ENS 40719
ENS Event | |
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06:17 May 2, 2004 | |
Title | Manual Scram Due to Rising Torus Temperature Due to Stuck Open Erv |
Event Description | Operators inserted a manual scram at 0217 (EDT) in anticipation of torus bulk temperature approaching 110 degrees F following an Electromatic Relief Valve (ERV) failing to close during ERV testing. Technical Specification 3.3.2.e requires the insertion of a manual scram prior to torus bulk temperature reaching 110 degrees F. The maximum average torus temperature was 104 degrees F.
Operators opened ERV 123 at 0209 for post maintenance testing from approximately 19% power. The ERV subsequently stuck open. Operators performed the off-normal procedure for a stuck open ERV, but this failed to shut the valve. This ported steam from the reactor vessel to the torus resulting in an uncontrolled torus temperature rise. Operators placed torus cooling in service but this did not stop the rising torus temperature. Following the manual scram, cooldown, and depressurization, shutdown cooling is being placed in service. Immediately following the manual scram, a turbine trip signal actuated the logic for high pressure coolant injection. High pressure coolant injection actuated and operators controlled level above 53 inches. With the ERV stuck open, the cooldown rate could not be controlled. The cooldown rate was approximately 190 degrees F during the first hour following the scram. All control rods fully inserted into the core. Decay heat is being removed by shutdown cooling (in service at the time of the report). The operators intend to cooldown to cold shutdown. The electrical buses are stable. Nine Mile Point Unit 2 was not affected. The licensee notified the NRC Resident Inspector. |
Where | |
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Nine Mile Point New York (NRC Region 1) | |
Reporting | |
10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown 10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | |
Time - Person (Reporting Time:+-2.13 h-0.0888 days <br />-0.0127 weeks <br />-0.00292 months <br />) | |
Opened: | Fred Ringwald 04:09 May 2, 2004 |
NRC Officer: | Bill Gott |
Last Updated: | May 2, 2004 |
40719 - NRC Website | |
Unit 1 | |
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Reactor critical | Critical |
Scram | Yes, Manual Scram |
Before | Power Operation (19 %) |
After | Hot Shutdown (0 %) |
Nine Mile Point with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
WEEKMONTHYEARENS 570042024-03-04T00:42:0004 March 2024 00:42:00
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Spec Required Shutdown Technical Specification Shutdown Due to a Degraded Seal in the "a" Reactor Recirculation Pump ENS 426332006-06-12T17:02:00012 June 2006 17:02:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Hpci Inititation Signal Due to Turbine Trip Signal During Startup ENS 426302006-06-11T05:26:00011 June 2006 05:26:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Shutdown Due to High Rcs Drywell Leakage ENS 424032006-03-10T03:14:00010 March 2006 03:14:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation Automatic Reactor Scram Due to Loss of Condenser Vacuum Turbine Trip ENS 419272005-08-18T13:49:00018 August 2005 13:49:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Automatic Scram Due to Loss of a Power Board ENS 415842005-04-10T10:00:00010 April 2005 10:00:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Scram Signal Resulting from Failure of a Supply Valve to the Scram Air Header ENS 414642005-03-07T09:37:0007 March 2005 09:37:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(2)(iv)(A), System Actuation - ECCS Discharge Automatic Turbine Trip/ Reactor Scram ENS 409982004-08-30T12:35:00030 August 2004 12:35:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation Unit 1 Manually Scrammed Due to Oscillating Reactor Vessel Water Level ENS 409192004-08-03T23:30:0003 August 2004 23:30:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Plant Shutdown Initiated Due to Inoperable Emergency Ups Inverter ENS 407192004-05-02T06:17:0002 May 2004 06:17:00 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Manual Scram Due to Rising Torus Temperature Due to Stuck Open Erv ENS 406842004-04-18T22:30:00018 April 2004 22:30:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Residual Heat Removal System Isolation Due to a Rise in Reactor Pressure ENS 405882004-03-15T15:30:00015 March 2004 15:30:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Shutdown Required by Technical Specifications Due to Inoperable Isolation Instrumentation ENS 404362004-01-10T18:00:00010 January 2004 18:00:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Ts Required Shutdown at Nmp1 Due to Inoperable Msiv ENS 403222003-11-14T02:49:00014 November 2003 02:49:00 10 CFR 50.72(b)(3)(iv)(A), System Actuation Loss of 115 Kv Line Results in Emergency Diesel Generator Auto-Start ENS 402322003-10-08T14:30:0008 October 2003 14:30:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Primary Coolant Boundary Leakage 2024-03-04T00:42:00 | |