Unveiling the SKALA System: Controlling Chernobyl's Reactor
Managing a nuclear power plant is no simple task, even with the advanced automation capabilities of a 1980s Soviet RBMK reactor. The [Chornobyl Family] channel has embarked on an ambitious project to recreate a full-sized, functional replica of the RBMK control room, which was retired in the early 2000s. Their latest endeavor focuses on the SKALA system (https://www.youtube.com/watch?v=Sjk2B0SzXUU), an industrial control system that played a crucial role in managing the Chernobyl Nuclear Power Plant.
The SKALA system consists of multiple V-3M processor racks, known as 'frames', each equipped with 20k 24-bit words of RAM. While less powerful than a PDP-11, its primary function was to gather and process sensor data in real-time. This data was then processed in dedicated racks, ensuring the reactor's safe operation. The SKALA system's DREG program, in particular, captured the last messages from the ill-fated #4 reactor.
However, the tragedy at Chernobyl highlights a critical issue. Despite the SKALA system's capabilities, the operators had disabled all safety features, rendering the system ineffective. When the accident occurred, the hardware struggled to keep up with the rapid changes, and not all sensor data could be recorded on the high-speed drum printer or RTA-80 teletypes, leaving gaps in our understanding of the disaster. Recreating a genuine RTA-80 teletype is a goal, but these old systems are challenging to operate.
The original software running on the V-3M computer frames, including the DREG program, was loaded from paper tape, a process that created executable code on magnetic tapes. Magnetic tapes were also used for storage, preserving the data for future use. The SKALA system's inner workings, along with its programs like KRV, DREG, and PRIZMA, are explained in the video, each focusing on different aspects of the RBMK reactor's status and overall health.
Operators interact with SKALA through a special keyboard, entering command codes to adjust set points, with parameters encoded within these codes. This method allows operators to set and request values, with parameters and error codes displayed on a dedicated screen. Additionally, the SKALA system features a Mnemonic Display, providing operators with real-time feedback on the system's status, including any faults.
It's important to recognize that the control system of a power plant extends beyond the control room itself. Systems like SKALA and its associated hardware are often overlooked, yet they play a vital role in ensuring the reactor's safe operation. Preserving this knowledge and creating physical models that simulate the system's experience is invaluable.
The longevity of nuclear power reactors means that industrial automation systems from the 1960s and 1970s are still in active use today. However, as reactors retire or undergo modernization, the institutional knowledge of these systems is at risk of disappearing, taking a significant portion of history with it. This highlights the importance of efforts like the [Chornobyl Family] channel's project in preserving our technological heritage.
