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
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Apr 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
May 2026
Nuclear Technology
March 2026
Fusion Science and Technology
Latest News
Access anywhere, anytime: Nuclear power, Ice Camp, and Rickover’s enduring standard of excellence
Admiral William Houston
As U.S. Navy submarines surface through Arctic ice during Ice Camp 2026, they demonstrate more than operational proficiency in one of the harshest environments on Earth. They reaffirm a technological truth first proven in August 1958, when the USS Nautilus completed its submerged transit of the North Pole: nuclear power enables access anywhere, anytime.
The Arctic is unforgiving, with vast distances, extreme cold, shifting ice, and no logistical infrastructure. Conventional propulsion is constrained by fuel, air, and endurance. Nuclear propulsion removes those constraints. Only a nuclear-powered submarine can operate anywhere in the world’s oceans, including under the polar ice, undetected and at maximum capability for extended periods. Nuclear power provides sustained high speed and the endurance to reposition across the globe without refueling.
J. C. Wagner, C. V. Parks
Nuclear Technology | Volume 136 | Number 1 | October 2001 | Pages 130-140
Technical Paper | Radioactive Waste Management and Disposal | doi.org/10.13182/NT01-A3233
Articles are hosted by Taylor and Francis Online.
This research examines the practice of equating the reactivity of spent fuel to that of fresh fuel for the purpose of performing burnup credit criticality safety analyses for pressurized water reactor (PWR) spent-fuel pool (SFP) storage conditions. The investigation consists of comparing keff estimates based on reactivity "equivalent" fresh fuel enrichment (REFFE) to keff estimates using the calculated spent-fuel isotopics. Analyses of selected storage configurations common in PWR SFPs show that this practice yields nonconservative results (on the order of a few tenths of a percent) in configurations in which the spent fuel is adjacent to higher-reactivity assemblies (e.g., fresh or lower-burned assemblies) and yields conservative results in configurations in which spent fuel is adjacent to lower-reactivity assemblies (e.g., higher-burned fuel or empty cells). When the REFFE is determined based on unborated water moderation, analyses for storage conditions with soluble boron present reveal significant nonconservative results associated with the use of the REFFE. Finally, it is shown that the practice of equating the reactivity of spent fuel to fresh fuel is acceptable, provided the conditions for which the REFFE was determined remain unchanged. Determination of the REFFE for a reference configuration and subsequent use of the REFFE for different configurations violates the basis used for the determination of the REFFE and, thus, may lead to inaccurate, and possibly, nonconservative estimates of reactivity.A significant concentration (~2000 ppm) of soluble boron is typically (but not necessarily required to be) present in PWR SFPs, of which only a portion ([less than or approximately equal]500 ppm) may be credited in safety analyses. Thus, a large subcritical margin currently exists that more than accounts for errors or uncertainties associated with the use of the REFFE. Consequently, the findings presented here do not represent a significant safety concern unless/until the subcritical margin associated with the soluble boron (that is not currently explicitly credited) is offset by the uncertainties associated with burnup credit and/or the expanded allowance of credit for the soluble boron.
