In that, I have no doubt.
Here's the real-life incident the release is based on:
For example, in March, the Hatch Nuclear Power Plant in Georgia went through an emergency shutdown as a result of a software update that was made on the plant's business network. The business network was in two-way communication with the plant's SCADA network and the update synchronized information on both systems. Reset after a reboot, the SCADA safety systems detected a lack of data and signaled that the water level in the cooling systems for the nuclear fuel rods had dropped, which caused an automatic shutdown. Engineers were aware of the two-way communication link, but they did not know that the update would synchronize data between the two networks.
There was no danger to the public, but any time an electric generation plant shuts down, the power company loses millions of dollars in revenue and has to incur the substantial expense of getting the plant back online -- no small task for a nuclear facility. And the Hatch incident was only the latest in a string of accidents and unnecessary shutdowns whose cause was due to some problem on the network. The Browns Ferry nuclear plant in Alabama, for example, shut down in 2006 when a network traffic overload locked up pump controls.
In the case of Hatch Nuclear Power Plant, engineers chose to sever all physical connections between the SCADA and business networks.
If you don't want to take the accounting of the incident from a press release (and who could blame you), read this account "Cyber Incident Blamed for Nuclear Power Plant Shutdown", from The Washington Post.
Lumeta advises facilities to regularly check that their SCADA networks are not connected to their business networks. I agree, and that goes without saying. But when it comes to security, like doing regular backups, many organizations Talk The Talk, but don't Walk the Walk. And all it takes is some nitwit, somewhere, to purposely, or more likely inadvertently, connect SCADA systems to the general LAN and risk to the utility goes up exponentially.
It's only a matter of time before we witness a nasty close call (hopefully that's all it is.)
Have a look at this now famous CNN/DHS video on YouTube:
Makes you wonder when, not if, there's ever going to be an incident.