[en] Based on the results of the Phase I of the titled research, we started Phase II scheduled to reach conclusion (develop basic methods necessary for FBR post-construction code) in three years. As the second year, the following results were obtained. (1) Development of assessment procedure for multiple defects due to creep damage. We first confirmed that multiple surface cracks in axial and circumferential direction inside a cylinder can be evaluated independently by investigating multiple flaws found in a cylinder due to cyclic thermal shock. Then a method to evaluate the stress intensity factors of the multiple circumferential cracks in a finite length cylinder under axisymmetric loads was developed. (2) Improving creep-fatigue crack growth (C-FCG) assessment procedure. We reviewed the French code A16 for flaw assessment and compared it with the JNC proposal. (3) Crack propagation assessment under thermal stresses (fatigue crack growth (FCG) resistance for small load). To improve accuracy of FCG assessment for components in FBR power plants (designed to minimize thermal stresses) under thermal cycles, we started to obtain FCG data for near threshold. This year, we obtained data for both carbon steels (S55C, 2.25Cr1Mo) and stainless steel SUS316 by K_max = constant test method. The results showed that FCG curves in the JSME post construction code (which is an extrapolation of the curves in ASME PVP code sec. XI) are valid in general. However, precise review of carbon steel data including S55C, SS400 (which we obtained last year) suggested that the JSME FCG evaluation curve may not have enough safety margin for all the carbon steels and this safety margin is a candidate for future examination. (author)