Nuclear decommissioning
The process usually runs according to a decommissioning plan, including the whole or partial dismantling and decontamination of the facility, ideally resulting in restoration of the environment up to greenfield status.
The process typically takes about 15 to 30 years, or many decades more when an interim safe storage period is applied for radioactive decay.
The final disposal of nuclear waste from past and future decommissioning is a growing still unsolved problem.
There are worldwide also hundreds of thousands small nuclear devices and facilities, for medical, industrial and research purposes, that will have to be decommissioned at some point.
It refers to the administrative and technical actions taken to remove all or some of the regulatory controls from the facility to bring about that its site can be reused.
The aim is ideally to restore the natural initial state that existed before the construction of the nuclear power plant, the so-called greenfield status.
At the final shutdown, a final decommissioning plan describes in detail how the decommissioning will take place, how the facility will be safely dismantled, ensuring radiation protection of the workers and the public, addressing environmental impacts, managing radioactive and non-radioactive materials, and termination of the regulatory authorization.
[12] The decommission of a nuclear reactor can only take place after the appropriate licence has been granted pursuant to the relevant legislation.
[13] On the basis of these general data, the Commission must be in a position to assess the exposure of reference groups of the population in the nearest neighbouring states.
Equipment, structures, systems and components that contain radioactive material are removed and/or decontaminated to a level that permits the ending of regulatory control of the facility and its release, either for unrestricted use or with restrictions on its future use.[5],p.
[6] Deferred dismantling (SAFSTOR in the United States; "care and maintenance" (C&M) in the UK) The final decommissioning is postponed for a longer period, usually 30 to 50 years.
[6] With deferred dismantling, costs are shifted to the future, but this entails the risk of rising expenditures for decades to come and changing rules.
50 The calculation of the total cost of decommissioning is challenging, as there are large differences between countries regarding inclusion of certain costs, such as on-site storage of fuel and radioactive waste from decommissioning, dismanting of non-radioactive buildings and structures, and transport and (final) disposal of radioactive waste.[17],p.
[19] In 2004, in a meeting in Vienna, the International Atomic Energy Agency estimated the total cost for the decommissioning of all nuclear facilities.
[21] The huge costs of research and development for (geological) longterm disposal of nuclear waste are collectively defrayed by the taxpayers in different countries, not by the companies.
[23] Germany has also a state-owned fund for decommissioning of the plants and managing radioactive waste, for which the reactor owners have to pay.
[25] Since 2010, owners of new nuclear plants in the Netherlands are obliged to set up a decommissioning fund before construction is started.
[26] The economic costs of decommissioning will increase as more assets reach the end of their life, but few operators have put aside sufficient funds.
[27] In Feb 2017, a committee of the French parliament warned that the state-controlled EDF has underestimated the costs for decommissioning.
According to the parliamentary commission, the clean-up of French reactors will take longer, be more challenging and cost much more than EDF anticipates.
The EDF's estimate was primarily based on the single historic example of the already dismantled Chooz A reactor.
[28] Similar concerns about underfunding exist in the United States, where the U.S. Nuclear Regulatory Commission has located apparent decommissioning funding assurance shortfalls and requested 18 power plants to address that issue.
Despite the huge investments in securing the dismantlement, radioactive elements such as plutonium, caesium-137 and cobalt-60 leaked out into the surrounding lake.
About two-thirds can be attributed to costs for termination of the NRC operating licence; 25% to management of spent fuel; and 10% to site restoration.
The biggest American military nuclear facility for the production of weapons-grade plutonium was Hanford site (in the State of Washington), now defueled, but in a slow and problematic process of decontamination, decommissioning, and demolition.
As May 2022, about 700 nuclear reactors have been retired from operation in several early and intermediate stages (cold shut-down, defueling, SAFSTOR, internal demolition), but only about 25 have been taken to fully "greenfield status".
[43] Many of these sites still host spent nuclear fuel in the form of dry casks embedded in concrete filled steel drums.
[9] Thus many entities do not include the cost of managing spent nuclear fuel, removed from the plant areas that will be decommissioned.
[68] 1) Defuelled 2) Extraction of Sodium[70] Pipe cutting with a robot [71][72] Immediate dismantling (underwater cutting) In dismantling since 1996 Safstor (underwater cutting) Immediate dismantling pilot project (underwater cutting) Since 2011 Tōhoku earthquake and tsunami of March 11 [84][85][86] Hydrogen explosion (INES 7)[87][88] Since March 11, 2011 Reactor defueled when tsunami hit Damage to spent fuel cooling-pool (INES 4) Since March 11, 2011 Cold shutdown [93] [94][95] Defueled Phases 1 and 2: €93 million Units 1, 2 BWR 1 x 638 MW Units 1, 2 PWR 1 x 904 MW ENTOMBMENT (armed concrete "sarcophagus") Demolition contract awarded December 2018[120] 14 MWe.
[121] [129][130] Fuel in insite long-term dry-cask storage In 2011, Edison finished replacing the steam generators in both reactors with improved Mitsubishi ones, but the new design had several problems, cracked, causing leaks and vibrations.
