ENS 53752
ENS Event | |
|---|---|
01:15 Nov 25, 2018 | |
| Title | En Revision Imported Date 1/22/2019 |
| Event Description | EN Revision Text: LOSS OF CONTROL ROOM ENVELOPE DUE TO DOOR FAILURE
On 11/24/18 at 2015 EST, a loss of Control Room Envelope (CRE) was declared due to failure of the control room boundary door, 204-36-008. [Abnormal Operating Procedure 8588A Mitigating Actions for Control Boundary Breach was implemented]. The door was repaired at 2030 EST, restoring CRE to operable [status]. A mechanical failure of the control room door latch prevented the door from closing. The licensee notified the NRC Resident Inspector.
The purpose of this call is to retract a report made on November 25, 2018, NRC Event Number EN53752. NRC Event Report number EN53752 describes a condition at Millstone Power Station Unit 2 (MPS2) in which a control room envelope boundary door was discovered to not be able to fully close due to the latching mechanism being stuck in the extended position. The condition was reported to the NRC pursuant to 10 CFR 50.72(b)(3)(v)(D) via an 8-hour prompt report as an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Upon further review, MPS2 determined that there was no loss of safety function. An engineering evaluation determined that even with the control room boundary door unable to be fully closed due to the latching mechanism being stuck in the extended position, control room air in-leakage would not have been sufficient to prevent the control room emergency ventilation system from performing its safety function. Therefore, this condition is not reportable and NRC Event Number EN53752 is being retracted. The basis for this conclusion has been provided to the NRC Resident Inspector. Notified the R1DO (Carfang). |
| Where | |
|---|---|
Millstone  Connecticut (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+1.53 h0.0638 days <br />0.00911 weeks <br />0.0021 months <br />) | |
| Opened: | Ryan Robillard 02:47 Nov 25, 2018 |
| NRC Officer: | Dan Livermore |
| Last Updated: | Jan 18, 2019 |
| 53752 - 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 53752\u003C/a\u003E - \u003Ca href=\"/Millstone\" title=\"Millstone\"\u003EMillstone\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EEn Revision Imported Date 1/22/2019\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 53752 - Millstone\n","link":"","lat":41.310722222222225,"lon":-72.16767777777778,"icon":"/w/images/b/b0/Dominion_icon.png"}],"imageoverlays":null} | |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Cold Shutdown (0 %) |
| After | Cold Shutdown (0 %) |