International Forum Generation IV — Wikipedia

The forum international Generation IV (English : Generation IV International Forum , or GIF ) is an initiative of the Energy Department of the United States intended to establish international cooperation within the framework of the development of so-called fourth generation nuclear systems.

The reactors currently in operation are considered to be generation II or III (EPR, AP1000). The first generation of reactors corresponds to experimental and industrial reactors built before 1970.

Nuclear reactors of generation IV Most of which are still in the state of concepts in the 2000s and 2010s, which is involved in the research coordinated within the framework of the International Forum Generation IV. In 2006 the commissioning of a commercial reactor based on one of these concepts was not envisaged before 2030, the date which could be postponed.

The objectives given to the reactors of 4 ^{It is} generation are ^{[ first ]} :

The concept of system appears: each reactor must be designed and associated with its own fuel cycle (from the manufacture of fuel to waste management) ^{[Ref. necessary]} .

The International Forum Generation IV must compare different possible nuclear systems in terms of the criteria set above, taking into account all the peculiarities of the different concepts, beyond the technical and economic models used to validate generation II reactors and III (cf. Means section to be implemented).

The original reactor concept list was, in a first phase, reduced to the most promising concepts according to the analysis carried out within the framework of the GIF. Six concepts were selected in fine For the research and development phase:

Depending on the concepts, specific applications can be envisaged beyond the production of electrical energy: hydrogen production, combustion of actinids, transmutation, etc. The nuclear reactor controlled by accelerator (ADS) has not been retained from the concepts, its commissioning cannot be considered by 2030.

Very high temperature reactor [ modifier | Modifier and code ]

The very high temperature reactor ( very high temperature reactor , VHTR) consists of a moderate heart with graphite. A heat transfer gas (helium) circulates there and causes a turbine with a direct cycle for electricity production. Several fissile fuels are possible (uranium, plutonium with possibly minor actinids), with a prismatic or bed of balls ( pebble-bed ). The temperature at the heart of the concept is approximately 1 000 °C .

There may also be a turbine but an interchange recovering calories at very high temperature (THT) supplying a thermo-chemical process (iodine-soufre type) for the production of H ₂ .

Cycle models with multi-recycling have been studied, but the possibility of reaching high combustion rates leads to favoring a direct storage cycle of irradiated fuel. In certain variants of the concept, the expected performance of confinement of the Triso type fuel would eliminate the reactor’s concrete speaker, which would be economically favorable.

Supercritical water reactor (RESC) [ modifier | Modifier and code ]

The concept of supercritical water reactor is an attempt to take up the best characteristics of pressurized water reactors (REP) and boiling water reactors (REB) from the early 2000s. It is a light water reactor including the Caloporter/ Moderator is supercritical water at a temperature and operating pressure greater than those of the reactors deployed in 2006. This concept therefore takes up the direct cycle of the REB and the single fluid phase of the REP.

It is also inspired by supercritical fossil fuel boilers, standing out for its improved thermodynamic efficiency (45% compared to 33% of PIS currently deployed). This concept is widely studied, beyond countries participating in the International Forum Generation 4.

It could allow moderate relief, thus offering access to energy reserves approximately a hundred times larger than in current reactors.

Fonded salt reactor (RSF) [ modifier | Modifier and code ]

The melted salt nuclear reactor uses melted salt as a heat transfer. Many variants have been studied and some prototypes built. Most of the concepts currently studied are based on a dissolved fuel within a fluorinated salt circulating in a graphite heart (which moderates neutrons and ensures criticality). Other concepts are based on a fuel dispersed in graphite, salt acting as a moderator. Innovative variants associate the reactor an online reprocessing plant to continuously extract fission products.

Rapid gas capacity reactor (RNR-GAZ) [ modifier | Modifier and code ]

The concepts of a quick reactor with gas caps are based on different fuel configurations (pencils, plates, prismatic), different physico-chemical forms of the fuel (especially ceramic-based) and a helium capper. The temperature at the heart is approximately 850 °C , electrical production is carried out by a gas turbine according to a direct cycle Brayton which ensures good thermal efficiency.

Quick Caloporteur Plomb (RNR-PB) reactor [ modifier | Modifier and code ]

The concept of a fast-capster-leafy reactor has experienced a strong development in the USSR, in particular through the Brest-300 project in Seversk. The calecorteur is metal lead or a lead-bismuth eutectic, transparent with fast neutrons. The fuel is metallic or nitrous and can contain transuranians. The circulation of the heat transfer in the heart is done by natural convection. The output temperature is of the order of 550 °C , some variants reaching 800 °C .

Sodium Caloporteur (RNR-NA) [ modifier | Modifier and code ]

The concept of a fast neutron reactor and sodium capster experienced a strong development and benefited from a notable feedback, before the oil counter-shock slows R&D in nuclear energy. In its reference version, it is based on an oxide type fuel based on uranium and plutonium (Mox), possibly added to minor actinids, the heat transfer fluid of primary and secondary circuits being sodium. During dismantling operations, the sodium emptying stage is particularly delicate for this type of reactor ^{[ 3 ] , [ 4 ]} .

About fifteen reactors of this type have been built in the world (including in France the Rapsody prototype, and the two phenix and superphenix generators). At the end of 2018 only the BN-600 and BN-800 Russians and the Chinese CEFR remain operational ^{[ 5 ] , [ 6 ]} . New reactors are under construction, especially in India (prototype Fast Breeder Reactor (in) ) and in China (CFR-600 reactor, scheduled for 2023) ^{[ 7 ]} . France has worked on the Astrid project ^{[ 8 ]} until 2019.

Technical assessment [ modifier | Modifier and code ]

The design of a nuclear sector depends on three main parameters:

Economic assessment [ modifier | Modifier and code ]

The innovative nuclear sectors considered in generation IV require new tools for their economic evaluation, since their characteristics differ significantly from those of nuclear installations of generations II and III. The current economic models have not been designed to compare technologies or alternative nuclear sectors, but rather to compare nuclear energy with fossil alternatives. Projections based on an estimate of the price of natural resources (uranium) have shown their limits ^{[Which ones?]} , in the case of fast neutron reactors.

Safety [ modifier | Modifier and code ]

The state of maturity of the six concepts of fourth generation reactors is strongly heterogeneous and they all raise, in a variable way, security issues involving research and technological advances compared to reactors of the same types already exploited ^{[ 9 ]} .

Following the Fukushima disaster in 2011, the motivation of members of the International Forum Génération IV fell due to the slowdown in the nuclear industry and the boom in renewable energies in the world ^{[ ten ]} .

The out of the nuclear network recalls “Failure” the superphenix prototype reactor in France and challenges the innovative aspects of the project Generation IV ^{[ 11 ]} . All relative failure because 41% of the time it was stopped for administrative reasons, 19% for repairs, 60% of which did not concern the nuclear boiler. Finally he worked 40% of the time and that for a prototype of this size it was a technological feat. And during the year 1996 alone, it was coupled to the 245 -day network and was criticized 265 days or 95% of the time excluding stopped stopped stops ^{[ twelfth ]} .

Participating international countries and organizations [ modifier | Modifier and code ]

In March 2021, the project participants were ^{[ 13 ]} :

Related articles [ modifier | Modifier and code ]

external links [ modifier | Modifier and code ]