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User:Cerluean/Chernobyl New Safe Confinement

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Waste storage

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For the removal and storage of nuclear waste within the New Safe Confinement area, the strategies for removing waste is split into three systems.[1] Disposal of solid nuclear waste has the Vector Radioactive Waste Storage Facility being built near to the Chernobyl site, consisting of the Industrial Complex for Solid Radwaste Management (ICSRM). It is being constructed by Nukem Technologies, a German nuclear decommissioning company, a subsidiary of the Russian Atomstroyexport. This storage is reported to be able to contain 75,000 cubic metres (98,000 cubic yards) of material. The storage is for both temporary high level waste as well as low and intermediate level long-term waste storage.

The Plant on Liquid Radwaste Management was constructed to remove, store, and process liquid nuclear waste from the Chernobyl site. [2][3] Processed liquid is turned into solid waste in 200-L barrels where it can then be stored long-term, at a rate of 2,500 cubic meters a year.[4]

Spent fuel is stored long-term in the Spent Fuel Storage Facility.[1][2] 232 storage containers of nuclear waste can be stored in the facility for an expected 100 years.[5]

Demolition of existing structures

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The operational phase of the New Safe Confinement involves the demolition of the unstable structures associated with the original Shelter Structure. The goal of demolition has imposed significant requirements upon the load carrying capacity of the arches and foundation of the New Safe Confinement, as these structures must carry the weight of not only the disassembled structure, but also the suspended cranes to be used in demolition.

Demolition equipment

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The New Safe Confinement design includes two bridge cranes suspended from the arches. These cranes travel east to west on common runways and each has a span of 84 metres (276 ft).

Each crane can carry a variety of interchangeable carriages. Three types of carriages have been designed for the New Safe Confinement:

  • One typical lifting carriage with a 50-tonne (55-ton) carrying capacity.
  • One secure lifting carriage for shielded transportation of personnel, with a 50-tonne (55-ton) carrying capacity.
  • One carriage suspends a mobile tool platform, extending up to 75 metres (246 ft), that can be fitted with a variety of end actuators useful for demolition.

The cranes' carriage interchangeability allows the rotation of the largest members to be demolished, reducing the overall size of the New Safe Confinement by approximately one arch bay.

Structural design

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Warm, dry air will be circulated in the gap between inner and outer roof sections to prevent condensation, which will reduce corrosion and prevent water from dripping into the interior.

To prevent corrosion of the structure, stainless steel was chosen as the material for the inner and outer walls. An air conditioning system also circulates warm, dry air at 50 Pa between the layers of the panels to further prevent corrosion. Dehumidifiers keep the air below 40% humidity, preventing both condensation and water from dripping into the interior of the structure.[6][7]

Project timeline and status

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April 25, 2019
Successful conclusion of the 72-hour trial operation test.[8]

July 2019

Construction on the €1.5 billion structure is completed and the sarcophagus is opened to media visits on July 3. On July 10, Ukrainian President Volodymyr Zelensky attended a ceremony where the transfer of ownership of the New Safe Confinement was given to the Ukrainian government.[8]

February 2022

Main article: Capture of Chernobyl

February 24, 2022

During the main invasion of the Russian invasion of Ukraine, Russian forces subsequently captured Chernobyl.[9] While there was a increase in radiation in the area, this was due to Russian forces disturbing the radioactive soil in the Red Forest and not from the reactor itself.[10] The New Safe Confinement was reportedly unharmed.[11]

March 31, 2022

Russian forces left Chernobyl and the New Safe Confinement.[12]

Worker safety and radioactive exposure

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Even with the distance given from the main reactor during construction of the New Safe Confinement, construction workers were still subject to radiation. Before the slippage procedure began, construction workers may only have been able to stay on the site for 30 minutes at a time due to radiation.[13] The concrete foundation reduced radiation to workers when assembling the structure, and workers were given decontaminated housing during construction.[14]

Radioactive dust in the shelter is monitored by hundreds of sensors. Workers in the 'local zone' carry two dosimeters, one showing real-time exposure and the second recording information for the worker's dose log. Workers have a daily and annual radiation exposure limit. Their dosimeter beeps if the limit is reached and the worker's site access is cancelled. The annual limit (20 millisieverts) may be reached by spending 12 minutes above the roof of the 1986 sarcophagus, or a few hours around its chimney. Workers are required to also check their radiation exposure before they leave the New Safe Confinement as an additional measurement.[15]

To minimize radiation to workers when working inside of the New Safe Confinement, many robots and tools are used to interact with objects inside the shelter remotely. The two installed bridge cranes can be operated from within an isolated control room, which allows for demolition to occur without posing risk to any operators.[16] For the radiation mapping that occurs within the New Safe Confinement, robots have been deployed in both areas of high contamination where humans cannot enter and replacing routes that operators would normally take.[17] [18] Boston Dynamic's Spot model has been implemented in higher radiation areas to provide high quality radiation mapping without causing additional radiation spikes by minimizing contact points with radiated surfaces.[17] Without posing risk to workers, the implemented systems were able to look inside reactor 4, deep within the New Safe Confinement.[19]

References

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  1. ^ a b Lidar, Per; Bergh, Niklas; Larsson, Arne; Hedin, Gunnar (2013-09-08). "Waste Management Strategy for Cost Effective and Environmentally Friendly NPP Decommissioning". Volume 2: Facility Decontamination and Decommissioning; Environmental Remediation; Environmental Management/Public Involvement/Crosscutting Issues/Global Partnering. American Society of Mechanical Engineers. doi:10.1115/icem2013-96006.
  2. ^ a b Semenova, Iryna Y.; Steinberg, Nikolay A. (2001-09-30). "Chernobyl NPP Decommissioning and "Shelter" Object Transformation: Problems of Activity Coordination". Volume 2: Mgmt. Low/Interm. Level Waste; Spent Fuel; Economics/Analyses for Waste Mgmt.; Radiological Characterization/Application Release Criteria; Panel Sessions; Solid Waste Reduction/Treatment; Current Activities in Central/Eastern Europe; Environmental Remediation Technology; LL/ILW; HLW/Spent Fuel; Chernobyl; D&D Waste; Performance Assessment; MOX and Spent UOX; D&D Nuclear Reactors; Decommissioning of Other Nuclear Facilities. American Society of Mechanical Engineers. doi:10.1115/icem2001-1177.
  3. ^ "Chernobyl starts tackling its liquid radioactive waste". Bellona.org. 2018-02-07. Retrieved 2022-05-07.
  4. ^ Татьяна, Грива. "Liquid Radioactive Waste Treatment Plant (LRTP)". chnpp.gov.ua. Retrieved 2022-05-07.
  5. ^ "Ukraine authorizes Chernobyl spent fuel storage". www.ans.org. Retrieved 2022-05-07.
  6. ^ "New Safe Containment Project Cuts Corrosion Risk at Chernobyl". www.materialsperformance.com. Retrieved 2022-05-01.
  7. ^ "Building Chernobyl's New Safe Confinement - ProQuest". www.proquest.com. Retrieved 2022-05-01.
  8. ^ a b "Delivery of the Chernobyl New Safe Confinement". VINCI. Retrieved 2022-05-03.
  9. ^ "Chernobyl nuclear plant targeted as Russia invades Ukraine". www.aljazeera.com. Retrieved 2022-05-06.
  10. ^ Reuters (2022-03-29). "Unprotected Russian soldiers disturbed radioactive dust in Chernobyl's 'Red Forest', workers say". Reuters. Retrieved 2022-05-06. {{cite news}}: |last= has generic name (help)
  11. ^ "Explained: Why did Russian troops seize control of Chernobyl nuclear disaster site?". The Indian Express. 2022-03-03. Retrieved 2022-05-06.
  12. ^ Varenytsia, Cara Anna and Inna. "A nuclear risk 'nightmare'? After seizing Chernobyl, Russian troops exposed themselves to radiation". USA TODAY. Retrieved 2022-05-06.
  13. ^ "Progress at Chernobyl New Safe Confinement - ProQuest". www.proquest.com. Retrieved 2022-05-07.
  14. ^ "Chernobyl New Safe Confinement (NSC), Ukraine". Power Technology. Retrieved 2022-05-07.
  15. ^ Parameswaran, N. A. (Vijay); Chornyy, Igor; Owen, Rob; de Saint Victor, François (2013-09-08). "Unique and Massive Chernobyl Cranes for Deconstruction Activities in the New Safe Confinement". Volume 2: Facility Decontamination and Decommissioning; Environmental Remediation; Environmental Management/Public Involvement/Crosscutting Issues/Global Partnering. American Society of Mechanical Engineers. doi:10.1115/icem2013-96346.
  16. ^ "See Chernobyl's Safe Confinement Shelter". Bechtel Corporate. Retrieved 2022-05-06.
  17. ^ a b "Boston Dynamics' Spot Is Helping Chernobyl Move Towards Safe Decommissioning". IEEE Spectrum. 2020-11-23. Retrieved 2022-05-06.
  18. ^ "Radiation-mapping robots deployed at Chernobyl". www.ans.org. Retrieved 2022-05-06.
  19. ^ "Bristol team gains unprecedented access to Chernobyl's Reactor 4". www.newswise.com. Retrieved 2022-05-06.
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