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(Updated January 2010)
Nuclear power provides about one third of Japan's electricity, and with the enhanced efficiency brought about by reprocessing used fuel to recycle the uranium and plutonium, it represents a major part of Japan's endeavours to achieve maximum self sufficiency in energy. Japan plans to have one third of its 53 reactors using some mixed uranium-plutonium oxide (MOX) fuel by 2010.
Reprocessing separates the waste, particularly the high-level waste containing nearly all of the radioactivity in spent fuel, from the uranium and plutonium which are recycled as fresh fuel. Separated high-level wastes - about 3% of the used fuel - remain.
A total of ten Japanese electric utilities had contracts with the French company Cogema (now Areva NC) to reprocess their used fuel. These Reprocessing Service Agreements date from 1977-78. Other contracts were with British Nuclear Fuels Limited (BNFL) in UK and are now held by the government's Nuclear Decommissioning Authority. About 40% of the used fuel involved was reprocessed by Cogema/Areva and the rest by BNFL.
From 1969-1990, some 2940 tonnes of used fuel in total was shipped (in over 160 shipments) by these utilities to France for reprocessing. Shipments of about 4100 tonnes were to the UK, and by mid 2007 more than 2600 tonnes of oxide fuel had been reprocessed there, plus a small amount of Japanese Magnox used fuel.
Reprocessing of Japanese used fuel in France finished in 2004 and all the high-level waste from reprocessing the used fuel in France has now been shipped back to Rokkasho in Japan for long-term (30-50 year) storage prior to ultimate disposal. Waste shipments from the UK should be completed by 2016.
Japan has a small (210 tonnes/yr) reprocessing plant already in operation at Tokai, associated with the Monju fast neutron reactor. A much larger (800 t/yr) reprocessing plant has been built at Rokkasho has been undergoing commissioning activities since March 2006. A 130 t/yr MOX Fuel Fabrication Plant at Rokkasho is under construction and due to enter operation in 2012.
Return of high-level wastes
In February 1995 the first of 12 shipments of vitrified high-level waste (HLW) departed from France for Japan. The last was in 2007. This waste belonged to the ten Japanese power utilities who are responsible for its safe storage and eventual disposal.
The 12 waste shipments over 12 years total 1310 canisters containing almost 700 tonnes of vitrified high-level wastes. These are packed in heavy steel shipping casks (see section on Marine transport below).
Shipment of the vitrified high-level wastes from UK to Japan commence early in 2010 and require about 11 shipments over 8-10 years to move about 1850 canisters. Under the Vitrified Residue Returns (VRR) program, some of this HLW will be substituting for a larger volume of intermediate-level wastes, on the basis that a radiologically-equivalent amount of HLW can be substituted in order to minimise the volume shipped. Both UK and Japan have legislation allowing this. The shipments are a continuation of the established waste return program from France.
Return of plutonium and MOX
So far one shipment of separated reactor-grade plutonium recovered from used fuel reprocessing has been returned to Japan, in 1993. This was reactor-grade material, with about 30% Pu-240 in it and therefore useable only as a reactor fuel. It is not suitable for nuclear weapons.
Further plutonium is being returned as mixed oxide (MOX) fuel, in which the plutonium is mixed with depleted uranium and fabricated into fresh fuel elements ready for use in a power station reactor (see information page on Mixed Oxide (MOX) Fuel). Shipments of MOX fuel assemblies were sent in mid 1999, early 2001 and early 2009. The 1999 shipment was returned to the UK due to doubts about quality control.
Vitrification of separated waste
To enable safe storage and transport, the separated high-level waste arising from reprocessing is immobilised in a process known as vitrification. This involves mixing the waste with molten borosilicate glass and poured into 1.3 metre high stainless steel canisters. The waste becomes locked into the matrix of the glass as it cools, making it stable and resistant to leaching. Lids are then welded on to the canisters to seal them.
Each canister contains 150 litres of glass weighing 400 kilograms. Some 14% of the content is high-level waste derived from the reprocessing of about two tonnes of used fuel. After storage for several years, the thermal output of each canister as shipped is less than 1.5 kilowatts.
Marine transport
The 500 kg stainless steel canisters containing high-level waste are transported in specially-engineered, heavily shielded steel and resin containers called casks or flasks. Each cask holds up to 28 canisters of vitrified waste and weighs about 100 tonnes. Those used for the high-level waste are very similar to those for transporting the spent fuel from Japan to Europe in the first place, and the MOX fuel on the return voyage.
The ships involved are 104-metre, 5100 tonne, specially designed double-hulled vessels used only for the transport of nuclear material. The ships belonging to a British-based company Pacific Nuclear Transport Ltd (PNTL), have been approved for the transport of vitrified residues, and conform to all relevant international safety standards, notably one known as INF-3 (Irradiated Nuclear Fuel class 3) set by the International Maritime Organization. This allows them to carry highly radioactive materials such as high-level wastes, used nuclear fuel, MOX fuel, and plutonium.
They have completed more than 170 shipments and travelled over 8 million kilometres in the 30 years to 2007 without any incident involving a radioactive release. PNTL is now owned by International Nuclear Services Ltd (INS, 62.5%), Japanese utilities (25%) and Areva (12.5%). It is currently renewing its fleet. INS is 51% owned by Sellafield Ltd and 49% by the UK's Nuclear Decommissioning Authority, and managed by Sellafield Ltd.
Further information
General sources
MOX Fuel Transport from Europe to Japan information file (2009 edition), Pacific Nuclear Transport Limited (www.pntl.co.uk)MOX Fuel Shipments from Europe to Japan fact sheet, Pacific Nuclear Transport Limited (www.pntl.co.uk), produced for the third shipment of MOX fuel from Europe to Japan (March 2009)Shipments of Nuclear Materials Between Europe and Japan, Media Brief, BNFL (4 December 1996). This source is no longer available but the information applying to MOX shipments is reproduced as an appendix to this page.Sea Shipments of MOX Fuel to Japan, Media Brief prepared by BNFL, Cogema and Japan's Overseas Reprocessing Committee (January 1999).
Related information pages
Processing of Used Nuclear FuelPlutoniumMixed Oxide (MOX) FuelWaste Management in the Nuclear Fuel CycleNuclear Power in JapanTransport of Radioactive Materials