Nuclear entombment
Encyclopedia
Entombment of a nuclear reactor
is a method of nuclear decommissioning
in which radioactive contaminants are encased in a structurally long-lived material, such as concrete
, that will last for a period of time to ensure the remaining radioactivity is no longer of significant concern. The entombment structure is appropriately maintained and continued surveillance is carried out until the radioactivity is no longer a major concern, permitting decommissioning and ultimate unrestricted release of the property.
Whether or not the radioactivity is of 'major concern' is mostly a financial question. Highly contaminated sites can only be decommissioned using remotely operated tools, and this is often very expensive. After waiting a certain amount of years, the amount of short lived radioisotopes has significantly reduced, making the final decommissioning process also cheaper. At the same time, nuclear decommissioning funds, which are often collected during the operation of a nuclear power plant, have a possibility to collect interest, making more funds available for final decommission.
There are some public doubts on nuclear entombment, as it does not uphold the polluter pays principle
. It is often not possible to make an exact estimate of total decommissioning costs, leaving a certain financial liability for a future generation. It is also difficult to guarantee that the necessary expertise for final decommissioning will be available in due time, or that the decommissioning fund has earned sufficient interest. In the United States, Nuclear Regulatory Commission
rules limit licensees to 60 years to decontaminate an installation to background levels. Long-lived isotopes in reactors may not have decayed to background level in only sixty years.
Nuclear reactor
A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...
is a method of nuclear decommissioning
Nuclear decommissioning
Nuclear decommissioning is the dismantling of a nuclear power plant and decontamination of the site to a state no longer requiring protection from radiation for the general public...
in which radioactive contaminants are encased in a structurally long-lived material, such as concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
, that will last for a period of time to ensure the remaining radioactivity is no longer of significant concern. The entombment structure is appropriately maintained and continued surveillance is carried out until the radioactivity is no longer a major concern, permitting decommissioning and ultimate unrestricted release of the property.
Whether or not the radioactivity is of 'major concern' is mostly a financial question. Highly contaminated sites can only be decommissioned using remotely operated tools, and this is often very expensive. After waiting a certain amount of years, the amount of short lived radioisotopes has significantly reduced, making the final decommissioning process also cheaper. At the same time, nuclear decommissioning funds, which are often collected during the operation of a nuclear power plant, have a possibility to collect interest, making more funds available for final decommission.
There are some public doubts on nuclear entombment, as it does not uphold the polluter pays principle
Polluter pays principle
In environmental law, the polluter pays principle is enacted to make the party responsible for producing pollution responsible for paying for the damage done to the natural environment. It is regarded as a regional custom because of the strong support it has received in most Organisation for...
. It is often not possible to make an exact estimate of total decommissioning costs, leaving a certain financial liability for a future generation. It is also difficult to guarantee that the necessary expertise for final decommissioning will be available in due time, or that the decommissioning fund has earned sufficient interest. In the United States, Nuclear Regulatory Commission
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
rules limit licensees to 60 years to decontaminate an installation to background levels. Long-lived isotopes in reactors may not have decayed to background level in only sixty years.
Examples
- ChernobylChernobyl Nuclear Power PlantThe Chernobyl Nuclear Power Plant or Chornobyl Nuclear Power Plant is a decommissioned nuclear power station near the city of Pripyat, Ukraine, northwest of the city of Chernobyl, from the Ukraine–Belarus border, and about north of Kiev. Reactor 4 was the site of the Chernobyl disaster in...
, Ukraine - entombed in 'sarcophagus'. - LucensLucens reactorThe Lucens reactor at Lucens, Vaud, Switzerland, was a small pilot nuclear reactor destroyed by an accident in 1969.In 1962 the construction of a Swiss-designed pilot nuclear power plant began. The heavy-water moderated, carbon dioxide gas-cooled, reactor was built in an underground cavern and...
, Switzerland - initially entombed in a cavern and later decontaminated. - DodewaardDodewaard nuclear power plantDodewaard nuclear power plant was a nuclear power plant with a boiling water reactor in the Dutch town of Dodewaard. The plant halted energy production in 1997.-History:...
, the Netherlands - entombed for 40 years, awaiting final decommissioning. Also referred to as 'safe enclosure'. - Boiling Nuclear Superheater (BONUS) Reactor FacilityBoiling Nuclear Superheater (BONUS) Reactor FacilityThe Boiling Nuclear Superheater Reactor Facility, also known as Museo Tecnologico BONUS Dr. Modesto Iriarte, is a decommissioned nuclear plant in Rincón, Puerto Rico. It was listed on the U.S...
, Rincón, Puerto Rico - Hallam Nuclear Power Facility , Hallam, NE, USA
- Piqua Nuclear Generating StationPiqua Nuclear Generating StationThe Piqua Nuclear Power Facility was a nuclear power plant which operated just outside the southern city limits of Piqua, Ohio in the United States. The plant contained a 45.5-megawatt organically cooled and moderated nuclear reactor...
, Piqua, OH, USA
See also
- Decommissioning
- Nuclear Decommissioning AuthorityNuclear Decommissioning AuthorityThe Nuclear Decommissioning Authority is a non-departmental public body of the United Kingdom formed by the Energy Act 2004. It came into existence in late 2004, and took on its main functions on 1 April 2005...
- SAFSTORSAFSTORFor nuclear power plants governed by the United States Nuclear Regulatory Commission, SAFSTOR is one of the options for nuclear decommissioning of a shut down plant. During SAFSTOR the de-fuelled plant is monitored for up to sixty years before complete decontamination and dismantling of the site,...