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Comparison with Uranium?

To solve the problems of the current nuclear industry, companies are investing in 3rd generation and 4th generation technologies.

The 3rd generation is a PWR reactor with a higher level of security. One of the improvements is the prevention of the famous "chinese syndrom" in case the core of the reactor would smelt. 

The 4th generation has still been tested in France with sur-regenerators called Phenix and super-Phenix, designed to burn U-238. The coolant was molten Natrium which appeared to be very difficult to manage.

Research and development


Thorium can be used now, but at the same time research for its commercial use is still going on. Some very safe processes are being developped, like Molten Salt Reactors or Accelerator Driven Systems.

usable Th technology

Thorium is actually usable in many technologies.

- The reuse of current U-235 based reactors, by replacing the U-238 blanket by Th-232 blanket. This could be done in Belgium too as demonstrated by the nuclear study center of Mol (SCK-CEN).

- The Pebble Bed Reactors, where  fissile (U-233) and fertile products (Th-232) are encapsulated in pebbles of the size of a tennis ball.

- The Molten Salt Reactors, where Thorium is smelted in a liquid salt circulating in the reactor.

- The Accelerator Driven Systems, where the neutrons are produced by an accelerator and no U-233 (or other fissile products) blanket is necessary to initiate the fission reaction.

The 6 nuclear technologies listed below have been selected by the World Nuclear Association to develop safe “Generation IV Nuclear Reactors” (in red = EU projects). Some of them are already identified as able to burn Thorium. 

Type of reactor

Coolant

Projects?

Use of Thorium?

Gas-cooled fast reactors

helium

·      Allegro, 75 MWt demo GFR (EU-project run by CEA+Czech, Hungary, Slovakia and Poland)

·      Energy Multiplier Module (EM²), 500 MWt (General Atomics (GA))

?

Lead-cooled fast reactors

lead or Pb-Bi

·      SVBR-100 & BREST-300 (Russia)

·      ALFRED 300 MWt (EU-project  in Romania)

·      MYRRHA (EU-project in Belgium)

·      LFR, pilot plant reactor (Westinghouse by 2021)

YES

“can use depleted U or Th fuel matrices”

Molten salt fast reactors

Fluoride salts

·    TAP MSR (US private project by Transatomic Power Corporation)

YES

“will take in Th fuel cycle,
recycling of actinides,
closed Th/U fuel cycle with no U enrichment”

Molten salt reactor - Advanced High-temperature reactors

Fluoride salts

·     TMSR Research Centre, small solid- fuel prototype (SINAP, under China Academy of Sciences / operation in 2015)

?

Sodium-cooled fast reactors

sodium

·      BN-800 at Beloyarsk in Russia (operations started in 2014 but not grid- connected by mid-2015)

·      PFBR Kalpakkam of 500 MWe in India (late 2015)

·      Astrid sodium-cooled fast reactor SFR (EU-project in France)

?

Supercritical water-cooled reactors

water

·      ?

?

Very high temperature gas reactors

helium

·      prismatic blocks’ core : HTTR (Japan) &  GTMHR (General Atomics)

·      pebble bed’s core : HTR-PM, demo unit (China,  Shidaowan, under construction in 2015)

YES

has been used in German Th-Pebble bed reactor THTR300







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Henri Marenne - Consulting Engineer in Energy - 2018.