PSI - Issue 77

Enrique Gómez et al. / Procedia Structural Integrity 77 (2026) 49–55 Enrique Gómez et al. / Structural Integrity Procedia 00 (2026) 000–000

53 5

( )= (1) ( )/ 2 ( )=0 where: =0.3 � 1 − � =1+ · =0.0375(1 − 0.001 ) , = + 2

for 1 < L r < L r,max

(6)

for L r ≥ L r,max

(7)

(8)

(9)

(10)

(11)

The assessment points are finally represented in a FAD, determining the situation of the component for the applied loads and the postulated defects being considered. The IAEA Safety Standards No. SSG-26 (2012) requires, additionally, a certain safety factor (SF) of the results. Here, regarding FAD assessments and resulting safety factors, and based on the proposal by Dillstroem et al. (2008) (which satisfies ASME Code requirements), the safety factors considered are shown in Table 4. Table 4. Safety factors for K r (SF K ) and L r (SF L ). Condition SF K SF L NOC √ 10 2.4 AC √ 2 1.2 With all this, the full sequence of the analysis is as follows: 1) Load cases defined from nuclear regulations. 2) Stress fields derived from the finite element analysis of the cask subjected to the different load cases. 3) Stress linearization following BS7910 (2019) (see example in Figure 2), and definition of both the membrane and bending components of the linearized stress field. 4) Definition of material properties (Table 1). 5) Definition of crack size, location and orientation. Sizes and orientations are defined in Section 2.2, whereas the location is always considered to be the section of the cask subjected to maximum stresses for each load case hypothesis. 6) Definition of K r and L r (equations (2) and (3), respectively), using BS7910 solutions for K I and σ ref . 7) Introduction of (K r , L r ) coordinates into BS7910 Option 1 FAD (equations (4) to (11)). 8) Check the safety/unsafety of the analysis, considering the safety factors gathered in Table 4. 3. Results and analysis This section provides the results derived from the structural integrity assessment of the ENUN cask. Table 5 gathers the (K r -L r ) results for the different conditions of location in the shells of the cask (base material vs. weld), type of defect (surface vs. embedded), stress orientation (circumferential vs. axial), load conditions (NOC vs AC, with only the worst load case being shown for each condition). Figure 3 shows the results graphically.