Select Committee on Environment, Food and Rural Affairs Minutes of Evidence

Further memorandum submitted by BNFL

  I hope that you and the sub-committee had an enjoyable and informative visit to Sellafield and further to our appearance to give evidence on 26 November and your letter of 27 November, I enclose notes on:

    —  The existing volumes of High and Intermediate Level Waste within BNFL attributable to Sellafield and our Magnox Reactor Sites. Included within this note are details of the existing stocks of spent fuel at Sellafield and the amounts of waste which will be generated when this fuel is reprocessed.

        You will be able to see from table 1 that at BNFL's reactor sites and at Sellafield we have about 50,000 m3 of untreated, not yet conditioned, ILW. This represents about a quarter of the 215,000 m3 which the 1998 national waste inventory identifies for disposal in the UK. In addition we had conditioned about 8,000 m3 of ILW in 1998, although this has now increased to about 10,000 m3. The remaining ILW is either "locked up" in the plant, equipment and structure of buildings, to be "released" as these are decommissioned, or has yet to be produced from our ongoing fuel reprocessing operations.

    —  The current level of orders for MOX fuel.

    —  Tritiated water discharges from Devonport and nuclear submarine decommissioning.

    —  The Nuclear Fuel cycle showing in very broad terms the management of spent fuel and how radioactive waste arises.

  Please let me know if you would like any further information to help with your deliberations.


December 2001


  1.  Table 1 summarises total BNFL waste volume information from the 1998 UK Radioactive waste Inventory. The table shows the existing stocks of unconditioned (ie untreated) waste, the volumes of waste which have been conditioned by vitrification, in the case of HLW, or conditioned by encapsulation in cement for ILW. Volumes of future wastes are also shown and when all reprocessing has been completed and all facilities decommissioned there will be 1,700 m3 of HLW and 152,000 m3 of ILW.

  2.  The wastes which have already been conditioned by vitrification or encapsulation are now stored in modern, purpose built, facilities which have design lives of 50 years. However it is expected that these facilities could safely store the waste for a longer period, if necessary, provided adequate refurbishment was carried out.

  3.  It can be seen that 1,300 m3 of HLW is stored in its unconditioned, liquid form awaiting vitrification and that about 50,000 m3 of ILW is stored in its raw form. Some of the raw waste stores for ILW date back to the 1950's and 1960's when safety and engineering standards were not as stringent as they are today. The retrieval and conditioning of this legacy waste at Sellafield and the associated reduction of hazard, is now a prime driver for BNFL.

  4.  When the existing reactors and facilities at Sellafield are decommissioned, some of the plant and equipment within the facilities will be ILW, as will some of the building structures. This ILW, which when conditioned will amount to 60,000 m3, already exists and as such could be considered to be a part of the existing waste stocks, increasing these from the 50,000 m3 already referred to, up to 110,000 m3.

  5.  Table 2 shows information on ILW in a similar format to that presented in table 1, but sub-divided between the power station sites and Sellafield.

  6.  Details on the existing quantities of spent fuel and the wastes which will result from reprocessing that fuel are given in table 3.

  7.  Because of the chemical reactivity of Magnox fuel, all existing and future arisings are planned to be reprocessed and this will generate HLW, ILW and LLW. The amounts of HLW and ILW which will be produced by the 1000 tU of spent Magnox fuel which is currently stored at Sellafield are shown in table 3. In addition to this 1,000 tU there is a further 10,500 tU which will eventually be sent to Sellafield, of which some 6,400 tU already exists today.

  8.  BNFL has contracts with UK and Overseas owners of oxide fuel to reprocess it through the Thorp plant. The waste arising under these contracts largely belongs to the customers and in the case of the overseas customers, all BNFL's new reprocessing contracts signed since 1976 have provided for the return of the waste.

Table 1

Total BNFL waste volumes, m3(1)(2)
Stocks at 1 April 1998
Not yet conditionedAlready conditionedTotalFuture arisings Total
(stocks and
ioning waste included in total
As stored/raw1,300200(3) 1,5002,7004,300
When conditioned 7001,000 1,700
As stored/raw50,0008,000(4) 58,00073,000131,000
When conditioned 56,00096,000 152,00060,000(5)
Total UK ILW,
BNFL's waste)


(1) Extracted from "The 1998 UK Radioactive Waste Inventory" DETR/RAS/99.009, UK Nirex Ltd N3/99/01.

(2) Volumes have been rounded and only wastes from committed Thorp business has been included.

(3) At 1 April 2000, this had increased to about 300 m3.

(4) At 1 April 2000, this had increased to about 10,000 m3.

(5) The majority of facilities which will need to be decommissioned, exist at the present time and hence the waste volume which will arise from decommissioning in the future could be considered to be an "existing" waste stock.

Table 2

BNFL ILW volumes, m3(1)(2)
Stocks at 1 April 1998
Not yet conditionedAlready conditionedTotalFuture arisings Total
(stocks and
ioning waste included in total
As stored/raw10,0000 10,00029,00040,000
When conditioned 12,00041,000 53,00040,000(4)
As stored/raw40,0008,000(3) 48,00044,00091,000
When conditioned 44,00055,000 99,00020,000(4)


(1) Extracted from "The 1998 UK Radioactive Waste Inventory" DETR/RAS/99.009, UK Nirex Ltd N3/99/01.

(2) Volumes have been rounded and only wastes from uncommitted Thorp business has been excluded.

(3) At 1 April 2000, this had increased to about 10,000 m3.

(4) The majority of facilities which will need to be decommissioned, exist at the present time and hence the waste volume which will arise from decommissioning in the future could be considered to be an "existing" waste stock.

Table 3

Fuel typeFuel currently in
store at Sellafield
  Waste to be generated by   reprocessing, m3(1)(2) HLWILW
Magnox1,00020 1,200
Oxide (AGR, PWR etc)4,300 3503,500

  (1) Packaged waste, using data on materials arising from reprocessing one tonne of spent fuel in The Radioactive Waste Management Advisory Committee's Advice to Ministers on the Radioactive Waste Implications of Reprocessing, November 2000. ie:
Fuel typeHWL
Magnox0.021.2 3
AGR0.080.8 3
LWR0.080.8 3

  (2) Waste volumes in this table are included in the values shown in tables 1 and 2—ie they do not represent additional volumes.


  1.  The business case for the Sellafield MOX plant was recently assessed in detail by international consulting firm Arthur D Little, at the request of the Department of Food, Rural Affairs and the Environment.

  2.  Their report, dated 15 June 2001, was released into the public domain on 27 July 2001. The report contained information on the contractual status of business, expressed as a percentage of the target volume. This showed:

    Contracts      11 per cent

    Heads of Agreement  14 per cent

    Letters of intent/support  74 per cent

  This shows evidence of customer support and commitment for 99 per cent of the target volume for the Sellafield MOX plant.

  3.  Since the publication of the Arthur D Little report in July, there has been no change to the status of contracts, heads of agreement or letters of intent/support.


1.   Liquid Discharges

  We understand that Devonport Management Limited (DML) have applied for a new liquid effluent discharge authorisation. One effect of this will be to allow the annual upper limit of discharges of tritiated water to increase from 120 to 700 GBq as part of changes to DML's suite of authorisations which the Environment Agency says will result in an overall reduction in their radiological impact to the local community.

  It would be impossible to develop a Best Practicable Environmental Option (BPEO) argument for transferring the DML liquid discharges containing tritium to Sellafield. The transport of the volume involved, some 1,000 m3 annually, transported by road or rail, would probably represent a much greater risk to members of the public (from conventional road/rail accidents) than the consequences of the sea discharge at Devonport. Moreover, there is no available treatment process at BNFL Sellafield and so the liquor would still end up being discharged to sea. Effectively this would move an extremely small risk from Devonport to Sellafield whilst probably introducing a larger risk as a result of the transportation.

2.   Treatment of Waste from Nuclear Submarines as they are Decommissioned

  On behalf of the Warships Support Agency and MoD, Lancaster University have conducted a Front End Public Consultation exercise on the future management of radioactive waste from decommissioning of nuclear submarines to ascertain the issues that the public and other stakeholders believe should be taken into account when deciding on the options and site(s) for the interim storage of wastes. The consultation ran from February to June 2001.

  The stated aim of the consultation was to:

    "define, develop and procure a safe and publicly acceptable method for interim storage of the radioactive material from decommissioned submarines".

  Information has been posted on the website under the project title of ISOLUS (Interim Storage and Laid-up Submarines).

  The Front End Consultation comprised discussion groups, stakeholder workshops, a citizens panel and a web site. Lancaster University published their final report and 16 detailed reports in September. A total of 65 recommendations were contained in the final report.

  BNFL is not in any special position to comment on what has been done to date in project ISOLUS but will be offering our capabilities and experience as the project is taken forward.


nuclear fuel cycle


  Wastes from the nuclear fuel cycle are categorised as high-, medium- or low-level waste by the amount of radiation that they emit. These wastes come from a number of sources and include:

    —  essentially non-radioactive waste resulting from mining

    —  low-level waste produced at all stages of the fuel-cycle

    —  intermediate-level waste produced during reactor operation and by reprocessing

    —  high-level waste, which is spent fuel and waste containing fission products from reprocessing.

  The enrichment process leads to the production of "depleted" uranium. This is uranium in which the concentration of U-235 is significantly less than the 0.7 per cent found in nature. Small quantities of this material, which is primarily U-238, are used in applications where high density material is required, including radiation shielding and some is used in the production of MOX. While U-238 is not fissionable it is a low specific activity radioactive material and some precautions must, therefore, be taken in its storage or disposal.


  With time, the concentration of fission fragments in a fuel bundle will increase to the point where it is no longer practical to continue to use the fuel. At this point the "spent fuel" is removed from the reactor. The amount of energy that is produced from a fuel bundle varies with the type of reactor and the policy of the reactor operator.

  Typically, more than 40 million kilowatt-hours of electricity are produced from one tonne of natural uranium. The production of this amount of electrical power from fossil fuels would require the burning of over 16,000 tonnes of black coal or 80,000 barrels of oil.


  When removed from a reactor, a fuel bundle will be emitting both radiation, primarily from the fission fragments, and heat. Spent fuel is unloaded into a storage facility immediately adjacent to the reactor to allow the radiation levels and the quantity of heat being released to decrease.

  These facilities are large pools of water; the water acts as both a shield against the radiation and an absorber of the heat released. Spent fuel is generally held in such pools for a minimum of about five months.

  Ultimately, spent fuel must either be reprocessed or sent for permanent disposal.


  Spent fuel is about 95 per cent U-238 but it also contains U-235 that has not fissioned, plutonium and fission products, which are highly radioactive. In a reprocessing facility the spent fuel is separated into its three components; uranium, plutonium and waste, containing fission products. Reprocessing facilitates recycling and produces a significantly reduced volume of waste.


  The uranium from reprocessing, which typically contains a slightly higher concentration of U-235 than occurs in nature, can be reused as fuel after conversion and enrichment, if necessary. The plutonium can be made into MOX fuel, in which uranium and plutonium oxides are combined.

  In reactors that use MOX fuel, plutonium substitutes for U-235 as the material that fissions and produces heat for steam production and neutrons to sustain a chain reaction.


  At the present time, there are no disposal facilities (as opposed to storage facilities) in operation in which spent fuel, not destined for reprocessing, and the waste from reprocessing can be placed. There is a reluctance to dispose of spent fuel because it represents a resource, which could be reprocessed at a later date to allow recycling of the uranium and plutonium.

  A number of countries are carrying out studies to determine the optimum approach to the disposal of spent fuel and waste from reprocessing. The most commonly favoured method for disposal being contemplated is placement into deep geological formations. This would involve cooling the spent fuel, probably in dry stores above ground, for several years. Then it would be conditioned, packed and buried in a deep repository.

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