Homogeneous nucleation of quark-gluon plasma, finite size effects and long-lived metastable objects

The general formalism of homogeneous nucleation theory is applied to study the hadronization pattern of the ultra-relativistic quark-gluon plasma (QGP) undergoing a first order phase transition. A coalescence model is proposed to describe the evolution dynamics of hadronic clusters produced in the nucleation process. The size distribution of the nucleated clusters is important for the description of the plasma conversion. The model is most sensitive to the initial conditions of the QGP thermalization, time evolution of the energy density, and the interfacial energy of the plasma-hadronic matter interface. The rapidly expanding QGP is first supercooled by about $\Delta T = T - T_c = 4-6$. Then it reheats again up to the critical temperature T_c. Finally it breaks up into hadronic clusters and small droplets of plasma. This fast dynamics occurs within the first $5-10 fm/c$. The finite size effects and fluctuations near the critical temperature are studied. It is shown that a drop of longitudinally expanding QGP of the transverse radius below 4.5 fm can display a long-lived metastability. However, both in the rapid and in the delayed hadronization scenario, the bulk pion yield is emitted by sources as large as 3-4.5 fm. This may be detected experimentally both by a HBT interferometry signal and by the analysis of the rapidity distributions of particles in narrow p_T-intervals at small p_T on an event-by-event basis.Comment: 29 pages, incl. 12 figures and 1 table; to be published in Phys. Rev.

International Nuclear Safety Center (INSC) database

As an integral part of DOE`s International Nuclear Safety Center (INSC) at Argonne National Laboratory, the INSC Database has been established to provide an interactively accessible information resource for the world`s nuclear facilities and to promote free and open exchange of nuclear safety information among nations. The INSC Database is a comprehensive resource database aimed at a scope and level of detail suitable for safety analysis and risk evaluation for the world`s nuclear power plants and facilities. It also provides an electronic forum for international collaborative safety research for the Department of Energy and its international partners. The database is intended to provide plant design information, material properties, computational tools, and results of safety analysis. Initial emphasis in data gathering is given to Soviet-designed reactors in Russia, the former Soviet Union, and Eastern Europe. The implementation is performed under the Oracle database management system, and the World Wide Web is used to serve as the access path for remote users. An interface between the Oracle database and the Web server is established through a custom designed Web-Oracle gateway which is used mainly to perform queries on the stored data in the database tables

Pin diameter optimization in 1200 MWe heterogeneous vs. homogeneous LMFBRs

LMFBRs with internal blankets (heterogeneous reactors) are known for reducing the sodium void reactivity and increasing the breeding ratio. As for homogeneous reactors, the optimization of the fuel pin diameter for heterogeneous reactors is of great interest. The optimum pin diameter is obtained by changing the fuel pin diameter until the homogenized fuel volume fraction is the same as the optimum fuel volume fraction of the homogeneous core. The optimization of the fuel pin diameter with respect to doubling time for a loosely coupled 1200 MWe oxide heterogeneous reactor is described. The results are compared with those of a homogeneous reactor

Optimization of radially heterogeneous 1000-MW(e) LMFBR core configurations. Design and performance of reference cores. Research project 620-25

A parameter study was conducted to determine the interrelated effects of: loosely of tightly coupled fuel regions separated by internal blanket assemblies, number of fuel regions, core height, number and arrangement of internal blanket subassemblies, number and size of fuel pins in a subassembly, etc. The effects of these parameters on sodium void reactivity, Doppler, incoherence, breeding gain, and thermohydraulics were of prime interest. Trends were established and ground work laid for optimization of a large, radially-heterogeneous, LMFBR core that will have low energetics in an HCDA and will have good thermal and breeding performance

Optimization of radially heterogenous 1000-MW(e) LMFBR core configurations. Appendix C. Research project 620-25

A parameter study was conducted to determine the interrelated effects of: loosely or tightly coupled fuel regions separated by internal blanket assemblies, number of fuel regions, core height, number and arrangement of internal blanket subassemblies, number and size of fuel pins in a subassembly, etc. The effects of these parameters on sodium void reactivity, Doppler, incoherence, breeding gain, and thermohydraulics were of prime interest. Trends were established and ground work laid for optimization of a large, radially-heterogeneous, LMFBR core that will have low energetics in an HCDA and will have good thermal and breeding performance

Optimization of radially heterogeneous 1000-MW(e) LMFBR core configurations. Appendixes D and E. Research project 620-25

A parameter study was conducted to determine the interrelated effects of: loosely or tightly coupled fuel regions separated by internal blanket assemblies, number of fuel regions, core height, number and arrangement of internal blanket subassemblies, number and size of fuel pins in a subassembly, etc. the effects of these parameters on sodium void reactivity, Doppler, incoherence, breeding gain, and thermohydraulics were of prime interest. Trends were established and ground work laid for optimization of a large, radially-heterogeneous, LMFBR core that will have low energetics in an HCDA and will have good thermal and breeding performance

Optimization of radially heterogeneous 1000-MW(e) LMFBR core configurations. Appendixes A and B. Research project 620-25

A parameter study was conducted to determine the interrelated effects of: loosely or tightly coupled fuel regions separated by internal blanket assemblies, number of fuel regions, core height, number and arrangement of internal blanket subassemblies, number and size of fuel pins in a subassembly, etc. The effects of these parameters on sodium void reactivity, Doppler, incoherence, breeding gain, and thermohydraulics were of prime interest. Trends were established and ground work laid for optimization of a large, radially-heterogeneous, LMFBR core that will have low energetics in an HCDA and will have good thermal and breeding performance