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At 09:33 on February 13, 2006, a Susquehanna field operator inadvertently tripped an essential instrument AC panel breaker, while applying an energy control tag. He immediately communicated this condition to the control room, and then closed the breaker to restore power. During the subsequent investigation to determine applicable technical specifications, control room operators discovered that the tripped breaker resulted in a momentary loss of both battery room exhaust subsystems. To comply with the required actions for a loss of both battery room exhaust subsystems, Susquehanna declared all Unit 1 and Unit 2 DC subsystems inoperable, which resulted in LCO 3.0.3. Although the entry into LCO 3.0.3 is not reportable, Susquehanna did discover an unanalyzed condition on both units that significantly degrades plant safety, which is reportable in accordance with 10CFR50.72(b)(3)(ii). The loss of a single power supply could result in the loss of ventilation and cooling for all DC subsystems on both units, leading to degradation of essential DC power sources. This condition does not meet single failure criteria for safety-related equipment. The licensee notified the NRC Resident Inspector.

• * * UPDATE 1342 EST ON 2/21/06 FROM GORDY ROBINSON TO S. SANDIN * * *

The licensee is retracting this report based on the following: At 0933 hours on February 13, 2006, a Susquehanna field operator inadvertently tripped an essential instrument AC panel breaker while applying an energy control tag. The field operator immediately communicated this condition to the control room and was directed to close the breaker to restore power. The breaker trip resulted in a momentary loss of exhaust flow from the Class 1E 125 VDC and 250 VDC battery rooms. In response, operators declared all Unit 1 and Unit 2 batteries inoperable. An ENS notification (# 42334) was initiated in accordance with 10CFR50.72(b)(3)(ii)(B), Unanalyzed Condition that Significantly Affects Plant Safety, because the loss of a single power supply rendered the status of all station essential DC power sources (Batteries) indeterminate and, thus, inoperable. It was believed that this condition did not meet single failure criteria for safety-related equipment. Subsequent analysis of this event has revealed that the battery room exhaust system acted per design. The system's design is consistent with intended logic that ensures single failure proof isolation of the system, in compliance with the single failure criterion, in response to a toxic gas release. The single failure proof design of the battery exhaust system ensures isolation, not continued operation, in the presence of a single failure. The analysis further concluded that a short term loss of battery room exhaust does not compromise a battery's ability to function. The insights obtained through this analysis provide the basis for retraction of the ENS report of February 13, 2006. The licensee informed the NRC Resident Inspector. Notified R1DO(Henderson).

At 21:27 on March 1, 2006, a Susquehanna security officer evacuated the security control center and notified the control room of a fire alarm and actuation of the Halon fire suppression system. The actuation of this system resulted in a potential atmosphere immediately dangerous to life and health (IDLH) of personnel in a plant vital area. The fire brigade responded to the event, donning respirators to enter the building, but saw no visible smoke or flames. As a result of an IDLH atmosphere in a plant vital area, Susquehanna entered the emergency plan at the Alert level. The NRC Resident Inspector was informed and responded to the site. The licensee notified state, local and other government agencies. The licensee plans on issuing a press release. Notified DHS (Hill), FEMA (Liggett), DOE (Bailey), EPA (National Response Center, Baumgartner), HHS (Riggs), and USDA (D. Timmons).

• * * UPDATE AT 0530 EST ON 3/2/06 FROM RICH KLINEFELTER TO S. SANDIN * * *

The licensee terminated the Alert 0433 EST based on the following: Habitability was restored to the security control center by 1. Stopping the Halon discharge 2. Ventilating the affected area 3. Restoring access 4. Isolating Halon sources in the adjacent area to prevent a recurrence and, 5. Posting Fire Watches. The licensee informed State/local agencies and the on-site NRC Resident Inspector. Notified Region I (Perry), NRR EO (Calvo), IRD (Leach), DHS (Hill), FEMA (Liggett), DOE (Pauley), EPA (National Response Center, McCrossen), HHS (H. Peagler), and USDA (D. Timmons).

While performing local leak rate testing (LLRT) during a planned refueling outage, Susquehanna discovered a Type C penetration on Unit 1 with a leak rate of 12,700 sccm. The limit for this penetration, which can bypass secondary containment, is 4,247 sccm or 9 scfh. Even with this leak rate, the combined leak rate for all penetrations and valves subject to Type B and C tests meets the acceptance criteria of 10CFR50 Appendix J, which is 190,744.7 sccm. This condition seriously degrades the condition of the nuclear power plant, including its principal safety barriers, and is reportable in accordance with 10CFR50.72(b)(3)(ii). The licensee informed the NRC Resident Inspector.

• * * UPDATE AT 1015 EDT ON 4/18/06 FROM JIM HUFFORD TO S. SANDIN * * *

THE FOLLOWING IS A RETRACTION OF ENS NOTIFICATION #42407 On March 12, 2006, Susquehanna Steam Electric Station reported that a Type C penetration valve on Unit 1 experienced a leak rate of 12,700 sccm during testing. This leakage rate exceeded the TS allowed limit of 4,247 sccm (9 scfh) for Secondary Containment Bypass Leakage (SCBL) valves. Although a non-intrusive investigation determined that a significant amount of the leakage was past a non-Technical Specification test boundary valve, workers were unable to immediately quantify the exact amount of leakage attributable to this valve. Susquehanna conservatively assigned all leakage experienced during the test to the primary containment isolation valve being tested and reported the situation as a condition that seriously degraded the nuclear power plant per 10CFR50.72(b)(3)(ii). Subsequently, Susquehanna successfully re-worked the test boundary valve that was adversely affecting the leak rate test results. With no other changes in test conditions beyond this improvement in the test boundary, the test was re-performed with 464 sccm leakage observed. Total calculated leakage for SCBL amounted to 1306 sccm, well within Tech Spec limits. These results indicate that the excessive leakage was leakage past the test boundary valve and not the tested PCIV. As such, the SCBL limit was never exceeded and the ENS notification (#42407) is, therefore, being retracted. The licensee informed the NRC Resident Inspector. Notified R1DO (Dan Holody).

At 2300 hours, on 03/14/2007, the Unit 2 SPDS and ERDS system will be removed from service to support restoration activities from a planned maintenance outage on the power supply. The duration of work is expected to be approximately 20 hours. (Scheduled for completion at 1900 hours on 03/15/2007). During this time, Control Room indications and alternate methods will be available. Since the Unit 2 SPDS computer system will be unavailable for greater than 8 hours, this is considered a Loss of Emergency Assessment Capability and reportable under 10CFR50.72(b)(3)(xiii). The licensee notified the NRC Resident Inspector.

• * * UPDATE FROM HUFFORD TO HUFFMAN AT 2336 EDT ON 3/15/07 * * *

The SPDS and ERDS systems were returned to service at approximately 2230 EDT on 3/15/07. The licensee notified the NRC Resident Inspector. The R1DO (Hott) has been notified.

On August 13, 2007 at 14:20 (EDT), the Susquehanna Control Room was notified that during review of calculations for the Secondary Containment Radiation Monitor Setpoints errors were identified in Tech Spec Allowable Values and TRM Trip Setpoints that rendered them non-conservative. The affected instruments are Refuel Floor Wall, Refuel Floor High, and Railroad Access radiation monitors. The condition affects both Susquehanna Units. The radiation monitors are required to be operable for conditions noted in footnotes (a), (b), and (c) in Tech Spec tables 3.3.6.2-1 and 3.3.7.1-1 (i.e. operations with a potential for draining the reactor vessel, during CORE ALTERATIONS and during movement of irradiated fuel assemblies in the secondary containment, and movement of irradiated fuel assemblies within or above the Railroad Access Shaft). The function of these instruments is to initiate systems that limit fission product release during and following certain postulated accidents and to minimize the consequences of radioactive material in the control room environment. The radiation monitoring instruments were declared inoperable. All movement of irradiate fuel assemblies was halted (dry fuel storage activities were in progress at the time of notification). Based on this action, these monitors are no longer within the specified Applicability, and are therefore not currently required to be operable. The event has been determined to be reportable within 8 hours under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector.

• * * UPDATE FROM G. ROBINSON TO J. KNOKE AT 1222 EDT ON 10/03/07 * * *

On August 13, 2007 PPL Susquehanna reported that during a review of calculations for the Secondary Containment Radiation Monitor Setpoints, errors were identified in Tech Spec Allowable Values and TRM Trip Setpoints that rendered them non-conservative. The affected monitors were declared inoperable and the required LCO & TRO Actions entered. A subsequent engineering review determined that the values used to establish the Tech Spec Allowable Values and TRM Trip Setpoints were based on a Realistic Source Term, not a Design Basis Source Term. These values were sufficiently conservative to compensate for the errors in the calculations and the dose release limits from a Design Basis Accident would not have been challenged. It was concluded that the existing Tech Spec values and setpoints remained valid and the monitors were operable in their original condition. Based on this conclusion Event Notification EN# 43563 is being retracted. The licensee notified the NRC Resident Inspector. R1DO ( Powell) was notified.

Susquehanna Unit 1 was being manually shutdown on 10/13/2007 for a planned maintenance outage to address control cell friction. Prior to the shutdown five control rods had been declared inoperable due to control cell friction. When reactor power was lowered to 10% at 0220, entry into Tech Spec 3.1.3 was required for 'One or more BPWS groups with four inoperable control rods'. The completion time for this specification is 4 hours. The inoperability of the control rods condition cannot be cleared in the specified time. This condition results in the unit being in a 'Shutdown Required By Technical Specifications'. The required action is to be in Mode 3 within 12 hours. The Shutdown required by Technical Specifications is reportable as a 4 hour Non-Emergency report under 10 CFR 50.72(b)(2)(i). Manual insertion of control rods will continue until all rods are fully inserted. Hot Shutdown is expected by 0800, 10/13/07. Shutdown activities will continue to place the unit in cold shutdown. A Press Release will be made concerning the planned maintenance outage. The licensee notified the NRC Resident Inspector.

• * * UPDATE AT 1438 ON 11/7/2007 FROM TODD CREASY TO MARK ABRAMOVITZ * * *

On October 13, 2007, Susquehanna operators began the process of shutting down Unit 1 for a planned maintenance outage to address known control cell friction issues. Because four of five control rods declared inoperable during the operating cycle were located in the same Banked Position Withdrawal Sequence (BPWS) group, station personnel realized that conditions for entry into Technical Specification (TS) 3.1.3 'Control Rod Operability' Condition E would already be met when thermal power reached 10% rated thermal power during the shutdown. (NOTE: TS 3.1.3 Condition E is not applicable when thermal power is > 10%). With power less than or equal to 10%, TS 3.1.3 Condition E mandates restoration of control rods to operable status within 4 hours. If this 4 hour completion time is not met, TS 3.1.3 Condition F mandates that the plant enter Mode 3 (Hot Shutdown) within the next 12 hours. At 0220 hours on October 13, power was lowered to 10% power and TS 3.1.3 Condition E was entered. Control Room personnel, anticipating that the 4 hour restoration window allowed by Condition E would expire before the LCO could be cleared, reported the shutdown as a shutdown required by Tech Specs per 10 CFR 50.72(b)(2)(i). The ENS report was made proactively before the 4 hour restoration window had expired. Subsequently, the Unit 1 mode switch was placed to Shutdown (Mode 3) at 0610 hours on October 13. Because the timing of this mode change was within the 4 hour restoration window provided by TS 3.1.3 Condition E and because TS 3.1.3 is no longer applicable once Mode 3 is attained, the Condition requiring shutdown (Condition F) was never entered as a result of the inoperable BPWS rods as was initially reported via EN #43722. However, TS 3.1.3 Condition F can also be directly entered if nine or more control rods become inoperable. As the controlled shutdown Progressed, four additional control rods had been conservatively declared inoperable because they failed to settle at latched position '00' in a reasonable period of time. (Note: LER reports 50-387/2005-002-00 and 50-387/2006-001-00 have previously discussed control rod friction experienced at Susquehanna.) Accordingly, TS 3.1.3 Condition F was entered at 0343 hours on October 13, 2007. This TS entry constitutes the initiation of a nuclear plant shutdown required by the plant's Technical Specifications and is thus reportable per 10CFR50.72(b)(2)(i). Sufficient compensatory measures had been enacted such that TS 3.1.3 Condition F was no longer applicable by the time the controlled plant shutdown was completed. Therefore, the 60-day reporting that is necessary when a nuclear plant shutdown is completed per a plant's Tech Specs does not apply. (Reference: 10 CFR 50.73(a)(2)(i)(A)) The licensee notified the NRC Resident Inspector. Notified the R1DO (Miller).

At 1035 hours, on 03/22/2008, the Unit 1 SPDS and ERDS system was removed from service to disconnect and remove a temporary power supply to support a planned maintenance outage on the PICSY computer normal power supply. The disconnection and removal of temporary power is expected to have a duration greater than 8 hours, but less than 24. During this time, control room hardwire indications will be available. An update will be provided when SPDS/ERDS becomes available. Since the Unit 1 SPDS/ERDS computer system will be unavailable for greater than 8 hours, this is considered a Loss of Emergency Assessment Capability and reportable under 10 CFR50.72(b)(3)(xiii). The licensee notified the NRC Resident Inspector.

• * UPDATE FROM JIM HUFFORD TO JOHN KNOKE AT 0423 EDT ON 3/23/08 * *

This is a follow-up courtesy notification to EN# 44087. As of 0213 EDT, on 03/23/08, Unit 1 ERDS and PICSY are now fully restored. The planned outage activities are now complete. No further maintenance scheduled. The licensee notified the NRC Resident Inspector.

At 0738 hours on 07/10/08, reactor operators noticed that information on displays of the Plant Integrated Computer System were not periodically updating. Investigation by computer maintenance personnel was initiated. Reactor power was reduced 1 % to ensure compliance with license limits. As of 1538 hours, reliable operation of the computer was not restored. This computer system also performs the Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS) functions. Redundant, normal control room indications are still available to the operators. Since the Unit 1 SPDS and ERDS computer system were not reliable for greater than 8 hours, this is considered a Loss of Emergency Assessment Capability and therefore reportable under 10CFR50.72(b)(3)(xiii). Prior to this event, plant personnel were performing plant computer modifications. Compensatory measures are in place to provide emergency assessment data should an event occurs that requires it. The licensee has notified the NRC Resident Inspector.

• * * UPDATE FROM JIM HUFFORD TO JOHN KNOKE AT2052 EDT ON 07/10/08 * * *

This is a follow-up courtesy notification to EN# 44342. As of 2017 on 07/10/08, Unit 1 ERDS and PICSY were fully restored to normal operation. Unit 1 reactor power was returned to full power of 94.4% as of 2042 on 7/10/08. The licensee has notified the NRC Resident Inspector. Notified R1DO (Art Burritt)

PPL Susquehanna is installing a backup diesel to supply power to the Emergency Operating Facility (EOF) during loss of power conditions. A power outage is required to tie-in the transfer switch for the new power supply. The scope of work includes connection of offsite power to a new transformer, connection from the transformer to the transfer switch and connection of power from the transfer switch to the building's distribution panel. This power outage, which is expected to be approximately 3 hours, is required to make final connections and to test the new service. During the outage, temporary power will be supplied to the phone lines only. HVAC, lighting and computer terminals will be without power. This condition is a loss of emergency response capability and is reportable to the NRC as an 8 hour ENS notification per 10CFR50.72(b)(3)(xiii). The licensee contacted the NRC Resident Inspector.

• * * UPDATE FROM R. KLINEFELTER TO J. KNOKE AT 1303 EDT ON 09/23/08 * * *

This is a follow-up courtesy notification to EN# 44513. As of 12:20, on 09/23/08, power has been restored to the Susquehanna Emergency Operating Facility (EOF). Licensee has notified the NRC Resident Inspector and the state. Notified R1DO (Conte)

At 1801 on 5/16/2009, the HPCI turbine steam supply valve (HV255F001) failed to close during shutdown of the system following performance of its quarterly flow surveillance. The auxiliary oil pump was de-energized to prevent an inadvertent start of HPCI and the HPCI system was declared inoperable. LCO 3.5.1 for the HPCI system being inoperable was entered at 1720 on 5/16/2009 at the start of the HPCI surveillance. An investigation is in progress to determine the nature of the problem. This is being reported as an event or condition that could have prevented fulfillment of a safety function required to mitigate the consequences of an accident in accordance with 10 CFR 50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector.

• * * RETRACTION ON 7/16/09 AT 1543 FROM TODD CREASEY TO CHARLES TEAL * * *

On May 16, 2009, the HPCI system was declared inoperable at 1720 hours and LCO 3.5.1 was entered to support the planned quarterly HPCI flow surveillance test. During the surveillance test, at 1801 hours, the HPCI turbine steam supply valve (HV255F001) failed to close during shutdown of the system. It was also identified that neither the open nor closed indication lamp in the control room were lit. Troubleshooting was performed by cycling the valve's breaker in an attempt to restore power to the HPCI steam supply valve. No movement of the valve was observed. Because the position of the HPCI steam supply valve was unknown, Operations secured HPCI by opening the auxiliary oil pump breaker for the purpose of conducting additional troubleshooting (maintenance) of the failure of the HV255F001 valve to close. On 5/16/09 at 2004 hours EDT, Susquehanna made an 8-hour ENS notification (45703) to the NRC, due to HPCI being declared inoperable when HV255F001 failed to close during performance of the quarterly surveillance. Subsequent investigation concluded that the HPCI turbine steam supply valve (HV255F001) did close as expected, but did not indicate closed due to a loss of position indication. It was determined that the closed indicating lamp had burned out. Upon replacement of the lamp, the valve was successfully stroked open and closed and HPCI was declared operable at 0800 EDT 5/17/2009. Because a condition did not exist at the time of discovery that could have prevented the fulfillment of a safety function in accordance with 10 CFR 50.72(b)(3)(v)(D), EN #45073 is hereby being retracted. It should be noted that the subsequent action to disable HPCI by opening the auxiliary oil pump break does not preclude retraction of the ENS notification. This action did not create a new reportable condition since HPCI was already inoperable for planned surveillance testing. This action was taken as part of troubleshooting activities (maintenance) on the HV255F001 valve and to prevent an inadvertent start of HPCI. The NRC Resident has been notified. Notified R1DO (Gray)

At 1210 hours on 08/17/09, reactor operators noticed (the) Plant Integrated Computer System was beginning to fail. This computer system also performs the Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS) functions. Investigation by computer maintenance personnel was initiated. It was determined that (the) Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS) were not reliable. Redundant, normal control room indications are still available to the operators. At 1955 hours on 08/17/09, the Plant Integrated Computer System was restored to service, including the Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS) functions. A few hours later at 0004 hours on 08/18/09, the Plant Integrated Computer System failed, including loss of Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS). Reactor power was lowered by 0.3% from the initial authorized limit of 94.4% to 94.1% due to the loss of the core thermal power heat balance provided by the computer system. Since the Unit 2 SPDS and ERDS computer systems were not available for greater than an 8 hour time period, this is considered a Loss of Emergency Assessment Capability and therefore reportable under 10CFR50.72(b)(3)(xiii). The licensee has notified the NRC Resident Inspector.

• * * UPDATE AT 1321 ON 8/17/2009 FROM JIM HUFFORD TO KARL DIEDERICH * * *

As of 1336 hours on 08/18/09, Unit 2 ERDS and SPDS were restored to normal operation. Unit 2 reactor power was returned to full power of 94.4% shortly thereafter." The licensee has notified the NRC Resident Inspector. Notified R1DO (Conte).

At 0950 the Plant Integrated Computer System started to fail as indicated by a loss of computer link to Generation. Investigation by computer maintenance personnel was initiated. The failure mode of the computer precluded accessing screens to allow use of Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS). Computer core thermal power indication remained available to the control room operators. Redundant, normal control room indications are still available to the operators. At 1217 hours on 08/20/09, a planned loss of computer core thermal power indication occurred due to ongoing computer maintenance activities. At 1458 hours on 08/20/09, the Plant Integrated Computer System was fully restored to service, including the Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS) functions. At 1643 hours on 08/20/09, the Plant Integrated Computer System started to fail again as indicated by loss of computer link to Generation. This problem with the computer again precluded accessing Safety Parameter Display System (SPDS) and Emergency Response Data System (ERDS). Core thermal power indication remained available via the plant computer system. However, anticipated troubleshooting actions will require a reduction in power by approximately 0.25-0.33% by reducing core flow. Due to the cumulative impacts of the loss of the plant computer system, this notification is being communicated ahead of the 8 hour unavailability of the Unit 2 SPDS and ERDS computer system. This is considered a Loss of Emergency Assessment Capability and therefore reportable under 10CFR50.72(b)(3)(xiii). The licensee notified the NRC Resident Inspector.

• * * UPDATE FROM RICHARD KLINEFELTER TO CHARLES TEAL AT 1222 EDT ON 8/25/2009 * * *

As of 1200 hours, Unit 2 ERDS and SPDS (Safety Parameter Display System) were restored to normal operation. The licensee has notified the NRC Resident Inspector. Notified R1DO (White).

At 0830 (EDT) on 09/22/2010, the Unit 2 High Pressure Coolant Injection (HPCI) system was determined to be inoperable due to a minor lube oil leak on the 'A' supply filter. LCO 3.5.1 for the HPCI system was entered at 0830 (EDT) on 09/22/2010. The leak on the 'A' filter could not be immediately corrected. The 'B' filter was placed in service and leak checked satisfactorily. The LCO 3.5.1 action statements were closed at 1454 (EDT) on 09/22/2010. This incident is being reported as an event or condition that could have prevented fulfillment of a safety function required to mitigate the consequences of an accident in accordance with 10CFR50.72(b)(3)(v)(D). The licensee notified the NRC Resident Inspector.

• * * RETRACTION FROM RONALD FRY TO DONG PARK AT 1609 EST ON 11/18/10 * * *

At 1501 on September 22, 2010, PPL Susquehanna, LLC reported that the Unit 2 High Pressure Coolant Injection (HPCI) system was inoperable due to a minor lube oil leak on the 'A' supply filter. Subsequent investigation and evaluation determined that HPCI was capable of performing all of its safety functions with the identified oil leak. The operability determination was based on the following: Investigation of the leak identified that the installed filter housing cover o-ring was undersized and had to be inappropriately stretched to fit in the o-ring groove in the housing cover. The cover is torqued to 75 ft-lbs by four bolts on the outer diameter of the cover, enclosing the o-ring in a metal to metal connection. There is no concern for the o-ring to extrude from the cover under this configuration. The worst case that can be postulated as a result of the undersized o-ring is a leak in which the drops break into a small stream. This type of leak is expected to result in less than 10 gallons of oil loss during the system's 6 hour mission time. The vendor recommended oil reserve level is approximately 124 gallons. The lube oil sump has a 155 gallon capacity and the remaining oil (approximately 145 gallons) is sufficient to support operability. As a result, the worst case leakage is not expected to affect operability of HPCI or result in system failure during the HPCI mission time. Operations verifies oil level weekly and prior to any planned run. The licensee has notified the NRC Resident Inspector. Notified R1DO (Gray).