 INES 0 |
REACTOR SCRAM ON PRM HIGH FLUX SUBSEQUENT TO SPURIOUS ACTUATION OF REACTOR RELIEF VALVES A & B (SRUOR-1-90-8) |
On 19.11.90 reactor scrammed on PRM high flux subsequent to spurious actuation of reactor relief valves A and B. Reactor pressure came down from 70 kg/cm2 to 66.2 kg/cm2. Within a minute, pressure shot up to 67.6 kg/cm2 when RVs went closed. On investigation, flash over in electrical penetration Q46 plug J5 was observed causing short circuit in RVs solenoid circuit. Defective plug was replaced.
BASIS FOR RATING: Degradation of defence in depth. Table 1, A-1R. 0/1
All safety systems/functions were available. Reactor trip proceeded normally. Rating -0.
DIFFICULTIES IN RATING: None.
Event date: Mon, 19-11-1990
