ENS 55972
ENS Event | |
|---|---|
04:05 May 2, 2022 | |
| Title | Invalid Specified System Actuation |
| Event Description | The following information was provided by the licensee via phone and email:
This non-emergency notification is being made pursuant to the provisions of 10 CFR 50.73(a)(1) to report the occurrence of an invalid automatic actuation satisfying the reporting criterion of 10 CFR 50.73(a)(2)(iv)(A), specifically for the actuation of one train of the Essential Service Water (ESW) system that occurred on May 1, 2022. On May 1, 2022, with the plant shut down and the core offloaded, control room personnel were performing a fast power transfer from Engineered Safety Feature (ESF) transformer XNB02 to ESF transformer XNB01. In anticipation of this activity, the `B' load shedder and emergency load sequencer (LSELS) had been removed from service. Also, at the time, a portion of the `A' ESW train was isolated to support performance of a local leak rate test (LLRT) of a containment isolation valve in the affected portion of `A' ESW train piping. Service Water was supplying cooling water flow to `A' train loads (in lieu of ESW cooling water). When the power transfer was performed, an unexpected automatic start of the `A' ESW pump, along with some associated, automatic valve repositioning, occurred. The actuation occurred due to inadvertent satisfaction of automatic start logic for the ESW pump. The logic is intended to detect loss of ESW flow when the opposite train LSELS isolates Service Water during an undervoltage condition on a safety bus. The flow transmitter involved in the actuation is situated in a portion of the ESW piping that was isolated for the LLRT. The low-flow signal from the transmitter was consequently not reflective of low cooling water flow to plant loads in light of the fact that cooling water flow was being supplied to plant loads and the transmitter was locally isolated. In regard to the ESW train actuation, therefore, although the undervoltage signal was considered a valid signal due to the voltage drop caused by the fast transfer activity, the low-flow signal from the noted transmitter was considered to be invalid. For this invalid actuation, it was concluded that the actuation was not part of a pre-planned sequence, that the affected system was not properly removed from service during the occurrence, and that the safety function had not already been performed relative to the occurrence. [The] NRC Resident Inspector has been notified and an email of this report has been sent to hoo.hoc@nrc.gov. |
| Where | |
|---|---|
Callaway  Missouri (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation Other Unspec Reqmnt | |
| Time - Person (Reporting Time:+1426.27 h59.428 days <br />8.49 weeks <br />1.954 months <br />) | |
| Opened: | Greg Cizin 14:21 Jun 30, 2022 |
| NRC Officer: | Ossy Font |
| Last Updated: | Jun 30, 2022 |
| 55972 - NRC Website
Loading map... {"minzoom":false,"maxzoom":false,"mappingservice":"leaflet","width":"350px","height":"250px","centre":false,"title":"","label":"","icon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"zoom":6,"defzoom":14,"layers":["OpenStreetMap"],"image layers":[],"overlays":[],"resizable":false,"fullscreen":false,"scrollwheelzoom":true,"cluster":false,"clustermaxzoom":20,"clusterzoomonclick":true,"clustermaxradius":80,"clusterspiderfy":true,"geojson":"","clicktarget":"","imageLayers":[],"locations":[{"text":"\u003Cb\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003E\u003Ca class=\"mw-selflink selflink\"\u003EENS 55972\u003C/a\u003E - \u003Ca href=\"/Callaway\" title=\"Callaway\"\u003ECallaway\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EInvalid Specified System Actuation\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 55972 - Callaway\n","link":"","lat":38.76076111111111,"lon":-91.78175833333333,"icon":"/w/images/0/06/Ameren_icon.png"}],"imageoverlays":null} | |
WEEKMONTHYEARENS 570912024-03-25T01:56:00025 March 2024 01:56:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Automatic Turbine Driven Auxiliary Feedwater Pump ENS 559722022-05-02T04:05:0002 May 2022 04:05:00 Other Unspec Reqmnt, 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 491412013-04-24T09:04:00024 April 2013 09:04:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephone Notification for an Invalid Specified System Actuation ENS 491032013-04-11T06:28:00011 April 2013 06:28:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephone Notification for an Invalid Specified System Actuation ENS 445602008-10-11T05:49:00011 October 2008 05:49:00 Other Unspec Reqmnt Discovery of an After-The-Fact Notification of Unusual Event ENS 428522006-09-08T15:15:0008 September 2006 15:15:00 Other Unspec Reqmnt Discovery of After-The-Fact Emergency Condition: Inapproriate Change Made to Emergency Action Level 3J Back in 1997 Caused an Emergency, Alert, Not to Be Declared. ENS 413262005-01-12T19:30:00012 January 2005 19:30:00 Other Unspec Reqmnt, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 24 Hour Condition of License Report Regarding Halon System Actuator Port Connection Error ENS 412052004-09-18T22:35:00018 September 2004 22:35:00 Other Unspec Reqmnt Discovery of After-The-Fact Emergency Condition (Unusual Event) ENS 407052004-04-26T22:11:00026 April 2004 22:11:00 Other Unspec Reqmnt Technical Specifications Required Report of Steam Generator Defective Tubes 2024-03-25T01:56:00 | |