Sellafield’s oldest nuclear storage pond to be decommissioned
The world’s largest open air nuclear storage pond, at Sellafield in Cumbria, is being decommissioned to make the site “safer”.
The Pile Fuel Storage Pond, built in 1948, was originally used to store fuel from the Windscale Pile Reactors.
Now, the radioactive sludge will be moved from the pond to a modern waste treatment plant.
Project Manager Chris Plane said the new plant will reduce “sludge hazard” and will be operational next year.
The Drum Filling Plant is designed to accelerate sludge retrieval from the pond by more than three years.
Using a petrol-pump style design, the plant said it will export the sludge from the pond at a “fraction” of the cost.
The pond ceased operation in the 1970s, but it is one of four sites at the plant that is identified as a top priority for risk and hazard reduction.
Dorothy Gradden, head of the Pile Fuel Storage Pond, said it was one of the “most challenging” decommissioning projects on the site.
She said: “The plan is to decommission and empty the pond to make this historic plant safer sooner.
“However, before the pond water can be drained, the radioactive sludge has to be removed. This sludge is similar in consistency to tomato ketchup and lies at the bottom of the 7m-deep pond.”
Mr Plane said move will provide a “cost effective solution”, which will save UK taxpayers money.
The estimated cost of the clean up of Sellafield’s old reactor, redundant structures and stored waste had risen to an “astonishing” £70bn, the Public Accounts Committee said in February.
It said progress had been “poor” but the consortium in charge of the site, Nuclear Management Partners, said it faced “unprecedented” challenges.
Source: BBC News
Decommissioning of Chernobyl units approaches
Work could soon start on decommissioning units 1 to 3 of the Chernobyl nuclear power plant in Ukraine after a project to put the units into care and maintenance was approved by a state review authority.
The review by State Enterprise Ukrderzhbudekspertiza confirmed that the project to ‘ultimately close and mothball’ the units is in accordance with all necessary regulatory and legal requirements.
Work to bring the three units into a ‘conserved’ state will be carried out in six stages between now and 2028. The first stage is to refurbish the water supply system for the plant’s fire protection system. The second stage will involve the dismantling of the pressure tubes and control and protection channels of units 1 to 3. The reactors of units 1 and 2 will then be put into a state of care and maintenance in which they will lie undisturbed, allowing the remaining radioactivity to decay naturally. In the fourth stage, the roofs of the reactor halls of units 1 and 2 will be refurbished while the fuel handling machines of those units will be dismantled. The plant’s third unit will then be put into care and maintenance, while in the final stage the unit’s reactor hall roof will be refurbished and its fuel handling machinery dismantled.
The Chernobyl site operator said that the ultimate aim of the project is to bring units 1, 2 and 3 “to a condition that ensures safe, controlled storage of radioactive substances and sources of ionizing radiation within them.” It said that the project will cost more than UAH385 million ($43 million).
The operator said that the review authority’s approval of the project will allow it to obtain a permit to perform the work and start decommissioning of the units.
For the period between 2028 and 2046, the most contaminated equipment will be removed from the units, while the reactors themselves will be dismantled between 2046 and 2064.
On 26 April 1986, the Chernobyl plant suffered the worst nuclear accident in history when a power runaway event wrecked reactor 4, leading to a hydrogen explosion that destroyed the reactor building and exposed the core of the ruined reactor. The three remaining reactor units, however, were vital to Ukraine’s electricity needs and continued to operate for some years. Unit 2 shut down in 1991, unit 1 in 1996 and unit 3 in 2000.
The decommissioning of units 1-3 is being carried out separately from that of the destroyed unit 4, which is expected to take many years longer to complete.
Source: World Nuclear News
IAEA Delivers Final Report on Decommissioning Efforts at Fukushima Daiichi
IAEA experts visiting TEPCO’s Fukushima Daiichi Nuclear Power Station on 27 November 2013 looked at the fuel assembly removal process in Reactor Unit 4. Last week, TEPCO began moving nuclear fuel assemblies from Reactor Unit 4 to the Common Spent Fuel Pool. (Photo: G. Webb/IAEA)
The International Atomic Energy Agency (IAEA) delivered a report on 12 February 2014 to the government of Japan describing the findings of a two-part review of the nation’s efforts to plan and implement the decommissioning of TEPCO’s Fukushima Daiichi Nuclear Power Station (NPS).
At Japan’s request, the IAEA organized two expert teams to provide an independent review of Japan’s Mid-and-Long-Term Roadmap towards the Decommissioning of TEPCO’s Fukushima Daiichi Nuclear Power Station Units 1-4. The first team visited Japan from 15 to 22 April 2013 and the second from 25 November to 4 December 2013.
“Japan has established a good foundation to improve its strategy and to allocate the necessary resources to conduct the safe decommissioning of Fukushima Daiichi,” said team leader Juan Carlos Lentijo, IAEA Director of Nuclear Fuel Cycle and Waste Technology.” The situation, however, remains very complex, and there will continue to be challenging issues that must be resolved to ensure the plant’s long-term stability.”
The expert teams examined a wide variety of issues relating to decommissioning the power plant, including Tokyo Electric Power Company’s (TEPCO’s) efforts to remove fuel assemblies from Reactor Unit 4’s Spent Fuel Pool and to manage the growing volume of contaminated water at the site.
The teams held extensive discussions with senior officials from the Ministry of Economy, Trade and Industry (METI) and TEPCO. The teams also visited the nuclear accident site twice to gain first-hand information on the conditions at the power plant and the progress made toward decommissioning the facility.
Trawsfynydd crosses halfway point
The decommissioning of Trawsfynydd Site, Wales’ first nuclear power station constructed during the 1960s, has crossed the halfway point.
Work to deliver the site into care and maintenance (C&M) by 2016 is more than 50 per cent complete. During its C&M phase, radiation levels will slowly decay naturally, allowing the two reactors and remaining building structures to be decommissioned safely and more efficiently from 2074 onwards.
Trawsfynydd has seen a huge increase in decommissioning activity since the plan to accelerate C&M was announced in 2010, including the removal of many plant and buildings, treatment of nuclear waste, reactor buildings maintenance and installing new infrastructure to accommodate the increased numbers of people working on the site.
Source: Nuclear Industry Association
Fukushima waste incinerator takes shape
Construction of an incinerator is underway at the Fukushima Daiichi plant to burn the low-level waste (LLW) being generated from the clean-up and decommissioning of the site.
The 3170-square-metre facility is expected to begin operating between September 2014 and March 2015. It will be used to reduce the volume of LLW – including such things as clothing, gloves and building materials – by burning it. The resulting radioactive ash will be stored in drums for later disposal.
The facility, known as the miscellaneous solid waste volume reduction treatment facility, is being constructed by Kobelco, part of Kobe Steel Group, under contract from Tokyo Electric Power Company (Tepco). Construction of the plant started in May and the reinforcing steel rebar has now been put in place in the building’s foundation. On 29 June, the first concrete was poured for its two-metre thick foundation.
The incinerator will be able to operate around the clock, burning some 14 tonnes of LLW per day. Three existing LLW incinerators on the site – with a combined capacity of handling over eight tonnes of waste per day – are not in operation as they are now being used to store and process radioactive water instead.
Source: World Nuclear News
Focus on Sellafield for NDA
Decommissioning work at Sellafield remains the number one priority for the UK’s Nuclear Decommissioning Authority (NDA) in its latest business plan. Its work continues with a range of completed projects and contract awards across the country.
The NDA’s business plan for 2013 to 2016 sets out the priorities for the organisation across all of its 19 sites, including Sellafield; the UK’s low-level waste repository (LLWR) in north-west England; Dounreay in northern Scotland; the UK’s Magnox power plants, including the still-operating Wylfa unit 1; and former fuel cycle and nuclear research facilities. NDA chief executive John Clarke said that Sellafield is the organisation’s number one priority, where the focus will remain on a program of major projects to decommission high-hazard legacy ponds and silos. Meanwhile, work continues towards the completion by the end of the decade of contracts at the site’s Magnox and Thorp reprocessing plants.
Elsewhere in the UK, key NDA activities over the next year include the continued defueling of the Oldbury and Sizewell A reactors, continued operation of Wylfa 1, and an accelerated decommissioning and demolition program at the Bradwell and Trawsfynydd sites, due to be placed in care and maintenance in 2015 and 2016 respectively. A new owner is also to be selected for the contract to operate the 12 sites in the NDA’s Magnox and Research Site Restoration Ltd fleets.
Sellafield plant decommissioning complete
One legacy plant can now be ticked off the NDA’s Sellafield decommissioning list: the Caesium Extraction Plant (CEP), built in the 1950s to produce radiation sources for medical uses, has now been decommissioned. The plant, which operated from 1950 to 1958, presented numerous decommissioning challenges. Not least amongst these was its position above tank cells used to store the highly active effluents which provided its operating feedstock, plus the presence of significant qualities of radioactive materials and high radiation levels. This meant that the project had to be completed remotely, using a specially built stand-alone decommissioning module.
Suitable for uprooting plants: The CEP project was the first at Sellafield to be completed entirely by remote methods using equipment as shown here
(Image: Sellafield Ltd)
The ten-year decommissioning project saw the retrieval of 16 tonnes of radioactive waste from a facility which “was never designed with decommissioning in mind,” Sellafield Ltd head of decommissioning Steve Slater explained. Lessons learned from each phase of the project were incorporated to develop tooling and techniques to manage the waste items encountered, and the project’s perfect safety record will provide a benchmark for future remote decommissioning at Sellafield.
Five more years for waste consortium
UK Nuclear Waste Management (UKNWM) has been awarded a further five year contract to manage LLW Repository Ltd (LLWR), the company that manages and operates the UK’s national low-level waste repository and implements the nation’s low-level waste strategy on behalf of the NDA.
The international consortium won the initial contract in 2008 in the first NDA competition to secure parent body organisations to manage site licence companies. During its first five-year term, the contract has realised savings of £30 million ($46 million) in savings, extended the life of the LLWR facility, reduced volumes of waste bound for the repository by a factor of three, and seen the opening a new vault at the repository, according to the NDA.
Hertel wins Calder Hall contract
Construction and maintenance services company Hertel has won a major contract for the deplanting of Calder Hall, the UK’s first commercial nuclear power station which closed in 2003 after 47 years of operation. The contract covers the removal of the top ducts, high- and low-pressure drums, external pipe works and all structural steelwork from the heat exchangers from the plant at the Sellafield site. Work is due to start in April 2013 and will take three and a half years. Hertel will build on its previous experiences with dismantling heat exchangers at the plant to fulfil the contract, which will complete the removal of all 16 of Calder Hall’s heat exchangers.
Source: World Nuclear News