ession 3 of the symposium focused on technical challenges associated with conversion of specific U. S. and Russian reactors. Eight case stud­ies of individual research reactors’ potential for conversion—three U. S. reactors and five Russian reactors—were presented in this session. These presentations and some key thoughts from the participant discussions are summarized in this chapter.

As was discussed in Chapter 2, there are several analyses that need to be performed to enable conversion of a research reactor from HEU fuel to LEU fuel:

1. Neutronics analysis[53] is performed to determine neutron fluxes in various regions of the new LEU core, reactivity effects, including burnup effects, and various reactor safety parameters.

2. Thermal and hydraulic analysis is performed to ensure that the new LEU core can be adequately cooled during normal and accident conditions.

3. Accident analysis is performed to analyze the potential for fission product release under hypothetical accident conditions.

Because of the uniqueness of many research reactors, conversion studies

need to be carried out for each individual reactor, and the challenges en­countered can be very different for different reactors.