THE WORLD has its fair share of prospective ‘revolutionary ideas’, objectives that have failed to pan out. Not for lack of trying, nor because a notion isn’t any good on paper but rather the expression of a thought may not be based upon sound physics, or could be missing a vital technological breakthrough or component. In the case of Theranos, the idea of a portable blood analysis machine was surely innovative, but the underlying technology did not exist and the project failed to deliver. The result is a fraud case involving over-sell — under-performance, gross deception and astonishingly optimistic claims by one Elizabeth Holmes.

Similarly in 2007 the Department of Environmental Affairs held a parliamentary inquiry into the nuclear industry, in particular the much vaunted Pebble-Bed Modular Reactor (PBMR) programme whose technology was essentially borrowed from Germany. As it turned out the programme was fundamentally flawed, and was deemed unsafe by the Germany government following a pebble bed reactor accident at Hamm-Uentrop.(1)

At this stage some R10bn had already been spent without so much as a working reactor. Submissions by civil society organisations Koeberg Alert and Earthlife Africa, provided engineering analysis of why Germany had dropped the thorium-uranium programme, in part due to the ‘tendency of the pebble fuel to disintegrate’. Other serious issues included problems of safety, lack of containment, waste fission products and a host of other technical issues.

This didn’t dissuade South Africa’s nuclear industry. Though government input into the programme seemingly ended with Minister Barbara Hogan cancelling further funds, the PBMR took on a new life under Kelvin Kemm, who began touting a gas-cooled version called High Temperature Modular Reactor (HTMR) produced by his own company Nuclear Africa, along with a supposedly ‘new fuel’.

Billions of rands of governmental spend was thus, for all intents and purposes, simply transferred to Nuclear Africa, under the auspice of Kemm who was then chair of NECSA in order to further a complex prestige project, one which readily leads to economic dependency (see below).

Steenkampskraal Thorium Limited (STL) is a subsidiary company ‘in the business of developing and commercialising thorium as a clean safe energy source for the future.” The STL company site however professes “The primary goal of the HTR fuel development programme at STL is to produce fuel spheres containing uranium for irradiation testing in the short term, thorium/uranium in the medium term as well as thorium and plutonium in the long-term.”

Enter the X Factor, Yet Another Fuel

Meanwhile Eben Mulder and Martin van Staden announced their company X-energy was using a new modular reactor design alongside a brand new fuel. “X-energy has developed the compact Xe-100 reactor, which delivers 80MW of electricity and is about the size of an elevator shaft in a four-storey building,”. They further claim, “the US military has also signed a contract with the company in March to deliver its Xe-Mobile reactors”.

While Kemm’s project certainly has some merit in its purported use of presumably thorium instead of uranium, but certainly fails when it comes to the economics of producing Thorium Dioxide (see below) the X-energy project insists it has developed an advanced new nuclear fuel known as “Triso-X”.

Triso-X appears to be nothing more than a complex “tri-structural isotropic (TRISO) particle fuel” already developed within the nuclear industry. The company thus also claims somewhat disingenuously: “We manufacture our own proprietary version (TRISO-X) to ensure supply and quality control.”

If the claims are to be believed, TRISO fuel may significantly alter the burnup rate of fission products and change the melting of fuel within reactors. It is claimed to “double the previous mark set by the Germans in the 1980s” and thus is ‘three times the burnup that current light-water fuels can achieve—demonstrating its long-life capability.”

According to pundits “TRISO particles cannot melt in a reactor and can withstand extreme temperatures that are well beyond the threshold of current nuclear fuels.”

A 2020 Nuclear Industry Journal article on ‘Uranium nitride tristructural-isotropic fuel particle’, demonstrates “testing of a novel coated fuel particle, uranium nitride tristructural-isotropic fuel” and claims “this fuel particle offers significantly higher uranium density over historic manifestations of coated fuel particles and may be more optimal for a range of advanced reactor applications”

There is however no consensus in the industry on the resulting fission products produced by the TRISO process impacting upon health and safety, nor the longevity of the fuel. One can only suggest that many of the objections to the latest Thorium-Uranium project, also apply. In fact many of the claims made by X-energy, beg the question, why Thorium?

Competing fuels, same economic model

Unlike TRISO, Kemm’s HTMR project is presumably a non-fissile reactor (the reactor cannot fission by itself), which is a major win for safety and reduces some waste concerns. However it still shows capability of proliferation, produces waste fission products requiring storage and has a massive price tag which runs into billions.

While thorium reactors produce less waste and cannot produce plutonium as such, they still produce U233, in other words, conventional nuclear fuel, that can still be used to re-enrich and produce plutonium.

Many of the waste products produced by HTMR may have a considerable lower half-life than conventional reactors, but nevertheless require storage in the region of 500 years. Protactinium also produced by Thorium decay has a half-life of 32,700 years, producing no advantage over Uranium.

One of the biggest challenges in developing a thorium reactor is still finding a way to ‘fabricate the fuel economically’. Making thorium dioxide, as an article in Forbes points out is expensive, “in part because its melting point is the highest of all oxides, at 3,300° C.” So the “options for generating the barrage of neutrons needed to kick-start the reaction regularly come down to uranium or plutonium”.

Production of UN TRISO fuel particles on the other hand follows a process almost identical to what has been demonstrated on an industrial scale for uranium oxide-carbide (UCO) TRISO.

The oxidation of uranium carbide is a complex process ‘dependent on temperature, the O₂ partial pressure, the separation of the reaction products, and the process state’. Its relative complexity results in what economists refer to as a “Gillette Razer-blade model”, one which easily leads to dependency.

One must therefore once again register objections to PBMR/HTMR on behalf of the communities affected by the dumping of nuclear waste products and the ludicrous cost to the exchequer. Renewables continue to outperform both fossil fuel and nuclear by yards.

SEE: What’s Wrong With the Modular Pebble Bed Reactor?

SEE: Burning Platinum no Solution to Power Crisis

Tag: HTMR