Browse wiki
Jump to navigation
Jump to search
100 +
On February 27, 2007, at approximately 220 … On February 27, 2007, at approximately 2200 hours, testing of the Unit 2 High Pressure Coolant Injection (HPCI) system was in progress in accordance with 0PT-09.2, HPCI System Operability Test following system maintenance. Soon after the HPCI turbine was started a high level alarm condition in the HPCI barometric condenser was experienced. Evidence suggests the most probable cause was due to failure of the 2-E41-F048, Condensate Pump Discharge Check Valve, to open. The adverse consequence of this check valve failing to open is inadequate cooling flow to the HPCI lube oil cooler. The HPCI turbine was removed from service per applicable plant procedures.</br>At the time of discovery, the HPCI system was inoperable for scheduled maintenance. However, this equipment failure would have prevented the HPCI system from fulfilling its safety function. Limiting Condition for Operation (LCO) per Technical Specifications (TS) 3.5.1. 'ECCS - Operating' Condition D had been previously entered on 2/25/07 at 1500, which required maintaining the Reactor Core Isolation Cooling (RCIC) system operable and restoration of HPCI operability in 14 days.</br>All other ECCS systems are operable including RCIC. The LCO allowed outage time is due to expire on 3/11/07 at approximately 1500 hours.</br>The licensee notified the NRC Resident Inspector.</br>** UPDATE FROM TURKAL TO KNOKE AT 11:33 EDT ON 04/26/07 ***</br>On February 28, 2007, at 0540 hours, the Control Room Supervisor made a notification (Event Number 43197) to the NRC Operations Center in accordance with 10 CFR 50.72(b)(3)(v)(D) (i.e., any 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). The notification was made as a result of an unexpected high level alarm condition for the High Pressure Coolant Injection (HPCI) system barometric condenser, which was received during the post-maintenance operability testing of the HPCI system. At the time of discovery, the HPCI system was inoperable; having been properly removed from service for planned maintenance. It was believed that check valve 2-E41-F048, which is in the discharge piping of the HPCI barometric condenser condensate pump, downstream of a connection from the HPCI lube oil cooler cooling water discharge line, did not open, as required, during the HPCI post maintenance operability run. With valve 2-E41-F048 closed, there is a potential for inadequate cooling flow for the HPCI lube oil and, as such, a potential that the HPCI system could be inoperable as a result.</br>Basis for Retraction</br>Upon further review, it has been determined that the 2-E41-F048 functioned properly during the post-maintenance HPCI system operability testing. The valve was disassembled and inspected during the recent Unit 2 refueling outage and confirmed to be operating properly. As such, adequate HPCI lube oil cooling existed and HPCI could have fulfilled its intended safety function.</br>Physical inspection of the HPCI lube oil cooler piping, during the Unit 2 refueling outage, revealed that the lube oil cooler outlet orifice was missing. The missing orifice can result in higher than design flows through the lube oil cooler and higher backpressure at the barometric condenser condensate pump discharge. The higher backpressure can affect the ability to pump down the barometric condenser vacuum tank. Additionally, during troubleshooting activities performed prior to the refueling outage, valve 2-E41-F058, which is in the discharge piping of the HPCl barometric condenser condensate pump, upstream of the connection from the HPCI lube oil cooler cooling water discharge line, showed evidence of sticking. Either of these conditions could have caused the barometric condenser high level alarm without affecting HPCI lube oil cooling. If the barometric condenser becomes completely full, a relief valve on the tank will lift and relieve water to the HPCI room sump. The room sump pump has adequate capacity to keep up with the maximum expected flow. Operability of the HPCI system will not be affected by this condition.</br>The higher than design cooling water flow rate does not adversely affect the capability of the lube oil cooler to remove heat from HPCI system lube oil and, as such, does not affect HPCI operability. Additionally, physical inspection of the cooler during the refueling outage found no damage or erosion of the cooler internals, and the cooler was successfully pressure tested.</br>The barometric condenser condensate pump, barometric condenser vacuum pump, and barometric condenser water level instrumentation are not required to support operability of the HPCI system.</br>Investigation of this condition is documented in the corrective action program in Nuclear Condition Report (NCR) 223820.</br>On this basis, the HPCI system was capable of performing its function to mitigate the consequences of an accident and the issue is not reportable under 10 CFR 50.72(b)(3)(v)(D). </br>The NRC resident was notified of this retraction." Notified R2DO(Payne).</br>*** UPDATE FROM TURKAL TO KNOKE AT 09:30 EDT ON 06/04/09 ***</br>On February 28, 2007, at 0540 hours, the Control Room Supervisor made a notification (EN 43197) to the NRC Operations Center in accordance with 10 CFR 50.72(b)(3)(v)(D), 'any 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'. The notification was made as a result of an unexpected high level alarm condition for the High Pressure Coolant Injection (HPCI) system barometric condenser, which was received during the post-maintenance operability testing of the HPCI system.</br>Revised Basis for Retraction</br>On April 26, 2007, EN 43197 was retracted. The basis for the retraction stated that the 2-E41-F048 functioned properly and adequate HPCI lube oil cooling existed. It also attributed the high level in the HPCI barometric condenser to either a missing lube oil cooler outlet orifice or potential sticking of valve 2-E41-F058 versus the originally believed malfunction of the 2-E41-F048 valve. In either case, the retraction stated that if the barometric condenser becomes completely full, a relief valve (2-E41-F018) on the tank will lift and relieve water to the HPCI room sump. The room sump pump has adequate capacity to keep up with the maximum expected flow. As such, operability of the HPCI system would not be affected by either a missing lube oil cooler outlet orifice or potential sticking of valve 2 -E41-F058.</br>During the Unit 2 refueling outage, which began on February 28, 2009, it was discovered that the HPCI barometric condenser relief valve (2-E41-F018) had been assembled incorrectly and would not have functioned as described in the April 26, 2007 retraction of EN 43197. However, EN 43197 can be retracted without relying on proper operation of the relief valve. At the time of the event, the HPCI barometric condenser condensate pump, the HPCI barometric condenser vacuum pump, and the HPCI barometric condenser water level instrumentation were functioning properly and would have prevented condensate from reaching the HPCI turbine casing. On this basis, the HPCI system was capable of performing its function to mitigate the consequences of an accident and the issue is not reportable under 10 CFR 50.72(b)(3)(v)(D).</br>The NRC Resident Inspector was notified of this revised retraction.</br>Notified R2DO (Mark Lesser)ed retraction.
Notified R2DO (Mark Lesser)
03:26:00, 28 February 2007 +
43,197 +
05:40:00, 28 February 2007 +
03:26:00, 28 February 2007 +
On February 27, 2007, at approximately 220 … On February 27, 2007, at approximately 2200 hours, testing of the Unit 2 High Pressure Coolant Injection (HPCI) system was in progress in accordance with 0PT-09.2, HPCI System Operability Test following system maintenance. Soon after the HPCI turbine was started a high level alarm condition in the HPCI barometric condenser was experienced. Evidence suggests the most probable cause was due to failure of the 2-E41-F048, Condensate Pump Discharge Check Valve, to open. The adverse consequence of this check valve failing to open is inadequate cooling flow to the HPCI lube oil cooler. The HPCI turbine was removed from service per applicable plant procedures.</br>At the time of discovery, the HPCI system was inoperable for scheduled maintenance. However, this equipment failure would have prevented the HPCI system from fulfilling its safety function. Limiting Condition for Operation (LCO) per Technical Specifications (TS) 3.5.1. 'ECCS - Operating' Condition D had been previously entered on 2/25/07 at 1500, which required maintaining the Reactor Core Isolation Cooling (RCIC) system operable and restoration of HPCI operability in 14 days.</br>All other ECCS systems are operable including RCIC. The LCO allowed outage time is due to expire on 3/11/07 at approximately 1500 hours.</br>The licensee notified the NRC Resident Inspector.</br>** UPDATE FROM TURKAL TO KNOKE AT 11:33 EDT ON 04/26/07 ***</br>On February 28, 2007, at 0540 hours, the Control Room Supervisor made a notification (Event Number 43197) to the NRC Operations Center in accordance with 10 CFR 50.72(b)(3)(v)(D) (i.e., any 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). The notification was made as a result of an unexpected high level alarm condition for the High Pressure Coolant Injection (HPCI) system barometric condenser, which was received during the post-maintenance operability testing of the HPCI system. At the time of discovery, the HPCI system was inoperable; having been properly removed from service for planned maintenance. It was believed that check valve 2-E41-F048, which is in the discharge piping of the HPCI barometric condenser condensate pump, downstream of a connection from the HPCI lube oil cooler cooling water discharge line, did not open, as required, during the HPCI post maintenance operability run. With valve 2-E41-F048 closed, there is a potential for inadequate cooling flow for the HPCI lube oil and, as such, a potential that the HPCI system could be inoperable as a result.</br>Basis for Retraction</br>Upon further review, it has been determined that the 2-E41-F048 functioned properly during the post-maintenance HPCI system operability testing. The valve was disassembled and inspected during the recent Unit 2 refueling outage and confirmed to be operating properly. As such, adequate HPCI lube oil cooling existed and HPCI could have fulfilled its intended safety function.</br>Physical inspection of the HPCI lube oil cooler piping, during the Unit 2 refueling outage, revealed that the lube oil cooler outlet orifice was missing. The missing orifice can result in higher than design flows through the lube oil cooler and higher backpressure at the barometric condenser condensate pump discharge. The higher backpressure can affect the ability to pump down the barometric condenser vacuum tank. Additionally, during troubleshooting activities performed prior to the refueling outage, valve 2-E41-F058, which is in the discharge piping of the HPCl barometric condenser condensate pump, upstream of the connection from the HPCI lube oil cooler cooling water discharge line, showed evidence of sticking. Either of these conditions could have caused the barometric condenser high level alarm without affecting HPCI lube oil cooling. If the barometric condenser becomes completely full, a relief valve on the tank will lift and relieve water to the HPCI room sump. The room sump pump has adequate capacity to keep up with the maximum expected flow. Operability of the HPCI system will not be affected by this condition.</br>The higher than design cooling water flow rate does not adversely affect the capability of the lube oil cooler to remove heat from HPCI system lube oil and, as such, does not affect HPCI operability. Additionally, physical inspection of the cooler during the refueling outage found no damage or erosion of the cooler internals, and the cooler was successfully pressure tested.</br>The barometric condenser condensate pump, barometric condenser vacuum pump, and barometric condenser water level instrumentation are not required to support operability of the HPCI system.</br>Investigation of this condition is documented in the corrective action program in Nuclear Condition Report (NCR) 223820.</br>On this basis, the HPCI system was capable of performing its function to mitigate the consequences of an accident and the issue is not reportable under 10 CFR 50.72(b)(3)(v)(D). </br>The NRC resident was notified of this retraction." Notified R2DO(Payne).</br>*** UPDATE FROM TURKAL TO KNOKE AT 09:30 EDT ON 06/04/09 ***</br>On February 28, 2007, at 0540 hours, the Control Room Supervisor made a notification (EN 43197) to the NRC Operations Center in accordance with 10 CFR 50.72(b)(3)(v)(D), 'any 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'. The notification was made as a result of an unexpected high level alarm condition for the High Pressure Coolant Injection (HPCI) system barometric condenser, which was received during the post-maintenance operability testing of the HPCI system.</br>Revised Basis for Retraction</br>On April 26, 2007, EN 43197 was retracted. The basis for the retraction stated that the 2-E41-F048 functioned properly and adequate HPCI lube oil cooling existed. It also attributed the high level in the HPCI barometric condenser to either a missing lube oil cooler outlet orifice or potential sticking of valve 2-E41-F058 versus the originally believed malfunction of the 2-E41-F048 valve. In either case, the retraction stated that if the barometric condenser becomes completely full, a relief valve (2-E41-F018) on the tank will lift and relieve water to the HPCI room sump. The room sump pump has adequate capacity to keep up with the maximum expected flow. As such, operability of the HPCI system would not be affected by either a missing lube oil cooler outlet orifice or potential sticking of valve 2 -E41-F058.</br>During the Unit 2 refueling outage, which began on February 28, 2009, it was discovered that the HPCI barometric condenser relief valve (2-E41-F018) had been assembled incorrectly and would not have functioned as described in the April 26, 2007 retraction of EN 43197. However, EN 43197 can be retracted without relying on proper operation of the relief valve. At the time of the event, the HPCI barometric condenser condensate pump, the HPCI barometric condenser vacuum pump, and the HPCI barometric condenser water level instrumentation were functioning properly and would have prevented condensate from reaching the HPCI turbine casing. On this basis, the HPCI system was capable of performing its function to mitigate the consequences of an accident and the issue is not reportable under 10 CFR 50.72(b)(3)(v)(D).</br>The NRC Resident Inspector was notified of this revised retraction.</br>Notified R2DO (Mark Lesser)ed retraction.
Notified R2DO (Mark Lesser)
Has query"Has query" is a predefined property that represents meta information (in form of a <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Subobject">subobject</a>) about individual queries and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
100 +
00:00:00, 4 June 2009 +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
22:32:20, 24 September 2017 +
05:40:00, 28 February 2007 +
true +
false +
0.0929 d (2.23 hours, 0.0133 weeks, 0.00305 months) +
03:26:00, 28 February 2007 +
URL"URL" is a <a href="/Special:Types/URL" title="Special:Types/URL">type</a> and predefined property provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a> to represent URI/URL values.