Event Notification Report for March 14, 2001

HPCI DECLARED INOPERABLE DUE TO FAILURE OF EXHAUST LINE VACUUM RELIEF VALVES TO FUNCTION DURING IST TESTING

"During routine testing of the Unit 2 High Pressure Coolant Injection system (HPCI) exhaust line vacuum relief valves (VRV), it was discovered that both VRVs failed to open at their In Service Test (IST) required differential pressure value. The Unit 2 HPCI system has been declared inoperable and repairs are in progress.

"This event is being reported in accordance with 10CFR50.72(b)(3)(v)(D) due to a failure of a single train system which prevents fulfillment of a safety function."

With HPCI inoperable this places Unit 2 in a 14-day Limiting Condition of Operation. All other ECCS systems have been verified operable.

The licensee informed the NRC resident inspector.


* * * RETRACTION ON 04/24/01 AT 1254 ET BY STEVE BECK TAKEN BY MACKINNON * * *

The original design function of the affected vacuum relief valves was to prevent damage to the HPCI exhaust line rupture disks. A failure of the rupture disks would result in steam being discharged into the HPCI Room and subsequent isolation of the HPCI system on high room temperature. A modification to the rupture disk installed backing support plates to ensure that repetitive vacuum conditions in the exhaust line would not result in fatigue failure of the rupture disks. As a result of the modification, the vacuum relief valves are no longer required to open to protect the rupture disks.

Based on an Engineering evaluation, it was concluded that the HPCI exhaust line vacuum relief valves design function is not required to support HPCI system operability.

NUREG 1022, Rev. 2, allows "removal of a system or part of a system from service as part of a planned evolution for maintenance or surveillance testing when done in accordance with an approved procedure and the plant's TS (unless a condition is discovered that could have prevent the system from performing its function)."

In this case, HPCI was removed from service for planned maintenance per plant procedures and Technical Specifications. The condition found (vacuum relief valve inoperability) would not have prevented HPCI from performing its safety function; therefore this event is not reportable per 10CFR50.72(b)(3)(D) or 10CFR50.73(a)(2)(v). R1DO (David Silk) notified.

The NRC Resident Inspector was notified of this retraction by the licensee.

UNIT 2 EXPERIENCED A TURBINE TRIP - REACTOR TRIP ON LOSS OF LOAD

"At 1752 hours on 3/14/01, the St. Lucie Unit 2 reactor automatically tripped on a turbine loss of load signal. Prior to the trip, the output breaker on the 2A Control Element Drive motor generator set opened for an unknown reason. Shortly thereafter, various Control Rod trouble alarms annunciated and the Control Rods dropped into the core due to loss of power on the Control Rod busses. The loss of power to the Control Rod busses initiated a turbine trip, which in turn generated a Reactor Protective System trip signal on loss of load. All Control Rods inserted fully. Standard Post Trip actions were completed satisfactorily with all safety functions met.

"Following the trip, it was noticed that the 2A1 non-safety related 6.9KV electric busses did not automatically transfer to the Startup Transformers. This resulted in the loss of power to the 2A1 and 2B2 Reactor Coolant Pumps and the 2A Main Feedwater pump. The cause for the failure to transfer is being investigated. Due to the loss of the Reactor Coolant Pumps, the Reactor Coolant System was manually depressurized to 1850 psia per plant procedures.

"The Auxiliary Feedwater Actuation System automatically actuated on low Steam Generator level as expected for reactor trips from high power level. Steam Generator level is currently being maintained by the 2B Main Feedwater pump.

"The reactor is currently stable in Mode 3 and the cause of the trip is under investigation."

No primary safety or reliefs lifted during the transient. Decay heat is being removed via the bypass valves to the main condenser. The AFW pumps are operating but not supplying feed to the Steam Generators. The licensee had not verified whether any atmospheric dumps cycled. There is no known Steam Generator tube leakage at this time. Normal offsite power remains available and there was no impact on Unit 1 which is operating at 100% power. Unit 2 will remain in Hot Standby pending development and completion of corrective actions. The licensee informed the NRC resident inspector.

POSSIBLE RADIATION EXPOSURE ABOVE THE NRC REGULATORY LIMIT OF 5 REM

Based on calculation methods used by the Pennsylvania Department of Environmental Protection and the National Society of Radiation Physicists, the total body dose received by a cardiologist at Jameson Memorial Hospital received last year was 3,069 mR which is less than the limit of 5,000 mR/yr. On 03/13/01, an NRC physicist using a different methodology for calculating total body dose calculated that the cardiologist received a total body dose of 5,401 mR last year. The cardiologist received most of the dose from x-ray related activities (regulated by the Commonwealth of Pennsylvania). However, the cardiologist received some exposure from doing stress tests on patients, which mostly involves the use of NRC licensed material (technetium-99m). No adverse health effects are expected.

On 03/14/01, NRC Region 1 issued a Preliminary Notification (PNO-I-01-006) describing this event in more detail.

AGREEMENT STATE REPORT INVOLVING A MISSING KRYPTON-85 SOURCE

The following event was E-mailed to the Headquarters Operation Center.


The licensee reported the loss of an approximately 147 millicurie Kr-85 source (originally 300 millicuries in 1989). The source, an Amersham model KAC.D3, serial number 7341-BK, was mounted in a Data Measurements Corporation source holder model BCL-1. The source assembly was supposed to have been removed from a Data Measurements Corporation Paper Weight Basis Profiler that was being decommissioned in late 1999. A wooden box, labeled as containing the source assembly, was transferred to the licensee's new RSO in 2000 and dutifully inventoried until March 2001. Based on survey measurements, the new RSO became suspicious of the wooden box and discovered upon opening it that it contained the detector assembly rather than the source assembly. A search of the site failed to locate the source. The licensee believes that the source was most likely left on the Paper Weight Basis Profiler and recycled as scrap metal. Alternatively, it could have been discarded into waste sent to the landfill. No records for the decommissioning of the Profiler have been found and the individual who performed the decommissioning is no longer employed by the licensee.

Disposition/recovery: Presumed to be irretrievably lost.

OFFSITE NOTIFICATION TO VARIOUS AGENCIES CONCERNING AN OIL SPILL ONSITE

"At 10:30 AM on 3/14/2001 the following agencies were notified of an oil leak on site.

New Hampshire DES
National Response Center
US Coast Guard
Environmental Protection Agency (EPA)

"About 1 gallon of oil was observed on top of a concrete pad near the vehicle maintenance shop. The oil came through the pad via cracks in the concrete. There is an oil line that runs under this pad from a 6000 gallon above ground tank. The tank has been isolated, local storm drains have been protected and a contractor is on site to excavate the area and determine the extent of the problem. The notifications were made as a precautionary measure since the quantity of oil under the concrete pad is unknown. The oil was first observed on 3/13/01 at approximately 1600."

The licensee informed the NRC resident inspector.

24-HOUR REPORT INVOLVING POTENTIAL PERSONNEL OVEREXPOSURE

At approximately 0710EST a technician at the Christiana Care Health Services spilled a tube in the corner of the hot lab containing between 30-50 ml of Technetium-99m milked from the generator. The activity was measured as 650 millicuries immediately prior to the spill. The hot lab was promptly evacuated. There was no personnel contamination involved. Initial rad surveys of the affected area showed between 80 and 200 mr/hr prior to decontamination. Following final decontamination measured rad levels taken at 1000EST were approximately 10 to 40 mr/hr. Access to the lab has been restored, however, the corner area is taped off and covered by plastic to minimize the spread of contamination and allow for decay.

UNIT 2 EXPERIENCED AN UNEXPECTED LOSS OF SHUTDOWN COOLING DUE TO TRIPPING OF VARIOUS POWER SUPPLY BREAKERS

"Unit 2 was in Mode 5 on the fifth day of its 10th Refuel and Inspection Outage. At 1508 hours, the unit experienced an unexpected loss of Division 1 RPS Power supply. The loss of power was a result of the Electrical Protection Assembly (EPA) A & C breakers and motor generator output breaker tripping. The cause is under investigation.

"The loss of power caused the RHR Shutdown Cooling suction valve HV251F009 to close. This is a common suction valve to both divisions of RHR and resulted in the complete loss of RHR Shutdown Cooling. The reactor currently has its head removed with the reactor cavity flooded up with the gates to the spent fuel pool removed. A Supplemental Decay Heat Removal system was in service at the time, but was not considered fully capable of decay heat removal. Reactor coolant temperature increased less than 2 degrees during the 37 minutes SDC was out of service. The RPS power supply was switched to its alternate supply and SDC was restored at 1545 hours. In accordance with 10CFR50.72(b)(3)(v) this represents a loss of a safety system which removes residual heat and requires an 8 hour ENS call. In addition to the isolation of RHR SDC, RWCU isolated due to containment valve HV244F001 closing, and Unit 2 HVAC Zone 3 (refuel floor) isolated. These isolations constitute an actuation of a Containment Isolation signal that affected multiple systems, and is reportable per
10CFR50.72(b)(3)(iv)(A)."

Peak temperature after losing SDC was 105 degrees. The licensee informed the NRC resident inspector.

***** UPDATE RECEIVED AT 1542 ON 05/15/01 FROM GORGON E. ROBINSON TO LEIGH TROCINE *****

The licensee is updating this event notification to change the event reporting requirements from an 8-hour event notification to a 60-day notification of invalid system actuations. The following text is a portion of a facsimile received from the licensee:

"ENS Notification # 37839 documented that the loss of the Unit 2 Division 1 RPS power supply on 3/14/01 required an 8-hour ENS notification for actuation of a containment isolation signal that affected multiple systems and a loss of a safety function required to remove residual heat (10CFR50.72(b)(3)(iv)(A) and 10CFR50.72(b)(3)(v)(B), respectively). After subsequent evaluation of the event, the reportability determination is being changed to retract the 8-hour notification and provide the required a 60-day ENS notification for an invalid actuation that affected multiple systems. See the discussion below."

"The initial condition was reported per 10CFR50.72(b)(3)(v)(B), loss of safety function that is needed to remove residual heat. A subsequent review of the event and reporting requirements by PPL has concluded that the event is not reportable per this section of the rule. In this case, the 37-minute interruption did not and would not have prevented the fulfillment of the RHR shutdown cooling function."

"The original notification stated that an actuation of a containment isolation signal that affected multiple systems was reportable as an 8-hour ENS notification per 10CFR50.72(b)(3)(iv)(A). For this event, a half-scram while the unit was shutdown, was the result of an invalid signal since it was due to loss of RPS power. Except for critical scrams, invalid actuations are not reportable by telephone under 10CFR50.72. Therefore, this 60-day optional report, as allowed by 10CFR50.73(a)(1), is being made under the reporting requirement in 10CFR50.73(a)(2)(iv)(A) to describe an invalid actuation of general containment isolation signals affecting isolation valves in more than one system."

"At 15:08 on March 14, 2001, with Unit 2 in Mode 5 at 0% power, the primary power supply to the 'A' Reactor Protection System (RPS) power distribution panel was lost when the Motor-Generator (MG) Set generator in that division failed. This resulted in Primary Containment Isolation System actuations including isolation of [a] Residual Heat Removal shutdown cooling suction valve and other automatic system initiations. RPS as well as other plant systems functioned as designed in response to the event. The 'A' RPS distribution panel was swapped to alternate power, and all isolations were reset by 16:10. The loss of power was due to a failure of the 'A' RPS M-G set generator. The generator failed due to a manufacturing defect of an internal conductor connection. The failed generator was replaced, and other like-in-kind generators will be inspected. There were no safety consequences or compromises to the health or safety of the public. This event has been entered into the site-specific corrective action program for resolution. Internal and industry events were reviewed to assess if a generic problem exits with this type of generator. No evidence of similar failures was found, which indicates that a generic problem does not exist."

"The NRC site Resident Inspector has been notified." The NRC operations officer notified the R1DO (Rogge)