INES-event
INES 0

FAILURE OF TWO PRESSURIZER SPRAY LINES

In the course of a power reduction inefficiency of two pressurizer spray valves was detected. The inspection showed that two manual isolation valves had broken steam and the wedge was fallen in the seat. No initator occurred. The affected spray function can only be used by reactor coolant pumps avaiable (not supplied by emergency power) and is therefore not classified as a full safety function. The other two safety related pressure reduction ways - three safety relief valves and one auxiliary spray - were available.
Basis for rating: Users Manual Table III.1.
Initiator: Steam generator tube rupture - possible (2)
Safety function: (Full) within tech. spec. (B) rating: Box (A) B/2=0
Because the affected function was not a full safety one no uprating (common cause) was made.

Location: BEZNAU-1
Event date: Wed, 11-09-1991
Nuclear event report
Legenda & explanation