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Nuclear energy plays an important role in the green low-carbon energy. The lead-based reactor is one of the most popular small modular reactor types. The pre-conceptual design of a 100 MW(e) small modular lead-bismuth eutectic cooled reactor was developed by Shanghai Nuclear Engineering Research & Design Institute CO., LTD. to meet the market demand of advanced small-scale nuclear plant. Representative accidents were analyzed for the 100 MW(e) small modular lead-bismuth reactor using ATHLET/MOD 3. The result shows that under the design basis conditions, the performance of the reactor can meet the safety criteria with the protection system working normally. The coolant solidification in the primary circuit under these transients should be prevented. Under the design extension condition, the highest cladding temperature is much lower than the melting point. In the unprotected reactivity insertion condition, there may be a short time of local melting of the fuel, which also meet the acceptance criteria. The safety analysis demonstrated the passive safety of the design with the negative temperature coefficient, strong natural circulation capability, and the passive residual heat removal system.

Molten Salt Reactor (MSR) has been recognized as one of the Next Generation Nuclear Power systems. Most MSR concepts are the variants evolved from the ORNL’s Molten-Salt Breeder Reactor (MSBR) which employs Molten-Salt as both fuel and coolant, and normally graphite is used as moderator. Many evaluations have revealed that such concepts have low breeding ratio and might present positive power coefficient. Facing these impediments, TMSR (Thorium Molten Salt Reactor) with redesigned lattice is proposed in this paper. Based on comprehensive investigation and screening, important lattice parameters including molten salt fuel composition, solid moderator material, lattice size, structure and lattice P/D ratio (lattice pitch to channel diameter) are redesigned. In this paper, new composition of fuel salt without BeF2, which is also recommend for Molten Salt Fast Reactor (MSFR), is employed instead of LiF-BeF2-ThF4-UF4 adopted in the design of single fluid MSBR. The new fuel composition makes TMSR to benefit from the increased solubility for actinides (e.g. Th4, UF4). Moreover, due to the decent slowing-down power and neutron multiplication effect by (n,2n) reaction of beryllium, BeO is employed as moderator to improve neutron economy instead of graphite. To avoid corrosion on the one hand, Ceramic cladding (e.g. SiC) is introduced to separate the flowing liquid fuel and fixed solid moderator. More importantly, ceramic cladding is capable of maintaining a stable flow channel and supporting the core structure on the other hand. Concerning neutron spectrum, P/D ratio is an important parameter indicating the volume fraction of fuel in the lattice. In order to obtain a suitable spectrum for better breeding and safety features, lattice size and P/D ratio have been optimized for TMSR. Furthermore, since online reprocessing capability and refueling control are key parameters influencing depletion behavior which concerns the sustainability of the reactor system, these issues are also discussed in this paper. Simulation of the redesigned TMSR system is performed to evaluate the outcomes of the lattice parameters optimization. SONG/TANG-MSR codes system is applied in the simulation, which is independently developed by Shanghai Nuclear Engineering Research & Design Institute (SNERDI). A traditional core model with LiF-BeF2-ThF4-UF4 fuel and graphite moderator is also evaluated by the codes for reference. Thanks to the optimized lattice parameters and as consequences of the redesigned lattice, TMSR has achieved a high breeding ratio close to 1.13. With a proper reprocessing and refueling strategy, the doubling time of TMSR can be shortened to about 15 years. Meanwhile a negative power coefficient is still maintained. Based on this lattice design, TMSR will have excellent performance on safety and sustainability.

In order to improve the breeding ratio and core safety, new thorium molten salt reactor (TMSR) core is designed. The new designed TMSR core is composed of hexagon moderator elements, which contain SiC tube to form a central fuel channel and employs BeO as moderator. The composition of the fuel salt, adopted in this core, is also optimized. Based on this core design, steady state and transient safety characteristic of TMSR are preliminarily analyzed using coupled multi-physics code. Power/temperature distribution and reactivity coefficients are analyzed for the steady state core, which demonstrated that the core has flat temperature distribution and large negative power coefficients at all power level. Transient simulations are carried out for power start-up, pump speed variation, loss of heat sink and so forth, the temperature and power response are also analyzed. The results indicate that the TMSR core power and temperature are closely related to the control rod position, velocity of flow and composition of fuel salt, and the new designed TMSR has excellent performance of safety under various operating conditions.

We have developed the 293-group cross-section library SONGLIB with complete reaction pathes, broad-spectrum solving ability and wide range isotopes, which is adopted in the lattice code SONG, the next generation reactor lattice calculation and analysis code. SONGLIB provides the multi-group data for the transport calculation, resonance calculation and burnup calculation of SONG. So the precision and reliability of data is very important. However, the size of the data is very large and there are still a lot of personal factors in determination of the processing parameters and methods. In order to evaluate the library, it’s necessary to carry out the test work comprehensively. Amount of test work is then undertaken based on three kinds of reactors such as pressurized water reactor with UO2 fuel, sodium cooled fast reactor and new-type molten salt reactor with none-beryllium core. In order to test the adaptivity of the library, 39 cases are designed totally, changing the fuel composition, the absorber compositon, the burnup depth and the working temperature. Only the results of a few cases are given in details to shorten the length of this article. For comparison, the Monte Carlo code MCNP is chosen and the library source of evaluated nuclear data is ensured to be the same. The model that has been calculated is simple, the cell with “fuel-cladding-modulator” the three-layer structure and total reflection boundary for the aim of minimizing the differences between the codes. From the macroscopic angle, the results of infinite multiplication factor fit well with each other in total. From the microscopic angle, the absorption rate for actinides, fission products and absorbers, the fission rate for fissile isotopes and scattering rate for moderators are compared with that of MCNP whose output is normalized to the actual cell power. The difference between the reaction rates for most isotopes can be neglected. But there still exist some obvious differences for some isotopes whose resonance effect should have been considered, such as Fe56, ZrNat and W, which might affect the macoscopic results to some extent. As a conclusion, the data of SONGLIB can be expected with high precision and reliability. And SONGLIB is adapted in solving various problems for reactors with different spectrum, depth of burnup, operation condition or fuel cycling. Nevertheless, there still exist some factors that may affect the final results during the process and use of the library, which should be paid attention to while taking a further step in optimizing and updating the library.

Multi-group cross section library is the basic condition for lattice calculation, which provides the necessary nuclear data parameters. The multi-functional lattice code SONG (Si et al. in Nucl Power Eng 35:111–115, 2014. doi: 10.13832/j.jnpe.2014.S2.0112 ; Chen et al. in Nucl Power Eng 35:127–130, 2014. doi: 10.13832/j.jnpe.2014.S2.0127 ) is developed to adapt to the research demands of different types of new reactors, especially the fourth generation (GEN-IV) reactors (Cerullo and Lomonaco in Nucl Fuel Cycle Sci Eng, 2012. doi: 10.1533/9780857096388.3.333 ; Giorgio et al. in Energy Policy 61:1503–1520, 2013. doi: 10.1016/j.enpol.2013.06.101 ). The corresponding multi-group cross section library of SONG (SONGLIB) is well designed with much effort considering the next generation reactors’ new feature in material, spectrum, burnup depth, etc. Therefore, the burnup chain (Maria and Jaakko in Nucl Sci Eng 164:140–150, 2010. doi: 10.13182/NSE09-14 ), energy group structure (Tholakele et al. in Ann Nucl Energy 80:279–292, 2015. doi: 10.1016/j.anucene.2015.01.038 ), and reaction path should be specially considered. The library SONGLIB is processed with the Evaluated Nuclear Data File (ENDF), nuclide data auxiliary processing code NJOYBAT (Si et al. 2014), and library management code MANLIB (Si et al. 2014). A series of verification work of SONGLIB is then carried out, and the calculated results are satisfied.

TMSR fuel lattice was reevaluated by varying the P/D ratio (Ratio of Lattice Pitch to Channel Diameter) and Lattice Size (Pitch); an in-house developed computer code named SONG/TANG-MSR was used to calculate the key TMSR parameters such as core reactivity, conversion or breeding ratio and power reactivity coefficient. The optimized lattice was recommended with trade off of the above key parameters, which can satisfy the requirements of Sustainability and Safety.Copyright © 2014 by ASME

In the new economic situation of logistics and procurement, the relationship between suppliers and manufacturers still exists crisis, even fight ceaselessly. This research devotes to solve this question effectively. On the basis of reading a large number of related literatures, this article mainly adopted literature research methodology to propose its own system frame, which means by deeply analyzing the relational crisis between suppliers and manufacturers, it proposes a feasible solution of this issue. It hopes to form a joint decision-making system on the basis of incentive mechanism and on the premise of bilateral information-sharing and knowledge-sharing, therefore it can optimize the overall interests and realize the fundamental shift in relations between the two parties.

Purpose Methods and Materials Results Conclusion References Personal Information, Purpose: Analyzing multislice CT(MSCT) appearance of renal cell carcinoma(RCC)by different pathological subtypes for improving the level of CT diagnosis and differential diagnosis among common pathologic subtypes of renal cell...