Category Archives: Nuclear Cleanup

New Safe Confinement Structure Moved into Place at Chernobyl Unit 4

Following the Chernobyl accident on 26 April 1986, a concrete and steel “sarcophagus” was built around the severely damaged Unit 4 as an emergency measure to halt the release of radioactive material into the atmosphere from that unit. For details on the design and construction of the sarcophagus, including many photos of the damage at Unit 4, visit the website at the following link:

The completed sarcophagus is shown below, at left end of the 4-unit Chernobyl nuclear plant. In 1988, Soviet scientists announced that the sarcophagus would only last 20–30 years before requiring restorative maintenance work. They were a bit optimistic.

Sarcophagus overview photoThe completed sarcophagus at left end of the 4-unit Chernobyl nuclear plant. Source:

Sarcophagus closeup photoClose-up of the sarcophagus. Source:

Inside-sarcophagusCross-section of the sarcophagus. Source:

The sarcophagus rapidly deteriorated. In 2006, the “Designed Stabilization Steel Structure” was extended to better support a damaged roof that posed a significant risk if it collapsed. In 2010, it was found that water leaking through the sarcophagus roof was becoming radioactively contaminated as it seeped through the rubble of the damaged reactor plant and into the soil.

To provide a longer-term remedy for Chernobyl Unit 4, the  European Bank of Reconstruction and Development (EBRD) funded the design and construction of the New Safe Confinement (NSC, or New Shelter) at a cost of about €1.5 billion ($1.61 billion) for the shelter itself. Total project cost is expected to be about €2.1 billion ($2.25 billion).

Construction by Novarka (a French construction consortium of VINCI Construction and Bouygues Construction) started in 2012. The arched NSC structure was built in two halves and joined together in 2015. The completed NSC is the largest moveable land-based structure ever built, with a span of 257 m (843 feet), a length of 162 m (531 feet), a height of 108 m (354 feet), and a total weight of 36,000 tonnes.

NSC exterior viewNSC exterior view. Source: EBRD

NSC cross section

NSC cross-section. Adapted from

Novarka started moving the NSC arch structure into place on 14 November 2016 and completed the task more than a week later. The arched structure was moved into place using a system of 224 hydraulic jacks that pushed the arch 60 centimeters (2 feet) each stroke. On 29 November 2016, a ceremony at the site was attended by Ukrainian president, Petro Poroshenko, diplomats and site workers, to celebrate the successful final positioning of the NSC over Chernobyl Unit 4.

EBRD reported on this milestone:

“Thirty years after the nuclear disaster in Chernobyl, the radioactive remains of the power plant’s destroyed reactor 4 have been safely enclosed following one of the world’s most ambitious engineering projects.

Chernobyl’s giant New Safe Confinement (NSC) was moved over a distance of 327 meters (1,072 feet) from its assembly point to its final resting place, completely enclosing a previous makeshift shelter that was hastily assembled immediately after the 1986 accident.

The equipment in the New Safe Confinement will now be connected to the new technological building, which will serve as a control room for future operations inside the arch. The New Safe Confinement will be sealed off from the environment hermetically. Finally, after intensive testing of all equipment and commissioning, handover of the New Safe Confinement to the Chernobyl Nuclear Power Plant administration is expected in November 2017.”

You can see EBRD’s short video of this milestone, “Unique engineering feat concluded as Chernobyl arch reaches resting place,” at the following link

The NSC has an expected lifespan of at least 100 years.

The NSC is fitted with an overhead crane to allow for the future dismantling of the existing sarcophagus and the remains of Chernobyl Unit 4.

Current Status of the Fukushima Daiichi Nuclear Power Station (NPS)

Following a severe offshore earthquake on 11 March 2011 and subsequent massive tidal waves, the Fukushima Daiichi NPS and surrounding towns were severely damaged by these natural events. The extent of damage to the NPS, primarily from the effects of flooding by the tidal waves, resulted in severe fuel damage in the operating Units 1, 2 and 3, and hydrogen explosions in Units 1, 3 and 4. In response to the release of radioactive material from the NPS, the Japanese government ordered the local population to evacuate. You’ll find more details on the Fukushima Daiichi reactor accidents in my 18 January 2012 Lyncean presentation (Talk #69), which you can access at the following link:

On 1 September 2016, Tokyo Electric Power Company Holdings, Inc. (TEPCO) issued a video update describing the current status of recovery and decommissioning efforts at the Fukushima Daiichi NPS, including several side-by-side views contrasting the immediate post-accident condition of a particular unit with its current condition. Following is one example showing Unit 3.

Fukushima Unit 3_TEPCO 1Sep16 video updateSource: TEPCO

You can watch this TEPCO video at the following link:

This video is part of the TEPCO Photos and Videos Library, which includes several earlier videos on the Fukushima Daiichi NPS as well as videos on other nuclear plants owned and operated by TEPCO (Kashiwazaki-Kariwa and Fukushima Daini) and other TEPCO activities. TEPCO estimates that recovery and decommissioning activities at the Fukushima Daiichi NPS will continue for 30 – 40 years.

An excellent summary article by Will Davis, entitled, “TEPCO Updates on Fukushima Daiichi Conditions (with video),” was posted on 30 September 2016 on the ANS Nuclear Café website at the following link:

For additional resources related to the Fukushima Daiichi accident, recovery efforts, and lessons learned, see my following posts on Pete’s Lynx:

  • 20 May 2016: Fukushima Daiichi Current Status and Lessons Learned
  • 22 May 2015: Reflections on the Fukushima Daiichi Nuclear Accident
  • 8 March 2015: Scientists Will Soon Use Natural Cosmic Radiation to Peer Inside Fukushima’s Mangled Reactor



Bacteria Could Help Clean Groundwater Contaminated With Uranium

On 15 June 2015, Rutgers University announced the discovery in uranium-contaminated groundwater of bacteria that can breathe uranium and employ it in a reduction chemical reaction that immobilizes the uranium and thereby removes it from solution in the groundwater. Professor Lee Kerkhof, in the School of Environmental and Biological Sciences, leads the Rutgers team that is working with U.S. Department of Energy (DOE) researchers on this project.

The bacteria were discovered in soil at an old uranium ore mill site in Rifle, Colorado, almost 200 miles west of Denver. The bacteria of interest are from a common class known as betaproteobacteria.

Rifle CO uranium mill siteThe Rifle, CO site today. Source:

The Rutgers University announcement states:

 “This bacterium can breathe either oxygen or uranium to drive the chemical reactions that provide life-giving energy”.

 “Exactly how the strain evolved, Kerkhof said, ‘we are not sure.’ But, he explained, bacteria have the ability to pass genes to each other. So just like bacteria pick up resistance to things like antibiotics and heavy metal toxicity, this bacterium ‘picked up a genetic element that’s now allowing it to detoxify uranium, to actually grow on uranium.’ “

You can read the Rutgers University announcement at the following link:

You can read the April 2015 Rutgers paper, Spatial Distribution of an Uranium-Respiring Betaproteobacterium at the Rifle, CO Field Research Site, at the following link:

An earlier paper published in October 2011, entitled, Influence of Uranium on Bacterial Communities: A Comparison of Natural Uranium-Rich Soils with Controls, identified Acidobacteria, Proteobacteria, and seven others phyla in uraniferous samples. This French study, supported by the Centre National de la Recherche Scientifique, concluded that:

 “…our results demonstrate that uranium exerts a permanent high pressure on soil bacterial communities and suggest the existence of a uranium redox cycle mediated by bacteria in the soil.”

You can read the paper written by the French team at the following link: