Oak Ridge National Laboratory (ORNL) performed several PTS tests as part of the HSST program. One test (TSE-7) was performed in the 1980s on a pres­sure vessel (steel A508 Cl. 2) with 152-mm wall thick — ness.31 The initial crack shape was semielliptic, but the form changed in the test to something very irreg­ular, which complicated the analysis of this test. The material was characterized by Kjc tests made in the transition region with 25.4 mm C(T) specimens. In the PTS test, neither KI nor temperature was constant along the crack length. Due to subsequent inaccura­cies in the original KI data, the Master Curve reanal — ysis30 was performed using the apparent maximum

Kj and the local temperature of the crack tip area. The crack length 2 c = 37 mm was used as the effec­tive crack length. Due to the crack shape changes in the test, only the first initiation was included in the Master Curve analysis. The estimated stress intensity in the first initiation is shown together with the fracture toughness data adjusted to a crack length of 37mm in Figure 25. Despite the inaccuracies, the result of the test is also consistent with the measured fracture toughness data.