why Belgium wants to build small nuclear reactors


Our country will focus on so-called small, modular nuclear reactors. A test reactor must be running in Mol by 2035. A first commercial reactor will not be available until about ten years later. What should it look like and what good does it do for us?

Dieter De CleeneNovember 8, 202319:36

What’s the plan?

The nuclear research center SCK CEN, together with research institutions in Romania and Italy, will focus on the construction of so-called small, modular nuclear reactors (SMRs). All partners signed a Memorandum of Understanding about this on Wednesday. The federal government previously released 100 million euros for research into SMRs.

Current nuclear power plants use water as a coolant, but the consortium wants to focus on lead-cooled reactors. SCK has experience with this because their research reactor MYRRHA is cooled with a mixture of lead and bismuth. A first, small-scale SMR that must prove technological feasibility should be built in Mol by 2035. A larger test reactor should then be built in Pitesti, Romania. To this end, SCK is working with the Italian research agency ENEA and the Romanian state-owned company RATEN, which have also investigated the technology.

How a small modular

reactor (SMR) is working

Become control rods

from the reactor core

withdrawn, true

by a nuclear one

reaction arises and there

heat is generated


Water (or eg

liquid metal /

molten salt /

helium gas), heated by

the response, rises to a

natural way


At the top passes the

hot reactor substance

cold along pipes

water in the steam generator

erator. This generator

water heated and the

reactor substance cools

occasionally, because this one

is denser, decreases.

The hot generatorwa

ter turns into steam

and is passed along pipes

to the steam turbine


The cooled reactor

substance drops back

to the reactor core,

will be there again

heated and the cycle

starts again.

After the turbine

was made by it

driven, condens

cools the steam

he finishes, and becomes

again to the

steam generator


Steam pipe

to steam


How a small modular reactor (SMR) works

Steam pipe

to steam


Control rods are withdrawn from the reactor core, causing a nuclear reaction and generating heat.

Water (or, for example, liquid metal / molten salt / helium gas), heated by the reaction, rises naturally.

At the top, the hot reactor substance passes through tubes of cold water into the steam generator. This generator water heats and the reactor substance cools and, because it is denser, sinks.

The hot generator water turns into steam and is led along pipes to the steam turbine.

The cooled reactor substance returns to the reactor core, is heated again and the cycle begins again.

After driving the turbine, the steam condenses, cools, and is pumped again to the steam generator.

The ultimate goal is a commercial SMR, built by the American company Westinghouse, which was already involved in the construction of the reactors in Doel and Tihange, and the Italian Ansaldo Nucleare. “In the coming months we will mainly look at how we can combine the expertise of all partners,” says Peter Baeten, Director General of SCK CEN. “We don’t expect a commercial reactor until around 2040 to 2045.” Where that will be located has not yet been determined.

What the capability of such a commercial SMR will be has also not yet been decided. According to Baeten, this amounts to an order of magnitude of about 300 megawatts, or about a third of the power of our largest current reactors.

Why lead-cooled small, modular reactors?

The lead-cooled SMRs offer a number of advantages compared to ‘classic’ nuclear power stations. For example, they use so-called passive cooling. In a traditional nuclear power plant, pumps are needed to circulate the water that removes the heat from the reactor. This makes a reactor vulnerable to power outages, which in the worst case can lead to a nuclear meltdown. With passive cooling, the coolant circulates under the influence of gravity, without human intervention.

Although passive cooling can also be done with water, lead was chosen because it results in a more efficient process. Water slows down the neutrons in the nuclear reactor, lead does not. “The consequence of those faster neutrons is that the fuel burns more efficiently and you are left with less long-lived radioactive waste,” says Baeten. “In addition, we can recover some of the current nuclear waste as fuel for these new reactors. It is circular economy applied to a nuclear reactor.”

Finally, smaller reactors can be built in more places than large nuclear power plants. ‘Modular’ refers to the possibility of producing the parts of such a reactor partly in advance in a factory. Standardized series production should reduce construction costs, an obstacle faced by some new nuclear power plants under construction.

What role can they play in our future energy supply?

Research institute EnergyVille previously investigated how our society could become net carbon neutral by 2050. In one of the scenarios, SMRs are responsible for approximately 6 gigawatts of electricity production, approximately 10 to 20 percent of the total. “If the technology is profitable, it can play a role in the energy system of the future,” says Pieter Vingerhoets (EnergyVille). “But there are also scenarios in which we can survive without nuclear energy.”

SMRs are coming into focus as a possible solution to the fickleness of solar and wind. We still deal with this by using gas-fired power stations at times when there is insufficient renewable energy. They are a climate-friendly alternative, with some additional advantages. This type of reactor generates very high temperatures, from 600 to 800 degrees Celsius. “That is heat that is very interesting for industrial processes, and which we can currently hardly generate without a fossil energy source,” says energy expert Joannes Laveyne (UGent).

In addition, the SMRs can produce hydrogen, which is sought after as a raw material for industry and as a medium for energy storage. This can be done via a process that uses the heat, as well as with the electricity generated, when there is enough sun and wind. “I wouldn’t call these SMRs a miracle solution, but it doesn’t make much of a difference,” says Laveyne. “On paper, at least, they offer several advantages.” However, that ‘on paper’ is not an unimportant detail. “The technology still has to prove itself,” says Laveyne. “Everything will depend on the cost of the electricity generated.”

It is not yet clear how much the construction of a commercial SMR will ultimately cost. Nor is the price of the electricity generated. An additional uncertainty is the question of how competing technologies, for example for electricity storage, will evolve in the meantime. However, according to Laveyne, these uncertainties are no reason to pull the plug in advance. “You only know whether this is viable if you develop it effectively.”

The article is in Dutch

Tags: Belgium build small nuclear reactors


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