Time was set aside during this session for free discussion among sym­posium participants. Some of the key comments from that discussion are presented in this section. [52]

• Current work under way in Russia on monolithic fuel development could pave the way for conversion of many Russian research reactors. Jim

Matos commented that the densities of the LEU dispersion fuels described in the Russian presentations are too low to be used in converting many Russian reactors. Jim Snelgrove noted that monolithic pin-type LEU fuel is also being tested in Russia. This fuel is a potential replacement for the tube — type fuel that is now being used in Russian research reactors. The recent agreement between DOE and Rosatom to assess the feasibility of converting six Russian research reactors could play an important role in assessing the potential utility of this LEU fuel.

• There may be some research reactors that cannot be converted.

V. Ivanov noted that there may be some reactors with unique purposes that cannot be converted. For example, the multipurpose fast breeder reactor to be built in Dimitrovgrad will be fueled with HEU and plutonium. The concept of reducing risk by eliminating HEU does not make sense for this reactor because the HEU is used alongside plutonium. This is also true for critical assemblies. He also noted that the concept of “unique mission” has not yet been defined in Russia, and he suggested that there should be a limited list of parameters that could be applied to determine uniqueness. N. V. Arkhangelsky reminded symposium participants that it was recognized from the very beginning of the RERTR program that there are a number of research reactors that would not lend themselves to conversion, including fast breeders.

• Reactor ageing is a potential complication for conversion, but it can be managed. V. Ivanov noted that unless national regulatory require­ments dictate conversion, the decision to convert, upgrade, or shut down a reactor will be made by the operator/owner. The owner/operator must determine whether it makes sense to convert the reactor if the remaining lifetime is negligible. H.-J. Roegler commented that, in his experience, re­search reactor ageing problems can be cured, although in some cases it can take time. A. N. Chebeskov commented that different reactor facilities may have access to different resources to manage ageing. Having a set of best practices to manage ageing could be a topic for international cooperation.

• Reactor customers (users) are an important part of the conversion process. V. Ivanov commented that conversion work needs to be trans­parent to customers, not just designers and research reactor specialists. He suggested that it would make sense for the international community, including the customers of research reactors, to cooperate more closely on conversion.

• There may be economic advantages to conversion. Richard Meserve noted that conversion may have economic advantages that were not dis­cussed by any of the symposium presenters. In particular, LEU costs could be lower, depending on how that material is priced, and costs for securing

LEU fuel should be much lower than for HEU fuel. Jordi Roglans com­mented that transportation costs, especially international transportation costs, will be lower for LEU fuel because HEU is often transported by the military.

• A worldwide ethic on conversion should be developed. Yu. S.

Cherepnin suggested that the world community should develop a new ethic against operating reactors with HEU. Strong signals should be sent to operators of HEU reactors that they need to convert, and funding should be demanded from governments to support conversion.

• Working together, the Russian Federation and the United States have played and will continue to play important global roles in research reactor conversion. N. Laverov noted that the Russian Federation has decommissioned 200 nuclear submarines and, working with the United States, has returned 100,000 tonnes of natural uranium and 500 tonnes of HEU from foreign countries. The recent agreement between DOE and Rosatom to assess the feasibility of converting six Russian research reac­tors is an important step for eliminating HEU use in Russian research reactors. It is important that the Russian Federation and the United States serve as an example to countries by reducing the enrichments of their research reactors to lower levels.