All systems ready for Fukushima fuel removal
Engineers at Fukushima Daiichi have done final checks before they begin removing fuel from unit 4’s storage pond, the highest priority safety-related task in the site’s decommissioning.
Technicians within the new building cover. The empty reactor vessel is beneath the circular section, the rectangular part is the used fuel pool (Image: Tepco)
A fuel transport container will be placed in the pool using the main crane. Workers will then use the smaller refuelling crane to move fuel assemblies one by one from their vertical storage racks to the container. When this is full it will be sealed, lifted from the water by the main crane, placed on the service floor for decontamination and then taken through a special route to a vehicle that will move it across the site to be unloaded at the site’s shared storage facility. This process will be repeated until the pool is empty.
With a total of 1533 fuel assemblies in the pool (1331 used, 202 unused) this is expected to take until the end of 2014. Tepco will move the fuel during the day and clean dust and debris from the pool water during the night. Two containers will be used in relay.
The Nuclear Regulatory Authority granted its approval for the security and radiological protection aspects of the work yesterday, and Tepco engineers conducted final functional checks of the cranes using non-radioactive dummy fuel today. One more round of feedback from local people is required before the operations begin, perhaps as soon as next week.
Unit 4 was off line for maintenance at the time of the 2011 accident with its full core load of fuel, as well as used fuel from previous operation, stored in a fuel pool at the top of the reactor building. Although this meant there was no possibility of a reactor accident at unit 4, there was a risk of the pool overheating. The stability of the pool was then reduced by major structural damage to the building caused by the ignition of hydrogen that leaked through ventilation systems shared with unit 3.
The building has since been reinforced, and thousands of tonnes of debris and rubble have been removed from its roof. The new cover has been constructed with all the fuel handling equipment of a normal nuclear power plant and inspections of the pool have shown the fuel to be undamaged and not suffering from corrosion.
Source: World Nuclear News
Japanese nuclear area cleared of contaminated turf with British supplied machines
British company Campey Turfcare Systems has supplied machines to assist in the decontamination of grass and soil in and around 53 Japanese cities affected by the devastated Fukushima Daiichi Nuclear Power Station.
The Koro Field Top Maker (FTM) from global machinery distributor Campeys, based in Macclesfield, Cheshire, and has been approved by the Japanese Ministry of the Environment as the preferred product to remove contaminated turf from radioactive areas near the nuclear plant.
Read the full press release here http://www.sourcewire.com/news/79256/japanese-nuclear-disaster-area-cleared-of-contaminated-turf-with-british-supplied?
Japan nuclear companies apply to restart 10 reactors
Nuclear operators in Japan have applied to restart 10 reactors, potentially paving the way for a widespread return to nuclear power in coming years.
The four companies applied under new rules introduced following Japan’s Fukushima nuclear disaster in 2011.
Japan’s Nuclear Regulation Authority (NRA) says it will take at least six months to review each reactor.
All but two reactors have been offline since the earthquake and tsunami which crippled the Fukushima plant.
Hokkaido Electric, Kansai Electric, Shikoku Electric and Kyushu Electric submitted applications to restart the plants under the new regulations on Monday. They sent applications for a total of 10 reactors at five plants.
The new rules require nuclear operators to put in place better safeguards against disasters including tsunamis, earthquakes and terrorist attacks.
NRA chairman Shunichi Tanaka said that bringing safety standards to international norms would “take a long time”.
The NRA is responsible for determining whether the reactors meet the new safety standards.
The nuclear companies are then required to seek approval from national and regional politicians.
“It is a precondition that host communities agree on the re-firing,” he added.
Prime Minister Shinzo Abe wants Japan’s nuclear reactors to be restarted. The country relied heavily on nuclear power for its energy supply prior to the 2011 disaster.
However, many in Japan are opposed to restarting the reactors.
The earthquake and tsunami on 11 March 2011 crippled the Fukushima Daiichi nuclear power plant, causing meltdowns at three nuclear reactors.
Engineers have since stabilised the plant but years
Source: BBC News
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
UK swaps plutonium to balance MOX policies
A series of exchanges has seen the UK take control of three tonnes of plutonium it had been storing for foreign firms. The country’s goal is to use plutonium stocks as reactor fuel for power generation.
Having embarked on a national nuclear energy and research program in the 1950s, the UK has over time separated and recovered plutonium from its used reactor fuel. The largest and most recent plant, Thorp, also undertook reprocessing for utility customers in Europe and Japan. Stockpiles of the resulting UK and foreign plutonium are all stored at Sellafield.
Today the British government announced it has simplified arrangements for managing these stocks with a series of swaps. The UK now will take over 750 kg of plutonium belonging to German utilities, 1850 kg previously loaned from France, and 350 kg from Dutch utility EPZ. At the same time, 650 kg of plutonium stored at Sellafield was transferred from German to Japanese ownership. A similar deal with Germany last year saw the UK take ownership of four tonnes of plutonium. All these changes have been agreed with the Euratom Supply Agency.
Among the factors motivating the swaps were the cancellation of MOX fuel for the ruined Fukushima Daiichi 3 unit, owned by Tokyo Electric Power Company (Tepco), and that company’s needs for MOX for other units which could not be made at Sellafield after the underperforming MOX plant there was closed in August 2011. Sellafield’s European MOX customers will also have their MOX made in France instead, also contributing to today’s swaps.
The swaps will save on transport jobs and give the UK the confidence of having national control over more the the plutonium stored in its territory. About 24.9 tonnes of foreign owned plutonium remains at Sellafield.
With its net gain of 2950 kg, the UK now has a civil plutonium stockpile of over 121.1 tonnes. This represents a significant energy resource roughly equivalent to 900 million barrels of oil – or even more if recycled multiple times.
However, liberating this energy is a complex challenge. Britain’s “preferred option” is to mix it with uranium oxide as mixed-oxide fuel (MOX), which can be used in many power reactors around the world. This would mean building a new production facility, on which the government “cannot yet make a specific decision,” it said. New reactors planned for the UK could use the MOX fuel, but the government has no right to demand this of commercial operators, at the same time the global market is limited and future demand from previous major customer Japan is highly uncertain. A move to build a new MOX plant would also be controversial, given the decision in August 2011 to close an underperforming and loss-making plant at Sellafield.
Other options are under consideration. GE-Hitachi has put forward its small Prism reactor design, which could generate power using plutonium-based fuel and at the same time get it into a form suitable for final disposal. Candu Energy has proposed its large Candu 6 units, which could run on the fuel over a longer period, generating power. Both companies are in discussion with the Nuclear Decommissioning Authority, which manages Sellafield and all the UK’s legacy from its previous national program.
Source: World Nuclear News
Fukushima nuclear plant: Cooling system power restored
Power has been restored to part of the cooling system at Japan’s tsunami-hit Fukushima nuclear plant, after it failed for the second time in a month.
The breakdown was not thought to pose any immediate danger, operator Tokyo Electric Power (Tepco) said.
An alarm at reactor number three earlier revealed the system had stopped at one of the pools containing spent, but highly radioactive, fuel rods.
Last month a power cut shut cooling systems for four spent fuel ponds.
The ponds cool the fuel – which generates intense heat – and provide shielding from radiation. The spent fuel remains in the ponds for a year or more.
Friday’s breakdown at the Fukushima Daiichi nuclear plant lasted around three hours, Tepco said.
Officials discovered the system failure after an alarm sounded at reactor number three.
As of 14:00 local time (05:00 GMT) on Friday, the temperature of water inside the cooling pool at reactor 3 was 15.1C, well below the safety limit of 65C, Tepco said.
This indicated that the spent fuel remained stable and did not pose an immediate danger to the environment, news agency AFP quoted Tepco as saying.
The power cut last month shut down cooling systems for four spent fuel ponds at reactors 1, 3 and 4, although cooling for the reactors themselves was not affected.
The company said a rat had damaged the electrics, causing a short circuit in a switchboard and triggering the power cut.
On 11 March 2011, an earthquake and tsunami crippled the plant. Waves knocked out cooling systems for the reactors, leading to meltdowns at three of them.
Engineers have since stabilised the plant but years of work lie ahead to fully contain the disaster and tackle its effects.
Source: BBC News