On June 10 we had the rare experience of touring some facilities at the Chernobyl Nuclear Power Plant. We’re deeply indebted to Irina Kovbich and other power plant personnel for making this visit possible. I hope Mike, Chad, and Edward chime in and add a fuller accounting of this tour, but I will get started by posting this modest gallery of photos from the Unit 1 Control Room–certainly a highlight for me. Click the “Next” button to advance the slide show, and please see the list below for descriptions of the individual photos.
Phase I of the Chernobyl plant consists of Units 1 and 2, two first-generation RBMK-1000 reactors whose design and layout is somewhat different from the later-generation Units 3-4. (click station map at left). The most obvious difference is the orientation of the nuclear block (the reactor, steam separators, main circulation pumps, etc.) relative to the turbines and ventilation equipment, but other important differences include the lack of pressure suppression pools like those under Units 3-4. Unit 1 began operation in May 1978 and shut down in November 1996. It was the second-last reactor to close at ChNPP. Its operational history includes a severe accident that caused fuel damage and released radiation in 1982. Today, fuel remains in the core and the spent fuel pools.
- Here we are (left to right: Edward, Chad, Carl, Mike) behind the reactor control desk. It’s astonishing they let us take photos in here! Behind us is a very prominent feature of RBMK control rooms, a servo dial display showing the positions (0-7 meters insertion) of various types of control rods and in-core instrumentation.
- East-to-west view of control room. In the foreground is “A” desk, with operator interfaces for the old “SKALA” process computer, for moving control rods, for reading the signals from various detectors, for measuring reactivity, and so forth. Next is “P” desk, with controls for condensate and circulation pumps, valves, and other components of the main plant hydraulics. Finally, in the background, is “T” desk, where the turbogenerators are controlled.
- Chad in front of “A” desk, Edward at “P” desk, Carl talking to the engineer at his desk.
- The senior engineer for Unit 1, a 24-year employee of ChNPP who began his career in Unit 3. He shared opinions on diverse subjects, ranging from the challenges of medical care for ChNPP workers, the relative ease of operating RBMKs versus VVERS (where operators are kept as busy as “pianists”), the differences in operator training between the US and the former USSR. He explained many of the control room features.
- Mike in front of the computerized reactor control system and its display in the background. I don’t have a good understanding of how the operator uses this system or what its display indicates. The original SKALA computer (a slow machine with core memory and tape drives) was evidently replaced with something better during Unit 1’s later career. The compartments east of the control room still bear its name, however. Please comment if you know how this thing works.
- Lamp covers for the computerized control system display, labeled according to the channel number in the reactor and color-coded to correspond with the channel contents (CPS channels, pressure tubes, detectors).
- Closeup of servo dials on CPS and instrumentation status display, color-coded to correspond with channel contents. I believe the blue dials, with 0 meters insertion at the six-o’-clock position, are for the axial shaping rods entering below the core, and dials of other colors correspond to various groups of manual and emergency protection rods entering from above the core. I was told the black boxes, e.g. Channel 24-22, are axial flux monitors. I’m thinking the control channels without dials, e.g. Channel 30-27, correspond to automatic regulating rods. I’m not sure though.
- View of “A” desk prominently featuring a reactivity monitor, ash tray, stopwatch mounted to desk with key attached (?), communications microphone, etc.
- Closeup of reactivity meter and SCRAM buttons on “A” desk. The meter computes reactivity in terms of the effective delayed neutron precursor fraction (βeff) using the signals from ion or fission chambers. The SCRAM buttons are sealed with wax seals. The level-5 protection system, AZ-5, is triggered by the top center button and sends all withdrawn rods into the core. The BAZ system, buttons at right, is a special set of control rods that is capable of entering the core faster than the others.
- Manual reactor operating controls on “A” desk. The meters seem to indicate reactor period (infinity – 20 seconds) and detector current (proxy for power). The buttons in front are used to select CPS channels in order to move the rods therein.
- Clock, water level gauges, parameter display systems
- Pump and valve switches on “P” desk
- Turbine power meter (0-600MW) on “T” desk. Each of the two turbogenerators is rated at 500 MWe.
- Electrical controls at the west end of “T” desk
Chernobyl Nuclear Power Plant