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
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Gregory A. Johnson
Nuclear Technology | Volume 175 | Number 2 | August 2011 | Pages 371-387
Technical Paper | Fission Reactors | doi.org/10.13182/NT11-A12310
Articles are hosted by Taylor and Francis Online.
A study was performed to examine power conversion system (PCS) options for the next generation nuclear plant, a very high temperature gas-cooled reactor. The purpose of the study was to provide insight into which PCS should be used and how should it be coupled to the reactor: direct or indirect. Seven PCSs were examined: direct helium Brayton, indirect helium Brayton, supercritical CO2 (SCCO2), cascaded SCCO2, combined-cycle gas turbine (CCGT), subcritical steam-Rankine, and supercritical steam-Rankine with double reheat. The results of the study show that the SCCO2 cycles are very promising and warrant further development, but the relative immaturity precludes it as a short-term option. Further, the results show a relative unattractiveness of the Brayton cycles when compared to the SCCO2 cycles. The best short-term options were the steam-Rankine cycles. The supercritical steam-Rankine cycle gave the best performance of the two. The CCGT was the most costly and provided little performance advantage over the supercritical steam-Rankine cycle. Issues associated with closed-loop operation, high-temperature compressor inlet temperature, and potential nitriding from the He/N2 working fluid cast uncertainty on the maturity of this cycle.
