A turbine operator could not by himself have caused the accident (see details below). The Israeli attack on the Iraq reactor as a motivation makes absolutely no sense. The RBMK reactor design is inherently dual use, but besides their dedicated weapons grade plutonium reactors they had sixteen in operation in 1986, with one more added the next year, and seven are still in operation
Note for the following you must understand positive feedback (it's ___bad___ in _control systems_) and thus the implication of positive void coefficients from the light water neutron poison that is used to cool the reactor, while graphite is used to moderate (slow down) the neutrons so they'll be easily adsorbed by uranium-235 atoms.
Voids are bubbles of steam in the light water, which decreases its neutron poisoning, that is, absorption of neutrons, converting light water with one proton to deuterium with one neutron, and tritium with two.
The people responsible are those who managed the control rods and on up. Rough mostly from memory sequence of events plus Wikipedia mostly for numbers:
1. Decide to do a test to use residual steam to power a turbine after an abrupt reactor shutdown ... but not from one running at full thermal power.
1. Start bringing down the power, nameplate 3200 MW to 700-1000 MW.
1. Utility grid controller requires more power, and this is halted.
1. Standard xenon-135 neutron poisoning brings it down to 500 MW (one of many surprises in the Manhattan project redeemed by conservative design).
1. For insufficiently known reasons of why, not how I think, it dropped to 30MW, 5% of what's needed for the test. This further reduces burn off of xenon-135 (to xenon-136).
1. The system is now in a weird, uncharted state, and gets more so as:
1. Pull out control rods, most to their max limits.
1. Power slowly goes back up to 200MW.
1. Test finished, scram the reactor.
1. Minor detail: the ends of the control rods are also moderating graphite (!!!).
1. As these ends displaced neutron poisoning light water, thermal power spikes to 30,000 MW, way past any normal design margin.
That is, as thermal power goes up, voids increase, so power continues to go up, more and bigger voids, power continues to go up, this is positive feedback. Oops
This Jew suspected of causing the Chernobyl accident would have to be a real life James Bond to bring it about as a lowly turbine operator.