ML070740430
| ML070740430 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/27/2007 |
| From: | Chernoff M NRC/NRR/ADRO/DORL/LPLII-2 |
| To: | Singer K Tennessee Valley Authority |
| Chernoff M, NRR/DORL, 415-4041 | |
| References | |
| Download: ML070740430 (11) | |
Text
March 27, 2007 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 - REVISION TO SAFETY EVALUATION FOR AMENDMENT NO. 267 DATED FEBRUARY 6, 2007
Dear Mr. Singer:
On February 6, 2007, the Nuclear Regulatory Commission (NRC) issued Amendment No. 267 to Facility Operating License No. DPR-33 for the Browns Ferry Nuclear Plant (BFN), Unit 1.
The amendment revised the numeric values of the safety limit minimum critical power ratio (SLMCPR) in the Technical Specification Section 2.1.1.2 for one and two reactor recirculation loop operation to incorporate the results of the BFN, Unit 1, Cycle 7, SLMCPR analysis. The amendment was issued in response to your application dated May 1, 2006, as supplemented by letters dated September 1 and November 6, 2006.
During a review of this amendment, the Tennessee Valley Authority staff identified a statement that needed clarification. This letter transmits revised page 2, which contains the clarification, and revised page 6, which contains a typographical error correction of the NRC staffs safety evaluation (SE) associated with Amendment No. 267. describes the revisions to the SE. The revised pages are provided in Enclosure 2 and replace the associated pages in the NRC staff's original SE. The revisions do not change the conclusions of the NRC staffs original SE. The changes transmitted in this letter also apply to the proprietary version of the SE that was sent to you in the NRC staff's letter dated February 6, 2007.
K. Singer If there are any questions concerning this matter, please contact me at (301) 415-4041.
Sincerely,
/RA/
Margaret H. Chernoff, Sr. Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-259
Enclosures:
As stated cc w/encls: See next page
.: ML070740430
- NLO with edits OFFICE LPLIII-1/PM LPLII-2/PM LPLII-2/LA SRXB/BC OGC*
LPL2-2/BC NAME AMuniz MChernoff BClayton GCranston JMartin LRaghavan DATE 3/26/07 3/26/07 3/26/07 3/22/07 3/26/07 3/27/07
BROWNS FERRY NUCLEAR PLANT, UNIT 1 CORRECTIONS TO THE NRC STAFFS SAFETY EVALUATION FOR AMENDMENT NO. 267 PAGE #
ORIGINAL TEXT REVISED TEXT REASON FOR THE CHANGE 2
once-burned fresh unburned Accurately describe Cycle 7 fuel 6
[ ]
(( ))
Use of double brackets to mark proprietary information
ENCLOSURE 2: REVISED SE PAGES 2.0 EVALUATION 2.1 Description of Change The licensee for BFN Unit 1 proposes to revise TS 2.1.1.2 for the dual recirculation loop and single recirculation loop SLMCPR values to reflect results of a cycle-specific calculation performed by Global Nuclear Fuels (GNF) for BFN Unit 1 Cycle 7 operation. Specifically, the licensee seeks to change the SLMCPR from 1.10 to 1.09 for dual-loop recirculation, and from 1.12 to 1.11 for single-loop recirculation, at steam dome pressures greater than 785 pounds per square inch gauge (psig) and at core flows greater than 10 percent of rated core flow.
The licensee shut down BFN Unit 1 voluntarily in 1985, and it has not operated since. As a result, the Cycle 7 core is an initial core designed for the restart of BFN Unit 1. Cycle 7, BFN Unit 1 will also implement operation at a higher power/flow operating domain known as the Maximum Extended Load Line Limit Analysis (MELLLA). The Cycle 7 core is designed for a nominal 24-month EPU operating cycle.
The BFN Unit 1, Cycle 7, initial core consists of predominantly fresh fuel. The EPU/MELLLA core is loaded with 564 fresh GE [General Electric]14 fuel assemblies, 108 fresh GE13 fuel assemblies, and 92 previously-irradiated assemblies from the BFN Unit 2, Cycle 13 core. The irradiated fuel is loaded in the periphery of the core, and the fresh fuel is loaded in the core interior. This fuel-loading pattern makes the BFN Unit 1 core design unique for upcoming Cycle 7, in which the core will be loaded with high reactivity fresh unburned fuel.
The SLMCPR is calculated on a cycle-specific basis, because it is necessary to account for the core configuration-specific neutronic and thermal-hydraulic response.
2.2 Regulatory Evaluation Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36, Technical specifications,"
provides the regulatory requirements for the content required in a licensees TSs. As stated in 10 CFR 50.36, the TSs will include Surveillance Requirements (SRs) to assure that the limiting conditions for operation (LCO) will be met.
At the time BFN was licensed, 10 CFR Part 50 Appendix A, "General Design Criteria (GDC) for Nuclear Power Plants," was not incorporated in the NRC regulations. BFN conformed to the draft Proposed GDC 27 (Units 1 and 2) and draft Proposed GDC 70 (Unit 3) criteria current at the time of the BFN design. The design bases of each unit of this plant were reevaluated by the licensee against the draft Proposed GDC 70 criteria current at the time of operating license application. The licensee concluded that each unit of this plant conforms with the intent of the GDC for Nuclear Power Plant Construction Permits. The references to the criteria below refer to these proposed GDC, not the GDC in Appendix A of 10 CFR Part 50.
Draft proposed Criterion 6, Reactor core design, states that the reactor core shall be designed to function throughout its design lifetime, without exceeding acceptable fuel damage limits that have been stipulated and justified. The core design, together with reliable process and decay Revised by letter dated March 27, 2007 provides assessment of the applicability of GENE, NRC-approved, analytical methods and codes used to support operation at EPU conditions at BFN Unit 1. The topical report covered the power distribution uncertainties applied to the SLMCPR calculation and the supporting measurement data. The report proposed applying a statistical treatment to currently available gamma scan data, which has resulted in an increase in power distribution uncertainties applied to the SLMCPR. The pin power uncertainties change from (( )) percent to (( )) percent. The bundle power allocation uncertainty (pal) changes from (( )) percent to (( )) percent. The increase in the pin and bundle power uncertainties yield a total of 0.02 increase of the SLMCPR.
Accordingly, for BFN Unit 1, the cycle-specific SLMCPR value has been increased by a value of 0.02. This SLMCPR adder will provide additional confidence that the power distribution uncertainties applied to the SLMCPR remains conservative.
3.2 Power Shape Penalties Based on the findings of an NRC staff audit of the GNF GEXL databases, the NRC staff requires plant specific justification for the validity of the GEXL correlation. In the case of BFN, Unit 1, ((
)) The NRC staff finds that penalties were not necessary at BFN, Unit 1, and that the GEXL correlation remains valid based on the above consideration.
3.3 Deviation from R-Factor Uncertainties The licensee proposes to deviate from R-factor uncertainties that have previously been accepted by the NRC. The R-factor is an input to the GEXL critical power correlation that captures the local peaking influence on the predicted onset of boiling transition. The R-factor uncertainty is related to the uncertainty associated with nuclear methods in determining the fuel pin power peaking, and it includes terms for manufacturing and channel bow uncertainties.
((
)) The NRC has reviewed this approach, and found it to influence the SLMCPR in a conservative manner. The NRC staff also considered that BFN, Unit 1 is a D lattice plant and, therefore, is not susceptible to control blade shadow corrosion induced channel bow. Finally, the NRC staff confirmed that the fuel channels used in the BFN Unit 1, Cycle 7, core are either new or once-burned. Therefore, the NRC staff finds that this deviation is both conservative and acceptable.
3.4 Zircaloy Spacer Issues The GEXL14 correlation used to determine the SLMCPR for the GE14 fuel was developed using test results at the ATLAS test facility. Communications submitted by GE in accordance with 10 CFR Part 21 indicated a potential problem with the GEXL14 correlation due to GE14 Revised by letter dated March 27, 2007
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, Vice President Nuclear Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Brian OGrady, Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Preston D. Swafford, Senior Vice President Nuclear Support Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, General Manager Nuclear Assurance Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Bruce Aukland, Plant Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Masoud Bajestani, 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, General Manager Browns Ferry Site Operations Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Larry S. Mellen Browns Ferry Unit 1 Project Engineer Division of Reactor Projects, Branch 6 U.S. Nuclear Regulatory Commission 61 Forsyth Street, SW.
Suite 23T85 Atlanta, GA 30303-8931 Ms. Beth A. Wetzel, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. William D. Crouch, 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. Robert H. Bryan, Jr., General Manager Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801