INES-event
INES 1

PRESSURIZER DISCHARGE TANK MEMBRANE RUPTURE

On 5 February 1991 at 12.00 pm during the routine survey of the reactor compartment a ruptured membrane of the pressurizer discharge tank was discovered. The gas-aerosol activity near the discharge tank was measured 3 x 10-8 Ci/l, and the activity in the hermetic steam generator box was measured 8 x 10-9 Ci/l. A possible reason for the rupture of the membrane is a routine blowing away of the hydrogen in the pressurizer by means of low-pressure nitrogen.
BASIS FOR RATING: All safety functions were available. This justifies level 0 accordingto Table A1 of the Addendum. The event reveals a deficiency in the safetyculture because the membrane was made of unproper material and the rupturewas discovered too late. Thus level 1 was selected. Point A6 of theAddendum.
DIFFICULTIES IN RATING:

Location: KOZLODUY-2
Event date: Tue, 05-02-1991
Nuclear event report
Legenda & explanation