Tag Archives: decommissioned nuclear power plants

Diving into a Nuclear Pool

nuclear pool

United Kingdom: Specialist divers have completed their mission to deal with radioactive waste from Sizewell A Site’s nuclear fuel storage ponds, nearly two months ahead. The divers, who are shielded from radiation by the water in the ponds, successfully cut up and ‘size reduced’ all of the 35 waste storage containers left in Sizewell A’s ponds. They also cut up around 100 tonnes of other redundant equipment before removing all the radioactive sludge from the pond floor.

Conventionally, pond clean-out is done using remotely operated equipment to lift the whole radioactive skips  (waste containers) and other pond furniture clear of the water, exposing them to the air, where they are carefully cut and decontaminated. This process is slow with potential radiation dose risks for workers,” Magnox Sites said.  “Using this innovative underwater decommissioning technique, radiation levels for workers were around 20 times less than with conventional techniques of decommissioning the waste items in air,” it added. The diving technique also has a lower environmental impact, is quicker and more efficient and therefore cheaper.  The next phase of work is to take the waste out of the ponds where it will be treated and safely packaged. The ponds are set to be completely emptied and drained by the end of 2019.

The team of 12 nuclear divers was supplied by Underwater Construction UK Ltd. They tackled their first UK ‘nuclear dive’ at the Dungeness A Site in 2016 and arrived on site at Sizewell A in October 2017.

Sizewell A’s two 210 MWe Magnox gas-cooled reactors operated from 1966 until 2006. Defuelling began in 2009, with fuel removed from the reactors placed in the site’s used fuel storage ponds before being packaged in transport containers for shipment to the Sellafield complex for reprocessing. The final flask of fuel was shipped to Sellafield in August 2014. Sizewell A was declared completely fuel free in February 2015.

Excerpts from Divers Complete Radwast work at Sizewell A, World Nuclear News, Aug. 3,  2018

The So Swiss Nuclear Plant Disposal

muhleberg Nuclear Power Plant. Image from wikpedia

On November 27, 2016 Swiss voters will decide whether to turn off the country’s nuclear power stations after 45 years of activity. But what does dismantling a nuclear power plant involve? ….

On December 20, 2019, the Mühleberg nuclear power plant in canton Bern will definitely be disconnected from the grid. A new chapter in the history of Swiss nuclear energy will thus begin: the complete dismantling of a power plant…Situated around 15 kilometres from the Swiss capital Bern, the reactor has been in service since 1972 and provides 5% of the electricity used in Switzerland….

Once the fuel is extracted from the reactor core, it will be submerged in the so-called deactivation pool, where it will stay for several years.  Around 2024, the cooled uranium will be transported by lorry to the interim storage facility at Würelingen, canton Aargau.

It will then be possible to begin the real disassembly of the cement and steel structure, starting with the reactor core. This is the most complex phase…“Fifty years ago, when a power station was built, no one thought about dismantling it. The old plants were made in an extremely compact manner for reasons of cost and safety. Therefore there isn’t much space for the dismantling and decontamination,” …[D]eveloping robots.. [is one way] of improving efficiency and staff safety.

At Mühleberg, unlike what has been done in the United States for example, the so-called “fast” version will be used.“Dismantling this [boiling water] type of reactor is well-known and therefore we’ll be able to begin directly,” said Stefan Klute. “In other places the preference is to seal the plant for 40-50 years and wait for some of the residual radioactivity to decay naturally.”

In his opinion, there are many advantages to the more rapid option. “We don’t have to second-guess what the political situation will be in half a century – an impossible prediction in any case.

Dismantling the Mühleberg nuclear power station will generate around 200,000 tonnes of waste. Most of the material will be decontaminated directly in situ and recycled or disposed of in appropriate landfills.The whole operation should finish around 2034.

Excerpts from  Luigi Jorio The end of a Swiss nuclear power plant, Swissinfo.ch,  Nov. 17, 2016

How Much it Costs to Close Down Nuclear Plants

Vermont Yankee Nuclear Power Plant

According to Callan Investment Institute, underfunded decommissioning costs could amount to $23 billion from investor-owned utilities.  The industry has already set aside $50 billion to fund specific trust funds designated exclusively for decommissioning expenses, mostly collected from ratepayers….

As part of the Nuclear Regulatory Commission commissioning and licensing of a power plant, the plant owners establish a trust fund, known as the Nuclear Decommissioning Trust, or NDT. The sole purpose of this trust fund is to provide funds for the cost to decommission the facility when that time comes. The owners contribute annually to the fund, in relationship to the percent ownership, based on projected costs and length of the license. The companies are the final backstop to shortfalls in funding to these trusts.

The origin of the capital for fund contributions is from customer rate cases – in other words, NDT funding is part of our monthly electric bills. Owners are required to review annually and submit every two years to the NRC both the fund balance and cost estimates for decommissioning. The NRC provides a formula of costs for operators to compare with the balances on the NDT, or the companies can file site-specific cost projections for each facility.

The total industry-wide decommissioning costs are estimated by Callan to be $80 billion….[For instance] Entergy, according to the study, their NDT could be short by about $2 billion and to make up this difference over the average life remaining of their licenses, management should be setting aside $186 million a year rather than the $39 million currently. However, ETR is not alone in the study. The industry contributed $315 million in 2013 when Callan calculates the amount should be closer to $1.6 billion. Below are some shortfall numbers for the five largest nuclear power generators,…

According to Callan, Exelon has potential net deficiencies of $7.7 billion including Constellation Energy; Duke has a potential net deficiency of $2.3 billion; Entergy of $2.0 billion; Dominion Resources  of $1.3 billion; and NextEra has a potential surplus of $208 million. Combined, the largest five producers of nuclear power have a potential decommissioning deficit of $13.1 billion, or 57% of the projected total industry-wide.

Excerpts from George Fisher, A $23 Billion Potential Shortfall For 27 Utilities With Nuclear Power Plants, Seeking Alpha,May. 15, 2015

Full Study (pdf)

The Cost of Decommissioning Nuclear Reactors

Reactor pressure vessel transported from site for burial. Image from wikipedia

The International Energy Agency (IEA) said late in 2014  (pdf) that almost 200 of the 434 reactors in operation around the globe would be retired by 2040, and estimated the cost of decommissioning them at more than $100 billion.  But many experts view this figure as way too low, because it does not include the cost of nuclear waste disposal and long-term storage and because decommissioning costs – often a decade or more away – vary hugely per reactor and by country…. The IEA’s head of power generation analysis, Marco Baroni, said that even excluding waste disposal costs, the $100 billion estimate was indicative, and that the final cost could be as much as twice as high. He added that decommissioning costs per reactor can vary by a factor of four.Decommissioning costs vary according to reactor type and size, location, the proximity and availability of disposal facilities, the intended future use of the site, and the condition of the reactor at the time of decommissioning.

The U.S. Nuclear Regulatory Commission estimates that the cost of decommissioning in the United States – which has some 100 reactors – ranges from $300 million to $400 million per reactor, but some reactors might cost much more.  France’s top public auditor and the nuclear safety authority estimate the country’s decommissioning costs at between 28 billion and 32 billion euros ($32-37 billion).  German utilities – such as E.ON, which last month said it would split in two, spinning off power plants to focus on renewable energy and power grids – have put aside 36 billion euros. .  Britain’s bill for decommissioning and waste disposal is now estimated at 110 billion pounds ($167 billion) over the next 100 years, double the 50 billion pound estimate made 10 years ago.  Japanese government estimates put the decommissioning cost of the country’s 48 reactors at around $30 billion, but this is seen as conservative. Russia has 33 reactors and costs are seen ranging from $500 million to $1 billion per reactor.

Excerpt, Global nuclear decommissioning cost seen underestimated, may spiral, Reuters, Jan, 19, 2014

Management of Nuclear Waste in Germany

Nuclear Power plant Brunsbüttel.  Image from wikipedia

Inspectors in northern Germany have found that a third of barrels containing radioactive waste at a decommissioned nuclear plant are damaged, the Schleswig-Holstein Environment Ministry said on Thursday.  Vattenfall, the energy company which manages the Brunsbüttel site in Schlewswig-Holstein, reported that 102 of the 335 barrels stored in the site’s six underground chambers were corroded, leaking or had loose lids.  Some of the containers are so deformed that they can no longer be moved, as they no longer fit into the robotic gripping arms installed at the site, the inspectors reported.  “The chambers are secure and there is no danger for the personnel or the local population,” Vattenfall said in a statement released on Thursday,

The Brunsbüttel site harbours 631 barrels of nuclear waste in its six chambers, which have been used for storing waste since 1979. The nuclear power plant was decommissioned in 2011.  The barrels contain resin used for water filters, residue from contaminated water and various other types of waste.

So far, Vattenfall has only inspected four of the six chambers using remote cameras.  The chambers themselves are built from concrete and have walls over a metre thick to prevent radiation escaping into the surrounding environment.  The energy company has sent a proposal to the Schlewsig-Holstein Environment Ministry for making the storage facility more secure, including by installing dehumidifiers to slow corrosion, which has yet to be approved by government experts.  “The chambers [at Brunsbüttel] were supposed to be a temporary storage facility,” Vattenfall said in a statement on Thursday. “They weren’t designed to for long-term containment.”

It was originally planned to store the barrels at Brunsbüttel until they were moved to the ‘Konrad’ mine shaft site in Lower Saxony.This permanent storage facility was to be completed by the mid- to late 90s, but has been subject to successive delays. Completion dates in 2014 has been missed and a target of 2019 is also unlikely.  The latest estimate for completion is the start of the next decade.

One in three nuclear waste barrels damaged, The Local Germany, Oct. 10, 2014