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On January 23, 2016, James A. FitzPatrick Nuclear Power Plant (JAF) was ascending in power when screenwell water level started to lower. At 89 percent power, at 22:23, Operators began taking compensatory measures to reduce power and mitigate water level lowering. At 22:40, a manual scram was initiated.

The scram was complicated by a residual transfer that resulted in non-vital equipment trips. This event resulted in the manual actuation of the Reactor Protection System, High Pressure Coolant Injection, Reactor Core Isolation Cooling, Main Steam Isolation Valves and automatic actuation of Emergency Diesel Generators, Emergency Service Water, and containment isolations in multiple systems, reportable per 10 CFR 50.73(a)(2)(iv)(A).

The lowering screenwell water level was caused by frazil ice blockage at the intake structure. The frazil ice stopped affecting screenwell water level after the manual scram. Corrective actions include strengthening mitigating actions in response to frazil ice.

The residual transfer was caused by lubrication hardening in the lower control valve assembly of the 71PCB-10042 breaker. Corrective actions included replacing or reworking the lower control valve assembly.

On Tuesday, July 16, 2013 at 1652 (EDT) and again on Wednesday, July 17, 2013 at 1054 (EDT) with the reactor at 100% core thermal power (CTP) the Pilgrim Nuclear Power Station (PNPS) declared the ultimate heat sink (UHS) and the salt service water (SSW) system inoperable due to high sea water inlet temperatures greater than 75°F. A maximum sea water inlet temperature reading of 75.5°F was observed and the maximum duration for either event was 5.5 hours.

The limiting condition for operation (LCO) action for technical specification (TS) 3.5.B.4 was entered then exited based on the rise and fall of sea water inlet temperature. Plant systems and components operated as required and no equipment failures occurred. The plant was not shutdown due to the short duration of the sea water temperature excursion.

The cause of the high sea water inlet temperature readings was sustained increased sea water surface temperature in Cape Cod Bay due to hot summer weather conditions and the contribution from recirculation of water from the plant's outfall due to wind and tidal conditions. Corrective action was completed to establish an operational decision making issue (ODMI) action plan to reduce station power levels prior to reaching the TS UHS LCO temperature limit.

This event posed no threat to public health and safety.

On December 13, 2012, it was questioned whether both emergency diesel generators (DGs) would be considered inoperable if one diesel oil storage tank (DOST) room water tight door was impaired because the door between the DOST rooms was not water tight. The Plant Barrier Impairment Program procedure contained a pre-evaluated compensatory action for impairment of one of the DOST room water tight doors, which required declaring only the affected emergency diesel generator (DG) inoperable. A subsequent technical review determined that the compensatory note was incorrect and that both DOST rooms would be vulnerable to flooding with the water tight door for one DOST room impaired. A review of prior plant barrier impairments identified one instance in the previous three years where only one DG was declared inoperable while the corresponding water tight door was impaired.

The cause of the event was determined to be inadequate technical rigor, which led to improper compensatory measures being included in the Plant Barrier Impairment Program procedure. The corrective action was to revise the procedure to consider both trains of the affected unit's DGs inoperable when either DOST water tight door was impaired.

On May 21, 2012, at 2:52 p.m., while the plant was operating at 100% power, an automatic reactor scram occurred due to a partial loss of vacuum in the main condenser. This condition initially caused a trip of the main turbine, and the fast closure of the turbine control valves provided the actuation signal to the reactor protection system (RPS).

Main condenser vacuum remained within the operating limits for use of the main turbine bypass valves, thus reactor pressure was automatically controlled following the initial transient. The reactor feedwater system remained in service. The decrease in main condenser vacuum resulted from the loss of two of four circulating water pumps.

This condition was caused by the failure of a splice in one of three 13.8kV cables providing power to half of the 4160V switchgear at the circulating water structure. The splice failure resulted in a small fire inside a manhole located outside the protected area. The plant fire brigade confirmed the fire was out within approximately 24 minutes of the onset of the event. Six reactor safety-relief valves actuated in response to the main turbine trip. The reactor core isolation cooling (RCIC) system steam supply valve automatically closed due to a false high-flow signal from the steam flow sensors. The system was restored to its standby configuration at 5:36 p.m. No plant parameters requiring the automatic actuation of the RCIC system were exceeded during the event. The failed splice was replaced, and the other cables in the circuit were tested for integrity, resulting in the replacement of one other splice. This event is being reported in accordance with 10CFR50.73(a)(2)(iv)(A) as an automatic actuation of the RPS system. There were no safety-related systems out of service at the time of the event.

On August 22, 2011, St. Lucie Unit 1 was operating in Mode 1 at 89% when it was manually tripped due to rising condenser back pressure. All control element assemblies (CEAs) fully inserted into the core. The cause of the rising back circulating water system performance. Decay heat removal was initially from the main feedwater and steam bypass to the main condenser. However, subsequent to the manual trip, the 1B main feedwater pump was manually secured due to a leak on the pump casing. The 1A main feedwater pump subsequently tripped due to low suction pressure after manually securing the 1B condensate pump and decay heat removal was transitioned to the atmospheric dump valves and auxiliary feedwater.

Root cause evaluation determined the jellyfish intrusion rate exceeded the current capacity of the traveling water screens and trash pits. In addition, procedural guidance did not anticipate the possible rapidly escalating jellyfish intrusion rate and the urgency for response regarding the negative effect of the rapid jelly intrusion on condenser back pressure was not recognized.

Contributing causes included: plant maneuvering did not account for condenser back pressure margin, equipment degradation and malfunctions, and design deficiencies.

Corrective actions include procedure revisions and design changes to address procedure deficiencies and correct design deficiencies.

On February 27, 2010, at approximately 0116 hours Eastern Standard Time (EST), Control Room Operators manually inserted a Reactor Protection System (RPS) trip to shutdown the reactor from approximately 21 percent of rated thermal power to begin a planned refuel outage. The 1B Reactor Feedwater Pump (RFP) had been removed from service at approximately 61% rated thermal power and isolated to support scheduled maintenance' activities. Following the insertion of the RPS trip, the lA RFP was shutdown due to high RFP turbine casing drain level. At 0158 hours, Unit 1 Control Room Operators manually started the Reactor Core Isolation Cooling (RCIC) system to maintain reactor pressure vessel (RPV) coolant level following the pre planned reactor scram. The RCIC system maintained RPV coolant level until the 1B RFP could be returned to service. The RCIC system was shutdown at 0306 hours. All systems functioned as designed.

The safety consequences of this event were minimal. The RPV level remained in the normal band while RCIC was being used for level control during the transient. All Emergency Core Cooling Systems (ECCS) were operable and available to provide adequate core cooling if needed. The root cause of this event was that Operators made the redundant RFP unavailable while still above the reactor pressure at which a RFP is required to feed the RPV. The corrective actions to prevent recurrence for this event are to revise operating procedures cautioning that a Reactor Feedwater Pump should not be made unavailable before reactor pressure is less than 350 psig.

On October 21, 2008, at 20:49 PDT, with Unit 2 in Mode 1 (Power Operation) at approximately 55 percent power, a manual Reactor Trip was initiated due to the failure of the Pacific Ocean Circulating Water System (CWS) debris removal system to maintain adequate flow for power operation. Plant operators stabilized Unit 2 in Mode 3 (Hot Standby) and made an emergency event notification (EN#44588) in accordance with 10 CFR 50.72(a)(1)(i) at 22:44 PDT.

This event was due to a sudden large influx of Moon Jellyfish in the Pacific Ocean CWS that exceeded the ability of the debris removal system to effectively remove. PG&E has developed extensive models to help predict the impact of Pacific Ocean storms associated with CWS debris removal, and to give adequate time to prepare for such events. PG&E could not have anticipated this event and the potential adverse affects from the sudden large influx of jellyfish.

On April 24, 2007 at approximately 2248, a manual reactor trip was initiated with reactor power level at approximately 40%.

The manual reactor trip was initiated in response to a degraded Circulating Water System (CWS) and in accordance with operating procedures. The degradation of the CWS was due to extremely heavy river debris loadings that affected the ability of plant equipment to operate under the condition.

The unit was returned to service on April 26, 2007 at 1236 following the cleaning of the condenser water boxes and lowering river debris conditions.On April 30, 2007, at approximately 1502, with the unit at approximately 80% power a sudden localized high amount of river water debris again affected the CWS intake resulting in the loss of four (4) circulating water pumps due to high screen differential levels, and a manual reactor trip.

The cause of manual reactor trips is attributed to unusual and severe external environmental conditions resulting in record high amounts of river debris loadings, which challenged the design of the CWS. Following cleaning and inspection of the Circulating Water Traveling Screens, condenser waterboxes, and lowering river debris conditions the unit was returned to service on May 3, 2007 at 0310. A root cause investigation has been initiated to improve the plant operation and to minimize challenges to the CWS design by: (a) Improving predictive tools and actions on high river debris conditions, and (b) Improving the availability and reliability of the Circulating Water System.

This report is being made in accordance with 10CFR50.73(a)(2)(iv)(A), "any event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(b)....

�NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-2004) 2. DOCKET1. FACILITY NAME 6. LER NUMBER 3. PAGE

At 11:15, on October 20, 2006, Progress Energy Florida, Inc. (PEF), Crystal River Unit 3 (CR-3) was operating in MODE 1 (POWER OPERATION) at 100 percent RATED THERMAL POWER when an evaluation concluded that flow through the Train B Nuclear Services and Decay Heat Seawater (RW) System cyclone separator (RWSP-1B) was severely reduced. A flow of

• approximately 9 gpm is required through RWSP-1B to ensure flush water with particles less than 250 microns to the bearings of RW System pumps RWP-2B and RWP-3B. A subsequent review concluded that Train B of the RW System was inoperable from July 6, 2006, through 11:15 on October 20, 2006. Additionally, Train A of the RW System was taken out of service for scheduled maintenance from 02:00 on July 18, 2006, to 15:00 on July 19, 2006, rendering both RW System trains inoperable during this time. The cause for this event was failure of a duplex strainer basket upstream of RWSP-1 B. This failure allowed debris to migrate to and block the RWSP-1 B drain port, stopping the filtration process. RWSP-1 B was cleaned and flushed. This report is being submitted pursuant to 10CFR50.73(a)(2)(i)(B) and 10CFR50.73(a)(2)(v)(B). This condition does not represent a reduction in the public health and safety. No previous similar occurrences have been reported.

• On 11/12/03 while restoring the Circulating and Service Water pump house electrical bus lineups to a normal configuration, two out of three electrical buses were de-energized resulting in a loss of the service water system and necessitating manual actuation of the Essential Service Water (ESW) system. The loss of service water coupled with a reduction in circulating water system capacity required Control Room Operators to manually reduce Main Generator electrical loading to prevent a loss of condenser vacuum and automatic main turbine runback.

After operator actions restored service water system operation, power stabilized at approximately 70 percent. An Event Review Team concluded the cause of the event was failure to follow an approved plant procedure. The Licensed Operator selected position 2201-2202 versus the proper position of 2201-2102, which is located on a different selector switch. A contributing cause was the fact the two bus transfer selector switches have identical name plate labels.

Once the cause of the event was understood, power was increased to 100 percent and normal operation resumed.

Corrective actions include revising the Main Contra! Board name plate labels for the bus transfer selector switches and revising plant procedures to reflect the new labels_

• NRC FORM 3(.41.(/-2001I

At 1443 hrs on June 14, 2002, Unit 1 was manually tripped following the trip of the East main feedwater (FW) pump (MFP). The East MFP tripped due to a loss of main feed pump turbine condenser vacuum caused by an influx of debris following the start of the #13 circulating water (CW) pump. On June 14, 2002, at 1751 hours, in accordance with 10 CFR 50.72 (b)(2)(iv)(B), a four-hour ENS notification (Event No. 38993) was made to the NRC for a condition that resulted in an actuation of the reactor protection system when the reactor is critical.

The cause of this event was the transport of debris (primarily zebra mussel shells and sand) into the East MFP turbine condenser upon the start of the #13 CW pump. A contributing factor was the closure of 12-WMO-30 (the center lake water intake valve) a few days prior to the start of the #13 CW pump.

The safety significance of this event was minimal since plant procedures and operator training provided sufficient direction for control room personnel to shutdown the plant and maintain it in a safe shutdown condition. In addition, this event had no impact on the ability of the main FW system to perform its feedwater isolation accident mitigation function.

The Unit 1 East and West MFP turbine condenser tubes and waterboxes were cleaned on June 14, 2002.

CNP will take actions to mitigate the effects of debris on CW pump startups with the unit on line. Specifically, precautions will be added to the CW system operating procedure to identify the potential vulnerability for debris intrusion associated with starting CW pumps with the unit on-line. The procedures will also include guidance for use of MFP turbine condenser waterbox lancing when starting a CW pump with a unit on-line.