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Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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!
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Commercial nuclear innovation "new space" age
In early 2006, a start-up company launched a small rocket from a tiny island in the Pacific. It exploded, showering the island with debris. A year later, a second launch attempt sent a rocket to space but failed to make orbit, burning up in the atmosphere. Another year brought a third attempt—and a third failure. The following month, in September 2008, the company used the last of its funds to launch a fourth rocket. It reached orbit, making history as the first privately funded liquid-fueled rocket to do so.
Kannan Umasankari, S. Ganesan
Nuclear Science and Engineering | Volume 167 | Number 2 | February 2011 | Pages 105-121
Technical Paper | doi.org/10.13182/NSE10-17
Articles are hosted by Taylor and Francis Online.
The design of an advanced heavy water reactor (AHWR) utilizing thorium is in an advanced stage. The AHWR is a boiling light water cooled, heavy water moderated pressure tube-type reactor, which derives most of its power from the thorium-uranium cycle with plutonium as the external fissile feed. The AHWR has several passive safety features, notably the negative coolant void coefficient of reactivity during both operational and transient conditions. It is of utmost importance to understand the mechanism of the coolant void reactivity (CVR), i.e., the effect of boiling on the neutron spectrum and hence the relative absorption in the different isotopes. We have performed a detailed reaction rate analysis for the isotopes in the AHWR lattice and estimated the individual components to the CVR. The AHWR fuel cluster is a heterogeneous one with both (Th,U) mixed oxide (MOX) and (Th,Pu) MOX fuel and also stainless steel as absorber in the central displacer region.The individual contributions of the different isotopes and reactions were calculated for three major energy domains - namely, fast, resonance, and thermal - as well as for an effective energy average (one-group). The general trend of the CVR with burnup is dictated by the relative absorptions. The major contributors to the CVR were hydrogen (in the coolant), 232Th, 233U, and 239Pu: 232Th and 233U exhibit a negative contribution, whereas 239Pu and H show a positive contribution to CVR. The net absorption reaction rate in 233U becomes less negative with burnup. Since it is close to the moderator, plutonium sees a more thermal spectrum and depletes faster. The positive contribution from 239Pu decreases with burnup. At higher burnups the relative absorption upon voiding in hydrogen increases, and this is a major contributor to the CVR becoming less negative.The results were compared for different nuclear data sets, ENDF/B-VI.8 (largely used for our design studies) and the newly available ENDF/B-VII.0. The CVR calculated with the ENDF/B-VII.0 showed significant differences at higher burnups. The ENDF/B-VII.0 data set gave lower negative value for the CVR at end of cycle. It was found that the difference in the capture cross section of the 232Th ENDF/B-VII.0 data set was largely responsible for the difference between the two data sets. All the simulations were done using the WIMSD code and the multigroup WIMS library using a 69-group structure.