ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
2021 Student Conference
April 8–10, 2021
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Latest Journal Issues
Nuclear Science and Engineering
Fusion Science and Technology
Don't forget to vote!
The 2021 ANS Election is open. This is your chance to help shape the future of your Society.
All ANS members were sent an email on February 22 with a unique username and password from Survey & Ballot Systems (SBS). If you did not receive this email or you do not have your election login information, please go to directvote.net/ANS, enter your email address that is on file with ANS, and your election login information will be emailed to you.
Alain Marmier, Michael A. Fütterer, Kamil Tucek, Jim C. Kuijper, Jaap Oppe, Biser Petrov, Jérôme Jonnet, Jan Leen Kloosterman, Brian Boer
Nuclear Technology | Volume 181 | Number 2 | February 2013 | Pages 317-330
Technical Paper | Fuel Cycle and Management | dx.doi.org/10.13182/NT13-A15786
Articles are hosted by Taylor and Francis Online.
As early as the 1970s, attempts have been made to reduce the peak fuel temperature in pebble bed-type high-temperature reactors (HTRs) by means of so-called "wallpaper fuel," in which the fuel is arranged in a spherical shell within a pebble. By raising the particle packing fraction, fuel kernels are condensed to the outer diameter of the fuel zone, leaving a central part of the pebble free of fuel. This modification prevents power generation in this central fuel-free zone and decreases the temperature gradient across the pebble.Besides the reduction of maximum and average particle temperature, the wallpaper concept also enhances neutronic performance through improved neutron economy, resulting in reduced fissile material and/or enrichment needs or providing the potential to achieve higher burnup. To assess such improvements, calculations were performed using the PANTHERMIX code. Among other tests, investigations of fuel cycle under steady-state conditions and loss-of-coolant-accident calculations were conducted. Based on PANTHERMIX steady-state conditions, both particle failure fraction [with the CRYSTAL code (Code foR analYsis of STress in coAted particLes)] and fissile material cost can be determined.It is demonstrated that the wallpaper fuel type positively impacts the fuel cycle, reduces the production of minor actinides (MAs), and improves the safety-relevant parameters of the reactor. A comparison of these characteristics with those of Pebble Bed Modular Reactor (Pty) Limited (PBMR) type of fuel is presented: In comparison with PBMR fuel, the wallpaper design results in an increase of the effective neutron multiplication coefficient (by [approximately]925 pcm). This reactivity increase can lead to a burnup extension (from 96.4 to 101.3 MWd/kg), therefore improving the burnup of HTRs, or to an enrichment reduction (from 9.6 to 9.277 wt%). Both options decrease MA production [as defined in g/TW(thermal)h, between 5.9% and 34.5%], making fuel reprocessing easier and reducing fuel cost (by 4.6% for the high-burnup option and by 3.7% for the low-enrichment option).Safety is also improved, with particle temperature being reduced during steady-state operations (by >55 K for the most exposed particles and by almost 10 K on average). This positively impacts particle failure fraction as calculated by the fuel performance code CRYSTAL, leading to a reduction of up to 85% of the particle failure fraction over its in-core lifetime. This reduces the in-core fission product release.While an increase of the graphite density in the central fuel-free zone increases thermal inertia, initiates a faster reactor shutdown, and delays recriticality, it also disturbs the thermal flux that raises pebble powers in the inner part of the core. This increases the highest kernel temperature during a depressurized loss-of-coolant accident from 1872 K for the PBMR case to 1876, 1917, and 1895 K, respectively, for the three wallpaper designs proposed.The fuel changes suggested in this paper offer more versatility to the HTR concept. The conversion ratio can be decreased, leading to lower MA buildup and fuel reprocessing cost, or raised, leading to lower fuel consumption and fuel cost.