14th ISRD Meeting
TransWare attended the 14th International Symposium on Reactor Dosimetry in May to learn about new methodologies and upcoming changes to cross-section libraries. We were asked to present two papers, one summarizing surveillance capsule and component activation analyses performed by TransWare using the RAMA Fluence Methodology software, the other to discuss TransWare's calculation of displacements per atom (DPA) versus the U. S. NRC Regulatory Guide 1.99 fluence attenuation method to predict neutron irradiation levels on reactor vessel materials. TransWare was the only company to demonstrate detailed 3D cavity dosimetry results for PWR reactors, further demonstrating our industry-leading technology. Since TransWare can calculate fluence for both in-vessel and ex-vessel locations without normalizing to capsule measurements, plants using the RAMA Fluence Methodology should soon be able to eliminate the requirement for costly cavity dosimetry programs, resulting in significant cost savings over the life of the plant.
This year will likely be remembered as one of nuclear turmoil as the events at Fukushima Daiichi devastated Japan and flooding and earthquakes threatened operation of our reactors at home. As debate over the safety of nuclear power intensifies, one of the biggest issues facing the industry continues to be one the public hears less about these days – used fuel management. As spent fuel pools (SFPs) continue filling and a near-term offsite repository seems unlikely, dry cask storage (DCS) becomes more important than ever.
DCS certainly poses challenges to utilities as it is a rapidly- changing part of plant management with room for improvement. Balancing current regulations, cask vendor CoC amendments, and industry best practices can be a daunting task for utilities.
To meet the growing needs of our clients, TransWare expanded its DCS efforts this year. Utility clients have asked for TransWare’s assistance with DCS procedure development, fuel characterization, database initializations and updates, and fuel selection. Our attention to detail and industry experience make TransWare a trusted partner in used fuel support services.
As the end of 2011 approaches, additional projects continue to keep our staff equally busy:
PWR Nozzle Fluence: TransWare recently signed a contract to develop highly-detailed nozzle models for PWR plants to investigate the fluence profiles through the nozzle forging walls. Using the RAMA Fluence Methodology, TransWare will analyze the through-wall fast fluence profiles for the inlet and outlet nozzles of at least two dominant PWR designs for EPRI and the Materials Research Program (MRP).
Decay Heat Calculations: Evolving from the increased interest in DCS, TransWare will support a benchmarking effort aimed at determining the applicability of multiple decay heat methodologies used for SFP heat load calculations. Decay heat from used fuel assemblies is one of many factors that must be evaluated prior to loading bundles into casks.
Gamma Heating Study: Further studies spawned by the concern about SFP integrity are being launched to examine concrete gamma heating. In 2011, TransWare developed a finite element analysis code designed to perform gamma heating calculations to assist with these studies. This methodology is also applicable for determining gamma heating in structural components, such as core baffles, formers, bolts, and shroud.
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Dean B. Jones, President