Neutronic analysis of an ads fuelled with minor actinide and designed for spent fuel enrichment and fissile fuel production

Abstract

This paper presents analyses of enrichments of uranium taken out from Canada Deuterium Uranium and pressurized water reactors spent fuels and fissile fuel breeding from thorium in two different helium cooled-accelerator driven system designs, DESIGN A and DESIGN B. In the beginning, the 235U percentages in the uranium fuels taken out from the reactors spent fuels are 0.17% and 0.91%, respectively. Both system cores are fuelled with two different minor actinides compositions extracted from PWR-MOX spent fuels. The DESIGN A has one transmutation zone (enrichment zone) surrounding the fuel core and containing thorium or spent uranium fuels, while DESIGN B has a second transmutation zone (fissile fuel breeding zone) surrounding the first transmutation zone and containing only thorium fuel. In brief, a total of ten cases formed by the combinations of accelerator driven system designs, minor actinides components, and spent uranium with thorium fuels are analysed, which are six in DESIGN A containing one transmutation zone and four in DESIGN B containing two transmutation zones. Lead-bismuth eutectic alloy, a liquid heavy metal, consisting of 45% lead and 55 % bismuth is used as target material in the investigated accelerator driven system. It is assumed that the target is bombarded with 1.2383?1017 protons per second and that the energy of each proton is 1000 MeV. This means a proton beam power of 20 MW. The 3-D and time-dependent neutronic analyses are conducted by using the MCNPX 2.7 and CINDER 90 nuclear code. Both accelerator driven system designs are operated until the values of keff rise to 0.985 to determine the longest operation times that are the effective burn times in all cases. Depending on the design, minor actinide composition, and fuel type (spent UO2 and ThO2), the results obtained at the end of cycle exhibit the effective burn times vary from 300 days to 2050 days, the fuel enrichments can reach up to 2.49-4.23% and the values of gain reach up to 10.8-25.1.

Analysis of thorium and transuranium utilization in a small modular reactor

“…In our pre vi ous stud ies [14][15][16][17][18], the uti li za tion of var i ous nu clear-spent fu els and tho rium fer tile fu els were an a lyzed in sev eral subcritical nu clear re ac tors to re ju ve nate or en rich them. As for the pres ent study, unlike them, the ef fec tive us abil ity of PWR-MOX spent fuel and tho rium fer tile fuel in an SMR op er at ing under crit i cal mode is in ves ti gated in terms of en ergy gen er a tion.…”

Potential of transuranics transmutation in a thorium‐based chloride salt fast reactor

“…To avoid 36 Cl formation, the chlorine will need to be enriched in 37 Cl, preferably above 99% 37 Cl/Cl. Similarly, since 14 N does have a higher capture cross section ($35 microbarns) than 15 N ($1.7 microbarns) in a fast spectrum, a high loading of nitrogen enriched in 15 N ($95 at% 15 N /N) reducing captures on nitrogen can save neutrons for causing fission in TRUs. Therefore, the effects of 37 Cl enrichment and 15 N enrichment on TRUs transmutation performance of TCLFR will be investigated in further work.…”

“…Second, increasing the transmutation time necessitates increasing the operation cycle of the transmutation system. To achieve this goal, for ADS, the difference of effective multiplication factor ( k eff ) between the early and late cycles should be increased, 15 and then, to maintain the core power, a larger proton beam value of the accelerator in the late cycles is required, increasing the difficulty of accelerator technology 16 . For a solid fuel critical fast reactor, increasing the transmutation time requires a considerably high initial excess reactivity of the reactor core, posing a challenge to reactor core safety control 3 .…”