Generation IV reactor R&D

Nuclear Monitor Issue: 

In January, the Generation IV International Forum (GIF) − comprising 12 countries plus Euratom − released its 'Technology Roadmap Update for Generation IV Nuclear Energy Systems'. It updates the GIF 2002 Technology Roadmap.1

The GIF has focused its efforts on six reactor concepts, and measures progress according to three (pre-commercialisation) phases:

* the viability phase, when basic concepts are tested under relevant conditions and all potential technical show-stoppers are identified and resolved;

* the performance phase, when engineering-scale processes, phenomena and materials capabilities are verified and optimised under prototypical conditions; and

* the demonstration phase, when detailed design is completed and licensing, construction and operation of the system are carried out, with the aim of bringing it to the commercial deployment stage.

The projections made in the 2002 Technology Roadmap have been revised as follows:

* Gas-cooled fast reactor: end of viability phase pushed back from 2012 to 2022; end of performance phase pushed back from 2020 to 2030

* Molten salt reactor: end of viability phase pushed back from 2013 to 2025; end of performance phase pushed back from 2020 to 2030

* Sodium-cooled fast reactor: end of viability phase pushed back from 2006 to 2012; end of performance phase pushed back from 2015 to 2022

* Supercritical-water-cooled reactor: end of viability phase pushed back from 2014 to 2015; end of performance phase pushed back from 2020 to 2025

* Very-high-temperature reactor: end of viability phase remains at 2010; end of performance phase pushed back from 2015 to 2025

* Lead-cooled fast reactor: end of viability phase brought forward from 2014 to 2013; end of performance phase pushed back from 2020 to 2021.

Averaging across the six reactor concepts: the end of the viability phase has been pushed back by an average of 4.7 years, and the end of the performance phase has been pushed back by an average of 7.2 years. That's a lot of slippage in the 11 years since the 2002 Technology Roadmap. All the more so since the latest projections may prove to be as optimistic as those in the 2002 report.

The GIF website states: "It will take at least two or three decades before the deployment of commercial Gen IV systems. In the meantime, a number of prototypes will need to be built and operated. The Gen IV concepts currently under investigation are not all on the same timeline and some might not even reach the stage of commercial exploitation."2 The World Nuclear Association is also downbeat, noting that "progress is seen as slow, and several potential designs have been undergoing evaluation on paper for many years."3

Metal-fuelled, sodium-cooled reactors

One of the Generation IV concepts is a metal-fuelled, sodium-cooled design called the 'Integral Fast Reactor' (IFR) or 'Power Reactor Innovative Small Module' (PRISM). These reactors might (or might not) operate in conjunction with pyroprocessing − recycling of nuclear fuel without the same proliferation risks as conventional reprocessing (i.e. without the separation of plutonium). IFR/PRISM reactors might (or might not) consume more high-level waste and weapons-useable material than they produce. Better still, they could be "up and running in 5 years – the PRISM is fully proven in engineering terms and basically ready to go" according to Mark Lynas.4 And it only gets better: these reactors will be dirt cheap. IFR cheerleader Steve Kirsch says the first 1 GWe IFR will probably cost around US$1−2 billion.5

As discussed in Nuclear Monitor #777, those claims need to be treated with scepticism.6 The UK Nuclear Decommissioning Authority (NDA) is considering the use of PRISM technology to manage the UK's stockpile of separated plutonium. But the NDA notes that the facilities required by the PRISM approach have not been industrially demonstrated. Internal 2011 emails, released under Freedom of Information laws, revealed that the NDA said it had carried out a "high-level assessment" of PRISM and "the technology maturity for the fuel, reactor and recycling plant are considered to all be low". Disposal of the waste produced by PRISMs is another unresolved issue, which could be further complicated if it is deemed necessary to remove sodium from spent fuel to facilitate safe, long-term disposal. As for the economics, General Electric Hitachi refuses to release estimates of PRISM capital and operating costs, saying they are "commercially sensitive".

The Plutonium Disposition Working Group of the US Department of Energy (DoE) released a report in April which considers the use of Advanced Disposition Reactors (ADR) to manage US plutonium stockpiles (mostly surplus weapons plutonium).7 The ADR concept it similar to General Electric Hitachi's PRISM according to the DoE.

The DoE's cost estimates for ADRs are as follows:

* 'capital project point estimate': US$9.42 billion

* operating cost estimate US$33.41 billion

* other program costs: US$7.62 billion

Which gives a total of US$50.45 billion (€36.8b), or "more than $58 billion life cycle cost when sunk costs cost are included." That is twice as much as the next most expensive option for plutonium management:

* immobilisation (ceramic or glass) with high-level waste: US$28.65 billion

* irradiation of MOX in light-water reactors: US$25.12 billion

* downblending and disposal: US$8.78 billion

* deep borehole disposal: no estimate provided

Claims that IFR/PRISM technology could be operational in five years are as laughable as the cost estimates provided by IFR/PRISM cheerleaders. The DoE report estimates that it would take 18 years to construct an ADR and associated facilities, with plutonium disposition beginning in 2033 and ending in 2075. Moreover, the DoE report states: "Final design of a commercial fast reactor would require significant engineering and licensing and as such carries uncertainties in being able to complete within the assumed duration."

On the technical challenges, the DoE report states: "Irradiation of plutonium fuel in fast reactors ... faces two major technical challenges: the first involves the design, construction, start-up, and licensing of a multi-billion dollar prototype modular, pool-type advanced fast-spectrum burner reactor; and the second involves the design and construction of the metal fuel fabrication in an existing facility. As with any initial design and construction of a first-of-a-kind prototype, significant challenges are endemic to the endeavor, however DoE has thirty years of experience with metal fuel fabrication and irradiation. The metal fuel fabrication facility challenges include: scale-up of the metal fuel fabrication process that has been operated only at a pilot scale, and performing modifications to an existing, aging, secure facility ... Potential new problems also may arise during the engineering and procurement of the fuel fabrication process to meet NRC's stringent Quality Assurance requirements for Nuclear Power Plants and Fuel Reprocessing Plants."

In short, the ADR option is associated with "significant technical risk", and metal fuel fabrication faces "significant technical challenges" and has only been operated at the pilot scale.









(Written by Nuclear Monitor editor Jim Green.)

From WISE/NIRS Nuclear Monitor #786, 16 May 2014

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