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Chernobyl Nuclear Power Plant sarcophagus

January 06, 2023

This article is about the original containment. For the new containment in place since 2016, see Chernobyl New Safe Confinement.

The Chernobyl Nuclear Power Plant sarcophagus or Shelter Structure (Ukrainian: Об'єкт "Укриття") is a massive steel and concrete structure covering the nuclear reactor number 4 building of the Chernobyl Nuclear Power Plant. Currently the sarcophagus resides inside the New Safe Confinement structure. The New Safe Confinement is designed to protect the environment while the sarcophagus undergoes demolition and the nuclear cleanup continues. The sarcophagus was designed to limit radioactive contamination of the environment following the 1986 Chernobyl disaster, by encasing the most dangerous area and protecting it from climate exposure.[1][2] It is located within a large restricted area known as the Chernobyl Exclusion Zone.

Chernobyl Nuclear Power Plant Sarcophagus
Ukrainian: Укриття Чорнобильської АЕС
The sarcophagus in 2006. The tall chimney is an original part of the reactor building.
Location in Ukraine
Alternative namesChernobyl Nuclear Power Plant Shelter Structure
General information
StatusDeteriorated; succeeded by Chernobyl New Safe Confinement
TypeConfinement shelter
LocationCovering Reactor 4 of the Chernobyl Nuclear Power Plant, within the Chernobyl Exclusion Zone, near Pripyat
CountryUkraine
Coordinates51°23′23″N 30°05′56″E / 51.3896°N 30.0990°E / 51.3896; 30.0990Coordinates: 51°23′23″N 30°05′56″E / 51.3896°N 30.0990°E / 51.3896; 30.0990
Construction startedJune 1986
CompletedNovember 1986
DemolishedTBC 2020

The original Russian name is Объект "Укрытие" (Obyekt Ukrytiye),[3] which means sheltering or covering, as opposed to sarcophagus.[2]

The sarcophagus locked in 200 tons of radioactive lava-like corium, 30 tons of highly contaminated dust and 16 tons of uranium and plutonium.[1]

By 1996 the structure had deteriorated to the point where numerous stabilization measures were required. Internal radiation levels were estimated to be as high as 10000 röntgens per hour in certain areas (normal background radiation in cities is usually around 20–50 microröntgens per hour, and a lethal dose is 500 röntgens over 5 hours).[4] It was decided that the sarcophagus would be replaced with a New Safe Confinement, the construction of which was completed in 2017.

Construction

 
Preparatory steps for mounting the sarcophagus in 1986

The design of the sarcophagus started on 20 May 1986, 24 days after the disaster. Subsequent construction lasted for 206 days, from June to late November of the same year.[2] Due to high radiation levels, it was impossible to directly screw down the nuts and bolts or apply any direct welding to the sarcophagus, so this work was done remotely where possible.[1] The seams of the sarcophagus, however, could not be fully sealed.

The entire construction process consisted of eight stages: clearing and concreting of territory around reactor unit 4, erection of initial reinforced concrete protective walls around the perimeter, construction of separation walls between units 3 and 4, cascade wall construction, covering of the turbine hall, mounting of a high-rise buttress wall, erection of supports and installation of a reactor compartment covering and finally the installation of a ventilation system.

More than 400000 m3 of concrete and 7,300 tonnes of metal framework were used during the erection of the sarcophagus.[2] The building ultimately enclosed 740000 m3 of heavily contaminated debris inside,[1] together with contaminated soil.[5] On 11 October 1986 the Soviet Governmental Commission accepted a report entitled "Conclusion on Reliability and Durability of a Covering Constructions and Radiation Safety of Chernobyl NPP Unit 4 Reactor Compartment".[6][verification needed] The sarcophagus has over 60 bore holes to allow observation of the interior of the core.[7] In many places the structure was designed to have ventilation shafts to allow some convection inside.[7] Filtration systems have been put in place so that no radioactive material will escape through these holes.[7]

Ongoing issues

 
A view of the sarcophagus in 2005

The present shelter is constructed on top of the ruins of the reactor building. The "Mammoth Beam" that supports the roof of the shelter rests partly on the structurally unsound west wall of the reactor building that was damaged by the accident.[8] The western end of the shelter roof is supported by a wall at a point designated axis 50. This wall is reinforced concrete and was cracked by the accident.

Designed Stabilisation Steel Structure

The DSSS is a yellow steel object that has been placed next to the wrecked reactor; it is 63 meters (207 ft) tall and has a series of cantilevers that extend through the western buttress wall, and is intended to stabilize the sarcophagus.[9] This was done because if the wall of the reactor building or the roof of the shelter were to collapse, then large amounts of radioactive dust and particles would be released directly into the atmosphere, resulting in a large new release of radioactivity into the environment. In December 2006 the "Designed Stabilisation Steel Structure" (DSSS) was extended until 50% of the roof load (about 400 tons) was transferred from the axis 50 wall to the DSSS.[citation needed]

Upper Biological Shield

A further threat to the shelter is the steel and concrete slab that formed the upper biological shield (UBS), situated above the reactor prior to the accident.[citation needed] This concrete slab was thrown upwards by the explosion in the reactor core and now rests at approximately 15° from vertical. The position of the upper bioshield is considered inherently unsafe, as only debris supports it in its nearly upright position. A collapse of the bioshield would further exacerbate the dust conditions in the shelter, possibly spreading some quantity of radioactive materials out of the shelter, and could damage the shelter itself. The UBS is a disk 17.7 meters in diameter, weighing 1000 tons. The shield is formally called Component E and nicknamed Elena. The twisted fuel bundles still attached to it are called Elena's hair.[10][11][12]

Replacement

Main article: Chernobyl New Safe Confinement

On 22 December 1988, Soviet scientists announced that the sarcophagus would only last 20–30 years before requiring restorative maintenance work. In 1998, with the help of the European Bank for Reconstruction and Development, a conservation programme was completed that included securing the roof beams from collapsing. Nonetheless, the rain-induced corrosion of supporting beams still threatens the sarcophagus' integrity.[5] It was revealed that the water is leaking through the sarcophagus via holes in its roof, becoming radioactively contaminated, and then seeping through the reactor's floor into the soil.[5]

The Chernobyl New Safe Confinement, rolled into place in November 2016, allows for the dismantling of the sarcophagus and for radioactive material to be removed.[13][14] The containment was expected to replace the existing sarcophagus in 2015. However, delays and a €100 million funding gap caused a yearlong delay, before being moved into place in November 2016.

As of 2020, the building is undergoing testing of its installed systems.[citation needed]

References

Notes

  1. ^ a b c d . Chernobyl International. Archived from the original on 4 December 2014. Retrieved 30 November 2010.
  2. ^ a b c d Ebel 1994, p. 1
  3. ^ code name given under the Soviet secrecy procedures,
  4. ^ Marples 1996, p. 30
  5. ^ a b c "What happened in Chernobyl?". Greenpeace. Retrieved 30 November 2010.
  6. ^ Объект "Укрытие": Сооружение. Чернобыль.by - Chernobyl.by (in Russian). Chernobyl.by. Retrieved 2 December 2010.
  7. ^ a b c Marples & Risovanny 1990, p. 17
  8. ^ See BBC documentary 29 February 2012 at the Wayback Machine
  9. ^ Nuclear Engineering International, July 2007, page 12.
  10. ^ "Chernobyl Glossary". Angelfire.com. Retrieved 22 March 2010.
  11. ^ Ann Larabee (2000). Decade of disaster. University of Illinois Press. p. 50. ISBN 978-0-252-06820-1. Retrieved 7 November 2019. corium silicate.
  12. ^ "Chernobyl Tour". United States Environmental Protection Agency. 28 June 2006. Retrieved 7 November 2019.
  13. ^ "Under The Shield: Inside Chernobyl's New Safe Confinement". RadioFreeEurope/RadioLiberty.
  14. ^ Wood 2007, p. 63

Further reading

External links

January 06, 2023
chernobyl, nuclear, power, plant, sarcophagus, this, article, about, original, containment, containment, place, since, 2016, chernobyl, safe, confinement, shelter, structure, ukrainian, Об, єкт, Укриття, massive, steel, concrete, structure, covering, nuclear, . This article is about the original containment For the new containment in place since 2016 see Chernobyl New Safe Confinement The Chernobyl Nuclear Power Plant sarcophagus or Shelter Structure Ukrainian Ob yekt Ukrittya is a massive steel and concrete structure covering the nuclear reactor number 4 building of the Chernobyl Nuclear Power Plant Currently the sarcophagus resides inside the New Safe Confinement structure The New Safe Confinement is designed to protect the environment while the sarcophagus undergoes demolition and the nuclear cleanup continues The sarcophagus was designed to limit radioactive contamination of the environment following the 1986 Chernobyl disaster by encasing the most dangerous area and protecting it from climate exposure 1 2 It is located within a large restricted area known as the Chernobyl Exclusion Zone Chernobyl Nuclear Power Plant SarcophagusUkrainian Ukrittya Chornobilskoyi AESThe sarcophagus in 2006 The tall chimney is an original part of the reactor building Location in UkraineAlternative namesChernobyl Nuclear Power Plant Shelter StructureGeneral informationStatusDeteriorated succeeded by Chernobyl New Safe ConfinementTypeConfinement shelterLocationCovering Reactor 4 of the Chernobyl Nuclear Power Plant within the Chernobyl Exclusion Zone near PripyatCountryUkraineCoordinates51 23 23 N 30 05 56 E 51 3896 N 30 0990 E 51 3896 30 0990 Coordinates 51 23 23 N 30 05 56 E 51 3896 N 30 0990 E 51 3896 30 0990Construction startedJune 1986CompletedNovember 1986DemolishedTBC 2020The original Russian name is Obekt Ukrytie Obyekt Ukrytiye 3 which means sheltering or covering as opposed to sarcophagus 2 The sarcophagus locked in 200 tons of radioactive lava like corium 30 tons of highly contaminated dust and 16 tons of uranium and plutonium 1 By 1996 the structure had deteriorated to the point where numerous stabilization measures were required Internal radiation levels were estimated to be as high as 10000 rontgens per hour in certain areas normal background radiation in cities is usually around 20 50 microrontgens per hour and a lethal dose is 500 rontgens over 5 hours 4 It was decided that the sarcophagus would be replaced with a New Safe Confinement the construction of which was completed in 2017 Contents 1 Construction 2 Ongoing issues 2 1 Designed Stabilisation Steel Structure 2 2 Upper Biological Shield 3 Replacement 4 References 4 1 Notes 4 2 Further reading 5 External linksConstruction EditThis section needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Chernobyl Nuclear Power Plant sarcophagus news newspapers books scholar JSTOR May 2017 Learn how and when to remove this template message Preparatory steps for mounting the sarcophagus in 1986 The design of the sarcophagus started on 20 May 1986 24 days after the disaster Subsequent construction lasted for 206 days from June to late November of the same year 2 Due to high radiation levels it was impossible to directly screw down the nuts and bolts or apply any direct welding to the sarcophagus so this work was done remotely where possible 1 The seams of the sarcophagus however could not be fully sealed The entire construction process consisted of eight stages clearing and concreting of territory around reactor unit 4 erection of initial reinforced concrete protective walls around the perimeter construction of separation walls between units 3 and 4 cascade wall construction covering of the turbine hall mounting of a high rise buttress wall erection of supports and installation of a reactor compartment covering and finally the installation of a ventilation system More than 400000 m3 of concrete and 7 300 tonnes of metal framework were used during the erection of the sarcophagus 2 The building ultimately enclosed 740000 m3 of heavily contaminated debris inside 1 together with contaminated soil 5 On 11 October 1986 the Soviet Governmental Commission accepted a report entitled Conclusion on Reliability and Durability of a Covering Constructions and Radiation Safety of Chernobyl NPP Unit 4 Reactor Compartment 6 verification needed The sarcophagus has over 60 bore holes to allow observation of the interior of the core 7 In many places the structure was designed to have ventilation shafts to allow some convection inside 7 Filtration systems have been put in place so that no radioactive material will escape through these holes 7 Ongoing issues Edit A view of the sarcophagus in 2005 The present shelter is constructed on top of the ruins of the reactor building The Mammoth Beam that supports the roof of the shelter rests partly on the structurally unsound west wall of the reactor building that was damaged by the accident 8 The western end of the shelter roof is supported by a wall at a point designated axis 50 This wall is reinforced concrete and was cracked by the accident Designed Stabilisation Steel Structure Edit The DSSS is a yellow steel object that has been placed next to the wrecked reactor it is 63 meters 207 ft tall and has a series of cantilevers that extend through the western buttress wall and is intended to stabilize the sarcophagus 9 This was done because if the wall of the reactor building or the roof of the shelter were to collapse then large amounts of radioactive dust and particles would be released directly into the atmosphere resulting in a large new release of radioactivity into the environment In December 2006 the Designed Stabilisation Steel Structure DSSS was extended until 50 of the roof load about 400 tons was transferred from the axis 50 wall to the DSSS citation needed Upper Biological Shield Edit A further threat to the shelter is the steel and concrete slab that formed the upper biological shield UBS situated above the reactor prior to the accident citation needed This concrete slab was thrown upwards by the explosion in the reactor core and now rests at approximately 15 from vertical The position of the upper bioshield is considered inherently unsafe as only debris supports it in its nearly upright position A collapse of the bioshield would further exacerbate the dust conditions in the shelter possibly spreading some quantity of radioactive materials out of the shelter and could damage the shelter itself The UBS is a disk 17 7 meters in diameter weighing 1000 tons The shield is formally called Component E and nicknamed Elena The twisted fuel bundles still attached to it are called Elena s hair 10 11 12 Replacement EditMain article Chernobyl New Safe Confinement On 22 December 1988 Soviet scientists announced that the sarcophagus would only last 20 30 years before requiring restorative maintenance work In 1998 with the help of the European Bank for Reconstruction and Development a conservation programme was completed that included securing the roof beams from collapsing Nonetheless the rain induced corrosion of supporting beams still threatens the sarcophagus integrity 5 It was revealed that the water is leaking through the sarcophagus via holes in its roof becoming radioactively contaminated and then seeping through the reactor s floor into the soil 5 The Chernobyl New Safe Confinement rolled into place in November 2016 allows for the dismantling of the sarcophagus and for radioactive material to be removed 13 14 The containment was expected to replace the existing sarcophagus in 2015 However delays and a 100 million funding gap caused a yearlong delay before being moved into place in November 2016 As of 2020 update the building is undergoing testing of its installed systems citation needed References EditNotes Edit a b c d Chernobyl Sarcophagus Chernobyl International Archived from the original on 4 December 2014 Retrieved 30 November 2010 a b c d Ebel 1994 p 1 code name given under the Soviet secrecy procedures Marples 1996 p 30 a b c What happened in Chernobyl Greenpeace Retrieved 30 November 2010 Obekt Ukrytie Sooruzhenie Chernobyl by Chernobyl by in Russian Chernobyl by Retrieved 2 December 2010 a b c Marples amp Risovanny 1990 p 17 See BBC documentary Archived 29 February 2012 at the Wayback Machine Nuclear Engineering International July 2007 page 12 Chernobyl Glossary Angelfire com Retrieved 22 March 2010 Ann Larabee 2000 Decade of disaster University of Illinois Press p 50 ISBN 978 0 252 06820 1 Retrieved 7 November 2019 corium silicate Chernobyl Tour United States Environmental Protection Agency 28 June 2006 Retrieved 7 November 2019 Under The Shield Inside Chernobyl s New Safe Confinement RadioFreeEurope RadioLiberty Wood 2007 p 63 Further reading Edit Asmolov V G Kozlova E A 2018 Neokonchennaya povest in Russian M ISBN 978 5 88777 064 2 Total pages 336 Ebel Robert E Center for Strategic and International Studies Washington D C 1994 Chernobyl and its aftermath a chronology of events 1994 ed CSIS ISBN 978 0 89206 302 4 Total pages 43 Marples David R Risovanny Yuri December 1990 Revelations of a Chernobyl Insider Bulletin of the Atomic Scientists 46 10 16 21 Bibcode 1990BuAtS 46j 16M doi 10 1080 00963402 1990 11459915 ISSN 0096 3402 Marples David R May 1996 The Decade of Despair Bulletin of the Atomic Scientists 52 3 20 31 Bibcode 1996BuAtS 52c 20M doi 10 1080 00963402 1996 11456623 ISSN 0096 3402 Wood Janet Institution of Engineering and Technology 2007 Nuclear power Volume 52 of Power engineer 2007 ed IET ISBN 978 0 86341 668 2 Total pages 239External links Edit Chernobyl 25 years on New Safe Confinement and Spent Fuel Storage Facility PDF European Bank for Reconstruction amp Development Retrieved from https en wikipedia org w index php title Chernobyl Nuclear Power Plant sarcophagus amp oldid 1131538342, wikipedia, wiki, book, books, library,

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