top of page

Background Stories

Supporting Information on Nuclear Development

BWR – A reactor development can be commercially driven

The Boiling Water Reactor development in the US has been started 1952 with a row of 3 governmentally financed experiments (BORAX-I to III) leading to the Experimental Boiling Water Reactor (EBWR) in 1956, further development steps have taken place which came to an end in mid of the 1960ies, see figure. However, meanwhile the General Electric Company had taken the initiative through its own built, completely privately funded test reactor at Vallecitos (VBWR) in California. The plan was approved by GE’s management in late 1955, construction began in June 1956 and was completed in 1957, being completed under budget and on schedule. The reactor was based in part, on the technical information developed through the BORAX experiments and the EBWR – thus it is a good example of priming the pump through early governmental investment into a promising technology leading to a commercial success. Meanwhile, GE was already actively marketing its BWR designs, e.g., Dresden Nuclear Power Station leading to the first nuclear power plant to be financed entirely with private funding, while it supported plans by General Electrical to rapidly move to demonstration and, ultimately, large plants, more details see (1). The BWR development is a good example of an attractive new nuclear technology which was investigated originally by the government, but due to the attractive market opportunities, it was taken over early by industry leading to a massive speed up in the development and a very successful product on the market. GE is still the major provider of BWR technology, partly in a joint-venture with Hitachi.

HTR – A zero power experiment helps designing the industrial demonstrator

The AVR, a gas cooled high temperature experimental reactor with 15 MW experimental power, was developed in the 1960ies and very successfully operated from 1967 until 1988 (2) . One of the main tasks of the AVR as small scale demonstrator was to test different kinds of fuel elements and to demonstrate in how far the concept of the pebble-bed reactor permits a safe and reliable operation at high gas temperatures (3) while the general reactor development partly relied on the experience in the DRAGON reactor of the UK. After the successful small scale demonstration, it seemed natural to go for the development process for the industrial demonstrator THTR-300 which was designed between 1966 and 1968 and the construction started 1971. However, even after the construction had already started, the zero power reactor KAHTER was built and put into operation mid of 1973. The facility was designed to verify and adjust theoretical models describing the pebble-bed high-temperature reactor. In addition, it was used for evaluating critical masses, flux mappings, and reaction rate measurements, as well as the demonstration of operational performance and safety behaviour. New, sophisticated experimental and theoretical methods have been developed to create exact information and interpretation of control rod efficiency, power determination, and neutron damage. This relatively late investment into a zero power experiment shows the expected value of an experimental facility, even after the successful demonstration of the technology in the AVR. The KAHTER experiments not only helped to deliver required safety demonstrations and code validation for the regulatory process, but also provided a much deeper understanding and improvement of the expected operational performance as well as the studies of potential design variants. It allowed quick testing of alternatives in a safe setting providing substantial cost savings for the project.

ZhSR – A stepwise process helps in the risk reduction in the modern world

The two stories above already demonstrate that there was a kind of stepwise process for developing a reactor system in early projects. Based on this Merk et al. (4) have developed a four-step process for the development of future innovative reactor projects consisting of basic studies, zero-power experiment, small scale demonstrator and industrial demonstrator to reduce the financial risks by providing a stepwise approach into solving the problems of a new technology. This process has already been taken over by ROSATOM for their new molten salt reactor program (5) . In the opening ceremony the General Director of “NIKIET noted: “We all have to solve an extremely ambitious task - to create a research reactor here. There is no similar real object anywhere in the world. I am convinced that we will succeed, we … will go in stages. First of all, the creation of a research facility for testing technologies. … The path is not fast, but it is new, and it is impossible to take risks.” (5) From this point it gets clear, risk reduction is a key for the success of new projects, thus modern project should follow almost the same approach as in history, but in a more streamlined manner and supported by massive modelling & simulation. The Russian project has recently entered into the design of a small scale demonstrator as next step for technology testing. (6)

National and International Interest

iMAGINE and the zero power reactor preparation project supported by the Royal Academy of Engineering (7) , EPSRC (8) , and STFC. The projects have already got significant national and international interest. Besides the academic team of the EPSRC proposal (Liverpool, Lancaster, and Manchester) the following national and international project partners have supported the proposal through a letter of support and in-kind contributions: NNL, Studsvik Scandpower, EdF Energy, Moltex Energy, Terrestrial Energy, EU-Project SAMOSAFER, and the BEIS Molten Salt Advisory Group/University of Edinburgh.

Following the announcement of the projects, we have already been contacted by Oak Ridge National Laboratory, ORANO, Copenhagen Atomics, Elysium Industries, NDA/DRSL, and ROSATOM to discuss the potential for collaboration.

bottom of page