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Aalo Atomics achieves criticality on July 4
Executive Order 14301 set an ambitious goal for at least three test reactors to achieve criticality by July 4. Two private companies participating in the Department of Energy’s Reactor Pilot Program—Antares and Valar Atomics—reached this stage earlier in June, and Deployable Energy—participating in the DOE's Nuclear Energy Launch Pad—became the third last week.
In the last few weeks, reports indicated that Aalo would be next, reaching criticality at Idaho National Laboratory with a low-enriched uranium–fueled, sodium-cooled reactor on or near the target date set forth by President Trump’s EO 14301. In the early hours of July 4, Aalo’s critical test reactor—a full-scale zero-power version of its planned 10-MWe Aalo-X—did just that, becoming the fourth DOE-authorized reactor to hit the milestone.
John S. Hendricks, Brian J. Quiter
Nuclear Technology | Volume 175 | Number 1 | July 2011 | Pages 150-161
Technical Paper | Special Issue on the 16th Biennial Topical Meeting of the Radiation Protection and Shielding Division / Radiation Transport and Protection | doi.org/10.13182/NT10-17
Articles are hosted by Taylor and Francis Online.
The angular distribution of scattered photons is incorrect in MCNPX and MCNP5 because the incoherent and coherent form factors are obsolete. The obsolete data affect all photon transport problems with E > 74 keV. Elastic backscatter for E > 105 keV is completely missing. Consequently, a new ACE-format photoatomic data library, tentatively named MCPLIB05 and referred to herein as MCPLIB05T, has been developed for MCNP/X. Data in MCPLIB05T other than form factors are identical to that in its predecessor photoatomic library, MCPLIB04. The new form factor data in MCPLIB05T come directly from ENDF/B-VII (rev. 0) and are in a format incompatible with older versions of MCNP/X. Consequently, a new version of MCNP/X has been developed to identify and use the new MCPLIB05T data and yet retain backward compatibility, including tracking, when MCPLIB04 is used. The NJOY nuclear data processing system is undergoing development to enable future generations of photoatomic data libraries with modern form factor data in the new format.
