INES-event
INES 0

REACTOR SHUTDOWN BY THE FAST-ACTING SCRAM SYSTEM DUE TO SPURIOUS SIGNALS OF INCREASED PRESSURE IN THE ISOLATION CONTROL VALVES ROOM

On 9 February 1996 Ignalina NPP Unit 1 was under normal operation at the thermal power of 4100 MW. Electrical power of Turbogenerators TG-1/2 was 620 MW/680 MW respectively.
At 12:32 p.m. the reactor was shut down by the fast-acting scram system (FASS AZ-1) due to the signals of increased pressure in the isolation control valves room (Reactor Building Room 209). The signals were actuated by 2 of 4 pressure sensors.
Provisional investigation confirmed that there was no pipe leaking in the room. The FASS actuation was spurious. It did not affect the radiological situation. The actuation is being analysed.
INES rating - level 0
Justification of the rating: Table II.A-1 of INES User's Manual

Location: IGNALINA-1
Event date: Fri, 09-02-1996
Nuclear event report
Legenda & explanation