Determination of void swelling in a PWR baffle bolt due to fast neutron exposure

Author

Tyson Derrik Bourbina

Abstract

"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.

Advisor(s)

Kumar, A. S. (Arvind S.)

Committee Member(s)

Gepford, Heather
Gadbury, Gary L.

Department(s)

Nuclear Engineering and Radiation Science

Degree Name

M.S. in Nuclear Engineering

Publisher

University of Missouri--Rolla

Publication Date

Summer 2003

Pagination

vii, 51 pages

Note about bibliography

Includes bibliographical references (pages 47-50).

Rights

© 2003 Tyson Derrik Bourbina, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Neutron irradiation
Bolts and nuts -- Reliability
Metals -- Effect of radiation on

Thesis Number

T 8331

Print OCLC #

54907093

Link to Catalog Record

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.

Recommended Citation

Bourbina, Tyson Derrik, "Determination of void swelling in a PWR baffle bolt due to fast neutron exposure" (2003). Masters Theses. 2407.
https://scholarsmine.mst.edu/masters_theses/2407