"As reactor operation lifetimes continue to increase, it is expected that the fast neutron exposure (E > 0.1MeV) experienced by reactor internals could result in levels of void swelling which might lead to swelling related failures such as freezing or breakage of bolts connecting the baffle plate to the former plates. A typical pressurized water reactor baffle bolt was neutronically and thermally modeled to estimate the void swelling possible in a reactor operation lifetime including reactor life extension.
The swelling of the baffle bolt material is a function of the fast neutron flux, fast neutron fluence, and temperature during irradiation. The fast neutron flux in the bolt was determined using the Monte Carlo transport code MCNP. A temperature distribution along the bolt was calculated using a nodal solution technique with heat generation due to gamma heating. Swelling in the bolt was estimated using results from published data on irradiated stainless steels.
It is expected that the bolt head will swell from almost 0% at the head surface to 3% at about one centimeter from the bolt head surface after reactor life extension. The middle of the bolt is expected to swell from 0.6% after standard reactor lifetime to 1% with life extension. The end of the bolt is expected to swell in the range of 0.4% after standard reactor lifetime up to 1.2% with life extension. The swelling at the location of peak temperature is expected to range from 0.5% after standard reactor lifetime up to 4.5% with life extension. Swelling of the bolt to 4.5% within two centimeters from the head surface could cause large stresses resulting in bolt failure, although swelling to this level does not substantially affect the mechanical properties of the steel"--Abstract, page iii.
Kumar, A. S. (Arvind S.)
Gadbury, Gary L.
Nuclear Engineering and Radiation Science
M.S. in Nuclear Engineering
University of Missouri--Rolla
vii, 51 pages
© 2003 Tyson Derrik Bourbina, All rights reserved.
Thesis - Restricted Access
Bolts and nuts -- Reliability
Metals -- Effect of radiation on
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://merlin.lib.umsystem.edu/record=b5073768~S5
Bourbina, Tyson Derrik, "Determination of void swelling in a PWR baffle bolt due to fast neutron exposure" (2003). Masters Theses. 2407.
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