On May 4, 2015 with Unit 1 in Mode 1 at 100 percent power, during performance of the 'A' channel
Auxiliary Feedwater Actuation System (AFAS) monthly functional test, an invalid 'A' channel AFAS actuation occurred. The monthly functional test resulted with AFAS-1 in a half trip condition. Due to a poor contact on a manual actuation switch, a pathway was dropped out causing the partial AFAS actuation to occur. The faulty mechanical switch was replaced and the post maintenance testing was satisfactory.
The partial AFAS actuation resulted in the successful start of 'A' AFW electric driven pump and the opening of its motor control valve, feeding the 'A' steam generator. The system responded to the invalid actuation as designed.
In accordance with 10 CFR 50.73(a)(1), this notification of the invalid actuation is provided in lieu of a written LER.
The licensee notified the NRC Resident Inspector.
