Program Element 2: Blanket and Shield Thermal-Hydraulic and Thermomechanical Testing of the First Wall/Blanket/Shield Program: Final Report

摘要

Two single-effect scoping tests were performed in Phase 1 of this project. These tests included the measurement of heat transfer contact resistance between a Li sub 2 O breeder pellet and stainless steel clad in argon gas - in the temperature range of 500 sup 0 to 700 sup 0 C. The effective heat transfer coefficient was found to lie in the range of 1100 to 1700 W/m sup 2 -K which is acceptable for the design of Li sub 2 O solid breeder blankets. This effective heat transfer coefficient is expected to improve in helium gas, which has a much higher thermal conductivity than argon. In the second set of tests, the thermomechanical behavior of Li sub 2 O pellets was determined under simulated blanket conditions, including thermal cycling, in the presence of a helium gas purge flow of controlled moisture content. The results showed that at a temperature below 800 sup 0 C and with a reasonable purge flow moisture content of approx. =10 ppM, Li sub 2 O pellet sintering and pore closure, pellet-clad interaction and vapor phase transport of LiOH are minimal. A multiple-effects solid breeder blanket integral simulation test, followed by an engineering-scale nuclear test are the proposed next steps in this series of tests. Preliminary designs for these experiments were completed. Fabrication techniques for the manufacturing of microspheres as an alternate fuel form for solid breeder fuel were also investigated in the study. Microspheres of LiAlO sub 2 from <30 mu m to 180 mu m were fabricated by the plasma spray technique. Production of approx.650 mu m spheres by a sol-gel process was demonstrated and feasibility was indicated from the production of spheres from approx.100 mu m to approx.800 mu m in diameter. (ERA citation 12:012951)