Please select any photo in the galleries for a larger version and descriptive caption.
The reactor hall and control room of Unit 2 at the Chernobyl Nuclear Power Plant are documented in these photo galleries and companion video.
Room 612/2 (Central Hall); Room 804/2 (Refueling Machine Control Room)
The RBMK reactor design features an ability for online refueling: withdrawal and insertion of fuel bundles while the reactor is at power. The charge face with its 2000-some channel covers is sited above the reactor within a massive “central hall” that is built like a hot cell, with concrete entryway mazes and leaded-glass windows for refueling operators. The dominant piece of equipment is, of course, the crane-mounted RZM (refueling machine). Also in the central hall are two spent-fuel basins, fresh fuel and instrumentation storage hangers, and metal plate covers for accessing the upper steamwater pipelines from the reactor and the peripheral ionization chambers. Unit 1 and 2’s central halls are on the +20.2m elevation, typical of first-generation RBMK plants, while the later Unit 3 and 4 central halls are on +35.5m. The chief reason for this is the introduction of a steam-suppressing pool and “Accident Localization System” below the reactor in the later design. Unit 2 has been offline since a turbine hall fire in 1991, and is defueled and dry (all spent fuel is in the ISF-1 facility). The spent fuel pools in the reactor hall are also dry, but are currently being used to store fuel support stringers. Measured exposure rates in the reactor hall range from surprisingly low (3 mR/h on uncovered fuel channels on the “pyatak” or reactor lid) to surprisingly high (2 R/h close to a point source-maybe a fuel flea?-on a fuel stringer). Like other RBMK reactors, including Unit 3 at Chernobyl, ChNPP-2 participated in transmutation doping of silicon for the Soviet semiconductor industry. A single channel ordinarily used for the control and protection system was assigned for this application.
Central Hall of Unit 2, ChNPP, looking south from the fresh fuel storage area. In the distance is the refueling machine and the circular reactor lid. In the foreground is a round portal in the floor for transferring fuel in casks out of the reactor building and onto a rail car beneath.
On the Unit 2 reactor lid, there is some streaming gamma radiation from the empty fuel channels. The exposure rate amounts to about 3.3 mR/h. Note the heavy removable steel blocks used to protect the channels.
2 R/h (yes, that’s two roentgens per hour!) from a local source, suspected of being a fuel flea, on one of the used fuel stringers in the spent fuel storage pool of Unit 2 reactor at ChNPP. Good times.
The crane-mounted RZM (fuel loading and unloading machine) in Unit 2 at ChNPP. Notice the person at the bottom for scale! The lead-glass window to the operator’s room is seen on the wall at right.
This is the reactor lid for Unit 2, Chernobyl Nuclear Power Plant. Metal blocks protect the upper penetrations for some 2000 channels through the graphite moderator of the reactor. The colored lids house electric control-rod drive mechanisms and in-core instruments, while the unpainted ones cover fuel channels and one special channel used to irradiate silicon. To the side of the reactor lid are smaller covers for the upper steamwater pipelines and the lateral ionization chambers.
Upper stringers for fuel bundles in the Unit 2 reactor hall. These pieces have a pin in the foreground for coupling to the RZM machine. At the far end is a spiral geometry designed to help shield streaming neutrons. Two fuel bundles, each about three meters long, would have been attached at the far ends for insertion into the reactor core.
Visitors prepare to enter the Central Hall of Unit 2 at Chernobyl, from the 607/2 anteroom on +20.2m. The Central Hall is a fuel handling area, and consequently has some loose radiological contamination.
Visitors prepare to enter the Central Hall of Unit 2 at Chernobyl from the 607/2 anteroom on +20.2m.
Electrical panels for the RZM refueling machine in the operator’s booth, Room 804/2. PHOTO CREDIT: LUCAS HIXSON
View through the RZM operator’s lead-glass window into the Central Hall, Unit 2, Chernobyl Nuclear Power Plant. PHOTO CREDIT: LUCAS HIXSON
Unit 2 reactor building, Chernobyl Nuclear Power Plant, +20.2m elevation
Video (via YouTube)
Room G364/2 (Unit 2 Control Room)
The control room, like all others at RBMK plants, is situated nominally at +10m elevation in the “deaerator stack” abutting the turbine hall. The tray-type deaerators themselves, and reactor steam and feedwater piping, are in compartments directly above the control rooms, leading to some interesting hypothetical accident scenarios whereby radioactive water might invade the control rooms from above. At ChNPP, the Unit 2 control room has a notable radiation “hot spot” above T Desk at the west end, possibly due to contamination in the steamwater piping compartment upstairs.
A visitor stands behind A Desk (reactor control engineer’s position) in the Unit 2 control room, ChNPP. On the panel behind him is a reactor core cartogram with lamps for each of the ~1700 fuel channels (white) and ~300 other channels for control rods and instrumentation. The lamps were used to indicate various parameters or activities in the individual channels. On the right is another cartogram with servoindicators displaying the position of control and protection rods in the reactor. PHOTO CREDIT: LUCAS HIXSON
Visitors enter Unit Control Room II, Chernobyl Nuclear Power Plant, from the “Gold Corridor” on +10m. PHOTO CREDIT: LUCAS HIXSON
A visitor and a career turbine engineer share a smoke in the Unit 2 control room at Chernobyl, hastening their demise by cancer much faster than radiation will. The engineer’s jacket has “ZSR” (“Strict Control Zone”) initialed on it, referring to more highly contaminated areas within the plant.
Servoindicators for the reactor control and protection system (“SUZ”) in Unit 2 control room at Chernobyl. Blue indicators are for the shortened absorbers (“USP”) that are pulled up from the bottom of the core, while all others descend from the top of the core. The channel marked “Si” was specially allocated to the neutron transmutation of silicon for the Soviet semiconductor industry.
The west end of the Unit 2 control room, where controls for plant electrical systems and the Nos. 3 and 4 turbogenerators are located. In October of 1991, No. 4 turbogenerator accidentally motorized and caught on fire, bringing the turbine hall roof down onto the reactor feedwater pumps. Unit 2 was permanently shut down following this accident.
Operational reactivity reserve (OZR) chart recorder in the Unit 2 control room at Chernobyl. Handwritten note on the paper indicates its decommissioning in October of 1991, following the fire that ended Unit 2’s service life. The OZR quantity–essentially the number of full-worth control rods remaining in the reactor core–has great safety significance in RBMK reactors, and the inclusion of displays of this quantity for the operators in the control room was one of the improvements adopted after the Unit 4 accident in 1986.
Controls for the No. 1 automatic power regulator on A Desk (reactor control engineer’s position) in Unit 2 at Chernobyl. This computerized regulator was one of two that were typically engaged under full-power routine operation.
Local Automatic Regulator (LAR) on A Desk (reactor control engineer’s position) in Unit 2 at Chernobyl. This regulator used in-core instrumentation to monitor and adjust the spatial neutron flux distribution at intermediate power levels during transition to or from full power.
Two visitors investigate the notable radiation hot spot in the Unit 2 control room, in front of T Desk (turbine controls for Turbogenerator No. 4 are visible). The radiation seems to be streaming from above, perhaps from the steamwater compartment that directly overlies the control room. (Purely by coincidence, the men’s pose resembles the famous Soviet socialist-realism sculpture, “Worker and Kolkhoz Woman.”)