ENS 47459
ENS Event | |
|---|---|
15:28 Nov 19, 2011 | |
| Title | the Low Pressure Safety Injection System Was Subjected to High Pressure Resulting in Both Trains Being Declared Inoperable |
| Event Description | On November 19, 2011, Unit 1 was in Mode 3. Boration of the four reactor coolant system (RCS) cold leg injection lines was in progress using High Pressure Safety Injection pump 'A'.
During this activity, 'SI CHK VLV Leak Pressure Hi' alarms were received at 0828 [MST]. The 'A' and 'B' Low Pressure Safety Injection (LPSI) subsystems were declared inoperable because the pressure downstream of the motor operated LPSI injection valves was above 1525 psia. This elevated pressure potentially impacts the ability of the LPSI RCS loop injection valves to open. The high differential pressure may exceed the capability of the motor operator. All four injection line pressures were found above 1525 psia and LCO 3.0.3 was entered due to both trains of LPSI being inoperable. At 0839 [MST], pressure in the 'A' train injection lines was lowered below 1525 psia and 'A' LPSI subsystem was declared operable and LCO 3.0.3 was exited. At 0842 [MST], pressure was reduced below 1525 psia on the 'B' train injection lines and the 'B' LPSI subsystem was declared operable and LCO 3.5.3 condition A was exited. This call is being made to report a condition that could have prevented the fulfillment of a safety function required to mitigate the consequences of an accident and unanalyzed condition that existed for 11 minutes while both LPSI subsystems were inoperable. The NRC Resident Inspector has been notified.
The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow-up notification will be made via ENS or under the reporting requirements of 10CFR50.73. This notification is a retraction of ENS 47459 which was made by Arizona Public Service to report a condition that could have prevented the fulfillment of a safety function required to mitigate the consequences of an accident and an unanalyzed condition that existed for 11 minutes while both LPSI subsystems were declared inoperable when pressure downstream of the motor operated injection valves for safety injection subsystem were declared inoperable. An engineering review of the motor operated valves thrust and torque calculations determined that the affected valves would have been fully capable of performing their intended safety function at the time of the pressure excursion. The NRC Resident Inspector has been notified of this retraction. |
| Where | |
|---|---|
Palo Verde  Arizona (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+1.33 h0.0554 days <br />0.00792 weeks <br />0.00182 months <br />) | |
| Opened: | Amado Fernandez 16:48 Nov 19, 2011 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Dec 15, 2011 |
| 47459 - NRC Website | |
Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Hot Standby (0 %) |
| After | Hot Standby (0 %) |
Palo Verde with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition | |
WEEKMONTHYEARENS 539682019-04-01T03:06:0001 April 2019 03:06:00
[Table view]10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material Unanalyzed Condition Due to Eccs Leakage ENS 520832016-07-12T20:00:00012 July 2016 20:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Degraded Fire Barrier ENS 494112013-10-04T16:46:0004 October 2013 16:46:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Postulated Fire Event Could Result in a Hot Short That Could Adversely Impact Safe Shutdown Equipment ENS 488142013-03-09T02:21:0009 March 2013 02:21:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Spent Fuel Pool Criticality Analysis of Record Not Revised Following Power Uprate ENS 474592011-11-19T15:28:00019 November 2011 15:28:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition the Low Pressure Safety Injection System Was Subjected to High Pressure Resulting in Both Trains Being Declared Inoperable ENS 454252009-10-11T11:50:00011 October 2009 11:50:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness Reactor Water Level Indication Inoperable ENS 448462009-02-11T20:18:00011 February 2009 20:18:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Possibly Inadequate Backup Nitrogen Supply for Atmospheric Dump Operation ENS 431402007-02-03T19:32:0003 February 2007 19:32:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Technical Specification 3.0.3 Entered During Routine Surveillance Testing of Control Element Assemblies (Cea'S) ENS 428472006-09-19T08:05:00019 September 2006 08:05:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Pressurizer Heater Capacity Less than Tech Spec Limit ENS 427322006-07-27T02:00:00027 July 2006 02:00:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Limiting Condition for Operation 3.7.4 Deemed to Be Nonconservative ENS 426512006-06-18T21:55:00018 June 2006 21:55:00 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 Loss of Onsite Emergency Safety Function - "B" Edg Failed to Start During Test Run ENS 420502005-10-11T23:02:00011 October 2005 23:02:00 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, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown of Both Unit 2 and 3 ENS 417892005-06-23T15:23:00023 June 2005 15:23:00 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Unit 2 Aux Feedwater Train Separation Not Maintained During Operation ENS 412242004-11-24T19:20:00024 November 2004 19:20:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Eccs Loops Declared Inoperable in Support of Log Term Accident Mitigation ENS 409132004-07-31T01:45:00031 July 2004 01:45:00 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 Air Void in Post-Loca Recirculation Piping System 2019-04-01T03:06:00 | |