No major technical hurdles are foreseen in fabricating thorium fuels due to a quite extensive experience base extending back to the 1960s. More recently, in the context of EC programmes, Pu/Th-pellets were fabricated and irradiated in a BWR and no specific problems were encountered; indeed, thorium oxide fuels had superior irradiation behaviour compared to uranium oxide fuels (see for example, reference 3 pages 28 to 42). Nevertheless, additional fabrication and especially irradiation testing will be needed if burn-ups are to match today’s UOX and MOX experience, i. e. the 50-60 GWd/tHM range, and even beyond 70 GWd/ tHM for some thorium-fuel options considered.

More than 40 years of experience have also been accumulated on HTR fuel fabrication. These reactors are considered to be among the best candidates to accommodate thorium fuels, because of their relatively high conversion ratios (a result of good neutron economy). In this regard, the fuel fabrication processes developed for the Fort St Vrain and THTR power reactors could be the starting basis for defining a new manufacturing plant for other reactor types. As a matter of fact, these two reactors were industrial prototypes (for the 300 MWe class, see

Table 8.1) and, thus, their associated fuel fabrication facilities used semi-industrial processes.

On the other hand, it must be underlined that India has recently manufactured thorium fuel on a scale that is beyond the R&D developmental phase (cf. Section 8.2.3): 7 tonnes of pellets have been manufactured for their PHWR 220 Units at their Nuclear Fuel Complex (NFC), Hyerband; and at BARC, 5 tonnes have been manufactured for their liquid metal cooled FNR programme.

Although development of a thorium-based fuel cycle would require significant additional work to bring it to an industrial scale, there are no major technical hurdles to the manufacture of thorium-based fuels. The experience gained from LEU fuel would provide a base line for the development of this fuel fabrication process.