Research Reactor Section


CRP on Conversion of Miniature Neutron Source Research Reactors (MNSR) to Low Enriched Uranium (LEU)

The Chinese-built Miniature Neutron Source (MNSR) Reactors (four in China, two of which in operation; and one each in Ghana, Iran, Nigeria, Pakistan, and Syria) are low-power (~30kW), neutron source research reactors used primarily for neutron activation analysis, education, and training. These reactors have cores consisting of about 1 kilogram of HEU, enriched to 90% or greater.

Since 1978, various national and international activities have been underway to convert research and test reactors from the use of HEU to LEU fuel. These activities support the objective of reducing and eventually eliminating the civil use of HEU. Achieving the conversion of all MNSR reactors would be a helpful step forward in this international effort to reduce and eventually eliminate the civil use of HEU.

In response to this international effort, the MNSR community established an IAEA Collaborative Research Project (CRP) in 2006 and subsequently a MNSR Working group to coordinate individual activities in the conversion of MNSR to LEU. In addition, the China Institute of Atomic Energy (CIAE), the designer of the MNSR, has designed a new version of MNSR using LEU to specially operate in hospitals for the specific application of Boron Neutron Capture Therapy.

At a Technical Meeting at IAEA Headquarters in May 2005, all the participating MNSR operators indicated their desire to convert to LEU fuel. It was acknowledged that to successfully carry out MNSR core conversions, a number of preparatory steps, including additional analysis and various calculations had to be made to confirm the feasibility of conversion. The US (Argonne National Laboratory) participated in the CRP, providing input to the generic analyses of the conversion. It has been established that conversions of the MNSRs are feasible and that China or other fuel fabricators will be able to produce LEU cores for the MNSR reactors in the near future.

A Technical Meeting of the CRP attended by China, Ghana, Iran, Nigeria, Pakistan, Syria and US, as well as observers from Sudan and Philippines was held in Beijing September 2010 to prepare for the CRP wrapping up. A draft of the CRP final report establishing the technical viability of the conversion to LEU was finalized at the Technical Meeting in March 2012. The final edition of the report is currently in progress. It will be a Technical Report Series titled “Best Practice Analyses Supporting Conversion of Research Reactors from Highly Enriched Uranium Fuel to Low Enriched Uranium Fuel – the Case of Miniature Neutron Source Reactors.

More details of CRP click here

Working Group

Parallel to the completion of the CRP, a MNSR Working Group has been established consisting of the MNSR operators, designer and stakeholders. The first working group meeting was held in January 2011. The meeting defined the primary objective of the working group, which is to coordinate activities and decision-making process related to the conversion of MNSRs to LEU and shipping of the HEU fuel to China. In the future, the scope of the working group may also include exchange of information and experience in reactor utilization, maintenance, code upgrading (validation, benchmarking), equipment and facility upgrading, training and R&D applications.

An agreement has been made between the CIAE and the ANL to cooperate in setting-up a Zero Power Testing Facility in China. This facilitates key testing required in validating the conversion analyses of MNSRs to LEU fuel. News link

A potential bottle-neck to the conversion projects is the selection of suitable transport cask and transportation means for returning spent HEU fuel to China. The Consultancy Meeting was organized in July 2011 to review systematically all available transportation cask options. The meeting recommended a collaborative effort between Czech Republic and China in modifying the design of IAEA’s spent fuel transportation cask, SKODA, and manufacturing of additional cask components for MNSR fuel transportation and storage. IAEA is facilitating and coordinating this on-going collaboration amongst all stakeholders.

The design concept, the technical requirements as well as the framework of collaboration among stakeholders of the cask were established in the subsequent Consultancy Meetings in March and April 2012, which were held in Vienna and Beijing respectively.


Working Group Members

More details on Working Group Activities click here

IAEA Scientific Officers

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