ENS 40962
ENS Event | |
|---|---|
20:00 Aug 16, 2004 | |
| Title | Part 21 60-Day Interim Notification: Narrow Range Water Level Instrument Level 3 Trip |
| Event Description | This letter provides a 10 CFR21(a)(2) 60 - Day Interim Report notification regarding a potential issue with the Level 3 trip from the narrow range water level instruments that initiate reactor scram. A conservative evaluation by GE Nuclear Energy (GENE) has determined that water level instruments may indicate high by as much as 8 inches, should the reactor water level drop below the dryer seal skirt. At issue is whether with the actual water level as much as 8 inches lower than indicated, the top of active fuel (TAF) will be uncovered for the limiting loss of feedwater event due to
1. Actual water level being lower than indicated when the Level 3 trip occurs, or 2. Failure of the Level 3 trip to occur if water level drops below the narrow range instrument variable leg tap prior to reaching the Level 3 trip setpoint. Because TAF is a Technical Specification Safety Limit, TAF uncovery for a loss of feedwater event would be a Reportable Condition. However, it would not lead to a significant safety hazard due to multiple automatic and passive protection features of a BWR. GENE has completed analysis for BWR 2/3 plants and determined that this is not a reportable condition (i.e., the TAF safety limit is protected). GENE has not completed the analyses for BWR /4-/6 plants. For these plants, GENE has determined that actual water level being lower than indicated by up to 8 inches when the Level 3 trip occurs does not lead to TAF uncovery. However, for these plants GENE has not determined if water level could drop below the narrow range instrument variable leg tap prior to reaching the Level 3 trip setpoint. Therefore, this letter is issued as a 60 - Day Interim Notification under 10 CFR21.21(a)(2) to the BWR/4-/6 plants listed in Attachment 1. The potentially affected plants are being concurrently notified of this situation by a GENE Safety Communication letter. GENE is committed to complete the evaluation by October 11, 2004. Attachment 1 Plants List Below: (Affected Plants - Evaluation incomplete) Clinton, Brunswick Units 1 & 2, Nine Mile Point Unit 2, Fermi Unit 2, Columbia, Fitzpatrick, Grand Gulf, River Bend, La Salle Units 1&2, Limerick Units 1 & 2, Peach Bottom Units 1 & 2, Perry, Cooper, Duane Arnold, Susquehanna Units 1 & 2, Hope Creek, Hatch Units 1 & 2, Browns Ferry Units 1 (plant is in an extended shutdown),2 & 3.
GENE has now completed the evaluation and has determined that all BWR/2/3/6 and ABWR plants, and most BWR/4-5 plants are not susceptible to the condition that could result in a failure of the Level 3 trip to occur. These plants are identified as Not Reportable in Attachment 1 [of GENE Part 21 final report to the NRC dated October 11, 2004]. However, for same BWR/4-5 plants, GENE does not have sufficient information to determine if the condition exists that could result in a failure of the Level 3 trip to occur. These plants are notified, as a Transfer of Information under 10CFR21.21(b), as identified in Attachment 1 [of GENE Part 21 final report to the NRC dated October 11, 2004]. The plants where insufficient information for a final determination have been identified by GENE as Columbia, Susquehanna 1 and 2, Browns Ferry 2 and 3. Notified R1DO (Barkley), R2DO(Ogle), R3DO (Clayton) and R4DO (Bywater) and NRR (Hodge). |
| Where | |
|---|---|
| General Electric Nuclear Energy Wilmington, North Carolina (NRC Region 1) | |
| Organization: | General Electric Nuclear Energy |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+-3.93 h-0.164 days <br />-0.0234 weeks <br />-0.00538 months <br />) | |
| Opened: | Jason S. Post 16:04 Aug 16, 2004 |
| NRC Officer: | Bill Gott |
| Last Updated: | Oct 11, 2004 |
| 40962 - NRC Website | |
General Electric Nuclear Energy with 10 CFR 21.21 | |
WEEKMONTHYEARENS 415472005-01-28T05:00:00028 January 2005 05:00:00
[Table view]10 CFR 21.21 Part 21 Report Involving Potential to Exceed Low Pressure Technical Specification Safety Limit ENS 409622004-08-16T20:00:00016 August 2004 20:00:00 10 CFR 21.21 Part 21 60-Day Interim Notification: Narrow Range Water Level Instrument Level 3 Trip 2005-01-28T05:00:00 | |