News & Views, Volume 47 | Introducing Pegasus: Optimize Fuel Performance
By: Vick Nazareth and Bill Lyon
The Pegasus code is a culmination of nuclear fuel behavior knowledge and experience that spans a period of over five decades. It is a total fuel-cycle simulation of fuel response from initial insertion in reactor to deposition in permanent storage. The goal of Pegasus is to treat, with equal fidelity, the modeling of fuel behavior during the active fuel cycle and the back-end cycle of spent-fuel storage and transportation in a single, self-consistent, and highly cost-effective analysis approach. In the active part of the fuel cycle, Pegasus’s superior three-dimensional thermo-mechanics, coupled with validated nuclear and material behavior models, and robust fuel-cladding interface treatment make it a high-fidelity predictor of fuel-rod response during flexible power operations and operational transients.
On October 1, 2019 the Pipeline and Hazardous Materials Safety Administration (PHMSA) published amendments to 49 CFR Parts 191 and 192 in the Federal Register issuing 
There have been several industry initiatives to support optimization of examination requirements for various items/components (both Class 1 and Class 2 components) in lieu of the requirements in the ASME Code, Section XI.
You’ve just completed the first in-line inspection (ILI) of a new pipeline asset. The ILI tool results are in, and there are no required repairs! However, how sure are we of the accuracy of the results? Could the tool have under-called some of the reported anomalies? Are there any regulatory requirements beyond the “response criteria” mentioned in CFR 192 and 195 for operators of hazardous transmission pipelines? These are the problems that ILI verification is trying to solve.
Longitudinal seam-welded hot-reheat steam piping operating in the creep regime is a continuing life-management challenge for many older fossil-fired power plants.
Recently, a client approached SI after finding a through-wall flaw in an autoclave at the head-to-shell weld as indicated by a visible dye liquid penetrant examination (Figure 1). The autoclave was one of eight similar vessels used for processing the client’s product. Three of the autoclaves are identical in construction to the flawed autoclave and operate with similar process conditions. Remote visual examination by the client indicated that all four autoclaves had similar observations at the inside of the head-to-shell weld, but only one was leaking. The remaining four autoclaves are smaller and are used infrequently. The initial call from the client was for SI to provide emergent support for inspection of the three autoclaves identical to the leaking one to meet production demands. SI responded quickly and examined all four autoclaves using a manual phased array ultra-sonic technique (PAUT) from the exterior of the vessel. The manual PAUT examination provided excellent coverage of the weld region and visualization of the through wall flaw (Figure 2).