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Initiation
- Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request, Request
- Acceptance...
- Supplement, Supplement, Supplement, Supplement, Supplement, Supplement
Administration
- Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance, Withholding Request Acceptance
- Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting
Results
Other: ML070370281, ML073100027, ML073510180, ML080360067, ML080430700, ML080500171, ML080530256, ML081010450, ML081010451, ML081120502, ML081700294, ML081720078, ML081760295, ML082040065, ML082050462, ML082100425, ML082810470, ML083120308, ML083240224, ML083250083, ML090130718, ML090340528, ML090720951, ML090760630, ML091320366, ML092020345, ML092430520, ML092440518, ML092460495, ML092460496, ML092460497, ML092460498, ML092460500, ML092540483, ML092680057, ML12319A076, ML13044A498
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MONTHYEARML0711503712007-04-24024 April 2007 Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) - Steam Dryer Evaluations Project stage: Request ML0712905652007-05-16016 May 2007 Withholding Information from Public Disclosure, Response to Nuclear Regulatory Commission (NRC) Request for Additional Information - Round 12 for Browns Ferry EPU: Supplemental to SBWB-64 Project stage: RAI ML0716303492007-06-15015 June 2007 Meeting with the Tennessee Valley Authority Concerning the Status of Browns Ferry Nuclear Plant, Units 1, 2 and 3, Steam Dryer Review Project stage: Meeting ML0718700242007-07-0303 July 2007 Technical Specifications (TS) Change TS-461 - Modification of Restart Large Transient Testing License Condition 2. (G) 2 - Supplement 1 Project stage: Request ML0717801902007-07-0505 July 2007 Request for Additional Information for Extended Power Uprate - Round 13 (TS-431 and TS-418 (TAC Nos. MD5262, MD5263, and MD5264) Project stage: RAI ML0719004762007-07-10010 July 2007 Meeting with the Tennessee Valley Authority (TVA) Concerning the Pending ACRS Meeting on the Browns Ferry Extended Power Uprate Project stage: Meeting ML0721501562007-07-18018 July 2007 Slides from Meeting with Tennessee Valley Authority on the Browns Ferry Power Uprate ACRS Presentation Project stage: Meeting ML0721303712007-07-27027 July 2007 Technical Specifications Changes TS-431 and TS-418, Extended Power Uprate - Steam Dryer Evaluations Project stage: Request ML0721400442007-08-0808 August 2007 Summary of Meeting with Tennessee Valley Authority on the Browns Ferry Power Uprate ACRS Presentation Project stage: Meeting ML0724805472007-08-31031 August 2007 Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) - Response to Round 13 Request for Additional Information (RAI) - Containment Overpressure Project stage: Request ML0727606602007-10-0909 October 2007 Request for Additional Information for Extended Power Uprate - Round 14 (TS-418) Project stage: RAI ML0728902372007-10-18018 October 2007 Request for Withholding Information from Public Disclosure Concerning Round 13 Request for Additional Information for Browns Ferry Nuclear Plant (Tac Nos. MD5262, MD5263 and MD5264) Project stage: RAI ML0729603112007-10-22022 October 2007 Technical Specification (TS) Changes TS-431 & TS-418, Extended Power Uprate - EPU Large Transient Testing Project stage: Request ML0731000272007-11-0909 November 2007 Request for Schedule Regarding Analysis for Steam Dryers on Extended Power Uprate Amendment Requests (TAC Nos. MD5262, MD5263, and MD5264) (TS-431 and TS-418-S) Project stage: Other ML0732303482007-11-15015 November 2007 Units 1, 2, and 3 - Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) - Response to Round 13 Request for Additional Information (RAI) - Containment Overpressure APLA-35/37 Project stage: Request ML0733304832007-11-21021 November 2007 Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) - Response to Preliminary Findings on Steam Dryer Stress Analysis Project stage: Request ML0735101802007-12-14014 December 2007 Technical Specifications Changes TS-431 and TS-418 - Extended Power Uprate - Schedule Regarding Analysis for Steam Dryers Project stage: Other ML0734607572007-12-19019 December 2007 Request for Withholding Information from Public Disclosure for Browns Ferry Nuclear Plant (Tac No. MD5262, MD5263 and MD5264) Project stage: Withholding Request Acceptance ML0735400102008-01-25025 January 2008 Summary of Meeting with Tennessee Valley Authority on Steam Dryer Portion of the Extended Power Uprate Review (TAC Nos. MD5262, MD5263, and MD5264), Browns Ferry Units 1, 2, and 3 Project stage: Meeting ML0801504182008-01-25025 January 2008 Plants, Units 1, 2, and 3 - (Public Version) - Summary of December 10, 2007 Meeting with TVA on Steam Dryer Portion of the Extended Power Uprate Review Project stage: Meeting ML0803205212008-01-25025 January 2008 Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) Response to Round 15 Request for Additional Information (RAI) - APLA-38/40, SRXB-71, and SRXB-72 Project stage: Request ML0803600672008-01-25025 January 2008 Steam Dryer RAI 15 Status, Slides Project stage: Other ML0802501652008-01-30030 January 2008 Request for Withholding Information from Public Disclosure for Browns Ferry Nuclear Plant (Tac Nos. MD5262, MD5263, and MD5264) Project stage: Withholding Request Acceptance ML0803805602008-01-31031 January 2008 Technical Specifications (TS) Change TS-431 and TS-418 - Extended Power Uprate (EPU) - Response to Round 15 Request for Additional Information (RAI) Regarding Steam Dryer Analyses Project stage: Request ML0804307002008-02-11011 February 2008 Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) - Schedule Regarding EPU Project stage: Other ML0803503812008-02-14014 February 2008 Summary of Meeting with Tennessee Valley Authority - on Extended Power Uprate Review Project stage: Meeting ML0805302562008-02-21021 February 2008 Unit 1 - Technical Specifications (TS) Change TS-431 - Extended Power Uprate (EPU) - Fuels Methods Commitments Project stage: Other ML0806501012008-02-21021 February 2008 Response to Round 16 Request for Additional Information SRXB-73 Project stage: Request ML0804506472008-02-27027 February 2008 Request for Withholding Information from Public Disclosure Project stage: Withholding Request Acceptance ML0803506982008-02-29029 February 2008 Request for Additional Information for Extended Power Uprate - Round 16 (TS-431 and TS-418) (TACs MD5262, MD5263, MD5264) Project stage: RAI ML0807104982008-03-0606 March 2008 (BFN) - Units 1, 2, and 3 - Technical Specifications (TS) Change TS-418 and TS-431 - Extended Power Uprate (EPU) - Response to Round 16 Request for Additional Information (RAI) - SRXB-74/86 and SRXB-87 Through SRXB-90 Project stage: Request ML0811205102008-03-20020 March 2008 Summary of March 20, 2008, Meeting with Tennessee Valley Authority Regarding Steam Dryer Portion of the Extended Power Uprate Review (TAC Nos. MD5262, MD5263, and MD5264) - Slides Project stage: Meeting ML0810104512008-04-0404 April 2008 Technical Specifications (TS) Changes TS-431 and TS-418 Extended Power Uprate (EPU) BFN Steam Monitoring Plan Project stage: Other ML0810104502008-04-0404 April 2008 (BFN) - Units 1, 2, and 3 - Technical Specifications (TS) Changes TS-431 and TS-418 - Extended Power Uprate (EPU) - Response to Round 15 and Round 16 Requests for Additional Information (RAI) Regarding Steam Dryer Analyses Project stage: Other ML0817602952008-04-0909 April 2008 Units 1, 2, & 3 - Technical Specifications Changes TS-431 and TS-418 - Extended Power Uprate - Confirmation of Commitment Completions Project stage: Other ML0811205022008-04-16016 April 2008 CDI Incoming Letter Dated April 16, 2008 Regarding NRC Presentation Entitled, Tennessee Valley Authority Browns Ferry Nuclear Plant - Extended Power Uprate Steam Dryers. Project stage: Other ML0811302312008-04-17017 April 2008 Public Slides - Summary of April 17, 2008, Meeting Regarding Steam Dryer Portion of the Extended Power Uprate Review, Project stage: Meeting ML0811200332008-04-30030 April 2008 Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Browns Ferry Nuclear Plant, Units 1, 2, and 3 - Request for Withholding Information from Public Disclosure for Round 15 Fuels Responses Project stage: Withholding Request Acceptance ML0812806272008-05-0101 May 2008 Technical Specifications Change TS-418, Extended Power Uprate Supplemental Response to Round 16 Request for Additional Information - SRXB-87 & SRXB-89 Project stage: Supplement ML0813502222008-05-0202 May 2008 Request for Additional Information for Extended Power Uprate - Round 17 (TS-431 and TS-410) Project stage: RAI ML0805001712008-05-0202 May 2008 - Schedule Regarding Analysis for Steam Dryers on Extended Power Uprate Amendment Requests (TAC Nos. MD5262, MD5263, and MD5264) (TS-431 and TS-418) Project stage: Other ML0812804712008-05-0202 May 2008 Request for Additional Information for Extended Power Uprate - Round 17 Project stage: RAI ML0813602912008-05-22022 May 2008 Summary of April 17, 2008, Meeting Regarding Steam Dryer Portion of the Extended Power Uprate Review Project stage: Meeting ML0815805532008-05-22022 May 2008 Summary of 5/22/08 Meeting Regarding Containment Overpressure Portion of the Extended Power Uprate Review - Browns Ferry - Handouts Project stage: Meeting ML0810604452008-06-0202 June 2008 Request for Withholding Information from Public Disclosure for Partial Round 13 Responses (Tacs. MD5262, MD5263 and MD5264) Project stage: Withholding Request Acceptance ML0810606162008-06-0202 June 2008 Request for Withholding Information from Public Disclosure for Browns Ferry Nuclear Plant Project stage: Withholding Request Acceptance ML0810607222008-06-0202 June 2008 Request for Withholding Information from Public Disclosure for Partial Response to Round 13 Project stage: Withholding Request Acceptance ML0816403252008-06-0303 June 2008 Units 2 & 3 - Technical Specifications Change TS-418 - Extended Power Uprate - Supplemental Response to Round 16 Request for Additional Information - SRXB-88 Project stage: Supplement ML0812607122008-06-0505 June 2008 Summary of Meeting with TVA Steam Dryer Portion of the Extended Power Uprate Review Project stage: Meeting ML0817002942008-06-12012 June 2008 Technical Specifications Changes TS-431 and TS-418 - Extended Power Uprate - Response to ACRS Conclusions and Recommendations Regarding Containment Overpressure Credit Project stage: Other 2008-01-30
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Category:Letter
MONTHYEARML24219A0272024-08-0606 August 2024 Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations IR 05000259/20244022024-08-0606 August 2024 Security Baseline Inspection Report 05000259/2024402 and 05000260/2024402 and 05000296/2024402 IR 05000259/20240022024-08-0202 August 2024 Brown Ferry Nuclear Plant – Integrated Inspection Report05000259/2024002 and 05000260/2024002 and 05000296/2024002 ML24199A0012024-07-22022 July 2024 Clarification and Correction to Exemption from Requirement of 10 CFR 37.11(c)(2) ML24172A1342024-07-15015 July 2024 Exemptions from 10 CFR 37.11(C)(2) (EPID L-2023-LLE-0024) - Letter ML24183A4142024-07-10010 July 2024 – License Renewal Regulatory Limited Scope Audit Regarding the Environmental Review of the License Renewal Application (EPID Number: L-2024-SLE-0000) (Docket Numbers: 50-259, 50-260, and 50-296) ML24184A1142024-07-0202 July 2024 Site Emergency Plan Implementing Procedure Revision ML24183A3842024-07-0101 July 2024 Registration of Use of Cask to Store Spent Fuel (MPC-364, -365) ML24179A0282024-06-26026 June 2024 Evaluation of Effects of Out-of-Limits Condition as Described in IWB-3720(a) ML24175A0042024-06-23023 June 2024 Interim Report of a Deviation or Failure to Comply Associated with a Valve in the Unit 3 High Pressure Coolant Injection System ML24176A1132024-06-23023 June 2024 American Society of Mechanical Engineers, Section XI, Fourth 10 Year Inspection Interval, Inservice Inspection, System Pressure Test, Containment Inspection, and Repair and Replacement Programs, Owner’S Activity Report Cycle 21 Oper ML24155A0042024-06-18018 June 2024 Proposed Alternative to the Requirements of the ASME Code (Revised Alternative Request 0-ISI-47) ML24158A5312024-06-0606 June 2024 Registration of Use of Cask to Store Spent Fuel (MPC-361, -362, -363) IR 05000259/20244032024-05-22022 May 2024 – Security Baseline Report 05000259/2024403 and 05000260/2024403 and 05000296/2024403 ML24141A0482024-05-17017 May 2024 EN 56958_1 Ametek Solidstate Controls, Inc ML24136A0702024-05-15015 May 2024 2023 Annual Radiological Environmental Operating Report IR 05000259/20240012024-05-14014 May 2024 Integrated Inspection Report 05000259/2024001, 05000260/2024001, and 05000296/2024001 CNL-24-040, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-05-0808 May 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure Revisions ML24123A2012024-05-0202 May 2024 NRC Cybersecurity Baseline Inspection (NRC Inspection Report 05000259/2024404, 05000260-2024404, 05000296/2024404) and Request for Information ML24122A6852024-05-0101 May 2024 2023 Annual Radioactive Effluent Release Report and Offsite Dose Calculation Manual ML24116A2522024-04-25025 April 2024 Site Emergency Plan Implementing Procedure Revision CNL-24-036, – 10 CFR 50.46 Annual Report2024-04-25025 April 2024 – 10 CFR 50.46 Annual Report CNL-24-037, Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 422024-04-22022 April 2024 Clinch River, Sequoyah, Units 1 and 2, Watts Bar, Unit 1 and 2, Nuclear Quality Assurance Plan, TVA-NQA-PLN89-A, Revision 42 CNL-24-024, Hydrologic Engineering Center River Analysis System Project Milestone Status Update2024-04-17017 April 2024 Hydrologic Engineering Center River Analysis System Project Milestone Status Update CNL-24-033, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2024-04-17017 April 2024 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions ML24032A4762024-02-0101 February 2024 Final Report of a Part 21 Evaluation Associated with Starter Contactors for the BFN Unit 1 High Pressure Coolant Injection Suppression Pool Inboard Suction Valve ML24023A2802024-01-23023 January 2024 Final Report of a Deviation or Failure to Comply Associated with a Relay in the Reactor Core Isolation Cooling Condensate Pump CNL-24-017, Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions2024-01-17017 January 2024 Tennessee Valley Authority - Central Emergency Control Center Emergency Plan Implementing Procedure and Emergency Preparedness Department Procedure Revisions ML24016A3042024-01-16016 January 2024 Final Report of a Part 21 Evaluation Associated with Check Valve 0-CKV-023-0565 for D1 Residual Heat Removal Service Water Pump CNL-23-071, Response to Request for Additional Information Regarding Browns Ferry Nuclear Plant, Units 1, 2, and 3, Inservice Inspection and Augmented Program Interval Revised Request for Alternative 0-ISI-472024-01-11011 January 2024 Response to Request for Additional Information Regarding Browns Ferry Nuclear Plant, Units 1, 2, and 3, Inservice Inspection and Augmented Program Interval Revised Request for Alternative 0-ISI-47 ML24022A1732024-01-0303 January 2024 Receipt and Availability of the Subsequent License Renewal Application ML23319A1992024-01-0303 January 2024 Issuance of Amendment Nos. 333, 356, and 316 Regarding the Technical Specification Surveillance Requirements 3.4.3.2 and 3.5.1.11 Regarding Safety Relief Valves ML23355A2062023-12-21021 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23348A3942023-12-14014 December 2023 Interim Part 21 Report of a Potential Deviation or Failure to Comply Associated with Starter Contactors for the High Pressure Coolant Injection Suppression Pool Inboard Suction Valve IR 05000259/20230102023-12-11011 December 2023 Commercial Grade Dedication Inspection Report 05000259/2023010 and 05000260/2023010 and 05000296/2023010 ML23335A0722023-12-0101 December 2023 Interim Report of a Deviation or Failure to Comply Associated with a Relay in the Unit 2 Reactor Core Isolation Cooling Condensate Pump ML23334A2492023-11-30030 November 2023 Site Emergency Plan Implementing Procedure Revision CNL-23-070, Submittal of Fifth 10-Year Interval Inservice Testing Program Plan2023-11-29029 November 2023 Submittal of Fifth 10-Year Interval Inservice Testing Program Plan ML23331A2532023-11-27027 November 2023 Summary Report for 10 CFR 50.9 Evaluations, Technical Specifications Bases Changes, Technical Requirement Manual Changes, and NRC Commitment Revisions CNL-23-067, Central Emergency Control Center Emergency Plan Implementing Procedure Revisions2023-11-27027 November 2023 Central Emergency Control Center Emergency Plan Implementing Procedure Revisions ML23325A1102023-11-21021 November 2023 Anchor Darling Double Disc Gate Valve Commitment Revision ML23320A2542023-11-16016 November 2023 Interim Part 21 Report of a Deviation or Failure to Comply Associated with Check Valve 0-CKV-023-0565 for D1 Residual Heat Removal Service Water Pump IR 05000259/20230032023-11-13013 November 2023 Integrated Inspection Report 05000259/2023003, 05000260/2023003 and 05000296/2023003 IR 05000259/20230402023-11-0202 November 2023 Supplemental Inspection Supplemental Report 05000259 2023040 and Follow-Up Assessment Letter ML23292A2532023-10-18018 October 2023 BFN 2024-301, Corporate Notification Letter (210-day Ltr) ML23282A0022023-10-0606 October 2023 Interim Part 21 Report of a Deviation or Failure to Comply Associated with Check Valve 0-CKV-023-0565 for D1 Residual Heat Removal Service Water Pump ML23278A0122023-10-0505 October 2023 Updated Final Safety Analysis Report, Amendment 30 ML23271A1702023-09-28028 September 2023 Site Emergency Plan Implementing Procedure Revision ML23270A0702023-09-26026 September 2023 SLRA Pre-Application Meeting Summary 09-13-2023 2024-08-06
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Text
Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 May 7, 2009 TVA-BFN-TS-431 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop OWFN, P1-35 Washington, D. C. 20555-0001 In the Matter of ) Docket Nos. 50-259 Tennessee Valley Authority )
BROWNS FERRY NUCLEAR PLANT (BFN) - UNIT 1 - TECHNICAL SPECIFICATIONS i (TS) CHANGE TS-431 - EXTENDED POWER UPRATE (EPU) - RESPONSE TO ROUND 23 REQUEST FOR ADDITIONAL INFORMATION (RAI) EMCB.207 (TAC NO. MD5262)
By letter dated June 28, 2004 (ADAMS Accession No. ML041840109), TVA submitted a license amendment application to NRC for the EPU of BFN Unit 1. The proposed amendment would change the operating license to increase the maximum authorized core thermal power level by approximately 14 percent to 3952 megawatts.
On April 22, 2009, NRC staff issued a Round 23 RAI (ML091000283) regarding the EPU license amendment request. The enclosure to this letter provides the response for Round 23 RAI EMCB.207. This RAI is associated with the steam dryer stress analyses performed for EPU.
TVA has determined that the additional information provided by this letter does not affect the no significant hazards considerations associated with the proposed TS change. The proposed TS change still qualifies for a categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51.22(c)(9).
U.S. Nuclear Regulatory Commission Page 2 May 7, 2009 No new regulatory commitments are made in this submittal. If you have any questions regarding this letter, please contact J. D. Wolcott at (256) 729-2495.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 7 th day of May, 2009.
Sincerely,
- R.G*.West Site Vice President
Enclosure:
Response to Round 23 Request for Additional Information (RAI) EMCB.207
U.S. Nuclear Regulatory Commission Page 3 May 7, 2009 Enclosure cc (Enclosure):
State Health Officer Alabama State Department of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, Alabama 36130-3017 Ms. Eva Brown, Project Manager U.S. Nuclear Regulatory Commission (MS 08G9)
One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Ms. Heather J. Gepford, Branch Chief 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 Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970
ENCLOSURE TENNESSEE VALLEY AUTHORITY ý BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 1 TECHNICAL SPECIFICATIONS (TS) CHANGE TS-431 EXTENDED POWER UPRATE (EPU)
RESPONSE TO ROUND 23 REQUEST FOR ADDITIONAL INFORMATION (RAI) EMCB.207 NRC RAI EMCB.207 (Unit 1)
In Enclosure 1 to the letter dated April 3, 2009, TVA responded to EMCB 206. The response considers the possibility of galloping of the unattached portion of the beam to demonstrate that galloping is not a problem. Although the analysis approach used by TVA appears reasonable, the questions regarding the initial assumptions remain. It was expected that the response would address the worst case scenario, especially if the stitch weld of the beam is not to be included in the inspection program. This worst case scenario should consider that the stitch weld is inactive along the whole base plate of the innermost dryer vane bank and, therefore, the beam would be cantilevered on the base plate of the adjacent vane bank.
In this case, the length of the free end of the beam appears to be substantially longer than the 14.5 inches assumed in the galloping analysis and the frequency would be substantially lower.
The relevant vibration mode and the relevant flow direction appear to be different from those assumed in the galloping analysis.
Provide an assessment of the worst case loose section length for galloping/flutter with more appropriate assumptions of the length of the unattached portion of the beam, the relevant vibration mode, and the relevant direction of the cross flow.
TVA Response to EMCB.207 (Unit 1)
Evaluations of the Unit 1 steam dryer support beams were discussed in Enclosure 1 of the submittal dated March 11, 2009, "Steam Dryer Analyses Additional Information,"
(ML090760630) and in the response to RAI EMCB.206 of the submittal dated April 3, 2009, "Response to Round 23 RAI EMCB.205 and EMCB.206," (ML091000291). Of concern is the portion of each support beam (T-beam) that is connected to the base plate of the inner plenum/vane bank. Approximately 24 inches of the end of each support beam is stitch welded on both sides to the inner base plate which is not in the direct steam flow path into the vane banks. Although only the nodes associated with the innermost weld sections exhibit an alternating stress ratio less than 2.0 at EPU conditions, the stress evaluation was conservatively performed by not taking credit for any welds for 14.5 inches from the end of the support beams.
The stress evaluation for this case determined that the EPU alternating stress ratios for this portion of the support beam were well above 2.0. On this basis, the galloping evaluation was performed for the conservative case of a 14.5 inch free end. Since this portion of the support beam is located adjacent to and under the steel plate beneath the vane bank and inner plenum, it is not located in the flow stream. Thus the galloping evaluation assumed steam flow directed horizontally onto the 14.5 inch free end. The analysis showed galloping will not occur.
1
As requested, the galloping analysis was repeated assuming a free end long enough to span the actual flow stream and with the flow directed in the upward direction. This analysis also shows that galloping will not occur. This analysis follows.
Analysis While 14.5 inches constitutes the worst case length, the galloping analysis is repeated here for a hypothetical configuration where a T-beam is completely disconnected from the inner base plate. Under this configuration the total length of detached beam is 39.75 inches, which is the sum of: (i) the inner base plate width (24 inches), or the total length of the T-beam / inner base plate stitch weld; plus, (ii) the width of the inner vane bank plenum (15.75 inches) for which no weld exists. The T-beam remains connected to the middle and outer base plates.
Aerodynamic loading is dominated by vertical flow of 15 feet per second (ft/sec) through the plenum. If the distance x is measured from the cantilever root towards the tip, where x = L = 39.75 inches, then the aerodynamic loading occurs over the range x = 0 to x = 15.75 inches. The equation governing beam vibrations is given by:
a 2w aw a4w pS---2 + a + El----4 =f (1) where w(x,t) is the lateral displacement, p is the density of steel (0.284 pounds per cubic inch (lbs/in 3)), S is the beam cross-sectional area (3.5 in2), D represents 1% structural damping, E is the Young's modulus for 304SS steel at 550' Fahrenheit (E = 25.55 x 106 pounds per square inch), I is the second moment of inertia of the beam about the vertical axis (I = 1.17 in4), and t and x are time and distance along the beam, respectively. Note that because the beam is now forced by flow in the vertical direction, the structural response will be in the horizontal plane, so that the second moment of inertia about the vertical axis is appropriate (the moment of inertia about the horizontal axis is higher and would be relevant to vertical vibrations). The flow-induced force per unit length is:
f 2=I PsU2W +dI (2) where Ps is the density of steam (2.24 Ibs/ft3 ), U is the vertical flow velocity (15 ft/sec), W is the width of the T-beam (3 inches), CD is the drag coefficient (which is always positive and is here conservatively taken to be zero), and dCL/da is the lift curve slope, which must be negative in order for galloping to occur. The parameter A(x) is equal to 1 over the part of the beam exposed to the flow (x = 0 to x = 15.75 inches) and zero elsewhere.
The cantilever is assumed to respond in the first mode. Denoting the associated mode shape by O(x) so that w(x,t) = y(t)4)(x) where y(t) is the modal amplitude, then substituting for w(x,t), multiplying by O(x), and integrating over the length L gives:
L (ý + pS2 D + dx=LfIdx dx f (3) f _y f -
2
Since the mode shape satisfies d 40/dx4 = "4(D,where p4 = pSw2/Ei and w is the angular modal frequency, the preceding result reduces to:
+2~C(Oý+
2 y- PsUW CdCL'+C ) (4) where:
A= LJD2 dxj (D2dx and 2*C = D (5)
Here , is the structural damping ratio (1%). This expression for y(t) is exactly the same as that given in the response to RAI EMCB.206 except for the appearance of the parameter A. In the response to RAI EMCB.206, A = 1 since the flow force acts along the entire beam. Here, the aerodynamic force only acts over the first 15.75 inches of the L = 39.75 inch beam, measured from the root. Using the analytical expression for the first mode shape of a cantilevered beam, A = 0.0174.
From Equation (4), it follows that galloping occurs if the net damping associated with the rate term , due to structural damping and flow-induced damping, d = dsd + dflo < 0 where:
2pS FdCL (6a, b) dsd =2Co) and dfow PsUW &o +CD I A The fundamental cantilever frequency is given by p 4 = pSw 2/EI with PIL = 1.875 or f = w/2rr = 38 Hertz (Hz), so that:
dn0 w - pUW rdCL +C1DX= 0 .0 7 3 7 dCL +CD lA (7) dsd 4pSo L dI& d j Galloping can only occur if this ratio dflow/dsd < -1. To evaluate the last expression, conservatively set Cc = 0. Next, from Figure 3 of Reference 1, the most negative lift curve slope dCL/da, where a is the angle of attack (nominally a = 0), is conservatively estimated as:
dCL dCL d(tanox) -0.3)( 1 ((8)
W CC C = - 1.5 dc d(tanct) dcx 0.2 0cos2ox*=
For added conservatism a working value of -3.0 (twice the estimate) is used to produce:
d = -..0.221A (9) dSd which implies that even for A = 1, which would occur if the entire 39.75 inch beam were exposed to the vertical flow, d,,0 /dsd > -1 and the flow would provide only 22.1 % of the forcing needed to overcome structural damping and induce galloping. Using the more appropriate value of A = 0.0174 derived above when only a part of the beam is 3
subjected to flow forcing, it may be seen that the flow provides less than 0.4% of the forcing needed to overcome structural damping. As a result, galloping is not a concern for this configuration and typical flow speeds U = 15 ft/sec.
Vortex Shedding The galloping phenomenon described above is caused by the negative damping introduced by hydrodynamics, specifically by the negative lift coefficient slope dCL/da.
Another phenomenon known as vortex shedding can also produce instabilities. In this case the formation of a vortex street downstream of a bluff body structure induces fluctuating loads back onto the structure. These shedding frequencies are given by f = 0.2(U/W), where U is the velocity and W is the characteristic cross-section dimension.
Using U = 15 ft/sec and W = 3 inches, one deduces a shedding frequency of 12 Hz, which is well below the fundamental frequency (38 Hz) of the cantilever beam. Given this disparity in frequencies, no vortex shedding induced oscillations will occur.
Conclusions The assumed T-beam disconnection length of 14.5 inches is shown to be conservative, since stress analysis using this disconnection length produces stresses that are significantly lower than the allowable levels. Moreover, any propagation of putative cracks near the T-beam tip is prevented because a stitch weld rather than continuous weld joins the T-beam to the base plates.
In response to the RAI, analysis of the T-beam for galloping is performed under the hypothetical scenario where it is completely disconnected from the inner base plate.
Again, with conservative assumptions regarding the hydrodynamic behavior, the beam is determined to be immune to galloping; the flow provides only 0.4% of the forcing needed to overcome structural damping. Even if the entire length of the disconnected T-beam were subjected to the vertical flow (A = 1), the aerodynamic forcing would be insufficient to produce galloping.
In summary, even for extremely conservative hypothetical scenarios, no galloping of the T-beam occurs.
References
- 1. Carpena, A. & Diana, G., (1972) IEEE Transactionson PowerApparatus and Systems PAS-91, 536-544.
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