Towards sustainable secure and safe energy future leveraging opportunities with thorium
This presentation is the property of its rightful owner.
Sponsored Links
1 / 24

Towards sustainable, secure and safe energy future: Leveraging opportunities with Thorium PowerPoint PPT Presentation


  • 62 Views
  • Uploaded on
  • Presentation posted in: General

Towards sustainable, secure and safe energy future: Leveraging opportunities with Thorium. Anil Kakodkar. Growing economic empowerment of a larger part of world population and little carbon space available necessitates a quick shift to non-fossil energy sources.

Download Presentation

Towards sustainable, secure and safe energy future: Leveraging opportunities with Thorium

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Towards sustainable secure and safe energy future leveraging opportunities with thorium

Towards sustainable, secure and safe energy future: Leveraging opportunities with Thorium

Anil Kakodkar


Towards sustainable secure and safe energy future leveraging opportunities with thorium

Growing economic empowerment of a larger part of world population and little carbon space available necessitates a quick shift to non-fossil energy sources.


Climate change stabilization scenarios

Climate Change Stabilization Scenarios

Source: IPCC (2007), Table 5.1, p. 67

We do not know how close we are to the tipping point. However we need to act now to secure survival of our future generations.

If total primary energy consumption doubles by 2050, 85% of energy must be supplied by clean technologies in order to attain a 70% GHG cut from 2000 levels.

Source: WNA Nuclear Century Outlook

Source IEO2013


What we should do

What we should do?

  • Business as usual approach is unlikely to work

  • Apart from electricity we need energy in fluid form derived through non-fossil means

  • This would need high temperature capability

  • Since time is running out we need to explore what can be done by reconfiguration of available technologies even as we develop new technologies


Towards sustainable secure and safe energy future leveraging opportunities with thorium

Transition to Fossil Carbon Free Energy Cycle

Carbon/

Hydrocarbons

  • ENERGY CARRIERS

  • (In storage or transportation)

  • Electricity

  • Fluid fuels

  • (hydro-carbons/ hydrogen)

Fossil

Energy

Resources

  • WASTE

  • CO2

  • H2O

  • Other oxides and products

Electricity

Electricity

Hydrogen

Sustainable development of energy sector

Sun

CH4

Fluid

Hydro carbons

Nuclear

Energy

Resources

CO2

Greater share for nuclear in electricity supplyreplace fossil hydro- carbon in a progressive manner recycle carbon- dioxidederive most of primary energy through solar & nuclear

Biomass

chemical

reactor

Other recycle modes

CO2

Nuclear Recycle

Sustainable Waste Management Strategies

Urgent need to reduce use of fossil carbon in a progressive manner


In spite of such strong motivation what has slowed the growth of nuclear power

In spite of such strong motivation, what has slowed the growth of nuclear power?

  • Irrational fear of radiation caused by LNT logic

  • Potential for large scale displacement of people following a

  • severe accident

  • Panic potential following a terrorist action

  • Unresolved spent fuel disposal & constraints on recycle

  • Regulatory delays


Evidence of threshold

Evidence of threshold

  • Colorado ,USA has a population over 5 millions residents. According to

    LNT model Colorado should have an

    excess of 200 cancer deaths per year

    but has a rate less than the national

    average.

    . Ramasar ,Iran, residents receive a

    yearly dose of between 100-260 mSv.

    This is several time higher than

    radiation level at Chernobyl and

    Fukushima exclusion zone.People

    living in Ramsar have no adverse

    health effect , but live longer and

    healthier lives.

    . We also know that China , Norway,

    Sweden, Brazil and India have similar

    areaswhere radiation level is many

    times higher than 2.4 mSv/yr world

    average.

Crosses show the mortality of Chernobyl firefighters (curve is for rats).The numbers show the number who died/total in each dose range.

In spite of evidence for no health consequences below a threshold, mindset driven by LNT logic has caused irrational fears in public mind with regard to potential accident impact in public domain. This has led us to a situation where significant off-site impact in a severe accident is no longer acceptable.


Can we eliminate serious impact in public domain with technology available as of now

Can we eliminate serious impact in public domain with technology available as of now?


Towards sustainable secure and safe energy future leveraging opportunities with thorium

Advanced Heavy Water Reactor (AHWR) is an innovative configuration that should nearly eliminate impact in public domain using available technologies.

Top Tie Plate

Displacer

Rod

Water Tube

Fuel Pin

Bottom Tie Plate

Major design objectives

  • Several passive features

    • grace period > 3 days

    • No radiological impact

    • in public domain

  • Passive shutdown system

  • to address insider threat

  • scenarios.

  • Design life of 100 years.

  • Easily replaceable coolant

  • channels.

  • Significant fraction of Energy

  • from Thorium

The design enables use of a range of fuel types including LEU, U-Pu , Th-Pu , LEU-Th and 233U-Th in full core

AHWR Fuel assembly


Towards sustainable secure and safe energy future leveraging opportunities with thorium

AHWR 300-LEU is a simple 300 MWe system fuelled with LEU-Thorium fuel, has advanced passive safety features, high degree of operator forgiving characteristics, no adverse impact in public domain, high proliferation resistance and inherent security strength.

Peak clad temperature hardly rises even in with extreme postulate of complete station blackout and simultaneous failure of both primary and secondary systems.

Reactor Block Components

AHWR300-LEU provides a robust design against external as well as internal threats, including insider malevolent acts.


Tho 2 has better physical chemical and nuclear properties to enable better safety

ThO2 has better physical, chemical and nuclear properties to enable better safety

> Higher thermal conductivity and lower co-efficient of thermal expansion compared to UO2. Melting point 3500o C as against 2800o C for UO2.

> Favourable reactivity coefficients

> Fission product release rate one order of magnitude lower than that of UO2.

> Relatively inert. Does not oxidise unlike UO2 which oxidizes easily to U3O8 and UO3. Does not react with water.

For a Typical PHWR

Ref. case

LEU

LEU

LEU+Th

Pu(RG)+D.U.

Pu(RG)+Th

U(WG)+Th

  • Lower fuel temperatures

  • Less fission gas release

  • Better dimensional stability

  • Stable reactor performance

  • Good stability under long-term storage

Pu(WG)+Th


Towards sustainable secure and safe energy future leveraging opportunities with thorium

PSA calculations for AHWR indicate practically zero probability of a serious impact in public domain

Plant familiarization & identification of design aspects important to severe accident

Level-3 : Atmospheric Dispersion With Consequence Analysis

Release from Containment

PSA level-1 : Identification of significant events with large contribution to CDF

Level-2 : Source Term (within

Containment) Evaluation through Analysis

Level-1, 2 & 3 PSA activity block diagram

10-10

10-11

10-12

10-13

10-14

1 mSv

0.1 Sv

1.0 Sv

10 Sv

SWS: Service Water System

APWS: Active Process Water System

ECCS HDRBRK: ECCS Header Break

LLOCA: Large Break LOCA

MSLBOB: Main Steam Line Break Outside Containment

SLOCA

15%

SWS

63%

Contribution to CDF

Iso-Dose for thyroid -200% RIH + wired shutdown system unavailable (Wind condition in January on western Indian side)

Variation of dose with frequency exceedence

(Acceptable thyroid dose for a child is 500 mSv)

12


Towards sustainable secure and safe energy future leveraging opportunities with thorium

How can we address issues related to long term waste (legacy as well as new arising), proliferation concerns and realisation of full potential of nuclear energy?


At high burn ups considered achievable today thorium requires lower fissile content

At high burn-ups considered achievable today, Thorium requires lower fissile content

Performance potential vs fissile topping in PHWR

Performance potential vs fissile topping in BWR

Performace potential vs fissile topping in PWR

Indicative results for a set of case studies with U235 as fissile material

  • Better fertile to fissile

  • conversion

  • Smaller reactivity swing

  • with burn up

  • Greater energy from in-situ

  • generated fissile material

  • Better Uranium utilisation


Towards sustainable secure and safe energy future leveraging opportunities with thorium

AHWR300-LEU

provides better

utilisation of

natural uranium,

as a result of

a significant

fraction of the

Energy being extracted from fission of 233U,

converted in-situ

from the thorium

fertile host.

LEU-Thorium fuel can lead to better/comparable utilisation of mined Uranium


Towards sustainable secure and safe energy future leveraging opportunities with thorium

  • There is already a

  • large (~200,000

  • tons) used Uranium

  • fuel inventory.

  • Another 400,000

  • tons are likely to be

  • generated between

  • now and the year

  • 2030 (as per WNA

  • estimate).

  • Permanent disposal

  • of used

  • Uranium fuel

  • remains an

  • unresolved issue

  • with unacceptable

  • security and safety

  • risks.

  • We need to adopt

  • ways to liquidate

  • the spent fuel

  • through recycle.

Disposal of used Uranium remains an unresolved issue

  • Thorium provides an

  • effective answer to safe recycle of spent nuclear fuel.

  • Much lower Plutonium production.

  • Plutonium in spent fuel contains lower fissile fraction, much higher 238Pu content which causes heat generation & Uranium in spent fuel contains significant 232U content which leads to hard gamma emitters.

  • The composition of the fresh as well as the spent fuel of AHWR300-LEU makes the fuel cycle inherently proliferation resistant.

  • Uranium in spent fuel contains about 8% fissile isotopes, and hence is suitable for further energy production through reuse in other reactors. Further, it is also possible to reuse the Plutonium from spent fuel in fast reactors.


Thorium an excellent host for disposal of excess plutonium

Options for plutonium disposition

Uranium-based fuel: Neutron absorption in 238U generates additional plutonium.

Inert matrix fuel (non-fertile metal alloys containing Pu): Degraded reactor kinetics - only a part of the core can be loaded with such a fuel, reducing the plutonium disposition rate.

Thorium: Enables more effective utilisation of Pu, added initially, while maintaining acceptable performance characteristics.

Thorium, an excellent host for disposal of excess plutonium

Plutonium destruction in thorium-plutonium fuel in PHWR


Adoption of thorium fuel cycle paves the way to elimination of long lived waste problem

Adoption of Thorium fuel cycle paves the way to elimination of long lived waste problem

  • While AHWR300- LEU enables comparable utilisation of Uranium in a safe manner, issues related to spent fuel disposal can be eventually addressed through recycle of fissile and fertile materials.

  • Production of MA – lowered with Thorium

  • MAs : fissionable in fast neutron spectrum.

  • Difficult power control system of critical reactor due to:

  • - Reduced delayed neutron fraction (factor called beff) giving lower safety margin to prompt criticality.

  • - Safety parameters: (1) Doppler coefficient, (2) reactivity temperature coefficient, and (3) void fraction- all would not be benign in TRU incinerating critical fast reactor.


Towards sustainable secure and safe energy future leveraging opportunities with thorium

We thus need accelerator driven sub-critical molten salt reactor systems with P&T working in tandem to be developed rather quickly. Growth of nuclear power capacity should however pick up immediately through innovative reconfiguration of existing technologies as time is running outThorium is a logical choice for fuel cycle in both present and future systems


Detectability of 233 u contaminated with 232 u for all the cases is unquestionable

Detectability of 233U (contaminated with 232U) for all the cases, is unquestionable

232U concentration in ppm

233U concentration (g/kg of HM)

232U concentration in ppm

Exposure time (hr) to acquire LD50 at 1 m for 8.4 kg 233U

233U

Exposure time for lethal dose

232U

232U

Burn up GWd/te

Burn up GWd/te

Case of Pu-RG+Thoria in AHWR

Lethal dose: LD 50/30( =5 Gy) for 8.4 kg Sphere of 233U one year after reprocessing, at 1 m distance


Towards sustainable secure and safe energy future leveraging opportunities with thorium

“IAEA is not concerned with the tenth or the thousandth nuclear device of a country. IAEA is only concerned with the first.

  • And that will certainly not be based on a thorium fuel cycle”

    • ---------Bruno

      -Bruno Pellaud, Former Deputy Director General,IAEA


Nuclear power with greater proliferation resistance

Present deployment

Of nuclear power

MOX

Thorium

Fast Reactor

Thermal reactors

Reprocess Spent Fuel

Enrichment Plant

Uranium

LEU

For growth in nuclear

generation beyond thermal reactor potential

Recycle

LEU Thorium fuel

Thorium

233U

Thorium

LEU-Thorium

Nuclear power with greater proliferation resistance

Safe &

Secure

Reactors

For ex. AHWR

Thorium

Reactors

For ex. Acc. Driven MSR

Recycle

Thorium


Towards sustainable secure and safe energy future leveraging opportunities with thorium

To Conclude:Thorium is a good host for efficient and safe utilisation of fissile materials. It can support greater geographical spread of nuclear energy with lower riskThorium can facilitate resolution of waste management issue and enable realisation of full potential of available Uranium.Fast breeder reactors would however be necessary for growth in nuclear power capacity well beyond thermal reactor potential Fast reactors as well as uranium fuel enrichment and recycle needs to be kept within a more responsible domain


Towards sustainable secure and safe energy future leveraging opportunities with thorium

Thank you


  • Login