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Division Spotlight
Young Members Group
The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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!
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Latest News
Virginia utility considers SMRs
Dominion Energy Virginia has issued a request for proposals from leading nuclear companies to study the feasibility of putting a small modular reactor at its North Anna nuclear power plant.
While the utility says it is not a commitment to build an SMR at the site, the RFP is “an important first step in evaluating the technology and the North Anna site to support Dominion Energy customers’ future energy needs consistent with the company’s most recent Integrated Resource Plan.”
Leonard W. Ward
Nuclear Technology | Volume 100 | Number 1 | October 1992 | Pages 25-38
Technical Paper | Nuclear Reactor Safety | doi.org/10.13182/NT92-A34751
Articles are hosted by Taylor and Francis Online.
Since the loss of vital alternating current power and the residual heat removal system (RHRS) during shutdown at Vogtle Unit 1 on March 20, 1990, much attention has been focused on the need to evaluate system performance following such an event in a light water reactor. To evaluate system response following loss of the RHRS, a simplified, transient, nonequilibrium methodology was developed to provide early insights into the accident consequences and identify key phenomenological and system behavior in need of further, more detailed studies. During shutdown, with the reactor coolant system (RCS) at reduced pressure and temperature, inventory reductions are achieved through the introduction of nitrogen into the system. On removal of the man way entries, air can then enter the system. If the RHRS fails under such conditions, the steam generators may be able to be used as an alternate means of decay heat removal provided RCS integrity can be ensured. Moreover, once boiling initiates, RCS pressure increases because of the presence of noncondensable gases in the system. As a consequence, there is a need to assess the RCS pressure response since the success of this strategy depends on whether the peak pressure is sufficient to cause failure of any of the RCS temporary boundaries used during plant refueling outages. If there is insufficient time to close an open RCS and boiling initiates, a source of coolant makeup is needed to prevent core uncovery and fuel damage. Should boiling persist for several hours, an appreciable amount of boric acid accumulates in the reactor vessel. The subsequent restoration of the RHRS may result in the inadvertent precipitation of the boric acid in the RHRS lines, preventing its further use for decay heat removal. The methodology serves as an analytical tool to assess the RCS peak pressure when attempting to utilize the steam generators following a loss of the RHRS during shutdown and the consequences of borated water addition for long-term core cooling in the event the RCS is open to the containment. The analyses demonstrate that the steam generators could be used for heat removal from reduced inventory conditions at shutdown provided the RCS integrity can be ensured. If the RCS cannot be closed and loss of the RHRS results in boiling, the simple action of adding borated water to the RCS to prevent core uncovery poses a potential boric acid precipitation concern during the long term. The results of the evaluation in which the steam generators are used as an alternate means of decay heat removal are pertinent to pressurized water reactors utilizing U-tube steam generator designs. Further research is being conducted to assess behavior in plants utilizing once-through steam generators. Peak pressures are not expected to differ significantly from that for the U-tube design.