Implementation of vented fuel assemblies in the supercritical CO₂-cooled fast reactor

Analysis has been undertaken to investigate the utilization of fuel assembly venting in the reference design of the gas-cooled fast reactor under study as part of the larger research effort at MIT under Gen-IV NERI Project No. 05-044, "Optimized Competitive Supercritical-CO₂ Cycle GFR for Gen-IV Service." The focus of this work is on selection and optimization of a fuel assembly configuration best suited for venting, assessment of the radionuclide release of such an assembly design, and identification of plant systems which must be altered in order to support fuel venting. The innovative tube-in-duct design of the reference GFR fuel assembly is particularly well suited to venting, allowing fission products to diffuse into a common header before being routed along a vent path and eventually being released to the primary coolant system. A set of equations were developed which model the transport of fission products from fuel to vent path to primary coolant inventory and then into the containment atmosphere, with emphasis on conservatism in calculations of coolant impurity levels. Using these equations in a computer code, the lengthy list of radioactive and chemically volatile fission products for study was reduced to only fifteen species of any great concern. Of these, 85Kr and 137Cs were considered conservative bounding cases on the behavior of the other nuclides. The chemistry of the fission products released to the coolant was explored. In particular, reactions between fission products and their surroundings were identified, and estimates of deposition of both compounds and free atoms on steel surfaces were made. Investigation of reactions between fission products and CO₂ revealed that the formation of stable oxides would lead to deposition of most volatile species within the fuel assembly's debris trap.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2008

Author dc:creator

• McKee, Stephanie A

Advisor dc:contributor.advisor

• Michael J. Driscoll.

• Nuclear Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/44772

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/44772