Monday, 6 October 2014

Best UK Electricity Policy - wait for molten salt reactors

No need to waste more money on wind, nor Hinkley C. Molten salt reactors will arrive soon. We can burn cheap fracked gas for electricity till then. The IMSR is

8 years to demonstration reactor
- David LeBlanc, 2013.

Q: What is the IMSR
A: The Integral Molten Salt Reactor is designed by David LeBlanc for Canadian nuclear startup Terrestrial Energy. It will be a Gen IV small modular reactor (SMR). A variation of the Denatured Molten Salt Reactor (DMSR), dating from 1980. By applying the KISS principle (Keep It Simple Stupid), the IMSR seeks to quickly pass regulatory approval. It uses:

  • LEU fuel (5% to 10% U-235 enrichment)
  • thermal neutrons, but with "substantial U-238 fast fission bonus"
  • Conversion ratio = 0.9
  • Has a much smaller waste footprint (even with no reprocessing)
  • Is orders of magnitude safer due to intrinsic, passive safety systems, that prevent any major accident
  • Operates at normal pressure, so preventing any possible air-borne contamination (as happened at Chernobyl and Fukushima). A total disaster scenario would only see local contamination.
  • Uses denatured fuel, so avoiding all proliferation risks
  • Uses only ⅙ the fuel of a LWR for same power output.
  • Will be able to generate electricity costing less than 1¢ / kWh (unit)
  • It is much cheaper to build than current reactors. The reactor vessel is much smaller and thinner. It does not need a huge, 8 foot thick, concrete dome around it. It will not need a spent fuel pool. Reactor operation is simpler and safer. Overnight costs should be < 13% of Hinkley C, with a construction time of less than 3 years per module.

Q: Is it real?
A: Yes. Terrestrial Energy have industrial partners and a business plan to guarantee finance from Canadian industrialists for industrial heat applications.

Q: How does the IMSR perform so well?
A: The key is minimal parasitic loss of neutrons

  • No internal reactor structure
  • No burnable poisons
  • Less neutron leakage
  • ½ of all fission products and all important Xe-135 leave due to Off Gas system
  • Comparing parasitic losses:
    3% - 5%

Q: Do we have enough uranium to fuel it?
A: Yes. There's thousands of years worth of easily accessible uranium available to fuel enough IMSRs to make all the planet's electricity. Although current 'known uranium reserves' are limited, we can find huge reserves of less concentrated ore. Even at a cost of $300/kg (many times the current world price), IMSR electricity will still be cheap

At the simplest, it can run without reprocessing for 30 years.

A better run mode will reprocess fuel after 10 years to remove fission products [using cheap pyro- / electro- / vacuum distillation processes which are ~ 1/7; the cost of PUREX]. Whether or not reprocessing will be cost effective is a separate issue. PUREX ~ $2000/kg of fuel produced. If simple reprocessing was 10% of that: $200/kg, it would need to compete with Uranium currently costing $78/kg. Reprocessing has other advantages - lowering the amount of waste, removing TRU from waste and putting it back into the reactor.

IMSR Cost estimates ($ / MWh):
------ IMSR ------
Old NuclearCoalNew LWRfirstmodule
Operating, Maintenance, Labor/Materials6.
Pensions, Insurance, Taxes1.
Regulatory Fees1.
Property Taxes2.
Decommissioning and DOE waste costs5.
Administrative / overheads1.

Table copied from Nextbigfuture, who think the IMSR can get down to 0.86 cents per Kwh.


1 comment:

  1. Hello William,

    I used to host the blog LFTRs to Power the Planet:

    I handed it over a couple of years ago and it's nearly died a death. I'm trying to get it back, as I think I could do a much better job for LFTRs, but with little success, I'm afraid.

    I now host the blogs PRISMs to Power the UK and Idiocy-Of-Renewables:

    I switched from LFTRs to PRISMs because I'm so ancient that I never expect to see an operational LFTR in my lifetime. But I may have a chance of seeing PRISM go into service up at Sellafield - if the NDA get their finger out.

    What's your take on PRISM - a Gen IV IFR? They do everything LFTRs do - burn 'nuclear waste - inherently safe - minuscule waste-stream, safe in 300 years - 'burn' U238 and Thorium.

    There's a meeting of the APPG on Energy from Thorium in the House of Lords on 20 October. If you're interested, you could get yourself an invite, if you email:

    Keep up the good work commenting on Guardian articles.