Materials challenges for nuclear systems

https://digital.library.unt.edu/ark:/67531/metadc882322/m2/1/high_res_d/911071.pdf

Key differences in the fabrication, irradiation and high temperature accident testing of US and German TRISO-coated particle fuel, and their implications on fuel performance

The International Atomic Energy Agency (IAEA) is an independent international organization with headquarters in Vienna and a membership of 130 states. The IAEA's most important task in the security policy sector is the verification of international agreements prohibiting the military use of nuclear energy, the most prominent such agreements being the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). To fulfill this task, the IAEA concludes Safeguards Agreements with the individual states and undertakes about 2,500 inspections per year. Concerning the future of the organization, one thing seems certain: the nuclear agenda will rather grow than shrink. The risks of nuclear weapons and nuclear power plants will remain; the latter may very well be aggravated through a rising demand for electricity, especially in developing countries, on the one hand, and the growing destruction of the planet's eco-system on the other. Keywords: International Atomic Energy Agency (IAEA); Non-Proliferation of Nuclear Weapons; safeguards agreements; security policy sector

IAEA – International Atomic Energy Agency

Microencapsulated fuel technology for commercial light water and advanced reactor application

Current knowledge on core degradation phenomena, a review

The high outlet temperatures and high thermal-energy conversion efficiency of modular high-temperature gas-cooled reactors (HTGRs) enable an efficient and cost-effective integration of the reactor system with non-electricity-generation applications, such as process heat and/or hydrogen production, for the many petrochemical and other industrial processes that require temperatures between 300°C and 900°C. The U.S. Department of Energy (DOE) has selected the HTGR concept for the Next Generation Nuclear Plant (NGNP) Project as a transformative application of nuclear energy that will demonstrate emissions-free nuclear-assisted electricity, process heat, and hydrogen production, thereby reducing greenhouse-gas emissions and enhancing energy security. The objective of the DOE Advanced Gas Reactor (AGR) Fuel Development and Qualification program is to qualify tristructural isotropic (TRISO)-coated particle fuel for use in HTGRs. An overview of the program and recent progress is presented.

/pdf/the-doe-advanced-gas-reactor-fuel-development-and-xwkzi0sr7x.pdf

The DOE Advanced Gas Reactor Fuel Development and Qualification Program

This paper reports on results from integral-effects core melt progression experiments and from the examination of the damaged core of the Three Mile Island Unit 2 (TMI-2) reactor which are reviewed to gain insight on key severe accident phenomena. The experiments and the TMI-2 accident represent a wide variety of conditions and physical scales, yet several important phenomena appear to be common to core melt progression. Eutectic interactions between core materials cause the formation of liquids and loss of original core geometry at low temperatures ({approximately}1500 K) in a severe accident. The first liquids to form are metallic in nature, and they relocate to lower elevations in the core, where they may freeze into a crust that forms a partial flow blockage. At temperatures above {approximately}2200 K, fuel liquefaction causes fuelbearing debris to accumulate in the core above the metallic lower crust. The liquefied material oxidizes in steam as it relocates, and the accumulated melt can incorporate unmelted fuel rod debris.

Review of Experimental Results on Light Water Reactor Core Melt Progression

Recent advances in the understanding of fission product release from fuel under severe accident conditions in light water reactors are reviewed. In addition to the effects of temperature and time a...

Fission Product Release from Fuel under Severe Accident Conditions

High temperature gas reactor technology is achieving a renaissance around the world. This technology relies on high quality production and performance of coated particle fuel. Historically, the irradiation performance of TRISO-coated gas reactor particle fuel in Germany has been superior to that in the United States. German fuel generally displayed in-pile gas release values that were three orders of magnitude lower than U.S. fuel. Thus, we have critically examined the TRISO-coated fuel fabrication processes in the U.S. and Germany and the associated irradiation database with a goal of understanding why the German fuel behaves acceptably, why the U.S. fuel has not faired as well, and what process/ production parameters impart the reliable performance to this fuel form. The postirradiation examination results are also reviewed to identify failure mechanisms that may be the cause of the poorer U.S. irradiation performance. This comparison will help determine the roles that particle fuel process/product attributes and irradiation conditions (burnup, fast neutron fluence, temperature, and degree of acceleration) have on the behavior of the fuel during irradiation and provide a more quantitative linkage between acceptable processing parameters, as-fabricated fuel properties and subsequent in-reactor performance.

/pdf/key-differences-in-the-fabrication-irradiation-and-safety-2qb2k1stl2.pdf

Key Differences in the Fabrication, Irradiation, and Safety Testing of U.S. and German TRISO-coated Particle Fuel and Their Implications on Fuel Performance

Richard R. Hobbins

Papers

Key differences in the fabrication, irradiation and high temperature accident testing of US and German TRISO-coated particle fuel, and their implications on fuel performance

The DOE Advanced Gas Reactor Fuel Development and Qualification Program

Review of Experimental Results on Light Water Reactor Core Melt Progression

Fission Product Release from Fuel under Severe Accident Conditions

Key Differences in the Fabrication, Irradiation, and Safety Testing of U.S. and German TRISO-coated Particle Fuel and Their Implications on Fuel Performance