Fukushima nuclear mess 2021 – the tasks ahead

The Fukushima Nuclear Disaster: Then and Now, The Chemical Engineer 25th February 2021 by Geoff Gill 

“………..Decommissioning and contaminated water management

The work to decommission the plants, deal with contaminated water and solid waste, and remediate the affected areas is immense. A “Mid-and-Long Term Roadmap”2 was developed soon after the disaster to set out how this will be achieved. Also, to facilitate decommissioning units 1-6, and dealing with contaminated water, TEPCO announced, at the end of 2013 the establishment of an internal entity: the Fukushima Daiichi Decontamination & Decommissioning Engineering Company, which commenced operations in April 2014. The entire decommissioning process will take 30–40 years, and, as noted above, the volume of tasks is gigantic. Therefore, the Government of Japan and TEPCO have prioritised each task and set the goal to achieve them. Essentially, it is a continuous risk reduction activity to protect the people and the environment from the risks associated with radioactive substances by:

• removing spent fuel and retrieval of fuel debris from the reactor buildings;
• establishing measures to deal with contaminated water; and
• establishing measures to deal with radioactive waste material.

Fuel removal from the reactor buildings

In the Fukushima Daiichi design of reactor, used and new fuel rod assemblies are stored in the upper part of the reactor. The used fuel rods are highly radioactive and continue to generate heat, and thus require continued cooling. Depending on the degree of damage, the process of removing the fuel assemblies presents different challenges in each of the reactors. For example, one of the significant challenges is to firstly remove the large quantities of rubble caused by the hydrogen explosions. As noted above, reactors 5 and 6 were shut down at the time of the accident. The reactor cores were successfully cooled, and thus suffered no damage. Given that the conditions of the buildings and the equipment for storing the fuel are stable, and risks of causing any problem in the decommissioning process are estimated to be low compared to the other units, the fuel assemblies of units 5 and 6 continue to be safely stored in the spent fuel pool in each building for the time being. The next step will be to carefully remove the fuel from the fuel pools in units 5 and 6 without impact on fuel removal from units 1, 2 and 3. All the remaining units are going through a number of stages to achieve fuel removal. They differ slightly for each unit, but essentially the stages are: survey of internal state, removal of rubble, installation of fuel handling facility, and removal of fuel. By way of example, the position regarding unit 3 is shown in Figure 3 [on original]. At unit 3, rubble removal and other work at the upper part of the reactor building, together with installation of a cover for fuel removal was completed in February 2018. After all preparations were in place, work to remove the 566 fuel rod assemblies, including 52 non-irradiated fuel assemblies, began in April 2019. The process of fuel removal is shown diagrammatically in Figure 4. The four stages are:

• Fuel rod assemblies stored on fuel racks in the spent fuel pool are transferred in the water one at a time to transport casks, using fuel handling equipment;
• after closing the cask cover and washing, a crane is used to lower the cask to ground level and load into a trailer;
• the cask is transported to a common pool on the site; and
• the fuel in the cask is stored in the common pool.

As of 8 January 2021, 468 assemblies including the 52 non-irradiated fuel assemblies had been removed from unit 3. Measurements of airborne contamination levels are being monitored in the surrounding environment throughout the fuel removal operations. The plan is that all fuel will have been removed from all of the reactor units by sometime during 2031.

Retrieval of fuel debris

At the time of the accident, units 1–3 were operating and had fuel rods loaded in the reactors. After the accident occurred, emergency power was lost, preventing further cooling of the cores. This resulted in overheating and melting of the fuel, together with other substances. Fuel debris refers to this melted fuel and other substances, which have subsequently cooled and solidified, and, of course, still remains dangerously radioactive. This clearly poses a very complex and difficult decommissioning challenge. Currently the state inside the containment vessel is being confirmed, and various kinds of surveys are being conducted prior to retrieval of the debris. The current aim is to begin retrieval from the first unit (unit 2), and to gradually enlarge the scale of the retrieval. The retrieved fuel debris will be stored in the new storage facility that will be constructed within the site. The distribution of debris between the pressure and containment vessels differs in each of the 3 units. By way of example, Figure 5 [on original] shows the current position in unit 2. Large amounts of debris are located in the bottom of the pressure vessel, with little in the containment vessel. The investigation to capture the location of fuel debris inside unit 2 was conducted from 22 March–22 July 2016. This operation applied the muon transmission method, of which effectiveness was demonstrated in its appliance for locating the debris inside unit 1. (Muon transmission method is a technique that uses cosmic ray muons to generate three-dimensional images of volumes using information contained in the Coulomb scattering of the muons.) These operations used a small device developed through a project called “Development of Technology to Detect Fuel Debris inside the Reactor’’.  Use of remote operations for decommissionings;

• establishing measures to deal with contaminated water; and
• establishing measures to deal with radioactive waste material.

…….. Understanding of the situation inside the stricken reactors was urgently needed following the accident in order to prevent the spread of damage and to mitigate the disaster. Tasks had to be carried out in a very complicated, difficult and unpredictable environment. In particular, the environment inside the reactor buildings reached high radiation levels due to the spread of radioactive contamination. To reduce the risk of radiation exposure to operators, remote control technologies  have proved indispensable for examining the reactor buildings and subsequently for decommissioning work. Thus, remote control technology, including robot  technology has been heavily utilised in response to the accident. Figure 6 [on original]shows a typical configuration of remotely-controlled robotic systems for decommissioning work. Reducing the risks associated with contaminated water Water has posed a very demanding challenge for the operators. The problem stems from groundwater flowing from the mountain side of the site toward the ocean. This flows into the reactor buildings and becomes mixed with radioactive water accumulated in the buildings, increasing the amount of contaminated water already  there. The solution to the contaminated water problem is being tackled through a three-pronged approach. These are redirecting groundwater from contamination sources, removing contamination sources, and prevent leakage of contaminated water. In order to achieve this, barriers have been installed on the land -side and sea-side of the plant. An impermeable barrier on the land-side has been achieved by freezing the ground. The frozen soil “wall” (which has a circumference of about 1,500 m) has been achieved by piping chilled brine through pipes to a depth of 30 m, which freezes the surrounding soil. On the sea-side, a wall has been constructed, consisting of 594 steel pipes (see Figure 7   -on original)……… Purification treatment of contaminated water and management of treated water…….Treatment and disposal of solid radioactive waste Waste materials resulting from the decommissioning work are sorted based on their radiation levels and are stored on the premises of the Fukushima Daiichi  Nuclear Power Station. Along with strict safety measures and studies on treatment and disposal methods, a solid waste storage management plan is drawn up  based on waste generation forecasts for around the next ten years, so that measures to deal with waste materials will be carried out effectively The storage management plan is updated once a year, while reviewing the waste generation forecasts, taking account of progress of the decommissioning work.  The illustration in Figure 9 [on original] shows the various facilities planned for treatment and storage of solid waste. TEPCO’s Mid and Long Term Roadmap shows all these facilities being completed by 2028. The amounts of waste generated are huge. For example, the latest edition of the roadmap estimates the amount of solid waste which will be generated over the next 10 years to be 780,000 m3 …….. https://www.thechemicalengineer.com/features/the-fukushima-nuclear-disaster-then-and-now/

Unsafe plan for abandoning nuclear reactors onsite, and developing Small Nuclear Reactors

“IAEA guidance that entombment is not considered an acceptable strategy for planned decommissioning of existing [nuclear power plants] and future nuclear facilities.”

Groups oppose plans to abandon defunct nuclear reactors and radioactive waste,  https://rabble.ca/columnists/2021/02/groups-oppose-plans-abandon-defunct-nuclear-reactors-and-radioactive-wasteThe Canadian Nuclear Safety Commission (CNSC) has just given a green light to the preferred industry solution for disposal of nuclear reactors — entomb and abandon them in place, also known as “in-situ decommissioning.” This paves the way for the introduction of a new generation of “small modular” nuclear reactors or SMRs.  SMRs bring many challenges, including safety of untested designs, nuclear weapons proliferation risks, high costs, disposal of radioactive waste, and public acceptance. Groups concerned about nuclear safety are objecting to plans in the works to abandon these nuclear reactors and the radioactive waste they produce once they are shut down. Over 100 Indigenous and civil society groups have signed a public statement opposing SMR funding, noting that the federal government currently has no detailed policy or strategy for what to do with radioactive waste. Many of these groups are also participating in a federal radioactive waste policy review launched in November 2020. The Assembly of First Nations passed resolution 62/2018 demanding that the nuclear industry abandon plans for SMRs and that the federal government cease funding them. It calls for free, prior and informed consent “to ensure that no storage or disposal of hazardous materials shall take place in First Nations lands and territories.” SMR waste includes not only reactor fuel but also the reactors themselves. An SMR emits no radiation before start-up (other than from uranium fuel) and could easily be transported at that stage. But during reactor operation, metal and concrete components absorb neutrons from the splitting of uranium atoms — and in the process, transform into radioactive waste. Removing an SMR after shut-down would be difficult and costly, and comes with the need to shield workers and the public from its radioactivity.   Abandoning nuclear reactors on site has been in the works for some time. CNSC helped draft a 2014 nuclear industry standard with in-situ decommissioning as an option and then included it in a July 2019 draft regulatory document. However, when the International Atomic Energy Agency (IAEA) released a peer-reviewed report on Canada’s nuclear safety framework last February, it said in-situ decommissioning is “not consistent” with IAEA safety standards. The IAEA suggested that CNSC “consider revising its current and planned requirements in the area of decommissioning to align with the IAEA guidance that entombment is not considered an acceptable strategy for planned decommissioning of existing [nuclear power plants] and future nuclear facilities.” It also noted that CNSC is reviewing license applications for in-situ decommissioning of shut-down federal reactors in Ontario and Manitoba, and encouraged Canada “to request an international peer review of the proposed strategy” for legacy reactors. But CNSC continued to pursue this strategy. Clever language in a June 2020 document appeared to rule out on-site reactor disposal, but left the door open where removal is not “practicable”: “In-situ decommissioning shall not be considered a reasonable decommissioning option for planned decommissioning of existing nuclear power plants or for future nuclear facilities in situations where removal is possible and practicable.” At public meeting last June, CNSC Commissioner Sandor Demeter asked: “why are future facilities in this sentence when in fact we should be designing them so that in-situ decommissioning is not the option?” Former CNSC staff member Karine Glenn replied that “leaving some small parts of a structure behind…especially if you are in a very, very remote area, may be something that could be considered.” Glenn is now with the industry-run Nuclear Waste Management Organization, tasked with leading the development of a radioactive waste management strategy for Canada. Commissioners decided to approve the regulatory document, but with added text to clarify where in-situ decommissioning would be acceptable. They asked for additional text on “legacy sites” and “research reactors,” stating that “[t]he Commission need not see this added text if it aligns with the oral submissions staff made in the public meeting.” But no new clarifying text was added to the final version of the document published on January 29, 2021. It enables abandonment of SMRs — by retaining the reference to future nuclear facilities — and of “research and demonstration facilities, locations or sites dating back to the birth of nuclear technologies in Canada for which decommissioning was not planned as part of the design.” The CNSC seems willing to ignore international safety standards — and a decision of its own commission — to accommodate nuclear industry proponents of SMRs and allow radioactive waste to be abandoned in place. Meanwhile, the federal government has assigned the nuclear industry itself — via the Nuclear Waste Management Organization — the task of developing a radioactive waste strategy for Canada. Barring public outcry, that strategy will be abandonment. Ole Hendrickson is a retired forest ecologist and a founding member of the Ottawa River Institute, a non-profit charitable organization based in the Ottawa Valley.

Microbes in nuclear fuel ponds slow down the decommissioning process

Manchester University 8th April 2020,Two new research papers from The University of Manchester, working with
colleagues at Sellafield Limited and the National Nuclear Laboratory show
that microbes can actively colonise some of the most intensively
radioactive waste storage sites in Europe.

When nuclear facilities such as
Sellafield were designed and built more than 50 years ago, it was sensible
to assume that the conditions in the pond would prevent microbial life from
taking hold, but now new research shows that this is not the case. The
growth of microbial life in nuclear facilities can cause uncertainty or
problems.

Understanding how microbial life can inhabit environments such as
fuel storage ponds is vital to progress nuclear decommissioning work such
as at Sellafield. Microbes are a group of organisms that, including
bacteria and algae, are known to inhabit a wide range of habitats on Earth.
Improvements in detection technology in recent years has allowed
microorganisms to be detected in environments previously thought to be
inhospitable to life. It is now becoming clear that some microorganisms are
capable of withstanding surprisingly high doses of radiation, at levels
significantly greater than seen in natural environments.https://www.manchester.ac.uk/discover/news/sellafield-research-uncovers-microbial-life-in-fuel-ponds/

Power Technology 8th April 2020, University of Manchester researchers have discovered microbial life can
survive intense radiation at European nuclear waste storage sites. Working
with the National Nuclear Laboratory at the Sellafield nuclear site,
researchers found that microbes, including bacteria and algae, can survive
in environments previously thought to be inhospitable to life.

Geomicromicrobiologists studied microbes that can cause summer blooms in
nuclear fuel storage ponds, slowing down the decommissioning process of
retired nuclear plants. Summer blooms reduce visibility and disrupt fuel
retrieval.

University of Manchester microbiology professor Jonathan Lloyd
said: “Our research focused on Sellafield’s First Generation Magnox
Storage Pond (FGMSP), which is a legacy pond that has both significant
levels of radioactivity in conjunction with a highly alkaline pH (11.4),
equivalent to domestic bleach. “The ultimate aim of this work was to
identify the microbes that can tolerate such an inhospitable environment,
understand how they tolerate high radiation levels, and help site operators
control their growth. “The growth of the microorganisms in the FGMSP
inhibits the operations in the pond, which is currently a priority for
decommissioning. “https://www.power-technology.com/news/microbes-survive-radiation-at-nuclea-sites-university-manchester-report/

Britain’s £1.2bn cleanup begins, of Berkeley power station, closed 30 years ago

Nuclear waste removal begins 30 years after power station closure, https://www.bbc.com/news/uk-england-somerset-50866867  5 Jan 2029, Work has begun on removing nuclear waste from Berkeley power station, 30 years after it was decommissioned.The disused Magnox generator, situated on the banks of the River Severn in Gloucestershire, closed in 1989. It was the world’s first commercial power station and its laboratories and many of its buildings have already been dismantled. Work emptying its vast concrete vaults of the nuclear waste Berkeley generated is only now able to safely begin. But it will not be safe for humans to go inside its reactor cores until 2074. The BBC has been given a rare glimpse of what is stored under the disused site.For the past 50 years parts of the coastline of the west of England have been dominated by nuclear power stations. The 1960s saw the construction of Hinkley A and Hinkley B in Somerset, with both Oldbury and Berkeley built on the banks of the River Severn in the 1950s. Only Hinkley B is still in use but the nuclear waste the stations generated has remained in place. It takes hundreds of years to decompose and has to be stored underground. It will cost an estimated £1.2bn to fully decommission Berkeley. About 200 people are currently working on the site under strict security. Work emptying waste products from the concrete vaults, eight metres (26ft) underground, is a complicated process. They contain used graphite from the fuel elements in the nuclear generating process, material from the cooling ponds and from the laboratories. The removal is expected to take five or six years to complete. Rob Ledger, waste operations director at Berkeley, said: “When the power stations first started generating I don’t think there was much thought put into how the waste was going to be dealt with or retrieved. “It’s taken a while to develop the equipment and the facilities [to do this]. “A mechanical arm moves the debris into position and then a ‘grab’ comes down through an aperture in the vaults and picks up the debris [and] puts it into a tray. “Each debris-filled tray weighs up to 100kg (220lb). “The automated machinery is controlled by computers [and] tips [the waste] into a cast iron container.” The containers will house the waste in an intermediate storage facility until a long-term solution can be found. “Nuclear waste does take a long time to decay… it’s hundreds of years. And that’s why we have to go to these lengths, to store it safely,” said Mr Ledger. Eventually the boxes will be housed deep underground in a long-term storage facility. The location has not yet been decided by the government. There are currently estimated to be almost 95,000 tonnes of nuclear waste in the form of graphite blocks across the UK. But if the Carbon 14 can be extracted from the blocks, they become much safer and easier to deal with. A new process is being explored, by scientists at Bristol University, to ensure not all of the waste will be discarded. They have developed a process that uses reactor core spent contents in a new power form. Carbon 14 from nuclear reactors is infused into wafer-thin diamonds, man-made in a lab at Bristol University. They then become radioactive and form the heart of a battery that would last for many thousands of years. The tiny batteries could be used in pacemakers, hearing aids or sent into space as part of the space programme. The process is being piloted in association with the UK Atomic Energy Authority in Abingdon. It is hoped the decommissioned Gloucestershire site may be redeveloped to manufacture the new batteries, creating jobs in the region.

Humboldt Bay – a case study in how not to involve the community in cleanup of a dead nuclear reactor

The audience found it noteworthy that no seats had been assigned to tribal representation.

 

the public has known very little about the decommissioning process. No seats on the CAB were given to the media, no one on the CAB thought it was their job to speak with the press, PG&E did not speak with the press, and the NRC has a very hands off approach to the decommissioning process and the utility’s relationship with the CAB. 

Input from the public included a strong sentiment that this was a very poor storage location for the spent fuel. 

Laird went on to say that while there’s already been half a meter of sea level rise, a meter more, which is predicted to occur within 40 years, will fully inundate the generation station, 101 in that area and cause the dry cask storage area to become an island, until it is eroded away.  

Notably, PG&E’s Decommissioning Fund will run out in 2025, a mere 5 years from now, the casks the waste are in only have a shelf life of 40 to 50 years, and the half life of the waste in storage in those casks in PG&E’s custody, is 24,000 years.  

NUCLEAR WASTE BEING STORED 115 FT FROM HUMBOLDT BAY AS SEA LEVEL RISES

https://kymkemp.com/2019/09/22/nuclear-waste-being-stored-115-ft-from-humboldt-bay-as-sea-level-rises/

Bruce Watson the Branch Chief in charge of Reactor Decommissioning at the NRC led the meeting. He instructed everyone that the sole purpose of the meeting was for him to collect their input on the best practices of the Citizen Advisory Boards. He said, “We are not here to talk about other issues related to decommissioning.” The speakers allowed some of their remarks to drift over to address what should be done about the spent fuel rod still being stored at the King Salmon site.

On January 14th, the Nuclear Energy Innovation and Modernization Act (NEIMA) was signed into law. According to Jurist Legal News and Research website, NEIMA makes several changes to the licensing process for nuclear reactors. The NEIMA gave the NRC less than a year to “develop and implement a staged licensing process for commercial advanced nuclear reactors.”

Captiol Hill briefing paper on the need for autopsies at decommissioning reactors

http://www.beyondnuclear.org/nuclear-reactors-whatsnew/2018/7/11/captiol-hill-briefing-paper-on-the-need-for-autopsies-at-dec.html

LINK TO FULL REPORT    

Decommissioning nuclear power stations need an “autopsy” to verify and validate safety margins projected for operating reactor license extensions  

                                                    Summary

The Issue

The Nuclear Energy Institute (NEI), the lead organization for the U.S. commercial nuclear power industry, envisions the industry’s “Bridge to the Future” through a series of reactor license renewals from the original 40-year operating license; first by a 40 to 60-year extension and then a subsequent 60 to 80-year extension. Most U.S. reactors are already operating in their first 20-year license extension and the first application for the second 20-year extension (known as the “Subsequent License Renewal”) is before the U.S. Nuclear Regulatory Commission (NRC) for review and approval. NEI claims that there are no technical “show stoppers” to these license extensions. However, as aging nuclear power stations seek to extend their operations longer and longer, there are still many identified knowledge gaps for at least 16 known age-related material degradation mechanisms (embrittlement, cracking, corrosion, fatigue, etc.) attacking irreplaceable safety-related systems including miles of electrical cable, structures such as the concrete containment and components like the reactor pressure vessel. For example, the national labs have identified that it is not known how radiation damage will interact with thermal aging. Material deterioration has already been responsible for near miss nuclear accidents.  As such, permanently closed and decommissioning nuclear power stations have a unique and increasingly vital role to play in providing access to still missing data on the impacts and potential hazards of aging for the future safety of dramatic operating license extensions.

The NRC and national laboratories document that a post-shutdown autopsy of sorts to harvest, archive and test actual aged material samples (metal, concrete, electrical insulation and jacketing, etc.) during decommissioning provides unique and critical access to obtain the scientific data for safety reviews of the requested license extensions. A Pacific Northwest National Laboratory (PNNL) 2017 report concludes, post-shutdown autopsies are necessary for “reasonable assurance that systems, structures, and components (SSCs) are able to meet their safety functions. Many of the remaining questions regarding degradation of materials will likely require[emphasis added]a combination of laboratory studies as well as other research conducted on materials sampled from plants (decommissioned or operating).” PNNL reiterates, “Where available, benchmarking can be performed using surveillance specimens. In most cases, however, benchmarking of laboratory tests will require(emphasis added)harvesting materials from reactors.” In the absence of “reasonable assurance,” it is premature for licensees to complete applications without adequate verification and validation of projected safety margins for the 60 to 80-year extension period.

Decommissioning is not just the process for dismantling nuclear reactors and remediating radioactive contamination for site restoration. Decommissioning has an increasingly important role at the end-of-reactor-life-cycle for the scientific scrutiny of projected safety margins and potential hazards at operating reactors seeking longer and longer license extensions.

The Problem

After decades of commercial power operation,the nuclear industry and the NRC have done surprisingly little to strategically harvest, archive and scientifically analyze actual aged materials. Relatively few samples of real time aged materials have been shared with the NRC.  The NRC attributes the present dearth of real time aged samples to “harvesting opportunities have been limited due to few decommissioning plants.” However, ten U.S. reactors have completed decommissioning operations to date and 20 units are in the decommissioning process. More closures are scheduled to begin in Fall 2018.  A closer look raises significant concern that the nuclear industry is reluctant to provide access to decommissioning units for sampling or collectively share this cost of doing business to extend their operating licenses. Key components including severely embrittled reactor pressure vessels were promptly dismantled by utilities and buried whole without autopsy. Many permanently closed reactors have been placed in “SAFSTOR,” defueled and mothballed “cold and dark” for up to 50 years without the material sampling to determine their extent of condition and the impacts of aging. Moreover, the NRC is shying away from taking reasonable regulatory and enforcement action to acquire the requested samples for laboratory analysis after prioritizing the need for a viable license extension safety review prior to approval. Meanwhile, the nuclear industry license extension process is pressing forward.

David Lochbaum, a recognized nuclear safety engineer in the public interest with the Union of Concerned Scientists, identifies that nuclear research on the impacts and hazards of age degradation in nuclear power stations presently relies heavily on laboratory accelerated aging—often of fresh materials—and computer simulation to predict future aging performance and potential consequences during license extension.  Lochbaum explains that “Nuclear autopsies yield insights that cannot be obtained by other means.” Researchers need to compare the results from their time-compression studies with results from tests on materials actually aged for various time periods to calibrate their analytical models.According to Lochbaum, “Predicting aging effects is like a connect-the-dots drawing. Insights from materials harvested during reactor decommissioning provide many additional dots to the dots provided from accelerated aging studies. As the number of dots increases, the clearer the true picture can be seen. The fewer the dots, the harder it is to see the true picture.”

The Path Forward

1) Congress, the Department of Energy (DOE) and the NRC need to determine the nuclear industry’s fair share of autopsy costs levied through collective licensing fees for strategic harvesting during decommissioning and laboratory analysis of real time aged material samples as intended to benefit the material performance and safety margins of operating reactors seeking license extensions, and;

2) As NRC and the national laboratories define the autopsy’s stated goal as providing “reasonable assurance that systems, structures, and components (SSCs) are able to meet their safety functions” for the relicensing of other reactors, the NRC approval process for Subsequent License Renewal extensions should be held in abeyance pending completion of comprehensive strategic harvesting and conclusive analysis as requested by the agency and national laboratories, and;

3) Civil society can play a more active role in the independent oversight and public transparency of autopsies at decommissioning reactor sites such as through state legislated and authorized nuclear decommissioning citizen advisory panels.

The nuclear decommissioning process

Why decommissioning South Africa’s Koeberg nuclear plant won’t be easy  The Conversation,  Hartmut Winkler  Professor of Physics, University of Johannesburg, January 26, 2018  

“……..There are three stages in the rehabilitation of a nuclear facility.

1. The plant must be dismantled. This is complicated because most of the material in and around the plant is radioactive to varying degrees and therefore dangerous to anything exposed to it. Radioactivity reduces with time, but for some isotopes commonly found in nuclear waste, the drop in radiation levels can be very slow. Because of this a plant will only be dismantled years after it’s been switched off.
2. The dangerous nuclear waste, or high level waste must be reprocessed. Most of the material stays dangerous for decades but some isotopes retain high levels of radiation levels for thousands of years. A portion of nuclear waste can be converted into reusable or less radioactive forms through nuclear engineering processes. These processes are complex and there are only a few facilities in the world that can perform them. This means that South Africa’s high level waste will have to be transported overseas. Reprocessing facilities include La Hague in France and the Russian Mayak site, thought to be responsible for the 2017 ruthenium leak incident.
3. The remaining nuclear waste must be secured in storage, virtually forever. This needs an isolated site that can’t be damaged by natural disasters or other processes that could cause radioactive material to seep into the surrounding environment, especially ground water. This final storage need is a massive headache worldwide. An example is the German Gorleben final repository site. It’s been the scene of protests for decades, preventing any further storage of waste on the site.

There are a handful of cases where the first two stages have been completed, typically over periods of ten years. But completing the final storage phase of nuclear waste hasn’t been achieved for any former plants. Their most hazardous waste is still in temporary storage, sometimes even on site……… https://theconversation.com/why-decommissioning-south-africas-koeberg-nuclear-plant-wont-be-easy-89888

The Era of Nuclear Decommissioning

Nuclear power in crisis: we are entering the Era of Nuclear Decommissioning, Energy Post, January 31, 2018 by Jim Green  “…………The Era of Nuclear Decommissioning     The ageing of the global reactor fleet isn’t yet a crisis for the industry, but it is heading that way. In many countries with nuclear power, the prospects for new reactors are dim and rear-guard battles are being fought to extend the lifespans of ageing reactors that are approaching or past their design date.

Perhaps the best characterisation of the global nuclear industry is that a new era is approaching ‒ the Era of Nuclear Decommissioning ‒ following on from its growth spurt from the 1960s to the ’90s then 20 years of stagnation.

The Era of Nuclear Decommissioning will entail:

• A slow decline in the number of operating reactors.
• An increasingly unreliable and accident-prone reactor fleet as ageing sets in.
• Countless battles over lifespan extensions for ageing reactors.
• An internationalisation of anti-nuclear opposition as neighbouring countries object to the continued operation of ageing reactors (international opposition to Belgium’s ageing reactors is a case in point ‒ and there are numerous other examples).
• Battles over and problems with decommissioning projects (e.g. the UK government’s £100+ million settlement over a botched decommissioning tendering process).
• Battles over taxpayer bailout proposals for companies and utilities that haven’t set aside adequate funds for decommissioning and nuclear waste management and disposal. (According to Nuclear Energy Insider, European nuclear utilities face “significant and urgent challenges” with over a third of the continent’s nuclear plants to be shut down by 2025, and utilities facing a €118 billion shortfall in decommissioning and waste management funds.)
• Battles over proposals to impose nuclear waste repositories and stores on unwilling or divided communities.

The Era of Nuclear Decommissioning will be characterised by escalating battles (and escalating sticker shock) over lifespan extensions, decommissioning and nuclear waste management. In those circumstances, it will become even more difficult than it currently is for the industry to pursue new reactor projects. A feedback loop could take hold and then the nuclear industry will be well and truly in crisis ‒ if it isn’t already.

Editor’s Note

Dr Jim Green is the editor of the Nuclear Monitor newsletter, where a longer version of this article was originally published.

http://energypost.eu/nuclear-power-in-crisis-welcome-to-the-era-of-nuclear-decommissioning/

 

Risky work: dismantling a nuclear reactor

Here’s what dismantling a nuclear reactor involves: Robots, radiation, risk  IEA says about 200 nuclear reactors around the world will be shut down over the next quarter century http://www.business-standard.com/article/international/here-s-what-dismantling-a-nuclear-reactor-involves-robots-radiation-risk-117061200298_1.html   Reuters  |  Muelheim-Kaerlich, Germany June 12, 2017 As head of the Muelheim-Kaerlich nuclear reactor, Thomas Volmar spends his days plotting how to tear down his workplace. The best way to do that, he says, is to cut out humans.

About 200 nuclear reactors around the world will be shut down over the next quarter century, mostly in Europe, according to the International Energy Agency. That means a lot of work for the half a dozen companies that specialise in the massively complex and dangerous job of dismantling plants.

Those firms — including Areva, Rosatom’s Nukem Technologies Engineering Services, and Toshiba’s Westinghouse — are increasingly turning away from humans to do this work and instead deploying robots and other new technologies.

That is transforming an industry that until now has mainly relied on electric saws, with the most rapid advances being made in the highly technical area of dismantling a reactor’s core — the super-radioactive heart of the plant where the nuclear reactions take place.

The transformation of the sector is an engineering one, but companies are also looking to the new technology to cut time and costs in a competitive sector with slim margins.

Dismantling a nuclear power plant can take decades and cost up to 1 billion euros ($1.1 billion), depending on its size and age. The cost of taking apart the plant in Muelheim-Kaerlich will be about 800 million euros, according to sources familiar with the station’s economics.

Some inroads have already been made: a programmable robot arm developed by Areva has reduced the time it takes to dismantle some of the most contaminated components of a plant by 20-30 per cent compared with conventional cutting techniques.

For Areva and rival Westinghouse, reactor dismantling is unlikely to make an impact on the dire financial straits they are mired in at present as it represents just a small part of their businesses, which are dominated by plant-building.

But it nonetheless represents a rare area of revenue growth; the global market for decommissioning services is expected to nearly double to $8.6 billion by 2021, from $4.8 billion last year, according to research firm MarketsandMarkets. Such growth could prove important for the two companies should they weather their current difficulties.

“We’re not talking about the kind of margins Apple is making on its iPhone,” said Thomas Eichhorn, head of Areva’s German dismantling activities. “But it’s a business with a long-term perspective.”

When reactors were built in the 1970s, they were designed to keep radiation contained inside at all costs, with little thought given to those who might be tearing them down more than 40 years later.

First, engineers need to remove the spent nuclear fuel rods stored in reactor buildings — but only after they’ve cooled off. At Muelheim-Kaerlich this took about two years in total. Then peripheral equipment such as turbines need to be removed, a stage Muelheim-Kaerlich has begun and which can take several years.

Finally, the reactor itself needs to be taken apart and the buildings demolished, which takes about a decade. Some of the most highly contaminated components are cocooned in concrete and placed in iron containers that will be buried deep underground at some point.

Robots under water

While the more mundane tasks, including bringing down the plants’ outer walls, are left to construction groups such as Hochtief, it’s the dismantling of the reactor’s core where more advanced skills matter — and where the use of technology has advanced most in recent years.

Enter companies such as Areva, Westinghouse, Nukem Technologies, GE Hitachi as well as GNS, owned by Germany’s four nuclear plant operators. They have all begun using robots and software to navigate their way into the reactor core, or pressure vessel.

“The most difficult task is the dismantling of the reactor pressure vessel, where the remaining radioactivity is highest,” said Volmar, who took charge of the RWE-owned Muelheim-Kaerlich plant two years ago. “We leave this to a specialised expert firm.”

The vessel — which can be as high as 13 metres and weigh up to 700 tonnes — is hidden deep inside the containment building that is shaped like a sphere to ensure its 30-centimetre thick steel wall is evenly strained in case of an explosion.

The 2011 Fukushima disaster and the Chernobyl accident of 1986 are imprinted in the world’s consciousness as examples of the catastrophic consequences of the leakage of radioactive material.

France’s Areva recently won the contract to dismantle the pressure vessel internals at Vattenfall’s 806 megawatts (Mw) Brunsbuettel nuclear plant in Germany, which includes an option for the Swedish utility’s 1,402 MW Kruemmel site.

There, the group will for the first time use its new AZURo programmable robot arm. It hopes this will help it outstrip rivals in what is the world’s largest dismantling market following Germany’s decision to close all its last nuclear plants by 2022, in response to the Fukushima disaster.

AZURo operates under water because the liquid absorbs radiation from the vessel components — reducing the risk of leakage and contamination of the surrounding area. The chamber is flooded before its work begins.

Areva’s German unit invests about 5 per cent of its annual sales, or about 40 million euros, in research and development, including in-house innovation such as AZURo. By comparison, the world’s 1,000 largest corporate R&D spenders, on average, spent 4.2 per cent last year, according to PwC.

The robot arm technology helped Areva beat Westinghouse by winning tenders to dismantle pressure vessel internals at EnBW’s Philippsburg 2 and Gundremmingen 2 blocks, industry sources familiar with the matter said.

Areva and EnBW both declined to comment. Westinghouse — whose US business filed for bankruptcy in March — did not respond to repeated requests for comment. Time and money

Britain’s OC Robotics has built the LaserSnake2, a flexible 4.5-metre snake arm, which can operate in difficult spaces and uses a laser to increase cutting speeds — thus reducing the risk of atmospheric contamination. It was tested at the Sellafield nuclear site in west Cumbria last year.

This followed France’s Alternative Energies and Atomic Energy Commission (CEA), whose laser-based dismantling technology generates fewer radioactive aerosols — a key problem during cutting — than other technologies.

The complexity of the dismantling process is also giving rise to modelling software that maps out the different levels of radiation on plant parts, making it easier to calculate the most efficient sequence of dismantling – the more contaminated parts are typically dealt with first – and gives clarity over what safety containers will be needed to store various components.

GNS, which is jointly owned by E.ON, RWE, EnBW and Vattenfall, is currently helping to dismantle the German Neckarwestheim 1 and Philippsburg 1 reactors, using its software to plan the demolition.

The company also hopes to supply its software services for the dismantling of PreussenElektra’s Isar 1 reactor, which is being tendered, and aims to expand to other European countries.

“Two things matter: time and money,” said Joerg Viermann, head of sales of waste management activities at GNS.

“The less I have to cut, the sooner I will be done and the less I will spend.”

100 billion pound cost of decommissioning Europe’s old nuclear power stations

Standard and Poor’s: dismantling Europe’s old nuclear power plants will run up a hundred billion  pound bill for EDF EON RWE and others 

http://www.cityam.com/229161/standard-poors-dismantling-europes-old-nuclear-power-plants-will-run-up-a-eur100bn-bill-for-edf-eon-rwe-and-others  Dismantling Europe’s old, uneconomic power plants will impose heavy costs on Europe’s biggest operators, something which could strain their balance sheets, and hit their credit rating.

Nuclear liabilities of the largest eight nuclear plant operators in Europe totaled €100bn at the end of last year, representing around 22 per cent of their aggregate debt, according to credit rating agency Standard & Poor’s.

Operators are legally responsible for decommissioning nuclear power plants, a process which can take several decades to implement, meaning the associated costs are high. Europe’s main nuclear operators include France’s EDF, Germany’s E.ON and RWE. They are legally responsible for decommissioning nuclear power plants, a process which can take several decades to implement, meaning the associated costs are high.

While the analysis by S&P treats nuclear liabilities as debt-like obligations, it recognises that several features differentiate them from traditional debt. But given the size of the liabilities against a company’s debt, they can impact a company’s credit metrics, and their credit rating.

The report noted that a company’s nuclear provisions are difficult to quantify, as well as cross compare, because accounting methods vary between different countries.

It also foresees many operational challenges ahead, including a reality check on costs and execution capabilities.