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 Report dateSiteEvent description
05000454/LER-2001-00226 November 2001Byron

At 1600 hours on September 26, 2001, it was determined that the two Surveillance Requirements (SR) for the Main Steam Isolation Valves (MSIVs) were not tested in Mode 3, as required. The failure to test the valves in Mode 3 resulted in missed Technical Specifications (TS) Surveillance Requirements (SRs) on all 4 MSIVs on each unit, which resulted in both units entering SR 3.0.3. SR 3.0.3 allows up to 24 hours to either perform the missed surveillances or take other remedial measures. In accordance with the TS Bases, these SRs must be performed in Mode 3. Byron Station has been previously testing the MSIVs in Mode 4. The surveillances can not be performed at power since the SRs require the MSIVs to close. Enforcement Discretion and a subsequent exigent License Amendment Request (LAR) were requested from the NRC to allow continued operations without satisfying the SRs in Mode 3. On September 27, 2001, the NRC granted verbal approval of the Notice of Enforcement Discretion (NOED). The LAR was approved on November 1, 2001. The cause of the missed SR occurred during the Improved Technical Specifications (ITS) implementation project. The procedure revision implementation for the MSIV SRs did not recognize that the more restrictive requirement (i.e., to perform the MSIV SR in Mode 3) was introduced into the TS Bases wording. The root cause of the implementation error was determined to be unknown. Corrective actions include correcting the outage schedule and procedures and reviewing for other potential ITS implementation errors. This event is being reported pursuant to 10CFR50.73(a)(2)(i)(b).

(p:01Iers1454-2001-002-00.doc)

05000455/LER-2001-00317 October 2001Byron

On August 17, 2001, a human performance error occurred on Unit 2, leading to Technical Specification (TS) 3.6.3, Containment Isolation Valves (CIV) non-compliance. A Unit 2 'A' train CIV for the Hydrogen Monitor System was mistakenly identified and used as the isolation boundary for the 'B' train Hydrogen Monitor. In addition to the wrong train, the valve selected was a "fail open" valve and would not isolate the penetration upon being de-activated. Because of this error, the Station failed to correctly isolate the correct containment penetration for the 2B Hydrogen Monitor. In addition the containment penetration for the 'A' Hydrogen Monitor was also rendered inoperable since the 'A' train CIV failed open when power was removed and would not have closed upon receipt of a containment isolation signal. Neither penetration was isolated within the required four hours of the occurrence as required by TS. The error was discovered and rectified approximately 22 hours later. The root cause of this event was determined to be a failure of the licensed operators to follow standard operating practices in determining and implementing equipment isolation boundaries as expressed in departmental procedures and policies. The Operations department is currently developing an Operations Gap Analysis and Excellence Plan. This plan will identify areas where personnel performance is not meeting expectations. Following completion of the plan, implementation of actions necessary to achieve performance improvement will be undertaken. There were no safety consequences impacting plant or public safety as a result of this event. The Hydrogen Monitors and their associated CIVs do not impact core damage frequency.

This event is reportable to the NRC in accordance with 10 CFR 50.73 (a)(2)(i)(b).

(p:01Iers 455-2001-003-00.doc)