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Title: Effects of irradiation and high heat flux on the lifetime performance of ferritic and 316 stainless steels

Thesis/Dissertation ·
OSTI ID:6120737

The effort of this thesis is concentrated on comparing 316 stainless steel to ferritic steel for high heat flux and irradiation conditions expected in fusion reactors. Under irradiation, metals form small bubbles within their grains; and because of (n,..cap alpha..) reactions, helium is usually concentrated within these bubbles. To model the pressure of the helium in a bubble, an Equation of State for helium was developed. The results are used as input into a void for bubble swelling model. With the void swelling model, swelling rates for the two steels were calculated. The ferritic steel is calculated to swell at a rate of about 0.3%/dpa; whereas, 316 stainless steel is calculated to swell at a rate of about 1%/dpa. Experimental results for 316 stainless steel show excellent agreement with the model. Other aspects of high heat flux and irradiation are the potentially steep thermal stresses. There is also the evolution of the stress distribution as a result of swelling, and irradiation and thermal creep. A model to calculate the stress distribution in a thin shell element has been developed. Finally, the stress distribution is used as input to a crack growth and failure model. Failure is assumed when brittle fracture occurs or when the structure fails by plastic collapse. Results indicate that 316 stainless steel is much more susceptible to failure by crack growth than is ferritic steel.

Research Organization:
Wisconsin Univ., Madison (USA)
OSTI ID:
6120737
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English