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.
BNFL
December 2001
NOTE BY
BNFL ON FUEL
AND WASTE
QUANTITIES
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 MANAGED HIGH AND INTERMEDIATE
LEVEL WASTE VOLUMES
| Total BNFL waste volumes, m3(1)(2)
|
| Stocks at 1 April 1998 |
| Not yet conditioned | Already conditioned | Total | Future arisings
| Total
(stocks and
future)
|
Decommiss-
ioning waste included in total
| | | |
| | |
| HLW | | |
| | |
|
| As stored/raw | 1,300 | 200(3)
| 1,500 | 2,700 | 4,300
| — |
| When conditioned | — |
— | 700 | 1,000
| 1,700 | — |
| ILW | | |
| | |
|
| As stored/raw | 50,000 | 8,000(4)
| 58,000 | 73,000 | 131,000
| — |
| When conditioned | — |
— | 56,000 | 96,000
| 152,000 | 60,000(5) |
| | | Total UK ILW,
conditioned
(including
BNFL's waste)
| 215,000 | |
| | |
| | | |
Notes:
(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 MANAGED INTERMEDIATE LEVEL WASTE VOLUMES FOR POWER
STATIONS AND SELLAFIELD
| BNFL ILW volumes, m3(1)(2)
|
| Stocks at 1 April 1998 |
| Not yet conditioned | Already conditioned | Total | Future arisings
| Total
(stocks and
future) |
Decommiss-
ioning waste included in total
| | | |
| | |
| REACTORS | |
| | | |
|
| As stored/raw | 10,000 | 0
| 10,000 | 29,000 | 40,000
| — |
| When conditioned | — |
— | 12,000 | 41,000
| 53,000 | 40,000(4) |
| SELLAFIELD | |
| | | |
|
| As stored/raw | 40,000 | 8,000(3)
| 48,000 | 44,000 | 91,000
| — |
| When conditioned | — |
— | 44,000 | 55,000
| 99,000 | 20,000(4) |
| | |
| | | |
Notes:
(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 IN STORAGE AT SELLAFIELD (SEPTEMBER 2001) AND SUBSEQUENT
REPROCESSING WASTE VOLUMES
| Fuel type | Fuel currently in
store at Sellafield
| Waste to be generated by reprocessing, m3(1)(2) HLWILW
|
| Magnox | 1,000 | 20
| 1,200 |
| Oxide (AGR, PWR etc) | 4,300
| 350 | 3,500 |
| | |
|
(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 type | HWL
(m3)
| ILW
(m3) | LLW
(m3)
|
| Magnox | 0.02 | 1.2
| 3 |
| AGR | 0.08 | 0.8
| 3 |
| LWR | 0.08 | 0.8
| 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.
NOTE BY
BNFL ON THE
CURRENT LEVEL
OF ORDERS
FOR MOX FUEL
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:
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.
NOTE BY
BNFL ON LIQUID
DISCHARGES FROM
DEVONPORT DOCKYARDS
AND TREATMENT
OF WASTE
FROM NUCLEAR
SUBMARINE DECOMMISSIONING
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 www.nucsubs.org.uk
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.
NOTES BY
BNFL ON THE
NUCLEAR FUEL
CYCLE
NUCLEAR WASTE
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.
SPENT FUEL/USED
NUCLEAR FUEL
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.
SPENT FUEL
STORAGE
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.
REPROCESSING
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.
URANIUM AND
PLUTONIUM RECYCLYING
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.
SPENT FUEL
DISPOSAL
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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