Stress Corrosion Cracking of Low Alloy Steels under BWR Conditions; Assessment of Crack Growth Rate Algorithms

The influence of ppb levels of chloride impurities on the stress corrosion crack growth behaviour of low-alloy steels under simulated boiling water reactor conditions

“…In the following paragraphs, the adequacy and conservative character of the BWRVP-60 SCC Disposition Line 2 [11] for SCC crack growth in LAS during and 100 h after water chemistry transients ( Figure 1) and of the EPRI BWR Water Chemistry Guidelines (Table 1) [13] are evaluated and assessed in the context of the recent test results and literature data presented in the previous sections.…”

“…These lab experiments also formed the basis for the definition of disposition lines for crack growth due to SCC (Figure 1) which were proposed by the Electric Power Research Institute (EPRI) as an interim disposition rationale and subsequently accepted by the US NRC [11]. Disposition Line 1 (DL 1) considers crack growth under constant load in BWR environments during transient-free steady-state power operation.…”

“…On the other hand, there is an obvious lack of qualified and well documented testing with chloride impurities for RPV steels under BWR conditions. [11] for SCC crack growth in LAS. Line 1: Stationary, transient-free BWR power operation (< EPRI Action Level 1), line 2: During and 100 h after water chemistry transients (> EPRI Action Level 1).…”

“…These tests should indicate, if hysteresis or long-term effects might occur and reveal information on the transition behaviour during and after chloride transients ( Figure 2). Furthermore, the adequacy and conservative character of the BWRVIP-60 SCC Disposition Line 2 [11] for SCC crack growth in LAS during and after water chemistry transients was evaluated and assessed in the context of the EPRI BWR Water Chemistry Guidelines (Table 1) [13]. The present paper summarizes the results of these tests.…”