickness for pressure and equal to:
pDo 2( S + 0.4 p )
In N-513-1, t is defined as the pipe thickness used in flaw evaluation model.
TVA describes the basis for its request as follows: It has previously been recognized by the ASME that the improper use of the value tmin in the original formula given in N-513 resulted in a very limiting (i.e., unduly conservative) value of W m because tmin is very small (usually
< 0.1 inch) for the typical low pressure conditions found in raw water systems. In addition, if the value tmin is used to determine the value of W m for piping evaluations of systems with high operating pressures, the resulting application of the planar flaw evaluation techniques could be under conditions that were not intended to be used with the Code Case alternative to the ASME Section XI evaluation rules shown in IWB-3600. The impact relative to use of Code Case N-513 is significant because the resulting value of Wm is, in most cases, too small to permit evaluation of the typical corrosion pitting observed in carbon steel raw water piping. This could result in unnecessary forced system and/or plant shutdowns in order to perform a Code repair or replacement of the degraded piping.
2.1.5 Alternative Examination No specific alternative examination process is to be incorporated by this request. This request addresses the evaluation techniques (when using Code Case N-513) employed with the results from the standard nondestructive examinations (NDE) techniques performed as part of the normally required ASME Section XI ISI program exams and augmented examinations performed under TVAs Corrosion Control Programs. TVA proposes to not use the formula in N-513 for computing the maximum width of a degraded flaw area (W m), when the planar flaw evaluation rules may be applied, and instead use the formula for W m as shown in the current ASME approved revision of the Code Case, N-513-1. TVA will apply the N-513-1 formula for calculation of the threshold value for use of evaluation techniques for planar flaws when the width, W m, of the flaw in the area where the wall thinning exceeds tmin, but is less than or equal to 0.5 (Rot)1/2.
2.1.6 Justification for Granting Relief TVA states as follows to justify its request: The basis for using the N-513-1 equation over the N-513 version of the formula for W m is that the previous Code Case version improperly uses the factor tmin to compute a value of W m that unduly restricts the planar flaw evaluation rules with the low pressure Class 3 systems and defeats the purpose of the allowed alternatives. In addition, the value of tmin increases as system design pressure values increase. The effect on the value of W m is to allow the use of planar flaw evaluation techniques on wide flaws where their use is not supported in all cases. The result is a condition that was not intended to be part of the alternative evaluation methods because the W m threshold value imposed with the N-513 formula becomes less restrictive as the required thickness for the piping design pressure increases. The use of the actual measured value of t in the formula for W m will result in better representation of the structural integrity of the piping in the flawed areas and allow for the accurate application of the rules for temporary acceptance of the piping for continued service.
As stated above, Code Case N-513 is currently approved for generic use in 10 CFR 50.55a(b)(2)(xiii) with special limitations for use. Except for the formula for W m, TVA will continue to apply the other remaining requirements of N-513 and the current specific limitations on its use as shown in the rule.
It should also be noted that the planar flaw evaluation process contained in Code Case N-513 is very similar to the provisions of Generic Letter (GL) 90-05, Guidance for Performing Temporary Non-Code Repair of ASME Code Class 1, 2, and 3 Piping, which was issued for licensee use on June 15, 1990. GL 90-05 recommended that licensees use one of two approaches in the evaluation and temporary acceptance of the structural integrity of flawed Class 3 piping. These two approaches included the through-wall flaw method and the wall-thinning method. Code Case N-513 currently employs much of the same evaluation technique as shown in the GL 90-05 through-wall flaw method. Specifically, the polynomial equation factors given in GL 90-05 to compute linear elastic crack stress intensity due to bending stresses are repeated and used in the linear elastic through-wall planar flaw evaluation techniques of both N-513 and N-513-1. This similarity indicates that the linear elastic fracture mechanics formula in both N-513 and N-513-1 will produce a crack stress intensity magnitude that is very close to the value produced by the formula in GL 90-05. Code Case N-513/N-513-1 and GL 90-05 methodologies both contain similar acceptance criteria (i.e., structural margin relative to failure). In addition, the objective of both methods is to determine the acceptability of a through-wall flaw without immediate physical repair/replacement.
However, even with the similarities, it is recognized that there are several substantive differences between Code Case N-513/N-513-1 and GL 90-05 methods. In particular, the N-513 methodology does not impose a safety factor on crack stress intensity due to piping thermal expansion load, whereas GL 90-05 provides for the same safety factor for both primary and secondary loads. Thermal expansion stresses for piping within the scope of N-513 (i.e.,
200 °F maximum operating temperature) are generally low and not a significant contributor to crack stress intensity. Conversely, GL 90-05 only calls for evaluation of a load combination involving safe shutdown earthquake effects (i.e., emergencies or faulted plant conditions);
whereas, the N-513/N-513-1 method includes consideration of the load combination involving operating basis earthquake effects (i.e., upset plant condition) along with a correspondingly higher safety factor (2.77 vs. 1.39) on the stress intensity factor due to primary load. Because of this, experience has shown that the upset condition evaluation, as required by N-513, will
generate a shorter (and more conservative) allowable flaw length than would be computed relative to either GL 90-05 or N-513 for just the emergency/faulted plant conditions. In addition, as part of its evaluation methods, GL 90-05 does not call for the restriction for the threshold of the application of the planar flaw evaluation techniques with a similar use of an equation for W m as is imposed in N-513. Therefore, it can be concluded that when the alternative evaluation process is applied, the use of the N-513 provisions in conjunction with the alternative W m formula using the value of t is more rigorous and conservative than the provisions of GL 90-05 and provides a similarly acceptable level of safety.
The use of the proposed alternatives described above in lieu of the formula for W m, as shown in ASME Code Case N-513 and as delineated in 10 CFR 50.55a(b)(2)(xiii), will therefore provide an adequate level of quality and safety for the evaluation of the degraded piping and its continued acceptability for use with the through-wall flaw evaluation processes. Accordingly, approval of this alternative evaluation process is authorized pursuant to 10 CFR 50.55a(a)(3)(i).
2.1.7 Implementation Schedule This alternative will be used for BFN, Units 1, 2, and 3; SQN, Units 1 and 2; and WBN, Unit 1 until the end of each units respective 10-year ISI program interval when the units corresponding ISI and repair and replacements programs are updated; or until such time that 10 CFR 50.55a(b)(2)(xiii) is amended to reflect the formula for the application of the threshold values for the use of the planar flaw evaluation rules in Code Case N-513-1. It should be noted that TVA currently performs, as a matter of procedure standardization, NDEs on each of the plants required components in accordance with the NDE methodology, acceptance criteria, and extent of examination requirements shown in the 1995 Edition of the ASME Section XI Code with the added requirements of the 1996 Addenda.
2.2 Staff Evaluation The NRC staff reviewed the information provided by the licensee in support of its request to use the formula provided in Code Case N-513-1 while retaining the use of all other requirements of Code Case N-513 to compute maximum flaw width for planar flaws. The NRC staffs evaluation of the request follows.
By a letter to the NRC dated November 25, 2003, TVA requested, pursuant to 10 CFR 50.55a(a)(3)(i), relief from using a specific formula in ASME Code Case N-513 to determine maximum flaw width for planar flaws. Instead, the licensee proposed to use the formula provided in Code Case N-513-1 while retaining the use of all other requirements of Code Case N-513. TVA will continue to comply with the current specific-use limitations in accordance with 10 CFR 50.55a(b)(2)(xiii). Code Case N-513 is approved, with conditions, for generic use in 10 CFR 50.55a(b)(2). Code Case N-513-1 is not yet approved for generic use in Section 50.55a(b). TVA will apply this relief to the piping evaluations as necessary to support the temporary continued operation of applicable piping systems in BFN, Units 1, 2, and 3; SQN, Units 1 and 2; and WBN, Unit 1.
TVA proposes to use the formula for W m as shown in Code Case N-513-1 instead of the formula specified in N-513 for computing the maximum width of a degraded flaw area. Detailed description of the formula and how the value of W m is computed using the rules of Code Case
N-513 or N-513-1 is provided in Section 2.1.4 above. In summary, in the Code Case N-513 formula for W m, the variable, tmin, is equal to the minimum required wall thickness needed to maintain the integrity of the pipe for a given system pressure, while in the Code Case N-513-1 formula for W m, the variable t is defined as the pipe thickness used in the flaw evaluation model. The value of t is usually a measured value determined by nondestructive examination thickness evaluation of the pipe wall area around the flaw, corrosion pit, or through-wall leak.
The NRC staff finds the TVA proposed alternative acceptable. This acceptance is based on the fact that the proposed formula would realistically determine the value of W m since the degraded wall thickness would be determined using actual measurement of the pipe. In addition, Section 2.0 of Code Case N-513 requires that the licensee perform frequent inspections of no more than 30-day intervals to determine if flaws are growing and to establish the time at which the detected flaws will reach the allowable size. This requirement would ensure that the pipe integrity would be maintained until a permanent Code repair is accomplished. Accordingly, TVAs proposed alternative to Code Case N-513 will provide an acceptable level of quality and safety. Moreover, since the submittal of this request, the NRC staff has completed its review of Code Case N-513-1. The NRC staff determined that Code Case N-513-1 is acceptable for generic use subject to the same restrictions and conditions as Code Case N-513. The NRC staff approval of Code Case N-513-1 is documented in Draft RG DG-1125 (Proposed Revision 14 of RG-1.147).
3.0 CONCLUSION
S Based on the above evaluation, the NRC staff concludes that the proposed alternative as discussed in the licensees request for relief is acceptable. Therefore, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the performance of piping evaluations to determine whether temporary continued operation of applicable ASME Class 3 piping systems is allowed in BFN, Units 1, 2, and 3; SQN, Units 1 and 2; and in WBN, Unit 1, for the remainder of the respective units 10-year ISI interval. All other ASME Code,Section XI, requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: G. Georgiev Date: October 6, 2004
Mr. Karl W. Singer BROWNS FERRY NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. Ashok S. Bhatnagar, Senior Vice President Mr. Robert G. Jones Nuclear Operations Browns Ferry Unit 1 Plant Restart Manager Tennessee Valley Authority Browns Ferry Nuclear Plant 6A Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Decatur, AL 35609 Mr. James E. Maddox, Vice President Mr. Mark J. Burzynski, Manager Engineering & Technical Services Nuclear Licensing Tennessee Valley Authority Tennessee Valley Authority 6A Lookout Place 4X Blue Ridge 1101 Market Street 1101 Market Street Chattanooga, TN 37402-2801 Chattanooga, TN 37402-2801 Mr. Michael D. Skaggs Mr. Timothy E. Abney, Manager Site Vice President Licensing and Industry Affairs Browns Ferry Nuclear Plant Browns Ferry Nuclear Plant Tennessee Valley Authority Tennessee Valley Authority P.O. Box 2000 P.O. Box 2000 Decatur, AL 35609 Decatur, AL 35609 General Counsel Senior Resident Inspector Tennessee Valley Authority U.S. Nuclear Regulatory Commission ET 11A Browns Ferry Nuclear Plant 400 West Summit Hill Drive 10833 Shaw Road Knoxville, TN 37902 Athens, AL 35611-6970 Mr. John C. Fornicola, Manager State Health Officer Nuclear Assurance and Licensing Alabama Dept. of Public Health Tennessee Valley Authority RSA Tower - Administration 6A Lookout Place Suite 1552 1101 Market Street P.O. Box 303017 Chattanooga, TN 37402-2801 Montgomery, AL 36130-3017 Mr. Kurt L. Krueger, Plant Manager Chairman Browns Ferry Nuclear Plant Limestone County Commission Tennessee Valley Authority 310 West Washington Street P.O. Box 2000 Athens, AL 35611 Decatur, AL 35609 Mr. Jon R. Rupert, Vice President Browns Ferry Unit 1 Restart Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609