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June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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Latest News
College students help develop waste-measuring device at Hanford
A partnership between Washington River Protection Solutions (WRPS) and Washington State University has resulted in the development of a device to measure radioactive and chemical tank waste at the Hanford Site. WRPS is the contractor at Hanford for the Department of Energy’s Office of Environmental Management.
Uffe C. Bergmann, Simon Baumgartner, Roger Bieli
Nuclear Technology | Volume 183 | Number 3 | September 2013 | Pages 298-307
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT13-A19419
Articles are hosted by Taylor and Francis Online.
An overview is given of existing design criteria to prevent fuel cladding dryout and the methods used in boiling water reactor reload analysis to evaluate the impact of channel bow on margins in the critical power ratio (CPR). Potential weaknesses in today's methodologies are discussed. Westinghouse in collaboration with KKL and Axpo - operator and owner of the Leibstadt NPP - has developed an enhanced CPR methodology based on a new criterion to protect against dryout during normal operation and with a more rigorous treatment of channel bow. The new steady-state criterion is expressed in terms of an upper limit of 0.01 for the dryout failure probability per year. This is considered a meaningful and appropriate criterion that can be directly related to the probabilistic criteria setup for the analyses of anticipated operation occurrences and accidents.In the Monte Carlo approach, a statistical modeling of channel bow and an accurate evaluation of CPR response functions allow the associated CPR penalties to be included directly in the plant safety limit minimum CPR and operating limit minimum CPR in a best-estimate manner. In this way, the treatment of channel bow is equivalent to all other uncertainties affecting CPR. Emphasis is put on quantifying the statistical distribution of channel bow throughout the core using measurement data.The enhanced CPR methodology has been implemented in the Westinghouse Monte Carlo code McSLAP. The methodology improves the quality of dryout safety assessments by supplying more-valuable information and better control of conservatisms in establishing operational limits for CPR.The methodology is demonstrated with application examples from the introduction at KKL.