This structure is at risk.
You could use threat modeling to determine potential threats against it. You could use situational awareness and threat intelligence to determine the threat du jour. You could put that in a formula to calculate risk. You could build a fence around the structure to mitigate some risk. You could do so much with risk management, and you could keep yourselves busy in a loop doing risk assessments ad infinitum.
Or you could simply fix the apparent fragility of that structure without even starting to speculate about threats. That’s the approach chosen in RIPE for critical infrastructure protection. It’s measurable, sustainable, and cost-effective. Stop speculating, start doing the obvious right away. Get RIPE.
To learn more about RIPE, check out this whitepaper and contact info(at)langner.com.