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
May 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
June 2026
Nuclear Technology
Fusion Science and Technology
Latest News
NRC proposes changes to its rules on nuclear materials
In response to Executive Order 14300, “Ordering the Reform of the Nuclear Regulatory Commission,” the NRC is proposing sweeping changes to its rules governing the use of nuclear materials that are widely used in industry, medicine, and research. The changes would amend NRC regulations for the licensing of nuclear byproduct material, some source material, and some special nuclear material.
As published in the May 18 Federal Register, the NRC is seeking public comment on this proposed rule and draft interim guidance until July 2.
Kiyonobu Yamashita, Isao Murata, Ryuichi Shindo
Nuclear Science and Engineering | Volume 110 | Number 2 | February 1992 | Pages 177-185
Technical Notes | doi.org/10.13182/NSE92-A23887
Articles are hosted by Taylor and Francis Online.
The accuracy of the nuclear design code system for the High-Temperature Engineering Test Reactor (HTTR) is evaluated for the neutronic characteristics that depend on core temperature by analyzing the overall temperature coefficients of reactivity and the effective multiplication factors obtained by an experiment in which the Very High Temperature Reactor Critical Assembly (VHTRC) is heated from ambient temperature to 200°C. The core of the VHTRC consists of block-type fuel containing low-enriched uranium (LEU). The nuclear design code system for the HTTR includes the DELIGHT, TWOTRAN-2, and CITATION-1000VP computer codes. The DELIGHT code is a one-dimensional cell burnup code developed to evaluate the nuclear characteristics of HTTR fuel and to calculate the group constants. The calculated overall temperature coefficients of reactivity between ambient temperature and 200°C agree well with the measured coefficients, and the calculated effective multiplication factors for different temperatures agree with measured factors within an uncertainty of 0.6%. From the results, it is concluded that the nuclear design code system for the HTTR predicts well the temperature-dependent neutronic characteristics of a core containing LEU fuel.
