On 24 March 1992, the number 3 power generating unit at the Leningrad Atomic Power Station in Sosnovyi Bor underwent an emergency shutdown. The plant suffered a steam leak, which spewed a total of some 3 thousand curies into the atmosphere.
On 24 March 1992, the number 1+2 power generating unit at the Leningrad Atomic Power Station
1+2=3, the number of the unit! I think the model got confused because it can't do addition
( z1 unit :ARG0-of ( z2 generate :ARG1 ( z3 power ) ) :location ( z4 facility :name ( z5 name :op "Leningrad" :op "Atomic" :op "Power" :op "Station" ) ) :ord ( z6 ordinal-entity :value 1 ) :ord ( z7 ordinal-entity :value 2 ) )