Thorium as an energy source opportunities for Norway

1
Thorium as an energy source opportunities
for Norway

• Report by the Thorium committee
• Dieter Røhrich
• UiB and CERN (from 1.3.08)

2
Thorium as an energy source opportunities
for Norway

• The mandate
• The Committees work and the resulting Report
  shall establish a solid knowledge base concerning
  both opportunities and risks related to the use
  of thorium for long-term energy production. The
  work should be conducted as a study of the
  opportunities and possibilities (screening),
  based on a review of Norways thorium resources
  and the status of key technologies....

• Concluding remarks
• The current knowledge of thorium based energy
  generation and the geology is not solid enough to
  provide a final assesment regarding the potential
  value for Norway of a thorium based system for a
  long term energy production.
• The Committee recommends that the thorium option
  be kept open in so far it represents an
  interesting complement to the uranium option to
  strengthen the sustainability of nuclear energy

3
Primary energy consumption

• World energy flows at the end of the last century

150
53
37
26
8
5
22
nuclear
oil
coal
gas
hydro
other
electricity generation
12
Residential and commercial 38
100
Transportation 24
Industry 38
4
Global energy consumption
5
Energy situation in Europe

• Status 2004
• 152 nuclear reactors -gt 31 of electricity
  consumption
• Nordic countries
• Sweden 10 units
• Finland 4 units, one nuclear power plant under
  construction
• The EU Climate and Energy Package - Targets by
  2020
• Reduction of greenhouse gas emissions by 20
  compared to 1990 level
• Reduction of energy consumption by 20 compared
  to 1990 level
• Increase the share of renewable sources in the EU
  energy mix to 20
• Increase the share of biofuels of transport
  petrol and diesel to 10

6
Cumulative natural uranium demand and reserves

• Nuclear Energy Agencys Reference Scenario
• Continued nuclear growth
• Reported uranium reserves last until about 2040
• Reported reserves depend on demand might
  increase
• Breeder reactor technology would change this
  development

7
Energy situation in Norway

• 100 hydro power
• Production matches the consumption
• Large fluctuations in production due to weather
  variations
• Import/export via power cables to Sweden,
  Finland, Netherlands

8
Thorium as nuclear fuel
1 235U nucleus 200 MeV 1 g 235U 1 MW.day
9
Thorium as nuclear fuel

• Thorium has been used as nuclear fuel since the
  1960s
• Preparation of thorium fuel is more complex and
  expensive than that of uranium fuel
• Thorium as a nuclear fuel is technically well
  established and behaves remarkably well in
  various reactors
• Reprocessing thorium fuel is complicated and will
  require a substantial effort for the development
  of a commercial plant
• Waste management will in principal follow known
  procedures and methods
• Radiation protection requirements for the thorium
  cycle might be lower than those of the uranium
  cycle
• Technically, one of the best ways to dispose of a
  plutonium stock pile is to burn it in a
  thorium-plutonium MOX fuel

10
Nuclear reactors for thorium fuel

• U-233 has some very attractive properties as
  fissile material
• U-233 emits so many neutrons per fission that
  they can sustain a chain reaction AND breed new
  U-233 from Th-232

number of neutrons produced per neutron
captured
?
11
Nuclear reactors for thorium fuel

• Advantage
• Practically NO production of longlived
  transuranic elements -gt reduced radiotoxicity of
  waste
• Disadvantage
• Smaller percentage of delayed neutrons -gt more
  difficult to control in extreme situations
• Management of parasitic Pa-233 -gt difficult
  reactor operation (online re-fuelling, special
  seed-blanket geometry)

12
(Industrial) experience with thorium in nuclear
reactors
13
Shippingport light water reactor

• Light water breeding reactor
• Fuelled with U-233 and Th-232
• Produced 1.4 more fuel than it burned

Pennsylvania, USA
14
Thorium high temperature reactor

• Gas-cooled (He) graphite-moderated reactor
• Fuel 675,000 spherical fuel elements
• Fuel element 30,000 coated particles
• Fuel elements are continuously loaded during
  operation
• They are recycled several times (about 6) to
  gain the final burn-up

Development costs (1960-80) 1 billion Deutsche
Mark for the fuel cycle, 5 billion for the
reactor (in current money)
15
Thorium high temperature reactor

• Balance of fissile material during the passage
  through the reactor in the thorium/denatured
  uranium cycle (MEU cycle)

16
Status of thorium projects today

• Most projects using thorium were terminated by
  the end of the 1980s
• Main Reasons
• The thorium fuel cycle could not compete
  economically with the well-known uranium cycle
• Lack of political support for the development of
  nuclear technology after the Chernobyl accident
• Increased worldwide concern regarding the
  proliferation risk associated with reprocessing
  of spent fuel
• Except for India
• long term energy plan which includes a
  complicated scheme of plutonium and thorium fuel

17
Future nuclear energy systems using thorium

• Goal
• self-sustaining thorium fuel cycle (no U-235,
  U-238 or plutonium)
• Two potential reactor types (conceptual level)
• Molten salt reactor
• One of the reactor types of the roadmap of the
  Generation IV International Forum
• Not specially designed for thorium
• 20-30 years of RD
• Accelerator Driven System (ADS)
• Proton accelerator spallation target
  subcritical reactor core
• Very versatile and flexible concept
• Part of the EURATOM FP6 roadmap(MYRRHA project
  in Belgium)
• Considered at the moment for the transmutation
  of waste (and not for energy production)
• 20-30 years of RD

18
Molten salt reactor

• Nuclear fuel is dissolved in flouride salt
  coolant which circulates through graphite core
  channels
• Online reprocessing of the salt
• Open problems
• rapid reprocessing
• corrosion

19
ADS (1)

• Proton accelerator
• high-intensity proton beam (10 MW)
• LINAC (probably)
• Spallation target
• liquid metal
• Sub-critical reactor core
• lead-bismuth eutectic coolant
• cooling by natural convection
• Reprocessing plant

20
ADS (2)

• Advantages (compared to a critical reactor)
• Additional neutrons from the spallation source
• increased breeding of U-233
• transmutation of long-lived fission products and
  transuranics (TRUs)
• better control of reactor dynamics
• Disadvantages
• lack of operating experience due to the
  non-existence of a demonstrator or prototype
• combination of two complex machines
• lead at high temperature is highly corrosive
• fragile interface between the beam tube and the
  target
• exposed to an intense flux of both high energy
  protons and neutrons
• thermal stress due to beam trips

21
Non-proliferation

• The fissile weapons quality is evaluated in terms
  of
• The critical mass of an isotope (or different
  isotopic composition),
• the weapon yield degradation due to the
  pre-initiation caused by spontaneous fission
  neutrons and
• the weapon stability degradation caused by heat
  emission.
• U-233 is at least as efficient as U-235 as a
  weapon material, e.g. the critical mass of U-233
  is approximately 5 - 8 kg
• Reprocessing of thorium-based fuel yields almost
  pure U-233 and therefore weapon-grade material
• However, traces of U-232 are always present in
  fissile U-233 which create a radiation hazard
  sufficiently large to require remote handling
  within a short time after chemical separation.
• Due to the lack of experience with
  industrial-scale thorium fuel cycle facilities
  similar safeguard measures as for plutonium are
  mandatory.

22
Thorium market

• There is no market for thorium as of today
• By-product of rare earth element mining
• Total amount of thorium produced worldwide 37
  500 tonnes(US, Australia, China, India)

23
Thorium in Norway

• US Geological Survey claims that
• Norway has one of the major thorium reserves in
  the world.
• The Geological Survey of Norway
• Thorium has never been specifically explored for
• Fen Complex most promising
• Low concentration 0.1 0.4 wt
• Volume estimates are uncertain
• Grain size too small for the traditional
  flotation processes
• Norway has a potential resource
• More investigations necessary to define as a
  reserve

24
Conclusions and recommendations (1)

• The potential contribution of nuclear energy to a
  sustainable energy future should be recognized.
• Volume estimates of Norwegian thorium resources
  are uncertain the grain size is too small for
  traditional extraction processes.
• It is essential to assess whether thorium in
  Norwegian rocks can be defined as an economical
  asset for the benefit of future generations.
• The development of an ADS using thorium is not
  within the capability of a Norway working alone.
• Joining the European effort in that field should
  be considered.

25
Conclusions and recommendations (2)

• Norway should strengthen its international
  collaboration by joining the EURATOM fission
  programme and GIF programme on Generation IV
  reactors suitable for the use of thorium
• The proliferation resistance of uranium-233
  depends on the reactor and reprocessing
  technologies.
• Due to the lack of experience with
  industrial-scale thorium fuel cycle facilities,
  similar safeguard measures as for plutonium are
  considered mandatory until otherwise documented.

26
Conclusions and recommendations (3)

• Any new nuclear activity in Norway, e.g. thorium
  fuel cycles, would need strong international
  pooling of human resources, and in the case of
  thorium strong long-term commitment.
• In order to meet the challenge related to the new
  nuclear era in Europe, Norway should secure its
  competence within nuclear sciences and nuclear
  engineering fields.