CAUSE DESCRIPTION Station personnel were performing a RHR valve interlock test in which the RHR system is automatically isolated from the reactor coolant system. When the applied test signal reached the setpoint, the RIR isolation valves closed removing the letdown path. Operator inadvertently isolated letdown while charging. Safety valves relieved to terminate transient. J Note 2485 Note 1 Following a main steam line Instrument Technician tripped wrong the Subcommittee files and the NRC Public Document Room. These materials include: 1. Detailed reports on overpressurization incidents. 2. Twenty day responses submitted by PWR licensees to |