05000247/LER-2003-005

LER-2003-005, 1

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2472003005R00 - NRC Website

DESCRIPTION OF EVENT

Note: The Energy Industry Identification System Codes are identified within the brackets II.

On August 14, 2003, at approximately 1611 hours0.0186 days <br />0.448 hours <br />0.00266 weeks <br />6.129855e-4 months <br />, during 100% steady state power, Indian Point Unit 2 experienced an automatic reactor trip (RT)(JE} initiated by a loss of off-site power due to a grid disturbance. The loss of off-site power (LOOP) was associated with the blackout that affected parts of northeastern United States and Ontario, Canada. The degraded grid caused an under-frequency breaker trip on the 22 Reactor Coolant Pump (RCP). The trip of 22 RCP breaker initiated a RT on low approximately 35% power, permissive set point). The plant stabilized in natural circulation and the Emergency Diesel Generators (EDGs)(Eg) 21, 22, and 23 started automatically and energized the 480V buses. Main feedwater system isolated and the Auxiliary Feedwater System (AFW) (BA) pumps automatically started. Certain equipment that failed to operate properly included a leak in the service water line, Technical Support Center (TSC) Diesel and Radiation Monitor R-45 (Condenser Air Ejector Discharge). The TSC Diesel did not start as expected and was recorded as Condition Report CR-I152-2003-5203. This condition did not prevent activation of the emergency plan when required. None of the equipment issues precluded the return of the Unit to power.

No actuation of the Safety Injection System occurred nor was required as a result of this trip and no Power Operated Relief Valves actuated during this event. The Pressurizer Code Safety Valves remain closed throughout this transient. This event was entered into the Entergy Corrective Action Process under CR-IP2-2003-05176.

As a result of the blackout event, Radiation Monitor R-45 for monitoring condenser air ejector discharge failed, and a compensatory sample required by the technical specifications was missed. This event is also reported in this LER under 50.73 (a)(2)(i)(B) as an "operation or condition prohibited by Technical Specifications," and was entered into the Entergy Corrective Action Process under CR-IP2-2003-05296.

CAUSE OF EVENT

The cause of the reactor trip was a loss of off-site power due to grid disturbance. The root cause of the grid disturbance which resulted in a blackout for parts of northeastern United States and Ontario, Canada is under investigation by a joint United States and Canadian government special task force. The grid disturbance caused the main generator to have lower frequency.

The 22 RCP breaker tripped on under-frequency, which resulted in a RPS logic trip of the reactor on loss of RCS loop flow.

The cause of the missed compensatory sampling for the Radiation Monitor R-45 was attributed to communication error and programmatic weakness and has been recorded as CR-IP2-2003-05296.

CORRECTIVE ACTIONS

The reactor experienced an automatic trip and the plant shutdown as designed. All emergency systems initiated as required. Corrective actions for the event included a post trip review, a root cause evaluation, and plant walkdown. No specific corrective actions to preclude loss of off-site power due to a similar event were identified.

The corrective action for the missed compensatory sampling for R-45 is being resolved as per CR-M-2003-05296.

EVENT REPORTING

This event is reportable under 10 CFR 50.73 (a) (2) (iv) (A). The licensee shall report any event or condition that resulted in manual or automatic actuation of any of the systems listed in 10 CFR 50.73 (a) (2) (iv) (B). Systems to which the requirements of 10 CPR 50.73 (a) (2) (iv) (A) apply includes the Reactor Protection System including reactor scram or reactor trip, AFW and EDGs. The event for the missed compensatory sample for radiation monitor R-45 for the failed condenser air ejector discharge is reportable under 10 CFR 50.73(a)(2)(i)(B).

PAST SIMILAR EVENTS

• A review of previous occurrences when /P2 had experienced unit trip due to a loss of off-site power was performed. Within the pant three years, three(3) occurrences were identified and were reported to the NRC in the following LERs:

experienced an automatic reactor trip initiated by a main turbine trip. The turbine trip was caused by an electrical disturbance associated with the 345kV North Ring Bus at the Buchanan Substation.

experienced an automatic reactor trip initiated by a was caused by a generator trip of the over-frequency disturbance associated with the 345kV North Ring Bus the Con Edison 138kV system.

turbine trip. The turbine trip relays actuated by a at the Buchanan Substation and experienced an automatic reactor trip initiated by a turbine trip. The turbine trip was caused by a generator trip of the over-frequency relays actuated by a disturbance associated with 345kV Bus W93. The cause for the over-frequency relays actuation was a failure of the blocking relay on Con Edison 345 kV feeder Y94.

As indicated in LER 2003-04-00, a corrective action has been assigned to the 345 kV System Engineer to follow up with Consolidated Edison and obtain their root cause report. This report will contain Consolidate Edison's actions to prevent re- occurrence and improve grid reliability to the Indian Point Station (Due December 31, 2003).

EVENT SAFETY SIGNIFICANCE

There were no significant safety consequences for this event because the plant systems responded as expected except as noted. No pressurizer safety valves lifted and no actuation of the safety injection system was required. There were no nuclear safety concerns exhibited during the event and all fission product barriers remained intact. There was no significant impact on the health and safety of the general public.

The loss of a reactor coolant pump is described in the UFSAR Section 14.1.6, "Loss of Reactor Coolant Flow." This event was initiated when the Unit was operating at 100 % power and is bounded by the UFSAR analysis.

The loss of power to station auxiliaries is described in UFSAR Section 14.1.12, "Loss of Station Auxiliaries." The design event as described in the UFSAR results in a loss of offsite power to both 6.9kV and 480V busses. In this event, the loss of power was per this design event and was bounded by the UFSAR analysis.

There was no safety significance for the missed compensatory sampling for R-45, because the chemistry sample before and after the missed sample had no measurable activity.

NRC FORM WM 11,2001)