05000219/LER-2010-002
| Oyster Creek | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2192010002R00 - NRC Website | |
Plant Condition Prior to Event Event Date: December 23, 2010 Event Time: 1407 EST Unit 1 Mode: Startup� Power Level: 0%
Description of Event
On December 23, 2010, a reactor startup was in progress in accordance with Procedure 201, Plant Startup. The reactor was critical with the mechanical vacuum pump operating to draw vacuum on the main condenser. The reactor had reached the point of adding heat and steam header warm-up was underway in accordance with Procedure 318, Main Steam System and Reheat System. "B" Condenser Vacuum had reached 19.6 inches mercury when the first set of steam jet air ejectors were placed in service. After the second and third set of air ejectors were placed in service, the mechanical vacuum pump was removed from service, and vacuum continued to improve to 23.9 inches mercury vacuum. Turbine Vacuum Trips were reset in accordance with the Procedure 315.1, Turbine Generator Startup.
Step 5.44.2 of Procedure 201 requires that RPS Low Vacuum Trips are clear prior to proceeding above 500 psig reactor pressure. The step states, "Confirm the following: All Main Condenser vacuum trips have cleared." The URO misinterpreted step 5.44.2 to be that the turbine trips were cleared. The URO then informed the Reactivity Senior Reactor Operator (SRO) that conditions were met to exceed 500 psig. At 14:07, reactor plant heat up brought reactor pressure in excess of the 600 psig low vacuum scram bypass reset prior to the RPS Condenser Vacuum Low/Turbine Trip set point being cleared, causing the reactor to automatically shutdown via scram.
Cause of Event
Inadequate procedure compliance by the URO initiated the event. The URO incorrectly validated the requirements to raise pressure above 500 psig and communicated this to the Reactivity SRO. Based on that information, the Reactivity SRO proceeded above the 500 psig milestone.
Analysis of Event
There were no plant or public health and safety consequences to this event. This report does not describe a safety system functional failure. The event is classified as a non-consequential event.
This event is being reported in accordance with 10 CFR 50.73 (a)(2)(iv)(A), which requires the reporting of any event or condition, which resulted in manual or automatic actuation of the RPS.
Corrective Actions
Plant startup and shutdown procedures will be revised to indicate significant steps (milestones) requiring Unit Supervisor concurrence to proceed.
Previous Occurrences
There have been no similar Licensee Event Reports submitted at Oyster Creek in the last three years.