ENS 40703
ENS Event | |
|---|---|
15:50 Apr 24, 2004 | |
| Title | Isolation Condenser Declared Inoperable |
| Event Description | This report is being made in accordance with 10 CFR 50.72(b)(3)(v)(B).
On 04/24/2004 at 06:03 [CDT], Dresden Unit 2 was using the Isolation Condenser to control reactor pressure following a Unit Scram. The isolation condenser operated properly until 10:50 [CDT] when the Isolation Condenser 2-1301-3 valve could not be opened to the full open position. ISO Condenser was declared INOPERABLE and Technical Specification Limiting Condition of Operation 3.5.3. Condition 'A' was ENTERED. High Pressure Coolant Injection has been administratively verified OPERABLE. Reactor Pressure is being maintained 550-1000 psig and being maintained with Reactor Water Clean Up Flow and Gland Seal System. Investigation into the cause of the valve failure is in-progress. Unit 2 had been operating approximately 30 days prior to the scram reported previously in EN#40702. The licensee informed the NRC Resident Inspector.
On April 24, 2004, Dresden made an ENS call due to the failure of Isolation Condenser valve 2-1301-3 to fully open and the subsequent determination that the Isolation Condenser was inoperable. The ENS call was made based on the decision that this was required by 10CFR50.72(b)(3)(v)(B), 'Any event or condition that at the time of discovery could have prevented fulfillment of the safety function of structures or systems that are needed to remove residual heat.' Isolation Condenser System operation is not credited in Dresden's accident analyses. Transients and Events treated as transients are listed under section 15.0.2.1 of the UFSAR. Accidents are described and analyzed under section 15.0.2.2 of the UFSAR. The isolation condenser is not credited for fulfilling safety function of removal of residual heat of any accident as described in section 15.0.2.2, Accidents. In accordance with the guidance contained in NUREG 1022, 'Event Reporting Guidelines 10CFR50.72 and 10CFR50.73,' Section 3.2.7, 'Event or Condition That Could Have Prevented Fulfillment of a Safety Function,' a functional failure of the Isolation Condenser System is not reportable under 10CFR50.72(b)(3)(v)(B). Therefore, Dresden is retracting this ENS call. This Isolation Condenser System event will be described in a Licensee Event Report in accordance with 10CFR50.73(a)(2)(i)(B), 'Any event or condition which was prohibited by the plant's Technical Specifications' The licensee notified the NRC Resident Inspector. Notified R3DO (Kozak). |
| Where | |
|---|---|
Dresden  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat | |
| Time - Person (Reporting Time:+-0.33 h-0.0138 days <br />-0.00196 weeks <br />-4.52034e-4 months <br />) | |
| Opened: | Dennis Francis 15:30 Apr 24, 2004 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Jun 23, 2004 |
| 40703 - 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 40703\u003C/a\u003E - \u003Ca href=\"/Dresden\" title=\"Dresden\"\u003EDresden\u003C/a\u003E\n\u003C/p\u003E\u003C/div\u003E\u003C/b\u003E\u003Cdiv class=\"mw-parser-output\"\u003E\u003Cp\u003EIsolation Condenser Declared Inoperable\n\u003C/p\u003E\u003C/div\u003E","title":"ENS 40703 - Dresden\n","link":"","lat":41.3886,"lon":-88.26909166666667,"icon":"/w/images/b/be/Constellation_icon.png"}],"imageoverlays":null} | |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Shutdown (0 %) |
| After | Hot Shutdown (0 %) |
WEEKMONTHYEARENS 560232022-07-30T03:17:00030 July 2022 03:17:00
[Table view]10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat RHR Capability Lost Due to Suction Bay Level ENS 480802012-07-10T07:36:00010 July 2012 07:36:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Invalid Group 5 Isolation Due to Failed Test Switch During Surveillance ENS 468572011-05-17T15:30:00017 May 2011 15:30:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Temporary Blockage of Suction Source for Containment Cooling Service Water ENS 454722009-11-02T12:12:0002 November 2009 12:12:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Loss of Shutdown Cooling ENS 446262008-11-03T12:52:0003 November 2008 12:52:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Recirc Loop Temperature Element Failed ENS 444702008-09-07T13:05:0007 September 2008 13:05:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Isolation Condenser Declared Inoperable Following Surveillance Testing ENS 441402008-04-15T12:00:00015 April 2008 12:00:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident High Pressure Coolant Injection Declared Inoperable ENS 413702005-02-04T01:15:0004 February 2005 01:15:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 4160 Volt Relaying and Metering Single Failure Vulnerability ENS 407032004-04-24T15:50:00024 April 2004 15:50:00 10 CFR 50.72(b)(3)(v)(B), Loss of Safety Function - Remove Residual Heat Isolation Condenser Declared Inoperable 2022-07-30T03:17:00 | |