FITNET Case Studies in FAD Assessment

Irradiation raises yield strength and lowers fracture toughness, so the assessment point of a cracked plate drifts toward the failure assessment line year by year. This post assesses the FITNET training example 'Plate under neutronic irradiation' with the BS 7910 Clause 7 fracture assessment calculator: 12 assessment points are compared one by one with the source, and the most critical point (year 20, 350 MPa) has a reserve factor on load of 1.19 against about 1.2 read from the source chart. All inputs, calculation steps and comparison tables are included.

FITNET's SSTP10 worked example — a welded stainless-steel wide plate with a through-thickness crack failing by ductile tearing. This post works out the assessment point in mechCalc's BS 7910 Clause 7 fracture assessment calculator (the calculator does not do a ductile tearing analysis, so K_mat is converted point by point and entered directly), shows where it lands on the Failure Assessment Diagram, and compares it point by point with FITNET: the horizontal coordinate L_r is close to the literature (0.511 vs 0.51), while the vertical coordinate K_r cannot be compared directly because the source includes an unquantified welding residual stress.