ML043130081
| ML043130081 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/07/2005 |
| From: | Chernoff M NRC/NRR/DLPM/LPD2 |
| To: | Singer K Tennessee Valley Authority |
| Jabbour K, NRR/DLPM, 415-1496 | |
| References | |
| GL-96-006, TAC MC3186 | |
| Download: ML043130081 (7) | |
Text
February 7, 2005 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, UNIT 1 CLOSEOUT OF GENERIC LETTER 96-06, ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS (TAC NO. MC3186)
Dear Mr. Singer:
On September 30, 1996, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 96-06, Assurance of Equipment Operability and Containment Integrity During Design Basis Accident Conditions, to holders of operating licenses for nuclear power reactors, except those that have been amended for a possession-only status. The GL requested information from licensees related to two concerns: (1) water hammer and two-phase flow in the cooling water systems that serve the containment air coolers during postulated accident conditions, and (2) thermally induced overpressurization of isolated water-filled piping systems that penetrate the containment.
By letter dated May 12, 2004, the Tennessee Valley Authority (TVA) provided its response to the GL for the Browns Ferry Nuclear Plant, Unit 1. The NRC staff has completed its review of the response, and concluded that, based on the evaluation contained in the enclosure, TVA has provided an acceptable resolution to the GL 96-06 concerns. If you have any questions regarding this matter, please contact me at (301) 415-4041.
Sincerely,
/RA/
Margaret H. Chernoff, Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No.: 50-259
Enclosure:
Safety Evaluation cc w/encl: See next page
ML043130081 NRR-106 OFFICE PDII-2/PM PDII-2/LA EMEB/SC SPLB/SC (A) SRXB/SC OES/SC (A) PDII-2/SC NAME MChernoff BClayton KManoly Input Dated JYerokun Input Dated FAkstulewicz AMcMurtray MMarshall DATE 12/15/04 12/15/04 10/7/04 7/2/04 11/9/04 11/10/04 2/7/05
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION GENERIC LETTER 96-06, ASSURANCE OF EQUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN-BASIS ACCIDENT CONDITIONS BROWNS FERRY NUCLEAR PLANT, UNIT 1 DOCKET NUMBER 50-259 INTRODUCTION On September 30, 1996, the U. S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 96-06, Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions. The GL included a request for licensees to evaluate cooling water systems that serve containment air coolers during postulated accident conditions to assure that they are not vulnerable to water hammer and two-phase flow conditions.
Additionally, licensees were requested to evaluate piping systems that penetrate containment to determine if they are susceptible to thermal expansion of fluid which could lead to overpressurization of piping. By letter dated May 12, 2004, the Tennessee Valley Authority (TVA or the licensee) provided its response to the GL for the Browns Ferry Nuclear Plant (BFN), Unit 1.
WATER HAMMER AND TWO-PHASE FLOW ISSUES By letter dated February 15, 2000, the NRC staff accepted TVAs resolution of the water hammer and two-phase flow issues for BFN Units 2 and 3. At that time, resolution of the GL issues for Browns Ferry Unit 1 was not addressed because the plant was being maintained in a shutdown and defueled condition. The staff indicated in its February 15, 2000, letter to TVA that resolution of GL 96-06 for BFN Unit 1 would be revisited in the event of plant restart.
Based on the analysis performed using the Generation of Thermal-Hydraulic Information for Containments (GOTHIC) 5.0c computer program, TVA has determined that the liquid in the containment cooler coils will not boil during a design-basis steam line break or loss-of-coolant accident. Therefore, water hammer and two-phase flow conditions will not occur. The licensees analysis and conclusions for BFN Unit 1 are similar to and consistent with those that were reached for BFN Units 2 and 3. Boiling in the Reactor Building Closed Cooling Water (RBCCW) System is precluded by the static pressure that is provided by the respective units RBCCW System head tank. Therefore, the NRC staff finds that the licensees resolution of the GL 96-06 waterhammer and two-phase flow issues for BFN Unit 1 is acceptable.
Although the staff considers the licensees response and resolution of the GL 96-06 water hammer and two-phase flow issues to be acceptable for BFN Unit 1, a detailed quantitative assessment of the licensees waterhammer and two-phase flow analyses, and a review of the licensees use and application of computer codes for performing these analyses have not been performed by the staff.
THERMALLY INDUCED PRESSURIZATION OF PIPING RUNS TVA submittal indicated that the conclusions from the BFN Unit 1 evaluation are consistent with the previous evaluations for Units 2 and 3. As a result of these evaluations, TVA committed to the following actions prior to the restart of BFN Unit 1:
Modify the Unit 1 drywell floor and equipment drain sump discharge lines to provide a designed method of overpressure protection.
Revise plant procedures to ensure water is partially drained from portions of the demineralized water system inside the drywell and the system left open to the drywell during power operation.
The NRC staff review of TVAs actions in response to GL 96-06 for BFN Units 2 and 3 is documented in a letter from NRC to TVA dated February 15, 2000. The staff noted in the letter that procedural modifications would be made at BFN to ensure that the demineralized water system cannot be overpressurized, and that the drywell floor and equipment drain sump discharge lines would be modified at BFN Units 2 and 3 to provide overpressure protection.
TVAs previous actions were reviewed and found acceptable by the staff.
The staff finds that TVAs evaluation and commitments for BFN Unit 1 are consistent with its previous actions regarding BFN Units 2 and 3. Therefore, the staff concludes that TVAs commitments provide an acceptable resolution for the issue of thermally-induced pressurization of piping runs penetrating containment for BFN Unit 1.
CONCLUSION Based upon the discussions above, the NRC staff concludes that the licensees response and resolution of the water hammer and two-phase flow issues, and its commitments to provide a satisfactory resolution for the thermally-induced pressurization of piping runs penetrating containment are acceptable for BFN Unit 1. This evaluation concludes the NRC staffs review on this subject and closes-out TAC No. MC3186.
Principal Contributors: James E. Tatum John R. Fair Date: February 7, 2005
Mr. Karl W. Singer BROWNS FERRY NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, General Manager Nuclear Engineering Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael D. Skaggs Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Kurt L. Krueger, Plant Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 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 Mr. Robert G. Jones Browns Ferry Unit 1 Plant Restart Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Fredrick C. Mashburn Senior Program Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Timothy E. Abney, Manager Licensing and Industry Affairs Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant 10833 Shaw Road Athens, AL 35611-6970 State Health Officer Alabama Dept. of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, AL 36130-3017 Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611 Mr. Karl W. Singer Tennessee Valley Authority cc:
Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael J. Lorek, General Manager Nuclear Engineering Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael D. Skaggs Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Kurt L. Krueger, Plant Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 BROWNS FERRY NUCLEAR PLANT 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 Mr. Robert G. Jones Browns Ferry Unit 1 Plant Restart Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Fredrick C. Mashburn Senior Program Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Timothy E. Abney, Manager Licensing and Industry Affairs Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant 10833 Shaw Road Athens, AL 35611-6970 State Health Officer Alabama Dept. of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, AL 36130-3017 Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611