ENS 47547
ENS Event | |
|---|---|
03:31 Nov 8, 2011 | |
| Title | Invalid Specified System Actuation Due to a Possible Faulty Temperature Switch |
| Event Description | This 60-day telephone notification is being made per the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe an invalid actuation signal affecting containment isolation valves in more than one system.
On November 7, 2011, Nine Mile Point Unit 2 (NMP2) received a Division 2 reactor building pipe chase high ambient temperature isolation signal, which resulted in closure of isolation valves in the reactor water cleanup (RWCU) system, the reactor core isolation cooling (RCIC) system, and the residual heat removal (RHR) system (isolation valve groups 5, 6, 7, and 10). All affected isolation valves responded as designed. The Division reactor building pipe chase high ambient temperature isolation signal was generated by a new NUS/Scientech ambient temperature indicating switch that had recently been installed as a replacement for the original Riley temperature switch, which is no longer being manufactured. Two temperature switches (one for Division 1 and one for Division 2) monitor the reactor building pipe chase area to detect a rise in area temperature, which is indicative of a leak in the RWCU, RCIC, or RHR system piping that exists in the area. At the time of the event, operations personnel confirmed that conditions requiring isolation of the RWCU, RCIC, and RHR systems did not exist, based on a check of the Division 1 reactor building pipe chase high ambient temperature channel and area radiation monitors. Therefore, the isolation signal was determined to be invalid. The NUS/Scientech temperature switch was subsequently removed and the original Riley temperature switch was re-installed. The apparent cause for generation of the trip signal from the new temperature indicating switch was determined to be the presence of signal noise that was not adequately filtered. This event was entered into the [Nine Mile Point] corrective action system as Condition Report (CR) 2011-010062. There were no safety consequences or impact on the health and safety of the public as a result of this event. The licensee notified the NRC Resident Inspector. |
| Where | |
|---|---|
Nine Mile Point  New York (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1079.53 h44.98 days <br />6.426 weeks <br />1.479 months <br />) | |
| Opened: | Patrick Walsh 03:03 Dec 23, 2011 |
| NRC Officer: | Vince Klco |
| Last Updated: | Dec 23, 2011 |
| 47547 - 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 47547\u003C/a\u003E - \u003Ca href=\"/Nine_Mile_Point\" title=\"Nine Mile Point\"\u003ENine Mile Point\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EInvalid Specified System Actuation Due to a Possible Faulty Temperature Switch\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 47547 - Nine Mile Point\n","link":"","lat":43.52021388888889,"lon":-76.40656388888888,"icon":"/w/images/b/be/Constellation_icon.png"}],"imageoverlays":null} | |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 535842018-03-19T04:00:00019 March 2018 04:00:00
[Table view]10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation ENS 527472017-03-20T06:16:00020 March 2017 06:16:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Telephone Notification for an Invalid High Pressure Coolant Injection System Actuation ENS 509092015-01-21T15:00:00021 January 2015 15:00:00 10 CFR 50.73(a)(1), Submit an LER 60-Day Optional Notification - Invalid Containment Isolation Signal ENS 490842013-04-02T13:46:0002 April 2013 13:46:00 10 CFR 50.73(a)(1), Submit an LER 6O-Day Optional Telephone Notification for an Invalid Specified System Actuation ENS 485702012-10-12T14:12:00012 October 2012 14:12:00 10 CFR 50.73(a)(1), Submit an LER Temperature Switch Failure Causes Division I Isolation Signal ENS 481132012-05-24T14:20:00024 May 2012 14:20:00 10 CFR 50.73(a)(1), Submit an LER 60 - Day Optional Telephone Notification of an Invalid Division 2 Containment Isolation Signal ENS 475472011-11-08T03:31:0008 November 2011 03:31:00 10 CFR 50.73(a)(1), Submit an LER Invalid Specified System Actuation Due to a Possible Faulty Temperature Switch ENS 457792010-03-15T16:43:00015 March 2010 16:43:00 10 CFR 50.73(a)(1), Submit an LER Inadvertent Start of Emergency Diesel Generator ENS 439232008-01-14T18:41:00014 January 2008 18:41:00 10 CFR 50.73(a)(1), Submit an LER Invalid Actuation of Group 5 and Group 10 Primary Containment Valves During Surveillance Testing ENS 438552007-11-08T15:21:0008 November 2007 15:21:00 10 CFR 50.73(a)(1), Submit an LER Invalid Primary Containment Isolation System (Pcis) Actuation ENS 407182004-04-01T07:06:0001 April 2004 07:06:00 10 CFR 50.73(a)(1), Submit an LER Invalid Automatic Start of Emergency Diesel Generator During Surveillance Test 2018-03-19T04:00:00 | |