Invalid Actuation of Spray Pond Pump System - 60 Day Reports
The following event descriptions are based on information currently available. If through subsequent reviews of these events additional information is identified that is pertinent to the events or alters the information being provided at this time a follow-up notification will be made via the ENS or under the reporting requirements of 10 CFR 50.73.
This telephone notification is being made pursuant to the reporting requirements of 10 CFR 50.73(a)(2)(iv)(A) and 50.73(a)(1) to describe invalid actuations of both trains of the Palo Verde Nuclear Generating Station (PVNGS) Unit 3 essential spray pond (SP) system, which serves as an emergency service water system that does not normally run and serves as an ultimate heat sink as described in 10 CFR 50.73(a)(2)(iv)(B)(9).
This notification covers two similar, but separate invalid actuations occurring in Unit 3 on March 14, 2020 at 12:44 (MST) and again on April 25, 2020 at 12:10 (MST). On each day, an invalid actuation of the Unit 3 train "B" Fuel Building Essential Ventilation Actuation Signal (FBEVAS) occurred during performance of the Balance of Plant Engineered Safety Features Actuation System weekly auto test. The auto/manual pushbutton was depressed to initiate the test and the sequencer immediately tripped FBEVAS train "B" with subsequent cross trip of FBEVAS train "A". These actuations resulted in complete and successful actuations of both trains of essential spray pond pumps.
The events were entered into the PVNGS corrective action program and a station evaluation is in progress. There was no adverse impact to public health and safety nor to plant employees.