Chernobyl Unit 4, November 2016

Please select any photo in the galleries for a larger version and descriptive caption.
In November 2016, the massive New Safe Confinement arch slid over Unit 4 of the Chernobyl Nuclear Power Plant, and the old “Sarcophagus” that had defined the appearance of the damaged unit for 30 years receded from view.  Over the last three years, the iconic ventilation chimney shared by Units 3 and 4 has been disassembled as well, and now rests in pieces in various places (including the deck of No. 5 turbogenerator).  Inside the unit, work continues to finish the Perimeter Closure Project–the effort to hermetically seal off the east and west boundaries of the New Safe Confinement from the rest of the power plant.  Floor by floor, barriers are going up.  The memorial to Valery Khodemchuk, the first victim of the 1986 accident whose remains have never been recovered, has been removed from its old location at the northwest end of the chemical treatment and ventilation block, and will be reinstalled somewhere else once the project is finished.  The photos in the second gallery show the state of the Arch and the Local Zone around Unit 4 only several days before the Arch began its movement, and are certainly among the last photos of the old Unit 4 exterior we have come to know and love.

Stanislav Shekstelo, an employee of the Chernobyl Nuclear Power Plant, contemplates the remains of the Unit 4 control room in November 2016. The wall at left is not original, and the last bench of A Desk and T Desk have been removed to allow the wall to be installed through the control room. Behind the wall is a corridor to allow worker movement. The original “gold corridor” that runs the length of the deaerator building is blocked in this area by the supports for the “Mammoth Beam” in the Sarcophagus.

Unit 4’s reactor cartogram displays behind A Desk (the reactor control engineer’s position) at the east end of the Unit 4 control room. Only a few of the ~200 control rod servoindicators remain in the panel, the others having been scavenged for other units and / or souvenirs.

Servoindicator for a control rod in the Unit 4 control room, Chernobyl Nuclear Power Plant, measuring rod insertion depth from 0 to 8 meters. The reading is no longer meaningful. The descending main control rod in Channel 40-37 would have become stuck at about 2m before the core disintegrated.

Slot for No. 8 turbogenerator’s tachometer on T Desk, the turbine control engineer’s position, Chernobyl Nuclear Power Plant. The 1986 accident took place in the context of an inertial run-down experiment on TG-8. A thick coating of pink polymer designed to trap contamination now lies over everything in the Unit 4 control room.

Annunciator lamps for Unit 4’s main circulation pumps, covered in contamination-immobilizing polymer.

Turbogenerator No. 8’s electrical output, from 0-600 MWe. The normal value was 500 MWe at full power. The accident of April 26, 1986 occurred in the context of an experiment on TG-8.

A pancake Geiger counter measures 33 kCPM on the balance-of-plant console (P Desk) in the Unit 4 control room.

Switch on A Desk (the reactor control engineer’s position) for the Unit 4 reactor’s automatic power regulators. The power regulators derive signal from lateral ionization chambers and are used to manage control rod movement under high-power operating conditions. The chain of events leading directly to the accident began with the automatic regulators, which stopped regulating power for some indeterminate reason at 12:30AM on the night of the accident. The operators failed to maintain power with the AR systems, leading to xenon poisoning and the unfortunate conditions for reactor runaway later on.

Slots for the reactor period monitors in Unit 4 control room at Chernobyl. These monitors probably derived their signal from the lateral ionization chambers, and would have read “0 seconds” for a brief, hair-raising moment on April 26, 1986.

A hot-spot warning is stenciled on the wall that now terminates the west end of the +10m deaerator corridor at Axis 53. The Fluke 451B ion chamber measures a respectable 22 mR/h here.

The original deaerator corridor on +10m outside the Unit 4 control room is rarely seen by visitors to the control room, but we had to use it because of work on the Perimeter Closure Project. The reserve control room to Unit 4 is behind the wall on the right, shielded with heavy lead plate. It looked directly out on the vast heap of radioactive debris from the reactor building. Some original linoleum flooring is also visible.

Looking east now, toward the barrier across the +10m deaerator hallway at Axis 53. Behind the wall are supports for the “Mammoth Beam” in the Sarcophagus. The lead paneling at left provides shielding from radiation shining into the plant from outside, via the Unit 4 reserve control room.

The G110/2 stairway at the end of the deaerator building in Unit 4 is in pretty ragged shape, and has been painted with some kind of immobilizing polymer that is pink in color. We are on our way to the Unit 4 control room via a somewhat unusual route on the +16.4m level.

Blast-resistant door leading to one of the steam and feedwater piping compartments below Unit 4’s deaerators on +16.4m elevation. Like all of Unit 4’s primary cooling circuit, it is probably quite contaminated.

Dating from Unit 4’s operational days–as attested by the overlying stratum of pink anti-contamination polymer–is a poster advising about safe welding practices.

The short western hall at the end of the Unit 4 deaerator building was once a “place for smoking”, per the red signage. A new sign has been posted, instructing workers that “smoking in the Object Shelter is PROHIBITED!” (Clearly the prohibition is widely ridiculed, as cigarette butts are everywhere in the Unit 4 control room.) Closer inspection of the sign reveals sarcastic additions, including a “penalty-100 Hryvnia” (about $5) modified to read “$1000000.”

I was honored to have Bionerd along for this trip, and her video record of the visit inside Unit 4 is on YouTube here:

Finally, here is a gallery showing the Arch of the New Safe Confinement and some of the “Local Zone” surrounding Unit 4.

The New Safe Confinement Arch at Chernobyl, only days away from its highly-anticipated move over the damaged Unit 4. PHOTO CREDIT: LUCAS HIXSON

American-made overhead cranes in the New Safe Confinement arch. The cranes will be used for various purposes relating to the study and deconstruction of Unit 4.

Workers in the “Local Zone” surrounding Unit 4 rush to finish the New Safe Confinement Technological Building, Perimeter Closure in the turbine hall, and other projects so that the Arch can be moved before the onset of bitter Ukrainian winter weather. Note that the ventilation stack visible on V Block is not the original, but a much smaller, offset stack that will not interfere with the New Safe Confinement.

Unit 4 is scarcely recognizable from the west, with the technological building of the New Safe Confinement nearing completion (left). The old western counterforce wall that keeps the Sarcophagus from collapsing is behind it. The striped ventilation chimney is a diminutive, offset version of the original. About the only original plant structure visible here is the western end of the deaerator building.

The Arch is designed to slide on rails. This is the southern rail. A lead-sheet shield for workers, at left, reduces the ambient dose rate by about a factor of 4.

One of hundreds of stray dogs on the Chernobyl Power Plant site. This one, however, is on the dirty side of the clean line in the 1430 Change Facility, and I doubt it has been taught to use the contamination monitors visible at left.

A stray dog, one of hundreds that roam the grounds of the Chernobyl Nuclear Power Plant, enjoys the meager nourishment of a radioactive boot heel inside the hot entrance to the 1430 Change Facility. In the foreground is a visitor with a jacket labeled “OU” (“Object Shelter”).