With regard to the BWR/4, Boiling Water Reactor "Reactor Protection System" design, which of the following correctly describes the basis for the "Turbine Stop Valve Closure" reactor trip signal?
1) The reactor is tripped upon closure of the turbine stop valve to prevent a significant addition of positive reactivity to the core, as reactor coolant pressure would rise and cause overpressure of the reactor vessel head.
2) The reactor is tripped upon closure of the turbine stop valve to prevent a significant addition of positive reactivity to the core, as reactor coolant pressure would rise and cause collapsing of steam voids.
3) The reactor is tripped upon closure of the turbine stop valve to prevent a significant addition of positive reactivity to the core, as reactor coolant pressure would rise and cause a significant increase on recirculation flow.
4) The reactor is tripped upon closure of the turbine stop valve to prevent a significant addition of positive reactivity to the core, as reactor coolant pressure would rise and cause expansion of steam voids.