High Temperature Gas-Cooled Reactors

Lord Vallance of Balham Excerpts

Monday 19th January 2026 Lords Chamber

[Baroness Bloomfield of Hinton Waldrist]

To ask His Majesty’s Government what plans they have for the National Nuclear Laboratory to work with the Japan Atomic Energy Agency to achieve early deployment of high temperature gas-cooled reactors in a mutually beneficial manner.

[The Minister of State, Department for Energy and Net Zero and Department for Science, Innovation and Technology (Lord Vallance of Balham) (Lab)]

The Government will publish very soon the advanced nuclear framework, setting a pathway for privately led advanced nuclear projects. The framework will introduce an assessment process, identifying credible projects that are potentially deliverable within the UK. We would welcome a proposal regarding deployment of a Japanese HTGR, Japanese-led or alongside a UK partner. UKNNL is open to proposals from any country, including Japan. Any developer can approach UKNNL to discuss support.

[Baroness Bloomfield of Hinton Waldrist (Con)]

I thank the Minister for that encouraging Answer and welcome him and all Peers to nuclear in Parliament week—my happy place. The Minister will know that HTGRs are classed as AMR technology and the UK is on track to be the first country outside Russia to produce HALEU, the base fuel for AMRs. I think the Minister will agree that the MOC between NNL and JAEA signed in 2023 is too modest. Does the Minister agree that it would be highly desirable in terms of securing the UK supply chain and employment to accelerate the commercial development of Japanese HTGR technology in the UK? In this regard, would he perhaps undertake to engage with his Japanese counterpart to provide the necessary commitment to progress this technology?

[Lord Vallance of Balham (Lab)]

We have two MOCs with Japan. One, as the noble Baroness rightly said, was signed in 2023, and a second, on HTGRs and fuel, was signed in 2024. We have regular meetings with our Japanese counterparts. Japan has long been held as an important collaborator for us in nuclear. The last of those meetings, the 14th, was held on 3 December last year, and we will continue with regular interactions with the Japanese, who we certainly view as extremely important partners, particularly in this area.

[Viscount Hanworth (Lab)]

My Lords, our much vaunted nuclear revival is based on the deployment of pressurised light-water reactors. These are grossly inefficient in their use of uranium fuels, which will be in short supply within a decade. They will need to be replaced by safer and more efficient reactors, such as thorium reactors and fast-neutron reactors that breed their own fuels. However, within the past 12 months we have seen the departure from the UK or the closure of projects aimed at developing such reactors. Are there any remaining prospects of developing advanced reactors in the UK, or will we be dependent in future on foreign technologies based on technologies pioneered in the UK?

[Lord Vallance of Balham (Lab)]

My noble friend is right that there are many different technologies coming along, and one of the reasons why we put the advanced nuclear framework together is to make it possible for all those technologies to have a pathway through to production in the UK. This is an important moment, when private-sector leadership of nuclear is real and can happen because of the new designs. We welcome all the different technologies as part of that framework, which, as I say, will be published shortly.

[Lord Hunt of Kings Heath (Lab)]

My Lords, perhaps in contrast to my noble friend, I congratulate the Government on the final investment decision on Sizewell C and the SMR programme by Rolls-Royce at Wylfa. This is the foundation for a fantastic new nuclear industry in the UK. But does he agree that in welcoming private-sector investment, we need to look at siting policy and making it more flexible, as the recent taskforce recommended?

[Lord Vallance of Balham (Lab)]

On the first part of my noble friend’s question, he should partially congratulate himself, because he was very involved in making that happen, and I join him in congratulating him. We have a very significant nuclear programme with SMRs coming along; and the Fingleton review and a series of other processes, including EN-7, which was laid on 18 December, make planning and other aspects much easier. Siting is very important. A siting review, by GBN, is going on at the moment, looking at potential sites for future gigawatt production as well; it will report in the autumn.

[Earl Russell (LD)]

My Lords, can the Minister outline how the continued co-operation with Japan on HTGR reactors will contribute to achieving the Government’s net-zero ambitions and improving our long-term energy security, in particular by providing a reliable low-carbon heat and power source to decarbonise industrial sectors that are otherwise particularly hard to abate, such as steel-making and hydrogen production? What assessment will be made of the cost-effectiveness of alternative types of technology?

[Lord Vallance of Balham (Lab)]

The point raised about the heat production of HTGRs is very important. This is not just about the electricity; it is about the heat and what can be done with it. It is why we are keen to encourage advanced modular reactors in the UK. There is also an opportunity to make them much smaller and to site them in different places, which will free up the link directly to industrial purposes. The advanced nuclear framework lays this out very clearly and encourages the private sector and others to join in putting forward new technologies.

[Lord Moynihan (Con)]

My Lords, given that the Minister has mentioned new technologies, is he aware that the Japanese high-temperature gas-cooled reactors operating at 950 degrees—he mentioned the importance of heat—produce hydrogen at scale and at reasonable cost? Would it not be beneficial to co-operate further with the Japan Atomic Energy Agency on multi-purpose nuclear heat applications, especially hydrogen production, using its high-temperature engineering test reactor, since the low-cost production of energy should be our overall policy objective?

[Lord Vallance of Balham (Lab)]

We have had two collaborations with the Japanese over the last couple of years, one on HTGRs and one on coated fuels, and we have an ongoing one on robotics. The point made about heat production is crucial. The Japanese, through our collaboration with them through UKNNL, have the demonstrator HTGR ready to go in 2028, specifically focused on hydrogen. We will keep in close contact with them over that, because that production of green hydrogen through nuclear is a very interesting opportunity.

[The Earl of Kinnoull (CB)]

My Lords, can the Minister update the House on the plans to replace Russia in the nuclear fuel supply chain, given that it has a very dominant place there at the moment?

[Lord Vallance of Balham (Lab)]

We have a committed ban on using any import from Russian nuclear fuel by 2028. As of now there is no direct use of Russian fuels; by 2028 indirect use will be eliminated as well. By that I mean fuel processed elsewhere that may have originated in Russia. We have also invested £300 million in making sure that we have our own fuel production, particularly high-assay low-enriched uranium, which is going to be particularly important. That is a major step forward in becoming self-sufficient in some of this fuel.

[Lord Naseby (Con)]

My Lords, the Government have done a considerably good job in this area in the limited time they have been there. There is a problem, in that I am not sure the general public understand, and they are still worried about, the development of nuclear in a variety of areas. Can the Government reassure us that they will look hard at that so that we can at least begin to reduce the extensive time for consultation that is holding back a fair number of developments?

[Lord Vallance of Balham (Lab)]

I think public opinion is changing, and it has changed quite a lot in the past few years, but the noble Lord is right that there remain a lot of obstacles to moving fast in this space. That is why the Fingleton report, with its 47 recommendations, is so important. We will be responding fully to that within the three-month period—that is, by the end of February—and will propose to drive that forward as fast as we can, for exactly the reasons he has raised.

[Lord Spellar (Lab)]

My Lords—

--- Later in debate ---

[Lord Spellar (Lab)]

My Lords, the Government’s impetus on the nuclear programme is extremely welcome, but would it not be even better for the nations and regions of this country, and for our important manufacturing industry, if our world-leading position were being reinforced by doing the maximum amount of engineering for the construction of these projects here in the UK?

[Lord Vallance of Balham (Lab)]

The short answer is yes. The slightly longer answer is that, as we move towards contract completion with Rolls-Royce for the small modular reactors, we want to ensure that 70% of the supply chain, both onsite and offsite, is through British construction.

[Lord Trefgarne (Con)]

My Lords, is not some of the work that would be done by the project that is the subject of the question of a highly sensitive nature? Is it properly protected?

[Lord Vallance of Balham (Lab)]

Sorry, I missed the middle of the noble Lord’s question. Is what properly protected—the fuel?

[Lord Trefgarne (Con)]

No, the information.

[Lord Vallance of Balham (Lab)]

Yes. There is a big focus on security of information across the nuclear space, including of course cybersecurity, and on making sure that we retain the intellectual property and the know-how that are so crucial for the safety of this technology.