Re-Evaluation of Fatigue Crack Growth Curve for Austenitic Stainless Steels in BWR Environment

The Rules on Fitness-for-Service for Nuclear Power Plants of the Japan Society of Mechanical Engineers (JSME Code) has the reference fatigue crack growth curve for austenitic stainless steels in BWR environment. This reference curve was determined as the upper bound of crack growth data excluding the outlier data. However, the other reference curves for fatigue crack growth rate such as austenitic stainless steels and ferritic steels in air environment and ferritic steels in water environment in the ASME Boiler and Pressure Vessel Code, Section XI and the JSME Code, austenitic stainless steels in PWR environment in the JSME Code and Ni-base alloys in PWR environment in the JSME Code Case are determined based on the 95% upper confidential limit by statistic data treatment. In the present study, the fatigue crack growth data of austenitic stainless steels in BWR environment were re-evaluated statistically. It was found that the current reference curve almost coincides with 95% upper confidential limit of fatigue crack growth data in the Paris region. Consequently, the current reference fatigue crack growth curve for austenitic stainless steels in BWR environment in the JSME Code can be regarded to stand on the same technical bases with other reference fatigue crack growth curves. Furthermore, the authors proposed to extend applicable upper bound of load rising time tr from 1000 s to 32000 s.

Glycated plasma proteins in normal and diabetic mothers and their offsprings

Glycated plasmaproteins (GPP) and glycated hemoglobin (G Hb) has been evaluated in 134 non-diabetics (ND), 299 women with potential abnormality of glucose tolerance (pot.AGT), 75 with impaired glucose tolerance (IGT) and 34 insulin dependent diabetics (IDDM) during pregnancy or postpartum including 94 cord blood determinations. Mean HbAIC levels were significantly elevated in IDDM (6.6 ± 1.3% m ± sd) compared to ND (5.1 ± 0.7%; P < 0.01), but were similar for the other groups studied. Mean GPP were increased for the IDDM (0.58 ± 0.29 nmol 5–HMF/mg protein; m ± sd) and the IGT-group (0.53 ± 0.22) over ND (0.3 ± 0.13; P < 0.01) and the Pot.AGT group (0.37 ± 0.14; P < 0.01). 6% of the ND, 15% of the Pot AGT-, 52% of the IGT- and 62% of the IDDM group were found to have GPP values exceeding the 97% confidential limit of the ND. However, the large overlap of individual values from patients with different degrees of glucose intolerance with the normal range of pregnancy precludes the use of GPP as a screening parameter for IGT during pregnancy. A 30–35% reduction of fetal hemoglobin- and plasma protein glycation relative to maternal values was observed.