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.
Explore membership for yourself or for your organization.
Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
Fusion Science and Technology
July 2025
Latest News
Hash Hashemian: Visionary leadership
As Dr. Hashem M. “Hash” Hashemian prepares to step into his term as President of the American Nuclear Society, he is clear that he wants to make the most of this unique moment.
A groundswell in public approval of nuclear is finding a home in growing governmental support that is backed by a tailwind of technological innovation. “Now is a good time to be in nuclear,” Hashemian said, as he explained the criticality of this moment and what he hoped to accomplish as president.
W. Breitung
Nuclear Science and Engineering | Volume 108 | Number 1 | May 1991 | Pages 1-15
Technical Paper | doi.org/10.13182/NSE91-A23804
Articles are hosted by Taylor and Francis Online.
Measurements of the total pressure from irradiated (U,Pu)-mixed oxide were analyzed with respect to the fission product release kinetics and availability for pressure generation in Bethe-Tait excursions. Two pressure sources acting on a millisecond time scale were identified: release of grain boundary fission products (gases and volatiles such as cesium) triggered by grain boundary separation and release of formerly intragranular fission products due to fuel boiling. The former process can provide pressures on a megapascal scale early, and the latter process, late in the accident progression. No fission product release was observed from nonboiling liquid fuel. Based on the experimental data, a model was formulated for the total pressure over irradiated (U,Pu)-oxide. Fuel vapor and gases interact by a suppression mechanism: pIF = max(pAG + pFP, psat). The total pressure over irradiated fuel pIF is equal to the pressure sum from ambient gas pAG and released fission products in the gaseous state pFP when this sum is greater than the saturation vapor pressure of fresh (U,Pu)-oxide psat. In this regime, fuel boiling is suppressed. At sufficiently high temperatures when psat > pAG + pFP, the oxide begins to boil and the total pressure pIF reaches the fresh fuel saturation vapor pressure psat. The switch-over in the controlling mechanism occurred at ∼5200 K.
