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Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000
Ashok S. Bhatnagar
Vice President, Browns Ferry Nuclear Plant
August 30, 2001
U.S. Nuclear Regulatory Commission 10CFR50.73
ATTN: Document Control Desk
Washington, D.C. 20555-0001
Dear Sir:
TENNESSEE VALLEY AUTHORITY - BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS 2 and 3 - DOCKET 50-260 AND 296 - FACILITY OPERATING LICENSE DPR -52 AND DPR -68 - LICENSEE EVENT REPORT (LER) 50-260/2001-002-00
The enclosed report provides details concerning a failure to meet the Technical Specifications. This report is submitted in according with 10CFR 50.73 (a)(2)(i)(B) as any operation or condition which was prohibited by the plant's Technical Specifications. In accordance with NRC RIS 2000-05, only one paper copy of this document is being sent to the NRC Document Control Desk. There are no commitments contained in this letter
Sincerely,
AshokS Bhatnagar
ABSTRACT
On July 2, 2001, TVA confirmed that a potential 10 CFR Part 21 condition related to the use of non-conservative parameters associated with calculation of Oscillation Power Range Monitor (OPRM) upscale trip setpoint was applicable to BFN. At approximately 1100 hours Central Daylight Time the OPRM upscale trip function was declared inoperable. Technical Specification (TS) Actions 3.3.1.1.1.1, and 3.3.1.1.1.2 were entered on both Units 2 and 3. TS Action 3.3.1.1.1.1 requires initiation of alternate method to detect and suppress thermal-hydraulic instability oscillations within 12 hours. Action 3.3.1.1.1.2 requires that the OPRM upscale trip be returned to service in 120 days. The OPRM upscale trip function has been inoperable on Unit 2 since May of 1999, and on Unit 3 since May of 2000. Hence, TVA is reporting this event pursuant to 10 CFR 50.73(a) (2)(i) (B), as any operation or condition which was prohibited by the plant's Technical Specifications. The root cause of this event is the original analysis performed by General Electric (GE) that defines the generic Delta Critical Power Ratio/Initial Versus Oscillation Magnitude curve was inadequate. GE identified a non-conservative deficiency for the high peak bundle power-to-flow ratios in the generic DIVOM curves. GE has proposed the development and licensing of a revised methodology for determining OPRM upscale trip setpoint. However, the revised methodology approval is not expected to meet the TS Action 120 day time limit. Subsequently, TVA proposed a TS change to delete TS Action 3.3.1.1.1.2. This change has been approved for Unit 2.
