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 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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
Dec 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
January 2026
Nuclear Technology
December 2025
Fusion Science and Technology
November 2025
Latest News
What’s the most difficult question you’ve been asked as a maintenance instructor?
Blye Widmar
"Where are the prints?!"
This was the final question in an onslaught of verbal feedback, comments, and critiques I received from my students back in 2019. I had two years of instructor experience and was teaching a class that had been meticulously rehearsed in preparation for an accreditation visit. I knew the training material well and transferred that knowledge effectively enough for all the students to pass the class. As we wrapped up, I asked the students how they felt about my first big system-level class, and they did not hold back.
“Why was the exam from memory when we don’t work from memory in the plant?” “Why didn’t we refer to the vendor documents?” “Why didn’t we practice more on the mock-up?” And so on.
Randy L. Simmons, Niel D. Jones, Frank D. Popa, Donald E. Mueller, James E. Pritchett
Nuclear Technology | Volume 80 | Number 3 | March 1988 | Pages 343-348
Technical Paper | Fission Reactor | doi.org/10.13182/NT88-A34058
Articles are hosted by Taylor and Francis Online.
The design advantages achievable from the use of zirconium diboride (ZrB2) integral fuel burnable absorbers (IFBAs) in two- and three-loop pressurized water reactor (PWR) cores are examined. The ZrB2 IFBAs were designed and have been extensively tested for use in PWRs. Two fuel loading patterns that utilize IFBAs are analyzed: (a) a three-loop core with an 18-month cycle, very low radial leakage loading pattern, and reduced vessel fluence concerns; and (b) a two-loop core with an annual cycle, very low radial leakage loading pattern, and natural uranium axial blankets (low axial leakage). Both designs demonstrate the versatility of IFBAs in difficult fuel loading patterns. Both designs demonstrate well-behaved radial and axial power peaking factors for annual (two-loop core) and 18-month (three-loop core) cycles. The ZrB2 IFBAs also provide added flexibility in the placement of fresh fuel. This flexibility can improve shutdown margin by placing fresh fuel under control rod locations and can improve fuel cycle cost. Neither design would have been possible with discrete burnable absorbers. By analyzing the two very different designs, it can be seen that ZrB2 IFBAs can be used in tightly constrained fuel loading patterns and will provide added flexibility and/or fuel cycle cost savings in future fuel management strategies.
