Iaea tecdoc 1450 code#
Similar to the deterministic code systems, the core calculation scheme is divided into two steps.
Iaea tecdoc 1450 full#
Coupled neutronic thermal-hydraulic analysis of full core with Monte Carlo has been done, but core burnup analysis with continuous energy Monte Carlo is still difficult nowadays.Ī “two-step” Monte Carlo core burnup analysis method is proposed in this work. With the rapid developing of computer technologies and parallel algorithms, the efficiency of Monte Carlo simulation has been greatly increased. However, the efficiency of Monte Carlo calculation is too low for the ordinary large scale core designs, due to the long simulation time to get reliable results.
Iaea tecdoc 1450 verification#
Monte Carlo method has been widely used for the verification and validation of deterministic codes, and also for the analysis of many newly developed nuclear energy systems since it can deal with arbitrary geometry and spectrum configuration. The “Two-Step” MC Core Burnup Analysis Method A typical SCFR blanket design is shown in Figure 1, in which a ZrH layer is adopted to slow down the fast neutron leaked from seed assemblies at void condition and decrease the fast fission at blanket assemblies. Thus, increasing neutron absorption at void condition is the key for achieving negative CVR in SCFR, and so blankets are very important since they are the only regions in the core where neutron capture strongly prevails over fission. But it is not an economical option for SCFR, since it is operated at a very high pressure and so a bigger and thicker pressure vessel is needed to contain the core. In order to decrease the CVR, the flat core design is usually adopted to increase the neutron leakage. Main concern arising from coolant voiding is the hardening of the neutron spectrum, which increases fast fission in both seed and blanket fuel regions and also increases neutron leakage at the same time. The coolant void reactivity (CVR) is a crucial safety aspect of fast reactor design. Thus, physically, SCFR is a kind of high conversion LWR design, for which the main approach to increase conversion ratio is to decrease the ratio of water to heavy metal, so as to decrease the moderation effect of water and make the spectrum hard. With a harder spectrum, SCFR can have a higher conversion ratio. In SCWR much less coolant water is needed for cooling the reactor, so a fast spectrum option (SCFR) is possible. The analysis shows that thorium-based fuel can provide inherent safety for SCFR without use of blanket, which is favorable for the mechanical design of SCFR.
The main issues discussed include the fuel conversion ratio and the coolant void reactivity. A core burnup simulation scheme based on Monte Carlo lattice homogenization is adopted in this study, and the reactor physics analysis has been performed with DU-MOX and Th-MOX fuel. A SCFR core is constructed in this work, with the aim of simplifying the mechanical structure and keeping negative coolant void reactivity during the whole core life. The fast spectrum of SCFR is useful for fuel breeding and thorium utilization, which is then beneficial for enhancing the sustainability of the nuclear fuel cycle. Super-Critical water-cooled Fast Reactor (SCFR) is a feasible option for the Gen-IV SCWR designs, in which much less moderator and thus coolant are needed for transferring the fission heat from the core compared with the traditional LWRs.
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