TURBINE SJAES STEAMING DUE TO PLANT PERSONNEL ERROR

The unit was operating at nominal power. Thermal Instrumentation and Controls Service (TICS) shift personnel admitted TICS maintenance personnel to perform work on hydrogen content monitoring sensors at the outlet of moisture separator of the hydrogen reburn facility without informing Turbine Service operating personnel and plant deputy shift supervisor. While performing work on one of the sensors spurious signal of hydrogen concentration increase to 0.4% was formed. This resulted in interlockings actuation, steam supply to dilute gaseous medium was started and Steam Jet Air Ejectors (SJAEs) steaming and turbine condenser vacuum decrease occurred. The TG was tripped by protection on vacuum deterioration. Unit power was reduced by AZ-3 protection system actuation.
BASIS FOR RATING: Initiator - turbine SJAEs steaming. Event expected, real. Safety function availability - full. The event corresponds to level 0/1 (A-1R). The event reveals deficiencies in operating personnel actions associated with the breach of procedure. This shows deficiency in safety culture and therefore the higher level has been chosen.
DIFFICULTIES IN RATING:

Location: 
SMOLENSK-3
Event date: 
Thu, 1990-12-06
Javascript is required to view this map.
»